Release v0.6.56: LAN mouse and keyboard sharing

CMakeLists.txt

@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.24)
-project(KSwitcher VERSION 0.6.46 LANGUAGES CXX RC)
+project(KSwitcher VERSION 0.6.56 LANGUAGES CXX RC)
 if(NOT WIN32)
   message(FATAL_ERROR "KSwitcher uses native Windows APIs")
 endif()
@@ -19,10 +19,10 @@ foreach(utilityTarget StayHere StayHereTest)
     target_link_options(${utilityTarget} PRIVATE -municode -static -static-libgcc -static-libstdc++)
   endif()
 endforeach()
-add_library(kscore src/core.cpp src/platform.cpp src/autostart.cpp src/autocorrect.cpp src/storage.cpp src/ocr.cpp src/richtext.cpp src/update.cpp src/sync.cpp)
+add_library(kscore src/lan_channel.cpp src/lan_input.cpp src/lan.cpp src/lan_pairing.cpp src/core.cpp src/platform.cpp src/autostart.cpp src/autocorrect.cpp src/storage.cpp src/ocr.cpp src/richtext.cpp src/update.cpp src/sync.cpp)
 target_include_directories(kscore PUBLIC src PRIVATE vendor)
 target_compile_definitions(kscore PUBLIC UNICODE _UNICODE WIN32_LEAN_AND_MEAN NOMINMAX _WIN32_WINNT=0x0A00)
-target_link_libraries(kscore PUBLIC winhttp user32 shell32 shlwapi advapi32 crypt32 imm32 comctl32 gdi32 ole32 oleaut32 taskschd comdlg32 uuid windowscodecs runtimeobject uiautomationcore)
+target_link_libraries(kscore PUBLIC ws2_32 bcrypt iphlpapi winhttp user32 shell32 shlwapi advapi32 crypt32 imm32 comctl32 gdi32 ole32 oleaut32 taskschd comdlg32 uuid windowscodecs runtimeobject uiautomationcore)
 add_executable(KSwitcher WIN32 src/main.cpp src/app.cpp src/screenshot_notifications.cpp src/screenshot_launcher.cpp src/screenshot_activation.cpp src/configuration.cpp src/ui.cpp resources/app.rc)
 target_compile_definitions(KSwitcher PRIVATE KS_RESIDENT_APP)
 target_link_libraries(KSwitcher PRIVATE kscore)
@@ -89,6 +89,31 @@ else()
   target_link_options(KSwitcherOcrTests PRIVATE -static -static-libgcc -static-libstdc++)
 endif()
 enable_testing()
+add_executable(KSwitcherLanTests tests/lan.cpp)
+target_link_libraries(KSwitcherLanTests PRIVATE kscore)
+if(MSVC)
+  set_property(TARGET KSwitcherLanTests PROPERTY MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
+else()
+  target_link_options(KSwitcherLanTests PRIVATE -static -static-libgcc -static-libstdc++)
+endif()
+add_test(NAME lan-pairing-regressions COMMAND KSwitcherLanTests)
+add_executable(KSwitcherLanInputTests tests/lan_input.cpp)
+target_link_libraries(KSwitcherLanInputTests PRIVATE kscore)
+if(MSVC)
+  set_property(TARGET KSwitcherLanInputTests PROPERTY MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
+else()
+  target_link_options(KSwitcherLanInputTests PRIVATE -static -static-libgcc -static-libstdc++)
+endif()
+add_test(NAME lan-input-regressions COMMAND KSwitcherLanInputTests)
+add_executable(KSwitcherChatProfileTests tests/chat_profiles.cpp src/screenshot_launcher.cpp src/screenshot_activation.cpp src/app.cpp src/screenshot_notifications.cpp src/screenshot.cpp src/configuration.cpp src/ui.cpp resources/app.rc)
+target_link_libraries(KSwitcherChatProfileTests PRIVATE kscore)
+if(MSVC)
+  target_compile_options(KSwitcherChatProfileTests PRIVATE /utf-8)
+  set_property(TARGET KSwitcherChatProfileTests PROPERTY MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
+else()
+  target_link_options(KSwitcherChatProfileTests PRIVATE -static -static-libgcc -static-libstdc++)
+endif()
+add_test(NAME chat-profile-regressions COMMAND KSwitcherChatProfileTests)
 add_executable(KSwitcherHistoryHostTests tests/history_host.cpp)
 target_link_libraries(KSwitcherHistoryHostTests PRIVATE kscore psapi)
 set_target_properties(KSwitcherHistoryHostTests PROPERTIES RUNTIME_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/history-host-fixture-$<CONFIG>")

LAN-PREVIEW.md

@@ -0,0 +1,106 @@
+# LAN mouse and keyboard — v0.6.56 (experimental)
+
+KSwitcher discovers other enabled KSwitcher instances, pairs them with the same
+code on both computers, and shares mouse and keyboard through a screen edge.
+The module runs inside the resident process. This experimental feature supports **one active
+pair of computers**, with the neighbour on the left, right, above or below.
+Several trusted pairs may be saved, but only the selected neighbour is active.
+Clipboard and file transfer are not implemented yet.
+
+## Set up two computers
+
+1. Update both PCs to v0.6.56 or newer using Update in the tray menu. Preserve local data; do not copy pairing identities between PCs.
+2. Open Settings → Tools → KSwitcher computers and enable discovery on both PCs.
+   Only running LAN-enabled KSwitcher instances appear, not generic network devices.
+3. Match the computer name and instance-ID prefix displayed on the other PC.
+   Select each other, generate one code, enter that same code on both, then click
+   Pair on both within two minutes. Spaces, hyphens and uppercase hex are accepted.
+4. Select the paired neighbour and its position relative to this computer.
+   Example: B stands to the right of A, so choose **Right on A** and **Left on B**.
+   For a vertical arrangement choose **Above** on the lower PC and **Below** on
+   the upper PC. Click **Apply position / enable input** on both.
+5. Stop MWB or another mouse/keyboard router on both computers before trying
+   KSwitcher input sharing, to avoid two tools forwarding the same events.
+6. Wait for the authenticated input connection. Move the cursor through the
+   configured outer screen edge with no keys or buttons held. After the other
+   computer acknowledges the handoff, both mouse and keyboard control that PC.
+   Crossing its return edge returns control to the source computer.
+
+The source cursor is parked and hidden beneath a tiny no-activation window. A
+small banner identifies remote control; no full-screen layered bitmap is retained.
+The destination uses its own keyboard layout and runs its own hotkeys/snippets.
+The source suppresses forwarded events before its local hotkeys, snippets and
+other low-level hook consumers. Received input is marked so it is not forwarded
+again. Source recent-input tracking resets when ownership changes.
+
+**Ctrl+Alt+Esc** is emergency return, not the normal switching mechanism. Local
+physical input on a remotely controlled PC takes control back as well. Stop input
+sharing, disabling discovery, forgetting the active pair, suspension, secure
+desktop changes and connection loss cancel remote ownership. TCP heartbeat loss
+is detected after two seconds; a handoff request expires after one second.
+Held remote keys/buttons are released. Releases blocked by a secure desktop are
+retried when the ordinary desktop is available. Source key-ups for keys already
+sent remotely are consumed after return, avoiding stray local modifier events.
+
+## Layout and limitations
+
+- Positions are relative to this PC and must be opposite on the two computers.
+  Inconsistent positions are rejected before input is authorized. Changes apply
+  immediately and reconnect the input channel.
+- Geometry uses the virtual desktop's outer bounding rectangle, including negative
+  monitor coordinates. Internal monitor boundaries do not transfer control.
+  Different resolutions map the entry position proportionally. Irregular layouts
+  can have gaps on an outer edge; this is not a per-monitor arrangement editor.
+- Transferring while a key or mouse button is held is intentionally blocked.
+  Dragging works within the controlled computer; dragging objects across PCs is
+  not implemented. There is a short return cooldown to avoid bouncing.
+- Windows can block SendInput to elevated apps and secure desktops. Run both
+  applications at suitable privilege levels for the target programs. The preview
+  does not install a service, bypass UAC or implement remote Ctrl+Alt+Delete.
+- This is Windows input injection, not a virtual USB HID device. Raw-input games,
+  exclusive full-screen applications and special device keys need separate testing.
+
+## Network, authentication and storage
+
+Discovery broadcasts on private IPv4 and link-local interfaces using UDP 45883.
+Input uses TCP 45884. Allow KSwitcher on your private network when Windows asks;
+the preview does not change firewall rules. Broadcast-blocked networks, separate
+VLANs, public IPv4 and IPv6-only networks are not supported by discovery yet.
+A second LAN-enabled KSwitcher cannot use the same ports on one computer.
+
+The instance ID belongs to a data directory, not a hostname/IP address. Discovered
+names and addresses are untrusted. Pairing uses a generated 128-bit code and
+mutual HMAC-SHA256 challenge proofs bound to both instance IDs. The code is never
+transmitted or logged. The pair key is separate from the setup code.
+
+The input channel authenticates both peers with the saved pair key and fresh
+session challenges. Directional AES-256-GCM session keys bind the identities,
+nonces and screen positions. Fixed-size authenticated frames use strict sequence
+numbers, so tampering, reflection and replay are rejected. Input is not dispatched
+until authentication succeeds. This PSK channel does not provide forward secrecy.
+Queues and frame sizes are bounded; overflow disconnects rather than dropping a
+key-up and leaving a key pressed. The input worker never injects Windows input;
+the resident's main thread owns the input state and hooks.
+
+Identity, trust, enablement and screen position stay in DPAPI-protected
+`data/lan-pairing.bin`, outside settings export and OpenBao sync. Do not clone this
+file between installations. Forget a pair on both PCs for bilateral removal.
+Closing the settings window does not cancel pairing or disable sharing.
+
+Disabled discovery has no socket or worker. Input sharing reuses the single LAN
+worker; there is no extra resident executable or service. The main input timer
+runs only while sharing is enabled. The existing configurator talks to the
+resident through local IPC.
+
+## Validation
+
+Tests cover pairing, encrypted frames, replay/tamper rejection, actual loopback
+TCP authentication and bidirectional delivery, all four edges, ownership races,
+source suppression, scan codes, clicks/wheel, emergency return, held-key release,
+blocked injection, secure desktop recovery, exact one-pixel movement and timeout.
+UI tests check all four positions and preserve an edited choice during refresh.
+
+Two physical computers still need an end-to-end trial for their adapters,
+firewalls, displays and application privilege levels. The automated TCP tests
+use local sockets, and input-state tests use simulated desktop environments;
+they do not claim a completed two-machine hardware test.

README.md

@@ -10,6 +10,22 @@ The original [Typlo](https://github.com/bitcodepro/Typlo) project and its data r
 
 [Donate via Monobank](https://send.monobank.ua/jar/88h2TddKfS) · Thank you for supporting KSwitcher.
 
+## KSwitcher computers — v0.6.56 (experimental)
+
+KSwitcher includes opt-in LAN discovery, same-code pairing and
+mouse/keyboard sharing for one active pair. Place the neighbour left, right,
+above or below; moving through that outer screen edge transfers both mouse and
+keyboard. Ctrl+Alt+Esc returns control in an emergency. See
+[LAN-PREVIEW.md](LAN-PREVIEW.md) for setup, encryption and validation limits.
+Clipboard and file sharing are still pending.
+
+**Українською.** У v0.6.56 є пошук KSwitcher у мережі, спарювання однаковим
+кодом і передача миші та клавіатури для однієї активної пари ПК. Укажіть, де
+стоїть сусідній ПК: ліворуч, праворуч, зверху або знизу. Курсор і клавіатура
+перемикаються разом через відповідний край екрана. Ctrl+Alt+Esc аварійно повертає
+керування. Передача буфера та файлів ще не реалізована; перевірка на двох
+фізичних ПК ще потрібна.
+
 ## Run
 
 Run `build/KSwitcher.exe`, or extract `dist/KSwitcher-win-x64.zip` and run the executable.
@@ -19,6 +35,11 @@ Double-click the tray icon to open Settings, the bold default menu item.
 Closing Settings with unsaved changes (including accepted auto-correction or OCR options)
 asks whether to save, discard changes, or keep editing. Unchanged settings close without a prompt.
 If saving fails, the window stays open with your edits intact.
+Settings displays **No unsaved changes** with **Save** disabled until an edit is made.
+**Unsaved changes — click Save to apply** appears for pending edits, including accepted
+chat-language, auto-correction and OCR changes. Cancelling a child dialog or restoring
+the original values clears its pending changes. Snippets saved in their own window
+remain saved independently; the Settings indicator reflects any other pending edits.
 Menus support access keys: press the underlined letter while the menu is open (for example,
 S for Settings or X for Exit in the tray menu). In forms, press Alt+the underlined letter
 to activate a button, toggle a checkbox or focus a labeled field. Dialog underline visibility
@@ -202,6 +223,22 @@ snapping and shape constraints are unchanged.
 Both drawn and recognized triangles have three independent vertex handles instead of bounding-box
 resize handles. Drag any vertex to reshape the triangle while keeping the other two fixed, even
 after rotation. Vertex edits support undo/redo, and the rotation and thickness handles remain available.
+**Arc (U)** draws an open half ellipse inside the dragged rectangle. Use the corner handles
+to resize it and the round handle to rotate it (Shift snaps to 15 degrees). Arcs support
+color, thickness, line style, moving, cloning, undo/redo and PNG export.
+
+**Smoothing (0–100%)** on the screenshot toolbar adjusts pencil paths. With a pencil
+stroke selected it affects that stroke; otherwise it sets the default for new strokes
+(initially 25%). **Apply to all strokes** applies the displayed amount to all pencil
+strokes in the current image and sets the default for new ones. Shapes, text and
+highlights are unchanged. Zero restores the original path; higher values reduce more
+jitter. The original samples are retained through moving, endpoint editing and cloning,
+so lowering the amount does not accumulate distortion. Each slider drag or bulk change
+is one undo step, and PNG export uses the displayed geometry. Very short strokes remain
+unchanged. Shift-constrained and linked strokes start without automatic smoothing;
+you can explicitly adjust them afterwards. Shape/straight-line recognition is separate
+and does not turn recognized shapes back into pencil strokes.
+
 **Trapezoid (B)** on the toolbar creates a trapezoid with parallel bases. Pencil recognition also
 fits nearly parallel, unequal bases into a clean trapezoid. Trapezoids support bounding-box resizing,
 rotation, styling and undo/redo; Ctrl+Z after recognition restores the original pencil stroke.
@@ -270,6 +307,80 @@ thumbnails and source labels aligned with the scaled fonts and spacing.
 
 ## Implemented
 
+### Chat language profiles — v0.6.48
+
+> From v0.6.50: Viber chat OCR is temporarily disabled. Saved Viber profiles are retained but inactive. Telegram and Teams profiles are unchanged; clipboard/image OCR remains available.
+>
+> З v0.6.50: OCR чатів Viber тимчасово вимкнений. Збережені профілі Viber залишаються, але не діють. Профілі Telegram і Teams та OCR зображень/буфера працюють як раніше.
+
+
+Settings separates General, Languages, Shortcuts, Clipboard and Tools into native tabs.
+Switching tabs preserves edits; Save, Cancel, Import and Export stay available below every page.
+
+Open the desired chat in Telegram Desktop or Microsoft Teams, then open Settings → Languages →
+**Languages for a chat…**. Select the chat and click the languages to include. Choose
+**Use languages**, then **Save** in Settings. The subset order is saved from the main
+layout list when editing the profile; one-language profiles are supported. **Remove profile** restores default behavior.
+
+For a matching chat, **Alt+Shift**, **Win+Space** (and reverse **Win+Shift+Space**) cycle
+through that subset. KSwitcher's **Next layout** conversion uses the same subset.
+Explicit KSwitcher hotkey bindings take precedence. Without a matching profile,
+Windows shortcuts keep their normal behavior and Next layout uses the global cycle.
+Unavailable layouts are skipped; if none remain installed, the global cycle is used.
+Direct layout shortcuts are unchanged. Profiles do not change Windows' installed languages.
+
+Matching uses the application and visible chat name, not a unique account/contact ID.
+Identically named chats in one application share a profile; renamed chats need a new
+profile. Telegram unread counters are ignored. Teams currently recognizes the desktop
+`Chat | name | Microsoft Teams` title format; other Teams title formats are not supported.
+Experimental Viber profiles introduced in v0.6.49 are disabled in v0.6.50 because repeated OCR caused delays. There is no background Viber OCR, recognition during language switching, or recognition when opening profiles. Saved Viber profiles are retained and marked inactive; Windows switching and Next layout use their normal/global behavior in Viber. Clipboard and image OCR are unchanged.
+From v0.6.53, chat profiles (application, visible chat name and ordered language IDs) are included in settings synchronization and manual export/import. Update every synchronizing PC to v0.6.53 or newer first: older clients reject this shared field. Profiles for different chats merge independently; conflicting edits or deletion versus editing of one chat require a choice. Missing Windows layouts stay saved and are skipped during switching, with global-cycle fallback if none are installed. Keep this PC's layouts preserves the global cycle and shortcuts while chat profiles still synchronize. Downloading a pre-v0.6.53 profile preserves existing chat profiles. Chat matching is unchanged; Viber profiles remain inactive.
+
+**Українською.** Налаштування розділено на вкладки General, Languages, Shortcuts, Clipboard
+і Tools. Перехід між ними зберігає незбережені зміни; Save, Cancel, Import і Export доступні
+на кожній вкладці. Відкрий потрібний чат у Telegram або Teams, потім **Settings → Languages → Languages
+for a chat…**. Вибери чат і потрібні мови, натисни **Use languages**, а потім **Save**.
+Набір діє для **Alt+Shift**, **Win+Space**, **Win+Shift+Space** та **Next layout** KSwitcher.
+Можна вибрати й одну мову; порядок зберігається із загального списку під час редагування профілю. **Remove profile**
+повертає звичайну поведінку. Без профілю системні комбінації працюють як раніше,
+а Next layout використовує загальний набір. Видалені з Windows розкладки пропускаються;
+якщо доступних мов профілю не залишилося, використовується загальний набір.
+Прямі комбінації мов не змінюються; явно задані комбінації KSwitcher мають пріоритет.
+Зіставлення виконується за програмою та назвою чату: однакові назви в одній програмі
+мають спільний профіль, після перейменування потрібен новий. Лічильник непрочитаних
+Telegram ігнорується. Teams підтримує зазначений вище формат заголовка.
+Експериментальні профілі Viber із v0.6.49 вимкнено у v0.6.50 через затримки від повторного OCR. Фонове розпізнавання, OCR при перемиканні мов та відкритті профілів більше не запускаються. Профілі Viber збережені й позначені як неактивні; системне перемикання та Next layout у Viber використовують звичайну поведінку й загальний набір. OCR буфера та зображень не змінено.
+Профілі локальні, входять до ручного експорту/імпорту, але не до
+хмарної синхронізації. Доступно з v0.6.48.
+
+
+### Telegram Web in Chrome — v0.6.51
+
+Open a chat in Telegram Web K (`https://web.telegram.org/k/`) in Chrome, then use **Settings → Languages → Languages for a chat...** and select **Telegram Web: name**. Choose languages, then **Use languages → Save**. The same subset applies to Alt+Shift, Win+Space, Win+Shift+Space and Next layout. Web profiles are separate from desktop Telegram profiles. Same-name chats across browser profiles/accounts share a web profile.
+
+Recognition uses Chrome accessibility: the address bar and active document must both identify a Telegram chat, then the visible header supplies the name. The app watches foreground/focus and address/header-change events; it does not use OCR, a polling timer, an extension, or message-history extraction. The address bar, home page and unsupported URLs do not match. Web A and other browsers have not been validated and are not advertised as supported. Page or accessibility changes can make a chat unavailable instead of guessing.
+
+**Українською.** З v0.6.51 підтримано Telegram Web K у Chrome. Відкрий чат, потім **Settings → Languages → Languages for a chat...**, вибери **Telegram Web: ім’я**, мови та **Use languages → Save**. Набір діє для Alt+Shift, Win+Space, Win+Shift+Space і Next layout. Вебпрофілі окремі від Telegram Desktop; однакові назви в різних акаунтах/профілях браузера мають спільний вебпрофіль. Адреса й назва беруться через accessibility, без OCR, таймера, розширення та читання історії повідомлень. В адресному рядку, на головній сторінці й для непідтримуваних адрес профіль не діє. Web A та інші браузери не перевірені й не заявлені як підтримувані.
+
+### Desktop chat snippet selection — v0.6.55
+
+ChatGPT and Codex desktop editors use paced selection for snippet triggers. If only a verified suffix is selected, KSwitcher extends the selection and verifies the full trigger before replacement. Unrelated text or changed focus cancels the operation. Triggers remain recognized across keyboard layouts. One snippet can target multiple applications: add each with **Add app**, or enter comma-separated process names. These existing application scopes also synchronize.
+
+**Українською.** У настільних ChatGPT і Codex тригер виділяється з паузами між натисканнями. Якщо виділилася лише перевірена кінцева частина, KSwitcher доповнює виділення й перевіряє весь тригер перед заміною. Інший текст або зміна фокусу скасовують операцію. Тригери розпізнаються в різних розкладках. Один сніпет можна прив’язати до кількох програм через **Add app** або назви процесів через кому; ці прив’язки вже підтримують синхронізацію.
+
+### Application-specific snippets — v0.6.51
+
+In **Tools → Snippets**, select a snippet and enable **Only in these applications**. Enter executable names separated by commas, or select a currently open application's process and choose **Add app**. For example: `ms-teams.exe, outlook.exe`. Uncheck the option for a global snippet. A checked but empty restriction cannot be saved. Save applies the changes; Cancel discards them.
+
+A matching application-specific snippet takes precedence over a global snippet with the same trigger. The same trigger can be used for different applications; overlapping scopes for the same trigger are rejected. Existing snippets without a scope remain global. Matching is case-insensitive by process name, with or without `.exe`, and is checked before insertion. No OCR or timer is involved. Chrome scope means the entire browser, not one website.
+
+Scopes are saved with snippets and included in manual import/export and synchronization; merge conflicts consider the application scopes. Use v0.6.51 or newer on every synchronizing PC before sharing scoped snippets: older versions do not understand the restriction and may treat the snippet as global.
+
+**Українською.** У **Tools → Snippets** вибери сніпет, увімкни **Only in these applications** та задай назви процесів через кому або вибери відкриту програму зі списку й натисни **Add app**. Наприклад: `ms-teams.exe, outlook.exe`. Вимкнений прапорець означає всі програми. Увімкнений прапорець із порожнім списком не можна зберегти. **Save** зберігає, **Cancel** відкидає зміни.
+
+Сніпет конкретної програми має пріоритет над глобальним із тим самим тригером. Для різних програм однакові тригери дозволені, для перетинних областей — ні. Старі сніпети залишаються глобальними. Зіставлення за назвою процесу не залежить від регістру та суфікса `.exe`; OCR і таймерів немає. Для Chrome це весь браузер, а не окремий сайт. Обмеження входять до експорту/імпорту та синхронізації. Перед синхронізацією онови всі ПК до v0.6.51 або новішої: старі версії не розуміють обмеження та можуть застосувати сніпет глобально.
+### Existing features
+
 - Installed Windows keyboard layouts, configurable cycle/order and direct shortcuts; IMEs are switch-only.
   Text conversion cycles skip layouts that leave the text unchanged and use the next enabled layout
   that changes it. If none changes the text, the operation keeps the text and advances one layout.
@@ -544,9 +655,9 @@ Protocol and conflict regressions run with `build.ps1 -Test` or CMake's `sync-re
 
 ## Portable utilities
 
-The tray menu's **Utilities** submenu lists `.exe` files in a `tools` folder beside
+The tray menu's **Tools** submenu lists `.exe` files in a `tools` folder beside
 `KSwitcher.exe`, sorted by filename. For example, place `StayHere.exe` at
-`tools/StayHere.exe` and choose **Utilities → StayHere** to launch it manually.
+`tools/StayHere.exe` and choose **Tools → StayHere** to launch it manually.
 The folder is rescanned whenever the menu opens; no configuration or restart is needed.
 Only files directly in `tools` are listed (not subfolders, shortcuts, or KSwitcher's
 own executables beside the main program). Utilities start with `tools` as their working
@@ -559,7 +670,7 @@ utility files. Updates preserve personal utilities and refresh bundled StayHere
 documentation. Repository development scripts
 are not included in the portable tools folder.
 
-Choose **Utilities → StayHere** to start the bundled activity utility. It starts
+Choose **Tools → StayHere** to start the bundled activity utility. It starts
 enabled; left-click its tray icon to pause/resume or right-click for Exit. While
 enabled it prevents automatic sleep and, after three minutes without input, sends
 F15 on its 15-second check. It does not move the mouse, bypass locking, start with
@@ -599,8 +710,10 @@ default and require the main **Automatic correction (experimental)** checkbox to
 
 - **Use custom replacements**: enter one `typo=correction` pair per line, for example
   `првиіт=привіт` or `helo=hello`. Entries are normalized to lowercase; duplicate source words
-  are rejected. Each side must contain 1–32 letters of the same supported language, without
-  spaces or punctuation. Explicit pairs take priority over dictionary recognition, including
+  are rejected. The typo must contain 1–32 letters. The correction may contain several words
+  separated by single spaces, for example `мамамила=мама мила`, up to 32 characters including
+  spaces. Both sides must use the same supported language, without punctuation; leading,
+  trailing and repeated spaces are not allowed. Explicit pairs take priority over dictionary recognition, including
   already valid words, and do not require dictionary membership or satisfy the frequency limit.
 - **Correct spelling typos using dictionaries**: checks unknown words in the current language
   after no layout correction is found. It accepts exactly one dictionary candidate reachable
@@ -616,6 +729,8 @@ ALL CAPS, mixed-case identifiers, numbers, URLs and email addresses are skipped.
 is applied once, without chaining. Click **OK**, then **Save** in Settings; pairs and switches
 are included in settings export/import and synchronization. Undo restores the original word
 and suppresses its correction until restart.
+When synchronizing phrase replacements, update all participating PCs to v0.6.47 or newer;
+older clients reject spaces in replacement pairs.
 
 ### Layout correction and shared options
 

Release/README.md

@@ -1,21 +1,23 @@
 # Latest Windows release
 
-## v0.6.46 — 2026-11-05
+## v0.6.56 — 2026-11-06
 
 ## Changes
-- Bundle **tools/StayHere.exe** and **tools/StayHere-README.md**. Start the activity utility from **Utilities → StayHere**; it does not start automatically with KSwitcher.
-- StayHere starts enabled. Left-click its tray icon to pause/resume or right-click for Exit. While enabled, it prevents automatic display/system sleep and checks inactivity every 15 seconds; after three minutes without input it sends F15. It does not move the mouse, bypass locking, install autostart or directly control Teams presence. Locked/disconnected sessions receive no simulated activity.
-- Include StayHere source and reproducible GCC/CMake builds. CLI status/pause/resume/exit parsing tolerates launcher whitespace. Normal updates replace bundled StayHere and documentation while preserving personal utilities. A running old instance continues until exited; relaunch to use the updated executable.
-- Retain all v0.6.45 Far snippet, Utilities and tools-folder changes and the v0.6.44 newest-history-selection fix.
-- Correct the Far test fixture's working directory: a long temporary path could scroll the command line and invalidate absolute cursor-coordinate assertions. Application snippet behavior is unchanged in this release.
+- Experimental, opt-in LAN mouse and keyboard sharing inside the existing resident process; no extra service.
+- Discover running KSwitcher instances and pair them using the same generated code on both PCs. Trust is DPAPI-protected locally, outside settings sync/export.
+- Arrange the active neighbour left, right, above or below. Select opposite sides on both PCs; mouse and keyboard transfer together through that screen edge.
+- Authenticated AES-256-GCM input channel; Ctrl+Alt+Esc emergency return, disconnect recovery and held-key release.
+- One active pair. Clipboard/files and remote secure desktops are not supported. Stop MWB before using input sharing. Disabled by default.
 
 ## Validation
-Passed isolated StayHere start/status/pause/resume/exit checks, Utilities regressions, dictionary equivalence (140,939 words), 105 sync checks, shared wheel tests, 319 native checks, 574 input checks, screenshot UI/save/registration, 54 updater checks and updater progress UI. The updater replaced a running isolated StayHere executable successfully. Final package manifests and downloaded assets are checked before completion. Real-Far spot checks confirmed expansion, caret placement and markers; the uninterrupted full interactive run remains outstanding because unrelated foreground changes cancel it. No additional Far application-code change is shipped in v0.6.46.
+124 input/channel, 41 pairing/configuration/network and 813 settings/chat-profile checks passed before release preparation. Full release regression passed: 124 LAN input, 34 LAN pairing (41 with network lifecycle), 813 chat/settings, 568 input, 332 native, 126 sync, dictionary equivalence (140,939 words), wheel, StayHere, Utilities, screenshot UI/save/registration, 54 updater checks and updater progress. Physical two-PC validation is pending: network tests use loopback and input-state tests simulate desktops. LAN sharing remains experimental; follow LAN-PREVIEW.md on both PCs.
 
-## Upgrade
+## Upgrade and compatibility
 Choose **Update** in the tray menu. Legacy v0.3.0–v0.4.1 clients first receive the v0.4.2 compatibility bridge, then the current full release. v0.2.3 and earlier require manual installation.
-For manual installation, exit KSwitcher, close its configurator and screenshot editors, and extract the entire ZIP into its installation folder. Keep personal `data/`, customized dictionaries and your own tools. Find `tools/StayHere.exe` beside the executable actually running.
+For manual installation, exit KSwitcher, close its configurator and screenshot editors, and extract the entire ZIP into its installation folder. Keep personal `data/`, customized dictionaries and your own tools. Keep the three KSwitcher executables together; StayHere runs independently.
 
-Download **KSwitcher-win-x64.zip** with **SHA256SUMS.txt**. Keep the three KSwitcher executables together; history uses another instance of KSwitcher.exe. StayHere runs independently. The package contains no personal settings, credentials or clipboard history.
+**Update every synchronizing PC to v0.6.51 or newer before sharing application-specific snippets. Older versions do not understand application restrictions and may treat scoped snippets as global.** Keep a backup before downgrading. Settings with Telegram Web profiles require v0.6.51 or newer. Chat profiles now synchronize from v0.6.53. Update every synchronizing PC to v0.6.53 or newer before syncing: older clients reject the chat-profile field. Synchronization stores application names, visible chat names and language IDs on your configured OpenBao server. No message contents are included.
+
+Download **KSwitcher-win-x64.zip** with **SHA256SUMS.txt**. The package contains no personal settings, credentials or clipboard history.
 
 Publish stable `release-vX.Y.Z` tags matching the executable version. Keep `v0.4.2` as the last legacy tag.

Release/SHA256SUMS.txt

@@ -1 +1 @@
-e6d26d59b18559ad226359b35cd403c68326384f8e1918d31b368cbd1110f6b9  KSwitcher-win-x64.zip
+7ddf8545bcd1694e760503e712b6b34f396311446596bca348b3cc27ee838abe  KSwitcher-win-x64.zip

Release/release-files.json

@@ -0,0 +1,86 @@
+{
+  "schema": 1,
+  "version": "0.6.56",
+  "files": [
+    {
+      "sha256": "02f709062f32047f2befc4de67efe5e033c48a8155bb0230bf012496fe20db9b",
+      "size": 1974784,
+      "path": "KSwitcher.exe"
+    },
+    {
+      "sha256": "9b3ec79ae158ee51e61249f01e46a20917db9c25c6a8f58c52d927f8a6c3ee9c",
+      "size": 1887232,
+      "path": "KSwitcher.Config.exe"
+    },
+    {
+      "sha256": "21a5422be5e97c7f758d46481fe2c9481d2c09b231cc7fe90b6e7a0793f32b9d",
+      "size": 3046912,
+      "path": "KSwitcher.Screenshot.exe"
+    },
+    {
+      "sha256": "d3c81140cce01c26bf6cbf52aa40e0825e1fa35b9a91d1387170a65d2597082c",
+      "size": 4401,
+      "path": "LICENSE"
+    },
+    {
+      "sha256": "61e08da79c44061654015ce6b0c4061c23ee1dd18237fbf09e9bfda3c0ea2831",
+      "size": 1096,
+      "path": "json-LICENSE.txt"
+    },
+    {
+      "sha256": "6b7b8a912c10c04c8bdddce90572a6a8addcb6c76d478fe8455c2685fc3384d8",
+      "size": 79329,
+      "path": "README.md"
+    },
+    {
+      "sha256": "a8ec24f5a6cc9145324a52b73525418d1f8bd0eb3b4cf75fc93b57dcc7918603",
+      "size": 6773,
+      "path": "LAN-PREVIEW.md"
+    },
+    {
+      "sha256": "d0c022b27b9fbc2ff7b6b8bec723cc1adc4eef517202f9ff77eed5d8bea3acb9",
+      "size": 732485,
+      "path": "dictionaries/en.txt"
+    },
+    {
+      "sha256": "0bdfb0201d1803634f268cdff0993b8349d2c70e956a06dbb667c8dd65254ec5",
+      "size": 20566,
+      "path": "dictionaries/LICENSE-CC-BY-SA-4.0.txt"
+    },
+    {
+      "sha256": "3017bf44d3be9d9dfab21bd6778aa52b7947e61acf9ce2bc86b41d6e949ac311",
+      "size": 2265,
+      "path": "dictionaries/README.md"
+    },
+    {
+      "sha256": "80e6b6a27815973535f7facb636c597eb845dfee45cfabfc4e9b3341b9332849",
+      "size": 1109134,
+      "path": "dictionaries/ru.txt"
+    },
+    {
+      "sha256": "98e5b3fe7304e37705c9e5ff48b0b399ccb16e806736d21f09921b99e5f2a408",
+      "size": 1280,
+      "path": "dictionaries/sources.json"
+    },
+    {
+      "sha256": "d30e990d6ec2983c04f3644a3c61c6c668e8c542323f5931916fdd55b916eebf",
+      "size": 940799,
+      "path": "dictionaries/uk.txt"
+    },
+    {
+      "sha256": "a34b5161a8315af037e1ec71d816bfc688f7c364141d4ee2347cf0515ef0c82a",
+      "size": 993,
+      "path": "tools/README.txt"
+    },
+    {
+      "sha256": "6ef5cf64708d62b7fc63c3c793cc99188a513433ff4774cae01dc014f6664376",
+      "size": 134656,
+      "path": "tools/StayHere.exe"
+    },
+    {
+      "sha256": "ba214e2aca7405e698b3ab21ceb1f41ce088edd996b3e30e4a9d58ff496f9413",
+      "size": 2796,
+      "path": "tools/StayHere-README.md"
+    }
+  ]
+}

build.ps1

@@ -15,14 +15,14 @@ Set-Content -LiteralPath (Join-Path (Split-Path $executablePath) '.local-dev') -
 Push-Location $root
 try {
     $common = @('-std=c++20','-Os','-DNDEBUG','-DUNICODE','-D_UNICODE','-DWIN32_LEAN_AND_MEAN','-DNOMINMAX','-D_WIN32_WINNT=0x0A00','-Wall','-Wextra','-Wno-missing-field-initializers','-Isrc','-Ivendor','-ffunction-sections','-fdata-sections')
-    $libs = @('-lwinhttp','-luser32','-lshell32','-lshlwapi','-ladvapi32','-lcrypt32','-limm32','-lcomctl32','-lgdi32','-lole32','-loleaut32','-ltaskschd','-lcomdlg32','-luuid','-lwindowscodecs','-lruntimeobject','-luiautomationcore')
+    $libs = @('-lws2_32','-lbcrypt','-liphlpapi','-lwinhttp','-luser32','-lshell32','-lshlwapi','-ladvapi32','-lcrypt32','-limm32','-lcomctl32','-lgdi32','-lole32','-loleaut32','-ltaskschd','-lcomdlg32','-luuid','-lwindowscodecs','-lruntimeobject','-luiautomationcore')
     $utilityDirectory = Join-Path (Split-Path $executablePath) 'tools'
     New-Item -ItemType Directory -Force $utilityDirectory,build/release/tools | Out-Null
     $stayHere = Join-Path $utilityDirectory 'StayHere.exe'
     & $compiler @common -Werror -mwindows -municode -static -s utilities/StayHere/main.cpp -luser32 -lshell32 -lgdi32 -lwtsapi32 -o $stayHere
     if ($LASTEXITCODE) { throw 'StayHere build failed' }
     Copy-Item -LiteralPath $stayHere -Destination build/release/tools/StayHere.exe -Force
-    foreach ($name in @('core','platform','autostart','autocorrect','storage','sync','ocr','richtext','update','screenshot','screenshot_main','screenshot_notifications','screenshot_activation','screenshot_launcher','app','ui','main','configuration','config_main')) {
+    foreach ($name in @('lan_channel','lan_input','lan','lan_pairing','core','platform','autostart','autocorrect','storage','sync','ocr','richtext','update','screenshot','screenshot_main','screenshot_notifications','screenshot_activation','screenshot_launcher','app','ui','main','configuration','config_main')) {
         & $compiler @common -c "src/$name.cpp" -o "build/$name.o"
         if ($LASTEXITCODE) { throw "Compilation failed: $name" }
     }
@@ -35,18 +35,26 @@ try {
     & windres --codepage=65001 -DKS_SCREENSHOT_RESOURCES resources/app.rc -O coff -o build/screenshot-res.o
     if ($LASTEXITCODE) { throw 'Screenshot resource compilation failed' }
     New-Item -ItemType Directory -Force build/release | Out-Null
-    & $compiler -mwindows -municode -static -s '-Wl,--gc-sections' build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui-resident.o build/main.o build/app-res.o @libs -o $executablePath
+    & $compiler -mwindows -municode -static -s '-Wl,--gc-sections' build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui-resident.o build/main.o build/app-res.o @libs -o $executablePath
     if ($LASTEXITCODE) { throw 'Link failed' }
     Copy-Item -LiteralPath $executablePath -Destination build/release/KSwitcher.exe -Force
     $configPath = Join-Path (Split-Path $executablePath) 'KSwitcher.Config.exe'
-    & $compiler -mwindows -municode -static -s '-Wl,--gc-sections' build/core.o build/platform.o build/storage.o build/sync.o build/ocr.o build/configuration.o build/config_main.o build/ui-config.o build/app-res.o @libs -o $configPath
+    & $compiler -mwindows -municode -static -s '-Wl,--gc-sections' build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o build/storage.o build/sync.o build/ocr.o build/configuration.o build/config_main.o build/ui-config.o build/app-res.o @libs -o $configPath
     if ($LASTEXITCODE) { throw 'Configurator link failed' }
     Copy-Item -LiteralPath $configPath -Destination build/release/KSwitcher.Config.exe -Force
     $screenshotPath = Join-Path (Split-Path $executablePath) 'KSwitcher.Screenshot.exe'
-    & $compiler -mwindows -municode -static -s '-Wl,--gc-sections' build/core.o build/platform.o build/storage.o build/ocr.o build/screenshot.o build/screenshot_notifications.o build/screenshot_activation.o build/screenshot_main.o build/screenshot-res.o @libs -o $screenshotPath
+    & $compiler -mwindows -municode -static -s '-Wl,--gc-sections' build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o build/storage.o build/ocr.o build/screenshot.o build/screenshot_notifications.o build/screenshot_activation.o build/screenshot_main.o build/screenshot-res.o @libs -o $screenshotPath
     if ($LASTEXITCODE) { throw 'Screenshot link failed' }
     Copy-Item -LiteralPath $screenshotPath -Destination build/release/KSwitcher.Screenshot.exe -Force
     if ($Test) {
+        & $compiler @common -Werror tests/lan_input.cpp build/lan_channel.o build/lan_input.o build/lan_pairing.o build/core.o build/platform.o @libs -static -s -o build/KSwitcherLanInputTests.exe
+        if ($LASTEXITCODE) { throw 'LAN input test build failed' }
+        & .\build\KSwitcherLanInputTests.exe
+        if ($LASTEXITCODE) { throw 'LAN input tests failed' }
+        & $compiler @common -Werror tests/lan.cpp build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o @libs -static -s -o build/KSwitcherLanTests.exe
+        if ($LASTEXITCODE) { throw 'LAN test build failed' }
+        & .\build\KSwitcherLanTests.exe
+        if ($LASTEXITCODE) { throw 'LAN pairing tests failed' }
         & $compiler @common -Werror -DSTAYHERE_TEST_INSTANCE -mwindows -municode -static -s utilities/StayHere/main.cpp -luser32 -lshell32 -lgdi32 -lwtsapi32 -o build/StayHereTest.exe
         if ($LASTEXITCODE) { throw 'StayHere fixture build failed' }
         & "$env:SystemRoot\System32\WindowsPowerShell\v1.0\powershell.exe" -NoProfile -ExecutionPolicy Bypass -File tests/stayhere.ps1 -Executable (Join-Path $outDir 'StayHereTest.exe')
@@ -55,11 +63,11 @@ try {
         if ($LASTEXITCODE) { throw 'Utilities test build failed' }
         & .\build\KSwitcherUtilitiesTests.exe
         if ($LASTEXITCODE) { throw 'Utilities tests failed' }
-        & $compiler @common tests/dictionary.cpp build/core.o build/platform.o build/autocorrect.o @libs -lpsapi -static -s -o build/KSwitcherDictionaryTests.exe
+        & $compiler @common tests/dictionary.cpp build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o build/autocorrect.o @libs -lpsapi -static -s -o build/KSwitcherDictionaryTests.exe
         if ($LASTEXITCODE) { throw 'Dictionary test build failed' }
         & .\build\KSwitcherDictionaryTests.exe
         if ($LASTEXITCODE) { throw 'Dictionary tests failed' }
-        & $compiler @common tests/sync.cpp build/core.o build/platform.o build/storage.o build/sync.o build/ocr.o @libs -static -s -o build/KSwitcherSyncTests.exe
+        & $compiler @common tests/sync.cpp build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o build/storage.o build/sync.o build/ocr.o @libs -static -s -o build/KSwitcherSyncTests.exe
         if ($LASTEXITCODE) { throw 'Sync test build failed' }
         & .\build\KSwitcherSyncTests.exe
         if ($LASTEXITCODE) { throw 'Sync tests failed' }
@@ -67,15 +75,19 @@ try {
         if ($LASTEXITCODE) { throw 'Scroll test build failed' }
         & .\build\KSwitcherScrollTests.exe
         if ($LASTEXITCODE) { throw 'Scroll tests failed' }
-        & $compiler @common tests/tests.cpp build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o @libs -static -s -o build/KSwitcherTests.exe
+        & $compiler @common tests/tests.cpp build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o @libs -static -s -o build/KSwitcherTests.exe
         if ($LASTEXITCODE) { throw 'Test build failed' }
         & .\build\KSwitcherTests.exe
         if ($LASTEXITCODE) { throw 'Tests failed' }
-        & $compiler @common tests/input.cpp build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o build/screenshot.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui.o build/screenshot-res.o @libs -static -s -o build/KSwitcherInputTests.exe
+        & $compiler @common tests/input.cpp build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o build/screenshot.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui.o build/screenshot-res.o @libs -static -s -o build/KSwitcherInputTests.exe
         if ($LASTEXITCODE) { throw 'Input test build failed' }
         & .\build\KSwitcherInputTests.exe
         if ($LASTEXITCODE) { throw 'Input tests failed' }
-        & $compiler @common tests/screenshot_ui.cpp build/core.o build/platform.o build/ocr.o build/screenshot-res.o @libs -static -s -o build/KSwitcherScreenshotUITests.exe
+        & $compiler @common tests/chat_profiles.cpp build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o build/screenshot.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui.o build/screenshot-res.o @libs -static -s -o build/KSwitcherChatProfileTests.exe
+        if ($LASTEXITCODE) { throw 'Chat profile test build failed' }
+        & .\build\KSwitcherChatProfileTests.exe
+        if ($LASTEXITCODE) { throw 'Chat profile tests failed' }
+        & $compiler @common tests/screenshot_ui.cpp build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o build/ocr.o build/screenshot-res.o @libs -static -s -o build/KSwitcherScreenshotUITests.exe
         if ($LASTEXITCODE) { throw 'Screenshot UI test build failed' }
         & .\build\KSwitcherScreenshotUITests.exe
         if ($LASTEXITCODE) { throw 'Screenshot UI tests failed' }
@@ -83,7 +95,7 @@ try {
         if ($LASTEXITCODE) { throw 'Screenshot save tests failed' }
         $registrationTest = Join-Path (Split-Path $executablePath) 'KSwitcherRegistrationTests.exe'
         try {
-            & $compiler @common tests/screenshot_registration.cpp build/core.o build/platform.o @libs -static '-Wl,--gc-sections' -s -o $registrationTest
+            & $compiler @common tests/screenshot_registration.cpp build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o @libs -static '-Wl,--gc-sections' -s -o $registrationTest
             if ($LASTEXITCODE) { throw 'Screenshot registration test build failed' }
             & $registrationTest
             if ($LASTEXITCODE) { throw 'Screenshot registration tests failed' }
@@ -95,7 +107,7 @@ try {
         if ($LASTEXITCODE) { throw 'Updater progress UI tests failed' }
     }
     if ($Far) {
-        & $compiler @common tests/far_snippets.cpp build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o build/screenshot.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui.o build/screenshot-res.o @libs -mwindows -municode -static -s -o build/KSwitcherFarSnippetTests.exe
+        & $compiler @common tests/far_snippets.cpp build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o build/screenshot.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui.o build/screenshot-res.o @libs -mwindows -municode -static -s -o build/KSwitcherFarSnippetTests.exe
         if ($LASTEXITCODE) { throw 'Far snippet test build failed' }
         $fixture = Start-Process -FilePath (Join-Path $outDir 'KSwitcherFarSnippetTests.exe') -WindowStyle Hidden -Wait -PassThru
         Get-Content -LiteralPath (Join-Path $outDir 'far-snippets.log')
@@ -107,28 +119,28 @@ try {
         Copy-Item $executablePath,(Join-Path (Split-Path $executablePath) 'KSwitcher.Screenshot.exe') -Destination $historyFixture
         Set-Content (Join-Path $historyFixture '.local-dev') 'Isolated history integration test'
         $historyTest = Join-Path $historyFixture 'KSwitcherHistoryHostTests.exe'
-        & $compiler @common tests/history_host.cpp build/core.o build/platform.o build/storage.o build/ocr.o @libs -lpsapi -static -s -o $historyTest
+        & $compiler @common tests/history_host.cpp build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o build/storage.o build/ocr.o @libs -lpsapi -static -s -o $historyTest
         if ($LASTEXITCODE) { throw 'History host test build failed' }
         & $historyTest
         if ($LASTEXITCODE) { throw 'History host tests failed' }
         $snapshotTest = Join-Path (Split-Path $executablePath) 'KSwitcherClipboardSnapshotTests.exe'
-        & $compiler @common tests/clipboard_snapshot.cpp build/core.o build/platform.o build/storage.o build/ocr.o @libs -lpsapi -static -s -o $snapshotTest
+        & $compiler @common tests/clipboard_snapshot.cpp build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o build/storage.o build/ocr.o @libs -lpsapi -static -s -o $snapshotTest
         if ($LASTEXITCODE) { throw 'Clipboard snapshot test build failed' }
         & $snapshotTest
         if ($LASTEXITCODE) { throw 'Clipboard snapshot tests failed' }
         $captureTest = Join-Path (Split-Path $executablePath) 'KSwitcherImageCaptureTests.exe'
-        & $compiler @common tests/image_capture.cpp build/core.o build/platform.o build/storage.o build/ocr.o @libs -static -s -o $captureTest
+        & $compiler @common tests/image_capture.cpp build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o build/storage.o build/ocr.o @libs -static -s -o $captureTest
         if ($LASTEXITCODE) { throw 'Image capture test build failed' }
         & $captureTest
         if ($LASTEXITCODE) { throw 'Image capture tests failed' }
-        & $compiler @common tests/integration.cpp build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o build/screenshot.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui.o build/screenshot-res.o @libs -static -s -o build/KSwitcherIntegration.exe
+        & $compiler @common tests/integration.cpp build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o build/screenshot.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui.o build/screenshot-res.o @libs -static -s -o build/KSwitcherIntegration.exe
         if ($LASTEXITCODE) { throw 'Integration test build failed' }
         & .\build\KSwitcherIntegration.exe
         if ($LASTEXITCODE) { throw 'Integration tests failed' }
     }
     if ($Ocr) {
         $ocrTest = Join-Path (Split-Path $executablePath) 'KSwitcherOcrTests.exe'
-        & $compiler @common tests/ocr.cpp build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o build/screenshot.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui.o build/screenshot-res.o @libs -static -s -o $ocrTest
+        & $compiler @common tests/ocr.cpp build/lan_channel.o build/lan_input.o build/lan.o build/lan_pairing.o build/core.o build/platform.o build/autostart.o build/autocorrect.o build/storage.o build/sync.o build/ocr.o build/richtext.o build/update.o build/screenshot.o build/screenshot_launcher.o build/screenshot_activation.o build/screenshot_notifications.o build/app.o build/configuration.o build/ui.o build/screenshot-res.o @libs -static -s -o $ocrTest
         if ($LASTEXITCODE) { throw 'OCR test build failed' }
         & $ocrTest
         if ($LASTEXITCODE) { throw 'OCR tests failed' }

package.ps1

@@ -9,13 +9,14 @@ Copy-Item -LiteralPath (Join-Path $root 'build\release\KSwitcher.Screenshot.exe'
 Copy-Item -LiteralPath (Join-Path $root 'LICENSE') -Destination $destination
 Copy-Item -LiteralPath (Join-Path $root 'vendor\json-LICENSE.txt') -Destination $destination
 Copy-Item -LiteralPath (Join-Path $root 'README.md') -Destination $destination
+Copy-Item -LiteralPath (Join-Path $root 'LAN-PREVIEW.md') -Destination $destination
 Copy-Item -LiteralPath (Join-Path $root 'dictionaries') -Destination $destination -Recurse -Force
 New-Item -ItemType Directory -Force (Join-Path $destination 'tools') | Out-Null
 Copy-Item -LiteralPath (Join-Path $root 'resources\portable-tools-README.txt') -Destination (Join-Path $destination 'tools\README.txt') -Force
 Copy-Item -LiteralPath (Join-Path $root 'build\release\tools\StayHere.exe') -Destination (Join-Path $destination 'tools\StayHere.exe') -Force
 Copy-Item -LiteralPath (Join-Path $root 'utilities\StayHere\README.md') -Destination (Join-Path $destination 'tools\StayHere-README.md') -Force
 # Enumerate the distributable files explicitly; do not include a user's data directory.
-$files = @('KSwitcher.exe','KSwitcher.Config.exe','KSwitcher.Screenshot.exe','LICENSE','json-LICENSE.txt','README.md','dictionaries','tools\README.txt','tools\StayHere.exe','tools\StayHere-README.md') | ForEach-Object { Join-Path $destination $_ }
+$files = @('KSwitcher.exe','KSwitcher.Config.exe','KSwitcher.Screenshot.exe','LICENSE','json-LICENSE.txt','README.md','LAN-PREVIEW.md','dictionaries','tools\README.txt','tools\StayHere.exe','tools\StayHere-README.md') | ForEach-Object { Join-Path $destination $_ }
 $entries = foreach ($path in $files) {
     foreach ($file in @(Get-ChildItem -LiteralPath $path -File -Recurse)) {
         @{path=$file.FullName.Substring($destination.Length+1).Replace('\','/'); size=$file.Length; sha256=(Get-FileHash -LiteralPath $file.FullName -Algorithm SHA256).Hash.ToLowerInvariant()}

resources/app.rc

@@ -9,8 +9,8 @@ IDC_SCREENSHOT_PENCIL CURSOR "icons/lucide/pencil.cur"
 1 RT_MANIFEST "app.manifest"
 201 RCDATA "update.ps1"
 1 VERSIONINFO
- FILEVERSION 0,6,46,0
- PRODUCTVERSION 0,6,46,0
+ FILEVERSION 0,6,56,0
+ PRODUCTVERSION 0,6,56,0
  FILEOS VOS_NT_WINDOWS32
  FILETYPE VFT_APP
 BEGIN
@@ -20,7 +20,7 @@ BEGIN
   BEGIN
    VALUE "FileDescription", "KSwitcher — native keyboard and clipboard utility"
    VALUE "ProductName", "KSwitcher"
-   VALUE "FileVersion", "0.6.46"
+   VALUE "FileVersion", "0.6.56"
   END
  END
  BLOCK "VarFileInfo"

resources/portable-tools-README.txt

@@ -1,14 +1,14 @@
 KSwitcher portable utilities
 
 Put your trusted portable .exe utilities directly in this tools folder,
-beside this README.txt. Right-click the KSwitcher tray icon and open Utilities.
-For example: tools/StayHere.exe appears as Utilities > StayHere.
+beside this README.txt. Right-click the KSwitcher tray icon and open Tools.
+For example: tools/StayHere.exe appears as Tools > StayHere.
 
 The list refreshes each time the tray menu opens. Subfolders and shortcuts
 are not listed. Utilities start only when you choose them, with this folder
 as their working directory. Closing KSwitcher does not close a utility.
 
-StayHere.exe is bundled. Choose Utilities > StayHere to start it; it starts
+StayHere.exe is bundled. Choose Tools > StayHere to start it; it starts
 enabled, prevents automatic sleep, and sends F15 after 3 minutes of inactivity.
 Left-click its tray icon to pause/resume; right-click for Exit. See StayHere-README.md.
 It does not start automatically with KSwitcher or bypass Windows locking.

src/app.cpp

@@ -559,6 +559,8 @@ App::App(HINSTANCE h, bool test, const std::filesystem::path &dataRoot, HWND ser
 }
 App::~App()
 {
+    lanService.reset();
+    stopBrowserChatMonitor();
     if (auto host = historyController(historyProcess)) PostMessageW(host, WM_CLOSE, 0, 0);
     if (historyProcess) CloseHandle(historyProcess);
     if (notificationRegistration) CloseHandle(notificationRegistration);
@@ -720,6 +722,15 @@ bool App::registerHotkeys(const Settings &s, bool rollback)
     return true;
 }
 
+Bytes App::lanCommand(const Bytes &command)
+{
+    if (!lanService) lanService = std::make_unique<LanService>(data);
+    auto reply = lanService->command(command);
+    if (lanService->inputEnabled()) SetTimer(window, 7, 10, nullptr);
+    else KillTimer(window, 7);
+    if (lanService->takeInputChange()) resetInput();
+    return reply;
+}
 void App::applySettings(const Settings &requested)
 {
     Settings s = requested;
@@ -918,9 +929,12 @@ void App::keyboard(const KBDLLHOOKSTRUCT &k, UINT mods)
     if (busy || settings.snippets.empty())
         return;
     auto keys = lower(run.keys);
+    auto snippetProcess = processName(fg);
+    for (int priority : {2, 1})
     for (size_t i = 0; i < settings.snippets.size(); ++i)
     {
         auto &sn = settings.snippets[i];
+        if (snippetAppPriority(sn, snippetProcess) != priority) continue;
         std::vector<std::wstring> variants{lower(sn.trigger)};
         for (auto &l : layouts)
         {
@@ -958,6 +972,32 @@ void App::keyboard(const KBDLLHOOKSTRUCT &k, UINT mods)
             }
     }
 }
+void App::refreshChatContext()
+{
+    HWND target = GetForegroundWindow();
+    chatWindow = target;
+    activeChatTitle = chatTitle(target);
+    activeChat = settings.chatCycles.empty() ? L"" : windowChatKey(target);
+}
+void App::switchChatLayout(bool reverse)
+{
+    HWND target = chatWindow;
+    auto key = activeChat;
+    if (!target || target != GetForegroundWindow() || key.empty() || windowChatKey(target) != key ||
+        !settings.chatCycles.contains(key) || busy.exchange(true)) return;
+    auto cycle = chatCycle(settings, key, layouts);
+    auto available = layouts;
+    resetInput();
+    enqueue([this, target, key, cycle, available, reverse]
+    {
+        struct Reset { std::atomic<bool> &busy; ~Reset() { busy = false; } } reset{busy};
+        auto valid = [&] { return GetForegroundWindow() == target && windowChatKey(target) == key; };
+        if (key.starts_with(L"telegram-web\n") && readChromeChat(target) != key) return;
+        if (!valid()) return;
+        auto next = nextChatLayout(cycle, available, windowLayout(target), reverse);
+        if (next) switchWindowLayout(target, next, valid);
+    });
+}
 bool App::handleKeyboard(const KBDLLHOOKSTRUCT &key, bool down, UINT mods)
 {
     // Filter before capture, hotkey latching and typing history. External injected
@@ -1008,6 +1048,23 @@ bool App::handleKeyboard(const KBDLLHOOKSTRUCT &key, bool down, UINT mods)
             return 1; // Record the chord without executing a global shortcut or typing into an editor.
         }
     }
+    bool chatEnabled = false;
+    if (down && ChatSwitchHook::candidate(key.vkCode, mods) && !settings.chatCycles.empty() &&
+        !isHotkey(key.vkCode, mods))
+    {
+        refreshChatContext();
+        chatEnabled = !activeChat.empty() && settings.chatCycles.contains(activeChat);
+    }
+    const int chatAction = chatSwitchHook.update(key.vkCode, down, mods, chatEnabled);
+    if (chatAction)
+    {
+        if (chatAction > 0)
+        {
+            chord(0xE8); // Suppress the shell's bare Alt/Win action.
+            switchChatLayout(chatAction == 2); // Captures this chat before another keyboard event.
+        }
+        return true;
+    }
     if (down)
     {
         auto action = hotkeyHook.update(key.vkCode, true, mods, hookBindings);
@@ -1071,6 +1128,13 @@ void App::replayTyping()
 }
 LRESULT CALLBACK App::keyProc(int code, WPARAM wp, LPARAM lp)
 {
+    if (code == HC_ACTION && current && current->lanService &&
+        (wp == WM_KEYDOWN || wp == WM_SYSKEYDOWN || wp == WM_KEYUP || wp == WM_SYSKEYUP))
+    {
+        bool consumed = current->lanService->keyboard(*(KBDLLHOOKSTRUCT *)lp, wp == WM_KEYDOWN || wp == WM_SYSKEYDOWN);
+        if (current->lanService->takeInputChange()) current->resetInput();
+        if (consumed) return 1; // Forwarded keys must not reach local hotkeys/snippets or other routers.
+    }
     // MWB suppresses source-machine events that it forwards elsewhere. Let
     // downstream hooks route the event before tracking it or starting a snippet.
     // Call the chain exactly once; a local event can still be consumed below.
@@ -1100,6 +1164,13 @@ LRESULT CALLBACK App::mouseProc(int code, WPARAM wp, LPARAM lp)
 {
     if (code == HC_ACTION && current)
     {
+        if (current->lanService)
+        {
+            bool consumed = current->lanService->mouse(UINT(wp), *(MSLLHOOKSTRUCT *)lp,
+                !current->busy && !current->suspended && !current->hotkeyCapture);
+            if (current->lanService->takeInputChange()) current->resetInput();
+            if (consumed) return 1;
+        }
         // KSwitcher generates no mouse input. Remote clicks invalidate a typing
         // range just like local clicks, including while a transaction is pending.
         if (wp == WM_LBUTTONDOWN || wp == WM_RBUTTONDOWN || wp == WM_MBUTTONDOWN || wp == WM_MOUSEWHEEL)
@@ -1215,8 +1286,9 @@ void App::transform(int command, int snippet)
         available = layouts;
         version = inputVersion;
     }
+    const auto requestedChat = config.chatCycles.empty() ? L"" : windowChatKey(target);
     enqueue(
-        [this, target, recent, previous, config, available, version, command, snippet, attempt, manual, requestedAt, preDeferred]
+        [this, target, recent, previous, config, available, version, command, snippet, attempt, manual, requestedAt, preDeferred, requestedChat]() mutable
         {
             struct BusyReset
             {
@@ -1231,6 +1303,9 @@ void App::transform(int command, int snippet)
                         b = false;
                 }
             } reset{busy, window, preDeferred};
+            auto effectiveChat = requestedChat;
+            if (lower(processName(target)) == L"chrome") effectiveChat = readChromeChat(target);
+            config.cycle = chatCycle(config, effectiveChat, available);
             auto start = GetTickCount64();
             std::wstring reason = L"cancelled-before-selection";
             std::wstring text, result, expected, actual, verification = L"not-attempted";
@@ -1425,6 +1500,7 @@ void App::transform(int command, int snippet)
                     if (snippet >= (int)config.snippets.size() || recent.window != target)
                         return;
                     const auto &sn = config.snippets[snippet];
+                    if (!snippetAppPriority(sn, processName(target))) return;
                     if (recent.keys.size() < sn.trigger.size())
                         return;
                     result = parseTemplate(sn.text).text;
@@ -1438,11 +1514,17 @@ void App::transform(int command, int snippet)
                     }
                     Run tail = recent;
                     tail.keys = tail.keys.substr(tail.keys.size() - sn.trigger.size());
-                    if (!tx.select(sn.trigger.size()))
-                        return;
                     autoSelected = true;
                     reason = L"snippet-verification-mismatch";
-                    text = tx.copy();
+                    if (farSnippet)
+                    {
+                        if (!tx.select(sn.trigger.size())) return;
+                        text = tx.copy();
+                    }
+                    else
+                        text = tx.copyRange(sn.trigger.size(), tail.keys,
+                            [&](const std::wstring &candidate) { return tail.match(candidate, available, physicalLayout()) >= 0; },
+                            [&](const std::wstring &candidate) { return tail.matchSuffix(candidate, available, physicalLayout()) >= 0; });
                     if (tail.match(text, available, physicalLayout()) < 0)
                         return;
                     automatic = true;
@@ -1520,9 +1602,9 @@ void App::transform(int command, int snippet)
                                 for (int i = 0; i < (int)available.size(); ++i)
                                     if (available[i].id == id && available[i].convertible)
                                         cycle.push_back(i);
-                            if (cycle.size() < 2)
+                            if (cycle.empty())
                             {
-                                reason = L"cycle-has-fewer-than-two-layouts";
+                                reason = L"cycle-has-no-layouts";
                                 if (automatic && tx.valid())
                                     chord(VK_RIGHT);
                                 return;
@@ -1839,7 +1921,7 @@ void App::trayMenu()
     if (utilities.empty())
         AppendMenuW(utilityMenu, MF_STRING | MF_GRAYED, 0,
                     utilitiesError ? L"Cannot read tools folder" : L"No utilities in tools folder");
-    AppendMenuW(menu, MF_POPUP, (UINT_PTR)utilityMenu, L"&Utilities");
+    AppendMenuW(menu, MF_POPUP, (UINT_PTR)utilityMenu, L"&Tools");
     AppendMenuW(menu, MF_SEPARATOR, 0, nullptr);
     AppendMenuW(menu, MF_STRING | (settings.awake ? MF_CHECKED : 0), 14, L"Keep screen a&wake");
     HMENU pause = CreatePopupMenu();
@@ -2063,6 +2145,13 @@ LRESULT CALLBACK App::windowProc(HWND hwnd, UINT msg, WPARAM wp, LPARAM lp)
     case WM_HOTKEY:
         app->dispatch((int)wp);
         return 0;
+    case WM_POWERBROADCAST:
+        if (wp == PBT_APMSUSPEND && app->lanService)
+        {
+            app->lanService->cancelInput();
+            app->resetInput();
+        }
+        return TRUE;
     case ReplayTypingMessage:
         app->replayTyping();
         return 0;
@@ -2134,6 +2223,15 @@ LRESULT CALLBACK App::windowProc(HWND hwnd, UINT msg, WPARAM wp, LPARAM lp)
         return TRUE;
     }
     case WM_TIMER:
+        if (wp == 7)
+        {
+            if (app->lanService)
+            {
+                if (app->suspended) app->lanService->cancelInput();
+                if (app->lanService->tickInput(!app->busy && !app->hotkeyCapture)) app->resetInput();
+            }
+            return 0;
+        }
         if (wp == 6)
         {
             if (app->notificationRegistration && WaitForSingleObject(app->notificationRegistration, 0) == WAIT_OBJECT_0)
@@ -2273,6 +2371,11 @@ int App::execute()
     // Resume pending OCR, including older images without a saved OCR state.
     scheduleHistoryOcr(settings);
     addTray();
+    if (!smoke) startBrowserChatMonitor();
+    if (!smoke && std::filesystem::exists(data / L"lan-pairing.bin"))
+        try { lanService = std::make_unique<LanService>(data); }
+        catch (const std::exception &e) { report(L"LAN module: " + wide(e.what())); }
+    if (lanService && lanService->inputEnabled()) SetTimer(window, 7, 10, nullptr);
     SetTimer(window, 1, 60000, nullptr);
     if (!smoke) SetTimer(window, 6, 1000, nullptr);
     SetThreadExecutionState(ES_CONTINUOUS |

src/app.h

@@ -3,6 +3,8 @@
 #include "storage.h"
 #include "update.h"
 #include "sync.h"
+#include "chat_context.h"
+#include "lan.h"
 #include <atomic>
 #include <condition_variable>
 #include <deque>
@@ -91,6 +93,7 @@ class App
     void checkUpdate(bool interactive, bool install = false, const std::wstring &version = {});
     std::wstring syncCommand(int action = 0, const std::vector<SyncChoice> &choices = {});
     Bytes syncConflictData();
+    Bytes lanCommand(const Bytes &);
     void pollSync();
     static App *current;
 
@@ -98,6 +101,7 @@ class App
     friend struct InputRegressionAccess;
     void releaseIdleMemory(ULONGLONG now);
     HHOOK keyboardHook{}, mouseHook{};
+    std::unique_ptr<LanService> lanService;
     HANDLE historyProcess{};
     std::mutex jobsMutex;
     std::condition_variable jobsReady;
@@ -134,6 +138,11 @@ class App
     int previousAttemptCommand{}, repeatAttempts{};
     std::vector<std::pair<int, Hotkey>> hookBindings;
     HotkeyHook hotkeyHook;
+    ChatSwitchHook chatSwitchHook;
+    HWND chatWindow{};
+    std::wstring activeChat, activeChatTitle;
+    void refreshChatContext();
+    void switchChatLayout(bool reverse);
     HWND typingTarget{};
     bool autoPending{};
     int snippetPending = -1;

src/autocorrect.cpp

@@ -257,7 +257,7 @@ std::optional<AutoSuggestion> AutoCorrector::suggest(const std::wstring &typed,
     {
         auto replacement = settings.autoReplacements.find(small);
         if (replacement != settings.autoReplacements.end() &&
-            replacement->second.find_first_not_of(alphabet) == small.npos)
+            replacement->second.find_first_not_of(alphabet + L" ") == small.npos)
             return sameLayout(replacement->second);
     }
     auto personal = [&](const std::wstring &language, const std::wstring &candidate)

src/browser_chat.inc

@@ -0,0 +1,143 @@
+// Chrome Telegram Web integration: native accessibility, no OCR or polling timer.
+#include "chat_context.h"
+#include <uiautomation.h>
+#include <atomic>
+#include <thread>
+namespace ks {
+namespace {
+template<class T> struct BrowserCom {
+ T *p{}; ~BrowserCom(){if(p)p->Release();}
+ T** out(){return &p;} T* operator->(){return p;}
+};
+std::wstring browserString(IUIAutomationElement* e, PROPERTYID id) {
+ VARIANT v;VariantInit(&v);std::wstring s;
+ if(SUCCEEDED(e->GetCurrentPropertyValue(id,&v)) && v.vt==VT_BSTR && v.bstrVal) s.assign(v.bstrVal,SysStringLen(v.bstrVal));
+ VariantClear(&v);return s;
+}
+struct ChromeElements { BrowserCom<IUIAutomationElement> address,document,header; int addresses{},documents{}; };
+void findChromeElements(IUIAutomationTreeWalker* walker,IUIAutomationElement* e,ChromeElements& found,int depth,int& budget) {
+ if(depth>12 || --budget<0)return;
+ CONTROLTYPEID type{};BOOL offscreen=TRUE;e->get_CurrentControlType(&type);e->get_CurrentIsOffscreen(&offscreen);
+ if(type==UIA_DocumentControlTypeId){
+  if(!offscreen && browserString(e,UIA_AutomationIdPropertyId)==L"RootWebArea"){
+   if(++found.documents==1){e->AddRef();found.document.p=e;}}
+  return; // Never traverse message content.
+ }
+ if(type==UIA_EditControlTypeId && !offscreen && browserString(e,UIA_ClassNamePropertyId)==L"OmniboxViewViews"){
+  if(++found.addresses==1){e->AddRef();found.address.p=e;}}
+ BrowserCom<IUIAutomationElement> child;walker->GetFirstChildElement(e,child.out());
+ while(child.p && budget>0){findChromeElements(walker,child.p,found,depth+1,budget);BrowserCom<IUIAutomationElement> next;walker->GetNextSiblingElement(child.p,next.out());child.p->Release();child.p=next.p;next.p=nullptr;}
+}
+IUIAutomationElement* chromeHeader(IUIAutomationTreeWalker* walker,IUIAutomationElement* document) {
+ // Web K's center pane is separate from its chat list and message history.
+ std::function<IUIAutomationElement*(IUIAutomationElement*,int)> center;
+ center=[&](IUIAutomationElement* e,int depth)->IUIAutomationElement* {
+  if(depth>3)return nullptr;
+  if(browserString(e,UIA_AutomationIdPropertyId)==L"column-center"){e->AddRef();return e;}
+  auto id=browserString(e,UIA_AutomationIdPropertyId);if(id==L"column-left"||id==L"column-right")return nullptr;
+  BrowserCom<IUIAutomationElement> c;walker->GetFirstChildElement(e,c.out());int limit=12;
+  while(c.p && --limit>0){if(auto result=center(c.p,depth+1))return result;BrowserCom<IUIAutomationElement> next;walker->GetNextSiblingElement(c.p,next.out());c.p->Release();c.p=next.p;next.p=nullptr;}return nullptr;
+ };
+ BrowserCom<IUIAutomationElement> pane;pane.p=center(document,0);if(!pane.p)return nullptr;
+ BrowserCom<IUIAutomationElement> header;walker->GetFirstChildElement(pane.p,header.out());if(!header.p)return nullptr;
+ BrowserCom<IUIAutomationElement> c;walker->GetFirstChildElement(header.p,c.out());int limit=16,buttons=0;IUIAutomationElement* title{};
+ while(c.p && --limit>0){CONTROLTYPEID type{};c->get_CurrentControlType(&type);if(type==UIA_ButtonControlTypeId)++buttons;
+  if(type==UIA_TextControlTypeId && !title){title=c.p;title->AddRef();}
+  BrowserCom<IUIAutomationElement> next;walker->GetNextSiblingElement(c.p,next.out());c.p->Release();c.p=next.p;next.p=nullptr;}
+ if(buttons<2 && title){title->Release();title=nullptr;}return title;
+}
+std::wstring chromeTitleKey(IUIAutomationElement* header){
+ if(!header)return {};
+ auto name=browserString(header,UIA_NamePropertyId);
+ if(name.empty()||name.size()>512||name.find_first_of(L"\r\n")!=name.npos)return {};
+ return L"telegram-web\n"+name;
+}
+std::wstring chromeSnapshot(IUIAutomation* uia,HWND window,ChromeElements& found) {
+ if(!IsWindow(window)||IsIconic(window)||lower(processName(window))!=L"chrome")return {};
+ BrowserCom<IUIAutomationElement> root;BrowserCom<IUIAutomationTreeWalker> walker;
+ if(FAILED(uia->ElementFromHandle(window,root.out()))||!root.p||FAILED(uia->get_ControlViewWalker(walker.out())))return {};
+ int budget=250;findChromeElements(walker.p,root.p,found,0,budget);
+ if(found.addresses!=1||found.documents!=1)return {};
+ auto address=telegramWebKey(browserString(found.address.p,UIA_ValueValuePropertyId));
+ auto document=telegramWebKey(browserString(found.document.p,UIA_ValueValuePropertyId));
+ BOOL editing=FALSE;found.address->get_CurrentHasKeyboardFocus(&editing);
+ if(editing || address.empty() || address!=document)return {};
+ found.header.p=chromeHeader(walker.p,found.document.p);
+ return chromeTitleKey(found.header.p);
+}
+std::mutex browserMutex;
+HWND browserWindow{};std::wstring browserKey;
+std::atomic<DWORD> browserThreadId{};
+std::atomic<bool> browserPending{}, browserStopping{};
+std::thread browserThread;
+void invalidateBrowser(){std::lock_guard lock(browserMutex);browserKey.clear();}
+void requestBrowser(){invalidateBrowser();auto id=browserThreadId.load();if(id && !browserPending.exchange(true))PostThreadMessageW(id,WM_APP+61,0,0);}
+void CALLBACK browserForeground(HWINEVENTHOOK,DWORD,HWND,LONG,LONG,DWORD,DWORD){requestBrowser();}
+class BrowserChanged final: public IUIAutomationPropertyChangedEventHandler {
+ std::atomic<ULONG> refs{1};
+ public:
+ HRESULT STDMETHODCALLTYPE QueryInterface(REFIID iid,void** out) override {if(!out)return E_POINTER;*out=nullptr;if(iid==IID_IUnknown||iid==IID_IUIAutomationPropertyChangedEventHandler){*out=static_cast<IUIAutomationPropertyChangedEventHandler*>(this);AddRef();return S_OK;}return E_NOINTERFACE;}
+ ULONG STDMETHODCALLTYPE AddRef() override{return ++refs;}
+ ULONG STDMETHODCALLTYPE Release() override{auto n=--refs;if(!n)delete this;return n;}
+ HRESULT STDMETHODCALLTYPE HandlePropertyChangedEvent(IUIAutomationElement*,PROPERTYID,VARIANT) override {requestBrowser();return S_OK;}
+};
+}
+std::wstring readChromeChat(HWND window) {
+ auto hr=CoInitializeEx(nullptr,COINIT_MULTITHREADED);
+ struct Apartment{bool own;~Apartment(){if(own)CoUninitialize();}} apartment{SUCCEEDED(hr)};
+ BrowserCom<IUIAutomation2> uia;
+ if(FAILED(CoCreateInstance(CLSID_CUIAutomation8,nullptr,CLSCTX_INPROC_SERVER,IID_IUIAutomation2,(void**)uia.out())))return {};
+ uia->put_ConnectionTimeout(150);uia->put_TransactionTimeout(150);
+ ChromeElements elements;return chromeSnapshot(uia.p,window,elements);
+}
+std::wstring cachedChromeChat(HWND window){std::lock_guard lock(browserMutex);return window==browserWindow?browserKey:L"";}
+void startBrowserChatMonitor(){
+ if(browserThread.joinable())return;
+ browserStopping=false;
+ browserThread=std::thread([] {
+  CoInitializeEx(nullptr,COINIT_MULTITHREADED);MSG message{};PeekMessageW(&message,nullptr,0,0,PM_NOREMOVE);
+  browserThreadId=GetCurrentThreadId();
+  auto foreground=SetWinEventHook(EVENT_SYSTEM_FOREGROUND,EVENT_SYSTEM_FOREGROUND,nullptr,browserForeground,0,0,WINEVENT_OUTOFCONTEXT);
+  // Focus changes cover tab selection and entering/leaving the address bar.
+  auto focus=SetWinEventHook(EVENT_OBJECT_FOCUS,EVENT_OBJECT_FOCUS,nullptr,browserForeground,0,0,WINEVENT_OUTOFCONTEXT);
+  BrowserCom<IUIAutomation2> uia;CoCreateInstance(CLSID_CUIAutomation8,nullptr,CLSCTX_INPROC_SERVER,IID_IUIAutomation2,(void**)uia.out());
+  BrowserCom<IUIAutomationElement> address,document,header;BrowserCom<BrowserChanged> handler;handler.p=new BrowserChanged;
+  if(uia.p){uia->put_ConnectionTimeout(150);uia->put_TransactionTimeout(150);}
+  requestBrowser();
+  if(browserStopping)PostThreadMessageW(GetCurrentThreadId(),WM_QUIT,0,0);
+  while(GetMessageW(&message,nullptr,0,0)>0){
+   if(message.message!=WM_APP+61){TranslateMessage(&message);DispatchMessageW(&message);continue;}
+   browserPending=false;
+   if(!uia.p)continue;
+   if(address.p){uia->RemovePropertyChangedEventHandler(address.p,handler.p);address.p->Release();address.p=nullptr;}
+   if(document.p){uia->RemovePropertyChangedEventHandler(document.p,handler.p);document.p->Release();document.p=nullptr;}
+   if(header.p){uia->RemovePropertyChangedEventHandler(header.p,handler.p);header.p->Release();header.p=nullptr;}
+   auto window=GetForegroundWindow();ChromeElements elements;auto key=chromeSnapshot(uia.p,window,elements);
+   PROPERTYID properties[]={UIA_ValueValuePropertyId};
+   bool subscribed=elements.address.p && elements.document.p;
+   if(subscribed){address.p=elements.address.p;elements.address.p=nullptr;document.p=elements.document.p;elements.document.p=nullptr;
+    subscribed=SUCCEEDED(uia->AddPropertyChangedEventHandlerNativeArray(address.p,TreeScope_Element,nullptr,handler.p,properties,1));
+    subscribed=SUCCEEDED(uia->AddPropertyChangedEventHandlerNativeArray(document.p,TreeScope_Element,nullptr,handler.p,properties,1)) && subscribed;
+    if(elements.header.p){header.p=elements.header.p;elements.header.p=nullptr;PROPERTYID nameProperty=UIA_NamePropertyId;
+     subscribed=SUCCEEDED(uia->AddPropertyChangedEventHandlerNativeArray(header.p,TreeScope_Element,nullptr,handler.p,&nameProperty,1)) && subscribed;}
+    // Close the read/subscribe race without scanning the content tree.
+    key=telegramWebKey(browserString(address.p,UIA_ValueValuePropertyId));
+    if(key.empty() || key!=telegramWebKey(browserString(document.p,UIA_ValueValuePropertyId)))key.clear();
+    else key=chromeTitleKey(header.p);
+    BOOL editing=FALSE;address->get_CurrentHasKeyboardFocus(&editing);if(editing)key.clear();
+   }
+   std::lock_guard lock(browserMutex);browserWindow=window;browserKey=subscribed && !browserPending && window==GetForegroundWindow()?key:L"";
+  }
+  browserThreadId=0;
+  if(foreground)UnhookWinEvent(foreground);
+  if(focus)UnhookWinEvent(focus);
+  if(uia.p){if(header.p)uia->RemovePropertyChangedEventHandler(header.p,handler.p);if(address.p)uia->RemovePropertyChangedEventHandler(address.p,handler.p);if(document.p)uia->RemovePropertyChangedEventHandler(document.p,handler.p);}
+  invalidateBrowser();
+  // COM objects release before uninitializing the apartment below.
+  if(header.p){header.p->Release();header.p=nullptr;}
+  if(address.p){address.p->Release();address.p=nullptr;}if(document.p){document.p->Release();document.p=nullptr;}
+  if(uia.p){uia.p->Release();uia.p=nullptr;}CoUninitialize();
+ });
+}
+void stopBrowserChatMonitor(){browserStopping=true;auto id=browserThreadId.load();if(id)PostThreadMessageW(id,WM_QUIT,0,0);if(browserThread.joinable())browserThread.join();browserPending=false;}
+}

src/chat_context.h

@@ -0,0 +1,119 @@
+#pragma once
+#include "platform.h"
+#include <algorithm>
+
+namespace ks
+{
+inline std::wstring telegramWebKey(std::wstring url)
+{
+    if (url.starts_with(L"https://")) url.erase(0, 8);
+    const std::wstring host = L"web.telegram.org/";
+    if (!url.starts_with(host)) return {};
+    url.erase(0, host.size());
+    if (!(url.starts_with(L"k/#") || url.starts_with(L"a/#"))) return {};
+    auto peer = url.substr(3);
+    if (peer.empty() || peer.size() > 128) return {};
+    if (peer.front() == L'@')
+    {
+        peer = lower(peer);
+        if (peer.size() < 2 || peer.find_first_not_of(L"abcdefghijklmnopqrstuvwxyz0123456789_", 1) != peer.npos) return {};
+    }
+    else
+    {
+        auto first = peer.front() == L'-' ? 1u : 0u;
+        if (first == peer.size() || peer.find_first_not_of(L"0123456789", first) != peer.npos) return {};
+    }
+    return L"telegram-web\n" + peer;
+}
+std::wstring readChromeChat(HWND);
+std::wstring cachedChromeChat(HWND);
+void startBrowserChatMonitor();
+void stopBrowserChatMonitor();
+struct ChatSwitchHook
+{
+    bool pressed[256]{};
+    static bool candidate(UINT key, UINT mods)
+    {
+        bool shift = key == VK_SHIFT || key == VK_LSHIFT || key == VK_RSHIFT;
+        bool alt = key == VK_MENU || key == VK_LMENU || key == VK_RMENU;
+        return (key == VK_SPACE && (mods == MOD_WIN || mods == (MOD_WIN | MOD_SHIFT))) ||
+            (shift && mods == MOD_ALT) || (alt && mods == MOD_SHIFT);
+    }
+    // 1 forward, 2 backward, -1 consumed repeat/release, 0 ordinary input.
+    int update(UINT key, bool down, UINT mods, bool enabled)
+    {
+        if (key >= 256) return 0;
+        if (pressed[key]) { if (!down) pressed[key] = false; return -1; }
+        if (!down || !enabled) return 0;
+        if (!candidate(key, mods)) return 0;
+        pressed[key] = true;
+        return key == VK_SPACE && (mods & MOD_SHIFT) ? 2 : 1;
+    }
+};
+inline std::wstring chatTitle(HWND window)
+{
+    wchar_t title[1024]{};
+    if (!window) return {};
+    int length = GetWindowTextW(window, title, std::size(title));
+    if (!length || length >= (int)std::size(title) - 1) return {};
+    return title;
+}
+inline std::wstring chatKey(std::wstring process, std::wstring title)
+{
+    process = lower(process);
+    if (process.ends_with(L".exe")) process.resize(process.size() - 4);
+    while (!title.empty() && (title.front() == 0x200e || title.front() == 0x200f)) title.erase(0, 1);
+    if (process == L"telegram")
+    {
+        // Telegram's unread badge is not part of the contact name.
+        auto badge = title.rfind(L" \u2013 (");
+        if (badge != title.npos && title.back() == L')')
+        {
+            auto digits = title.substr(badge + 4, title.size() - badge - 5);
+            if (!digits.empty() && digits.find_first_not_of(L"0123456789") == digits.npos)
+                title.resize(badge);
+        }
+        if (title.empty() || title == L"Telegram" || title.starts_with(L"Telegram (")) return {};
+    }
+    else if (process == L"ms-teams")
+    {
+        // Only the observed chat title format; meetings/search are not chats.
+        const std::wstring prefix = L"Chat | ", suffix = L" | Microsoft Teams";
+        if (!title.starts_with(prefix) || !title.ends_with(suffix) ||
+            title.size() <= prefix.size() + suffix.size()) return {};
+        title = title.substr(prefix.size(), title.size() - prefix.size() - suffix.size());
+        if (title.empty()) return {};
+    }
+    else return {};
+    return process + L"\n" + title;
+}
+inline std::wstring windowChatKey(HWND window)
+{
+    if (window && lower(processName(window)) == L"chrome") return cachedChromeChat(window);
+    return window ? chatKey(processName(window), chatTitle(window)) : L"";
+}
+inline std::vector<std::wstring> chatCycle(const Settings &settings, const std::wstring &key,
+                                         const std::vector<Layout> &layouts)
+{
+    auto found = settings.chatCycles.find(key);
+    if (key.empty() || found == settings.chatCycles.end()) return settings.cycle;
+    std::vector<std::wstring> result;
+    for (const auto &id : found->second)
+        if (std::any_of(layouts.begin(), layouts.end(), [&](const Layout &l) { return l.id == id; }))
+            result.push_back(id);
+    return result.empty() ? settings.cycle : result;
+}
+inline HKL nextChatLayout(const std::vector<std::wstring> &cycle, const std::vector<Layout> &layouts,
+                          HKL current, bool reverse)
+{
+    std::vector<HKL> handles;
+    for (const auto &id : cycle)
+        for (const auto &layout : layouts)
+            if (layout.id == id) handles.push_back(layout.handle);
+    if (handles.empty()) return nullptr;
+    auto found = std::find(handles.begin(), handles.end(), current);
+    if (found == handles.end()) return handles.front();
+    auto next = (size_t(found - handles.begin()) + (reverse ? handles.size() - 1 : 1)) % handles.size();
+    return handles[next];
+}
+}

src/config_main.cpp

@@ -112,6 +112,7 @@ void App::reloadLayouts()
 }
 void App::clearHistory() { request(*this, ConfigClearHistory); }
 Bytes App::syncConflictData() { return request(*this, ConfigSyncConflicts); }
+Bytes App::lanCommand(const Bytes &bytes) { return request(*this, ConfigLan, bytes); }
 std::wstring App::syncCommand(int action, const std::vector<SyncChoice> &choices)
 {
     auto result = action == 4 ? request(*this, ConfigSyncResolve, encodeSyncChoices(choices)) :

src/configuration.cpp

@@ -40,6 +40,13 @@ LRESULT configurationRequest(App &app, HWND sender, const COPYDATASTRUCT &messag
     {
         switch (message.dwData)
         {
+        case ConfigLan:
+        {
+            if (!message.cbData || message.cbData > 4096) throw std::runtime_error("Invalid LAN request.");
+            auto first = static_cast<const unsigned char *>(message.lpData);
+            reply = app.lanCommand(Bytes(first, first + message.cbData));
+            break;
+        }
         case ConfigSyncConflicts:
             reply = app.syncConflictData();
             break;

src/configuration.h

@@ -7,7 +7,7 @@ inline constexpr ULONG_PTR ConfigRead = 0x4b530100, ConfigSave = ConfigRead + 1,
     ConfigCapture = ConfigRead + 4, ConfigLogs = ConfigRead + 5,
     ConfigReply = ConfigRead + 6, ConfigClearLog = ConfigRead + 7,
     ConfigSync = ConfigRead + 8, ConfigSyncConflicts = ConfigRead + 9,
-    ConfigSyncResolve = ConfigRead + 10, ConfigEnd = ConfigRead + 11;
+    ConfigSyncResolve = ConfigRead + 10, ConfigLan = ConfigRead + 11, ConfigEnd = ConfigRead + 12;
 inline constexpr size_t ConfigLimit = 8 * 1024 * 1024;
 bool configurationPeer(HWND, const wchar_t *filename);
 void launchConfiguration(App &, bool snippets = false, bool logs = false);

src/core.cpp

@@ -6,6 +6,21 @@
 
 namespace ks
 {
+std::wstring snippetAppName(std::wstring name)
+{
+    auto first = name.find_first_not_of(L" \t"), last = name.find_last_not_of(L" \t");
+    if (first == name.npos) return {};
+    name = lower(name.substr(first, last - first + 1));
+    if (name.ends_with(L".exe")) name.resize(name.size() - 4);
+    return name;
+}
+int snippetAppPriority(const Snippet &snippet, const std::wstring &process)
+{
+    if (snippet.apps.empty()) return 1;
+    auto name = snippetAppName(process);
+    for (const auto &app : snippet.apps) if (snippetAppName(app) == name && !name.empty()) return 2;
+    return 0;
+}
 int HotkeyHook::update(UINT key, bool down, UINT modifiers,
                        const std::vector<std::pair<int, Hotkey>> &bindings)
 {

src/core.h

@@ -32,7 +32,10 @@ struct Snippet
 {
     std::wstring trigger, text;
     std::wstring id;
+    std::vector<std::wstring> apps; // Empty means everywhere; executable names without .exe.
 };
+std::wstring snippetAppName(std::wstring);
+int snippetAppPriority(const Snippet &, const std::wstring &process);
 std::wstring snippetId(const Snippet &);
 std::wstring newSnippetId();
 struct Template
@@ -76,6 +79,8 @@ struct Settings
                  translit = L"Ctrl+Alt+Shift+T", undo = L"Ctrl+Alt+Shift+Z", clipboard = L"Win+V",
                  screenshot = L"Win+Shift+S";
     std::vector<std::wstring> cycle, direct, directIds;
+    // Exact application + visible chat name; an absent entry uses the global cycle.
+    std::map<std::wstring, std::vector<std::wstring>> chatCycles;
     std::vector<std::wstring> excluded{L"KeePass", L"KeePassXC", L"1Password", L"Bitwarden"};
     std::vector<Snippet> snippets;
     std::vector<std::wstring> snippetTombstones;

src/lan.cpp

@@ -0,0 +1,338 @@
+#include <winsock2.h>
+#include <ws2tcpip.h>
+#include <iphlpapi.h>
+#include "lan.h"
+#include "lan_pairing.h"
+#include "lan_input.h"
+#include <atomic>
+#include <mutex>
+#include <thread>
+#include <map>
+
+namespace ks
+{
+using lan::Json;
+namespace
+{
+Bytes encoded(const Json &j) { auto s=j.dump(); return Bytes(s.begin(),s.end()); }
+bool localAddress(ULONG network)
+{
+    auto ip=ntohl(network);
+    return (ip>>24)==10 || (ip>>20)==0xac1 || (ip>>16)==0xc0a8 || (ip>>16)==0xa9fe;
+}
+std::string hostName()
+{
+    wchar_t name[256]{}; DWORD size=256;
+    return GetComputerNameW(name,&size) ? utf8(std::wstring(name,size)) : "KSwitcher";
+}
+std::vector<ULONG> broadcasts()
+{
+    ULONG size=16384; Bytes data(size);
+    auto flags=GAA_FLAG_SKIP_ANYCAST|GAA_FLAG_SKIP_MULTICAST|GAA_FLAG_SKIP_DNS_SERVER;
+    auto result=GetAdaptersAddresses(AF_INET,flags,nullptr,(IP_ADAPTER_ADDRESSES*)data.data(),&size);
+    if(result==ERROR_BUFFER_OVERFLOW) { data.resize(size); result=GetAdaptersAddresses(AF_INET,flags,nullptr,(IP_ADAPTER_ADDRESSES*)data.data(),&size); }
+    std::vector<ULONG> out;
+    if(result!=NO_ERROR) return out;
+    for(auto a=(IP_ADAPTER_ADDRESSES*)data.data();a;a=a->Next)
+        if(a->OperStatus==IfOperStatusUp)
+            for(auto u=a->FirstUnicastAddress;u;u=u->Next)
+                if(u->Address.lpSockaddr->sa_family==AF_INET && u->OnLinkPrefixLength>0 && u->OnLinkPrefixLength<31)
+                {
+                    auto ip=((sockaddr_in*)u->Address.lpSockaddr)->sin_addr.s_addr;
+                    if(localAddress(ip)) out.push_back(htonl(ntohl(ip) | (0xffffffffu >> u->OnLinkPrefixLength)));
+                }
+    return out;
+}
+}
+struct LanService::Impl
+{
+    struct Peer { std::string name,epoch; sockaddr_in address{}; uint64_t seen{},verified{}; };
+    std::filesystem::path path;
+    std::string id,epoch=lan::randomHex(16),name=hostName(),status="Disabled.";
+    std::map<std::string,Peer> peers;
+    Json trusted=Json::object();
+    std::unique_ptr<lan::Pairing> pending;
+    bool enabled{};
+    std::atomic<bool> stopping{false};
+    std::mutex mutex;
+    std::thread worker;
+    bool shareInput{};
+    std::string inputPeer;
+    int inputEdge=1;
+    std::atomic<bool> inputConnected{false},abortInput{false};
+    std::atomic<uint64_t> inputEpoch{0};
+    std::atomic<uint64_t> inputConfiguration{0};
+    uint64_t observedEpoch{},observedRevision{};
+    std::mutex inputMutex;
+    std::vector<lan::InputFrame> inputOut,inputIn;
+    std::unique_ptr<lan::InputRouter> router;
+    std::string inputStatus="Input sharing disabled.";
+    explicit Impl(const std::filesystem::path &root) : path(root/L"lan-pairing.bin")
+    {
+        if(std::filesystem::exists(path))
+        {
+            auto j=Json::parse(unprotect(readFile(path,256*1024)));
+            if(j.value("version",0)!=1 || !lan::identifier(j.value("id",""))) throw std::runtime_error("Invalid local LAN configuration.");
+            id=j.at("id"); enabled=j.value("enabled",false); trusted=j.at("trusted");
+            shareInput=j.value("shareInput",false);inputPeer=j.value("inputPeer","");inputEdge=j.value("inputEdge",1);
+            if(inputEdge<0||inputEdge>3||(shareInput&&!trusted.contains(inputPeer)))throw std::runtime_error("Invalid input sharing configuration.");
+            if(!trusted.is_object()||trusted.size()>64) throw std::runtime_error("Invalid paired computer list.");
+            for(auto &[key,entry]:trusted.items())
+                if(!lan::identifier(key)||key==id||entry.at("key").get<std::string>().size()!=64||
+                   !entry.at("name").is_string()||entry.at("name").get<std::string>().size()>128)
+                    throw std::runtime_error("Invalid paired computer key.");
+        }
+        else id=lan::randomHex(16);
+        configureRouter();
+        if(enabled) start();
+    }
+    ~Impl() { stop(); }
+    void save() { atomicWrite(path,protect(encoded({{"version",1},{"id",id},{"enabled",enabled},{"trusted",trusted},
+        {"shareInput",shareInput},{"inputPeer",inputPeer},{"inputEdge",inputEdge}}))); }
+    bool queue(lan::InputFrame frame)
+    {
+        if(!inputConnected)return false;
+        std::lock_guard lock(inputMutex);
+        if(inputOut.size()>=512){abortInput=true;return false;}
+        inputOut.push_back(frame);return true;
+    }
+    void configureRouter()
+    {
+        router.reset();inputConnected=false;abortInput=true;++inputEpoch;++inputConfiguration;
+        {std::lock_guard lock(inputMutex);inputOut.clear();inputIn.clear();}
+        if(enabled&&shareInput)router=std::make_unique<lan::InputRouter>(lan::windowsInputEnvironment(),[this](auto f){return queue(f);},inputEdge,id<inputPeer);
+        inputStatus=enabled&&shareInput?"Connecting input channel...":"Input sharing disabled.";
+        observedRevision=0;
+    }
+    bool takeChange()
+    {
+        auto revision=router?router->revision():0;bool changed=revision!=observedRevision;observedRevision=revision;return changed;
+    }
+    bool tickInput(bool allowEnter)
+    {
+        if(!router)return false;
+        auto epoch=inputEpoch.load();if(epoch!=observedEpoch){router->cancel(GetTickCount64());observedEpoch=epoch;}
+        router->tick(inputConnected,GetTickCount64());
+        std::vector<lan::InputFrame> incoming;
+        {std::lock_guard lock(inputMutex);incoming.swap(inputIn);}
+        for(auto &frame:incoming)
+            if(!allowEnter&&frame.type==lan::InputType::Enter)queue({lan::InputType::Return,frame.token,32768});
+            else router->receive(frame,GetTickCount64());
+        return takeChange();
+    }
+    void start()
+    {
+        stopping=false; epoch=lan::randomHex(16); status="Searching for KSwitcher computers...";
+        worker=std::thread([this]{ run(); });
+    }
+    void stop()
+    {
+        if(router)router->cancel(GetTickCount64());
+        stopping=true;
+        if(worker.joinable()) worker.join();
+        inputConnected=false;++inputEpoch;
+        {std::lock_guard lock(inputMutex);inputOut.clear();inputIn.clear();}
+        std::lock_guard lock(mutex); pending.reset(); peers.clear();
+    }
+    void send(SOCKET socket,const sockaddr_in &address,const Json &j)
+    {
+        auto bytes=j.dump(); if(bytes.size()>2048) return;
+        sendto(socket,bytes.data(),int(bytes.size()),0,(const sockaddr*)&address,sizeof(address));
+    }
+    std::string heartbeat(const std::string &from,const std::string &to,const std::string &a,const std::string &b)
+    { return "KSwitcher LAN v1|presence|"+from+"|"+to+"|"+a+"|"+b; }
+    void receive(SOCKET socket,const sockaddr_in &address,const Json &j,uint64_t now)
+    {
+        if(j.value("app","")!="KSwitcher-LAN" || j.value("version",0)!=1) return;
+        auto other=j.value("id",""); if(!lan::identifier(other)||other==id) return;
+        auto type=j.value("type","");
+        if(type=="hello")
+        {
+            auto display=j.value("name",""); auto session=j.value("epoch","");
+            if(display.empty()||display.size()>128||!lan::identifier(session)||
+               std::any_of(display.begin(),display.end(),[](unsigned char c){return c<32||c==127;})) return;
+            // Discovery is untrusted and never grants input access.
+            if(!peers.contains(other) && peers.size()>=64) return;
+            auto &peer=peers[other];
+            if(peer.epoch!=session || peer.address.sin_addr.s_addr!=address.sin_addr.s_addr) peer.verified=0;
+            peer.name=display; peer.epoch=session; peer.address=address; peer.seen=now;
+            if(trusted.contains(other))
+            {
+                auto response=lan::envelope("presence",id); response["to"]=other; response["epoch"]=epoch;
+                response["proof"]=lan::mac(trusted[other].at("key"),heartbeat(id,other,epoch,session));
+                send(socket,address,response);
+            }
+            return;
+        }
+        if(!peers.contains(other)||j.value("to","")!=id) return;
+        auto &peer=peers.at(other);
+        if(peer.address.sin_addr.s_addr!=address.sin_addr.s_addr) return;
+        if(type=="presence" && trusted.contains(other) && j.value("epoch","")==peer.epoch &&
+           lan::equal(j.value("proof",""),lan::mac(trusted[other].at("key"),heartbeat(other,id,peer.epoch,epoch))))
+        { peer.verified=now; return; }
+        if(pending && pending->peer==other)
+        {
+            for(const auto &response:pending->receive(j,now)) send(socket,address,response);
+            if(pending->confirmed && (!trusted.contains(other)||trusted[other].at("key")!=pending->derived))
+            {
+                auto previous=trusted;
+                trusted[other]={{"name",peer.name},{"key",pending->derived}};
+                try {save();} catch(...) {trusted=std::move(previous);throw;}
+                peer.verified=now; status="Paired. Select a screen position and enable mouse and keyboard on both PCs.";
+            }
+        }
+    }
+    void run() noexcept
+    {
+        WSADATA startup{}; SOCKET socket=INVALID_SOCKET; bool winsock=false;
+        try
+        {
+            if(WSAStartup(MAKEWORD(2,2),&startup)) throw std::runtime_error("Cannot start Windows networking.");
+            winsock=true; socket=::socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
+            BOOL yes=TRUE; u_long nonblock=1;
+            if(socket==INVALID_SOCKET || setsockopt(socket,SOL_SOCKET,SO_EXCLUSIVEADDRUSE,(char*)&yes,sizeof(yes)) ||
+               setsockopt(socket,SOL_SOCKET,SO_BROADCAST,(char*)&yes,sizeof(yes)) || ioctlsocket(socket,FIONBIO,&nonblock))
+                throw std::runtime_error("Cannot open LAN discovery socket.");
+            sockaddr_in bound{}; bound.sin_family=AF_INET; bound.sin_port=htons(lan::Port);
+            if(bind(socket,(sockaddr*)&bound,sizeof(bound))) throw std::runtime_error("UDP port 45883 is in use. Only one LAN-enabled KSwitcher may run per computer.");
+            uint64_t nextHello=0,nextOffer=0,lastChannelGeneration=0;
+            std::unique_ptr<lan::InputChannel> channel;
+            std::string channelPeer,channelSecret;int channelEdge=-1;
+            while(!stopping)
+            {
+                auto now=GetTickCount64();
+                std::string selectedPeer,selectedSecret;int selectedEdge=-1;uint32_t selectedAddress=0;uint64_t configuration=0;
+                {
+                    std::lock_guard lock(mutex);
+                    configuration=inputConfiguration.load();
+                    if(shareInput&&trusted.contains(inputPeer))
+                    {
+                        selectedPeer=inputPeer;selectedSecret=trusted.at(inputPeer).at("key");selectedEdge=inputEdge;
+                        if(peers.contains(inputPeer))selectedAddress=peers.at(inputPeer).address.sin_addr.s_addr;
+                    }
+                    if(now>=nextHello)
+                    {
+                        epoch=lan::randomHex(16); // Fresh challenge prevents replayed presence from staying online.
+                        auto hello=lan::envelope("hello",id); hello["name"]=name; hello["epoch"]=epoch;
+                        for(auto ip:broadcasts()) { auto address=bound; address.sin_addr.s_addr=ip; send(socket,address,hello); }
+                        nextHello=now+3000;
+                    }
+                    for(auto it=peers.begin();it!=peers.end();) {
+                        if(now-it->second.seen>lan::PeerLifetime) it=peers.erase(it); else ++it;
+                    }
+                    if(pending && pending->expired(now)) {
+                        status=pending->confirmed ? "Pair saved. Select a computer to manage it." : "Pairing expired. Enter the same code and click Pair on both computers.";
+                        pending.reset();
+                    }
+                    if(pending && now>=nextOffer && peers.contains(pending->peer)) {
+                        send(socket,peers.at(pending->peer).address,pending->offer()); nextOffer=now+1000;
+                    }
+                }
+                if(channelPeer!=selectedPeer||channelEdge!=selectedEdge||channelSecret!=selectedSecret)
+                {
+                    inputConnected=false;++inputEpoch;channel.reset();
+                    {std::lock_guard lock(inputMutex);inputOut.clear();inputIn.clear();}
+                    channelPeer=selectedPeer;channelEdge=selectedEdge;channelSecret=selectedSecret;lastChannelGeneration=0;
+                    if(!selectedPeer.empty())channel=std::make_unique<lan::InputChannel>(id,selectedPeer,selectedSecret,selectedEdge);
+                }
+                if(channel)
+                {
+                    std::vector<lan::InputFrame> out,in;
+                    {std::lock_guard lock(inputMutex);out.swap(inputOut);}
+                    if(abortInput.exchange(false)){channel->disconnect();out.clear();}
+                    channel->poll(selectedAddress,out,in,now);
+                    if(configuration!=inputConfiguration.load()){in.clear();channel->disconnect();}
+                    if(lastChannelGeneration!=channel->generation())
+                    {
+                        lastChannelGeneration=channel->generation();inputConnected=false;++inputEpoch;
+                        std::lock_guard lock(inputMutex);inputOut.clear();inputIn.clear();
+                    }
+                    inputConnected=channel->ready()&&!abortInput.load()&&configuration==inputConfiguration.load();
+                    {std::lock_guard lock(inputMutex);if(inputIn.size()+in.size()>512)abortInput=true;else inputIn.insert(inputIn.end(),in.begin(),in.end());}
+                    {std::lock_guard lock(mutex);inputStatus=channel->status();}
+                }
+                fd_set read; FD_ZERO(&read); FD_SET(socket,&read); timeval delay{0,channel?5000:100000};
+                int ready=select(0,&read,nullptr,nullptr,&delay);
+                if(ready==SOCKET_ERROR) throw std::runtime_error("LAN discovery socket failed.");
+                if(ready>0) for(int count=0;count<64;++count)
+                {
+                    char buffer[2049]; sockaddr_in sender{}; int size=sizeof(sender);
+                    int received=recvfrom(socket,buffer,sizeof(buffer),0,(sockaddr*)&sender,&size);
+                    if(received<=0) break;
+                    if(received>2048||sender.sin_port!=htons(lan::Port)||!localAddress(sender.sin_addr.s_addr)) continue;
+                    try { auto j=Json::parse(buffer,buffer+received); std::lock_guard lock(mutex); receive(socket,sender,j,GetTickCount64()); }
+                    catch(const Json::exception &) {} // Malformed network data cannot interrupt discovery.
+                }
+            }
+        }
+        catch(const std::exception &e) { std::lock_guard lock(mutex); status=std::string("LAN stopped: ")+e.what(); }
+        inputConnected=false;++inputEpoch;
+        {std::lock_guard lock(mutex);if(shareInput)inputStatus="Input connection closed.";}
+        if(socket!=INVALID_SOCKET) closesocket(socket);
+        if(winsock) WSACleanup();
+    }
+    Bytes command(const Bytes &input)
+    {
+        auto j=Json::parse(input); auto action=j.value("action","status");
+        if(action=="enable")
+        {
+            stop();
+            bool previous=enabled; enabled=j.at("enabled").get<bool>();
+            try {save();} catch(...) {enabled=previous;if(enabled) start();throw;}
+            configureRouter();
+            if(enabled) start(); else status="Disabled. No discovery sockets or worker thread.";
+        }
+        std::lock_guard lock(mutex);
+        if(action=="input")
+        {
+            bool active=j.at("enabled");auto peer=j.value("peer",inputPeer);int edge=j.value("edge",inputEdge);
+            if(edge<0||edge>3||(active&&(!enabled||!trusted.contains(peer))))throw std::runtime_error("Enable discovery and select a paired KSwitcher first.");
+            auto beforePeer=inputPeer;int beforeEdge=inputEdge;bool beforeActive=shareInput;
+            shareInput=active;inputPeer=peer;inputEdge=edge;
+            try{save();}catch(...){shareInput=beforeActive;inputPeer=beforePeer;inputEdge=beforeEdge;throw;}
+            configureRouter();inputStatus=active?"Connecting input channel...":"Input sharing disabled.";
+        }
+        if(action=="code") return encoded({{"code",lan::randomHex(16)}});
+        if(action=="cancel") { pending.reset(); status="Pairing cancelled."; }
+        if(action=="pair")
+        {
+            auto peer=j.at("peer").get<std::string>();
+            if(!enabled||!peers.contains(peer)) throw std::runtime_error("Select an available KSwitcher computer first.");
+            if(!trusted.contains(peer)&&trusted.size()>=64) throw std::runtime_error("Remove an old pair before adding another computer.");
+            pending=std::make_unique<lan::Pairing>(id,peer,j.at("code").get<std::string>(),GetTickCount64());
+            status="Waiting for the same code and Pair on the other KSwitcher (2 minutes)...";
+        }
+        if(action=="forget")
+        {
+            auto peer=j.at("peer").get<std::string>();auto oldTrusted=trusted;bool oldSharing=shareInput;
+            trusted.erase(peer);if(peer==inputPeer)shareInput=false;
+            try{save();}catch(...){trusted=std::move(oldTrusted);shareInput=oldSharing;throw;}
+            if(pending&&pending->peer==peer)pending.reset();
+            if(peer==inputPeer)configureRouter();
+            status="Pair removed on this computer.";
+        }
+        Json result={{"enabled",enabled},{"id",id},{"name",name},{"status",status},{"pending",pending&&!pending->confirmed},{"peers",Json::array()},
+            {"shareInput",shareInput},{"inputPeer",inputPeer},{"inputEdge",inputEdge},{"inputConnected",inputConnected.load()},
+            {"inputStatus",enabled&&shareInput?inputStatus:"Input sharing disabled."},{"controlMode",router?int(router->mode()):0}};
+        auto now=GetTickCount64();
+        for(const auto &[peer,p]:peers)
+        {
+            char ip[INET_ADDRSTRLEN]{}; InetNtopA(AF_INET,(void*)&p.address.sin_addr,ip,sizeof(ip));
+            result["peers"].push_back({{"id",peer},{"name",p.name},{"address",ip},{"paired",trusted.contains(peer)},
+                {"verified",p.verified && now-p.verified<lan::PeerLifetime},{"online",true}});
+        }
+        for(const auto &[peer,p]:trusted.items()) if(!peers.contains(peer))
+            result["peers"].push_back({{"id",peer},{"name",p.at("name")},{"address",""},{"paired",true},{"verified",false},{"online",false}});
+        return encoded(result);
+    }
+};
+LanService::LanService(const std::filesystem::path &path) : impl(std::make_unique<Impl>(path)) {}
+LanService::~LanService()=default;
+Bytes LanService::command(const Bytes &command) { return impl->command(command); }
+bool LanService::inputEnabled()const{return impl->enabled&&impl->shareInput;}
+bool LanService::tickInput(bool allowEnter){return impl->tickInput(allowEnter);}
+bool LanService::keyboard(const KBDLLHOOKSTRUCT &k,bool down){return impl->router&&impl->router->keyboard(k,down,GetTickCount64());}
+bool LanService::mouse(UINT message,const MSLLHOOKSTRUCT &m,bool allowEnter){return impl->router&&impl->router->mouse(message,m,GetTickCount64(),allowEnter);}
+bool LanService::takeInputChange(){return impl->takeChange();}
+void LanService::cancelInput(){if(impl->router)impl->router->cancel(GetTickCount64());impl->abortInput=true;}
+}

src/lan.h

@@ -0,0 +1,23 @@
+#pragma once
+#include "platform.h"
+#include <memory>
+
+namespace ks
+{
+// Discovery, pairing and optional encrypted input within the resident process.
+class LanService
+{
+    struct Impl;
+    std::unique_ptr<Impl> impl;
+  public:
+    explicit LanService(const std::filesystem::path &);
+    ~LanService();
+    Bytes command(const Bytes &);
+    bool inputEnabled() const;
+    bool tickInput(bool allowEnter = true);
+    bool keyboard(const KBDLLHOOKSTRUCT &, bool down);
+    bool mouse(UINT, const MSLLHOOKSTRUCT &, bool allowEnter);
+    bool takeInputChange();
+    void cancelInput();
+};
+}

src/lan_channel.cpp

@@ -0,0 +1,185 @@
+#include <winsock2.h>
+#include <ws2tcpip.h>
+#include "lan_channel.h"
+#include <bcrypt.h>
+#include <limits>
+
+namespace ks::lan
+{
+namespace
+{
+void checked(NTSTATUS s){if(s<0) throw std::runtime_error("Input channel authentication failed.");}
+void put32(Bytes &b,uint32_t v){for(int n=24;n>=0;n-=8)b.push_back(static_cast<unsigned char>(v>>n));}
+uint32_t get32(const unsigned char *p){return (uint32_t(p[0])<<24)|(uint32_t(p[1])<<16)|(uint32_t(p[2])<<8)|p[3];}
+Bytes keyBytes(const std::string &key)
+{
+    if(key.size()!=64||key.find_first_not_of("0123456789abcdef")!=key.npos) throw std::runtime_error("Invalid input key.");
+    Bytes bytes;for(size_t i=0;i<key.size();i+=2)bytes.push_back(static_cast<unsigned char>(std::stoul(key.substr(i,2),nullptr,16)));return bytes;
+}
+bool nonblocking(SOCKET s){u_long value=1;BOOL yes=TRUE;return !ioctlsocket(s,FIONBIO,&value)&&!setsockopt(s,IPPROTO_TCP,TCP_NODELAY,(char*)&yes,sizeof(yes));}
+void closeSocket(SOCKET &s){if(s!=INVALID_SOCKET){closesocket(s);s=INVALID_SOCKET;}}
+}
+struct InputCipher::Impl
+{
+    BCRYPT_ALG_HANDLE alg{};BCRYPT_KEY_HANDLE key{};uint64_t sequence{};
+    explicit Impl(const std::string &secret)
+    {
+        auto bytes=keyBytes(secret);
+        try {
+            checked(BCryptOpenAlgorithmProvider(&alg,BCRYPT_AES_ALGORITHM,nullptr,0));
+            checked(BCryptSetProperty(alg,BCRYPT_CHAINING_MODE,(PUCHAR)BCRYPT_CHAIN_MODE_GCM,sizeof(BCRYPT_CHAIN_MODE_GCM),0));
+            checked(BCryptGenerateSymmetricKey(alg,&key,nullptr,0,bytes.data(),ULONG(bytes.size()),0));
+        } catch(...) {if(key)BCryptDestroyKey(key);if(alg)BCryptCloseAlgorithmProvider(alg,0);throw;}
+        SecureZeroMemory(bytes.data(),bytes.size());
+    }
+    ~Impl(){if(key)BCryptDestroyKey(key);if(alg)BCryptCloseAlgorithmProvider(alg,0);}
+    Bytes crypt(Bytes payload,Bytes &tag,bool encrypt)
+    {
+        if(sequence==std::numeric_limits<uint64_t>::max())throw std::runtime_error("Input session exhausted.");
+        unsigned char nonce[12]{};for(int i=0;i<8;++i)nonce[11-i]=static_cast<unsigned char>(sequence>>(i*8));
+        BCRYPT_AUTHENTICATED_CIPHER_MODE_INFO info;BCRYPT_INIT_AUTH_MODE_INFO(info);
+        info.pbNonce=nonce;info.cbNonce=sizeof(nonce);info.pbTag=tag.data();info.cbTag=ULONG(tag.size());
+        // Protocol/direction are bound by key derivation; sequence and payload length by GCM.
+        Bytes result(payload.size());ULONG written{};
+        auto fn=encrypt?BCryptEncrypt:BCryptDecrypt;
+        checked(fn(key,payload.data(),ULONG(payload.size()),&info,nullptr,0,result.data(),ULONG(result.size()),&written,0));
+        if(written!=payload.size())throw std::runtime_error("Invalid input frame size.");
+        ++sequence;return result;
+    }
+};
+InputCipher::InputCipher(const std::string &key):impl(std::make_unique<Impl>(key)){}
+InputCipher::~InputCipher()=default;
+Bytes InputCipher::encrypt(const InputFrame &f)
+{
+    Bytes plain;put32(plain,uint32_t(f.type));put32(plain,f.token);put32(plain,uint32_t(f.a));put32(plain,uint32_t(f.b));put32(plain,uint32_t(f.c));
+    Bytes tag(16);auto result=impl->crypt(std::move(plain),tag,true);result.insert(result.end(),tag.begin(),tag.end());return result;
+}
+InputFrame InputCipher::decrypt(const Bytes &packet)
+{
+    if(packet.size()!=36)throw std::runtime_error("Invalid encrypted input frame.");
+    Bytes tag(packet.begin()+20,packet.end());auto plain=impl->crypt(Bytes(packet.begin(),packet.begin()+20),tag,false);
+    auto type=get32(plain.data());if(type>uint32_t(InputType::Wheel))throw std::runtime_error("Unsupported input frame.");
+    return {InputType(type),get32(plain.data()+4),int32_t(get32(plain.data()+8)),int32_t(get32(plain.data()+12)),int32_t(get32(plain.data()+16))};
+}
+std::string inputSessionKey(const std::string &secret,const std::string &from,const std::string &to,const std::string &a,const std::string &b,int edge)
+{
+    if(!identifier(from)||!identifier(to)||from==to||!identifier(a)||!identifier(b))throw std::runtime_error("Invalid session identity.");
+    return mac(secret,"KSwitcher input v1|"+from+"|"+to+"|"+a+"|"+b+"|"+std::to_string(edge));
+}
+struct InputChannel::Impl
+{
+    std::string local,peer,secret,nonce,state="Waiting for the paired computer...";
+    int edge;uint16_t port;SOCKET listener=INVALID_SOCKET,socket=INVALID_SOCKET;
+    bool connecting{},authenticated{},helloRead{};
+    uint64_t changed{},lastRead{},lastPing{},retry{};
+    Bytes incoming,outgoing;
+    std::unique_ptr<InputCipher> tx,rx;
+    Impl(std::string a,std::string b,std::string key,int side,uint16_t p):local(std::move(a)),peer(std::move(b)),secret(std::move(key)),edge(side),port(p){}
+    ~Impl(){closeSocket(socket);closeSocket(listener);}
+    void reset(uint64_t now,const std::string &reason)
+    {
+        closeSocket(socket);connecting=authenticated=helloRead=false;incoming.clear();outgoing.clear();tx.reset();rx.reset();++changed;retry=now+1500;state=reason;
+    }
+    void begin(uint64_t now)
+    {
+        nonce=randomHex(16);lastRead=lastPing=now;
+        auto hello=Json{{"app","KSwitcher-input"},{"version",1},{"id",local},{"to",peer},{"nonce",nonce},{"edge",edge}}.dump();
+        put32(outgoing,uint32_t(hello.size()));outgoing.insert(outgoing.end(),hello.begin(),hello.end());
+        state="Authenticating paired KSwitcher...";
+    }
+    void poll(uint32_t address,const std::vector<InputFrame> &frames,std::vector<InputFrame> &received,uint64_t now)
+    {
+        try
+        {
+            if(socket==INVALID_SOCKET&&now<retry)return;
+            if(listener==INVALID_SOCKET && local>peer)
+            {
+                listener=::socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);BOOL yes=TRUE;
+                if(listener==INVALID_SOCKET||setsockopt(listener,SOL_SOCKET,SO_EXCLUSIVEADDRUSE,(char*)&yes,sizeof(yes))||!nonblocking(listener)){closeSocket(listener);throw std::runtime_error("Cannot open input listener.");}
+                sockaddr_in a{};a.sin_family=AF_INET;a.sin_port=htons(port);
+                if(bind(listener,(sockaddr*)&a,sizeof(a))||listen(listener,1)) {closeSocket(listener);throw std::runtime_error("TCP input port is unavailable.");}
+            }
+            if(socket==INVALID_SOCKET && address && now>=retry)
+            {
+                if(local<peer)
+                {
+                    socket=::socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);if(socket==INVALID_SOCKET||!nonblocking(socket))throw std::runtime_error("Cannot open input connection.");
+                    sockaddr_in a{};a.sin_family=AF_INET;a.sin_port=htons(port);a.sin_addr.s_addr=address;
+                    int result=connect(socket,(sockaddr*)&a,sizeof(a));
+                    if(result && WSAGetLastError()!=WSAEWOULDBLOCK)throw std::runtime_error("Paired computer is not accepting input connections.");
+                    connecting=result!=0;begin(now);
+                }
+                else
+                {
+                    sockaddr_in a{};int length=sizeof(a);socket=accept(listener,(sockaddr*)&a,&length);
+                    if(socket!=INVALID_SOCKET)
+                    {
+                        if(a.sin_addr.s_addr!=address){closeSocket(socket);return;}
+                        if(!nonblocking(socket))throw std::runtime_error("Cannot configure input connection.");
+                        begin(now);
+                    }
+                }
+            }
+            if(socket==INVALID_SOCKET)return;
+            if(now-lastRead>2000)throw std::runtime_error("Input connection timed out; control returned locally.");
+            if(connecting)
+            {
+                fd_set writes,errors;FD_ZERO(&writes);FD_ZERO(&errors);FD_SET(socket,&writes);FD_SET(socket,&errors);timeval wait{};
+                if(select(0,nullptr,&writes,&errors,&wait)<=0)return;
+                int error=0;int size=sizeof(error);if(getsockopt(socket,SOL_SOCKET,SO_ERROR,(char*)&error,&size)||error)throw std::runtime_error("Cannot connect to paired KSwitcher.");
+                connecting=false;
+            }
+            if(authenticated)
+            {
+                for(auto &f:frames){auto bytes=tx->encrypt(f);outgoing.insert(outgoing.end(),bytes.begin(),bytes.end());}
+                if(now-lastPing>=400){auto bytes=tx->encrypt({InputType::Ping});outgoing.insert(outgoing.end(),bytes.begin(),bytes.end());lastPing=now;}
+            }
+            if(outgoing.size()>32768)throw std::runtime_error("Input queue overflow; control returned locally.");
+            if(!outgoing.empty())
+            {
+                int count=::send(socket,(char*)outgoing.data(),int(outgoing.size()),0);
+                if(count>0)outgoing.erase(outgoing.begin(),outgoing.begin()+count);
+                else if(count==0||WSAGetLastError()!=WSAEWOULDBLOCK)throw std::runtime_error("Input send failed.");
+            }
+            unsigned char data[4096];
+            for(int batch=0;batch<8;++batch)
+            {
+                int count=recv(socket,(char*)data,sizeof(data),0);
+                if(count==0)throw std::runtime_error("Other KSwitcher disconnected.");
+                if(count<0){if(WSAGetLastError()!=WSAEWOULDBLOCK)throw std::runtime_error("Input receive failed.");break;}
+                incoming.insert(incoming.end(),data,data+count);
+            }
+            if(incoming.size()>32768)throw std::runtime_error("Input receive queue overflow.");
+            if(!helloRead && incoming.size()>=4)
+            {
+                size_t length=get32(incoming.data());if(length>512||length<32)throw std::runtime_error("Invalid input handshake.");
+                if(incoming.size()<length+4)return;
+                auto hello=Json::parse(incoming.begin()+4,incoming.begin()+4+length);
+                if(hello.value("app","")!="KSwitcher-input"||hello.value("version",0)!=1||hello.value("id","")!=peer||hello.value("to","")!=local)
+                    throw std::runtime_error("Unexpected input peer.");
+                if(hello.value("edge",-1)!=(edge^1))throw std::runtime_error("Screen positions must be opposite on the two computers.");
+                auto remoteNonce=hello.value("nonce","");
+                tx=std::make_unique<InputCipher>(inputSessionKey(secret,local,peer,nonce,remoteNonce,edge));
+                rx=std::make_unique<InputCipher>(inputSessionKey(secret,peer,local,remoteNonce,nonce,edge^1));
+                incoming.erase(incoming.begin(),incoming.begin()+4+length);helloRead=true;
+                auto bytes=tx->encrypt({InputType::Ready});outgoing.insert(outgoing.end(),bytes.begin(),bytes.end());
+            }
+            while(helloRead && incoming.size()>=36)
+            {
+                auto f=rx->decrypt(Bytes(incoming.begin(),incoming.begin()+36));incoming.erase(incoming.begin(),incoming.begin()+36);lastRead=now;
+                if(!authenticated){if(f.type!=InputType::Ready)throw std::runtime_error("Input received before authentication.");authenticated=true;state="Input connected. Move through the configured screen edge.";}
+                else if(f.type==InputType::Ready)throw std::runtime_error("Repeated input handshake.");
+                else if(f.type!=InputType::Ping)received.push_back(f);
+            }
+        }
+        catch(const std::exception &e){received.clear();reset(now,e.what());}
+    }
+};
+InputChannel::InputChannel(std::string a,std::string b,std::string key,int edge,uint16_t port):impl(std::make_unique<Impl>(std::move(a),std::move(b),std::move(key),edge,port)){}
+InputChannel::~InputChannel()=default;
+void InputChannel::poll(uint32_t ip,const std::vector<InputFrame>&out,std::vector<InputFrame>&in,uint64_t now){impl->poll(ip,out,in,now);}
+bool InputChannel::ready()const{return impl->authenticated;}
+uint64_t InputChannel::generation()const{return impl->changed;}
+std::string InputChannel::status()const{return impl->state;}
+void InputChannel::disconnect(){impl->reset(GetTickCount64(),"Input disconnected; local control restored.");}
+}

src/lan_channel.h

@@ -0,0 +1,40 @@
+#pragma once
+#include "lan_pairing.h"
+#include <memory>
+namespace ks::lan
+{
+enum class InputType : uint32_t { Ready, Ping, Enter, Accept, Return, Move, Key, Button, Wheel };
+struct InputFrame
+{
+    InputType type{};
+    uint32_t token{};
+    int32_t a{},b{},c{};
+    bool operator==(const InputFrame &) const = default;
+};
+// One directional AES-256-GCM key per session. Strict sequence numbers prevent replay.
+class InputCipher
+{
+    struct Impl; std::unique_ptr<Impl> impl;
+  public:
+    explicit InputCipher(const std::string &hexKey);
+    ~InputCipher();
+    Bytes encrypt(const InputFrame &);
+    InputFrame decrypt(const Bytes &);
+};
+std::string inputSessionKey(const std::string &secret,const std::string &from,const std::string &to,
+                            const std::string &fromNonce,const std::string &toNonce,int fromEdge=-1);
+// Network-thread-only nonblocking TCP channel. No Windows input is injected here.
+class InputChannel
+{
+    struct Impl; std::unique_ptr<Impl> impl;
+  public:
+    InputChannel(std::string local,std::string peer,std::string secret,int edge,
+                 uint16_t port=45884);
+    ~InputChannel();
+    void poll(uint32_t peerAddress,const std::vector<InputFrame> &out,std::vector<InputFrame> &in,uint64_t now);
+    bool ready() const;
+    uint64_t generation() const;
+    std::string status() const;
+    void disconnect();
+};
+}

src/lan_input.cpp

@@ -0,0 +1,242 @@
+#include "lan_input.h"
+#include <algorithm>
+
+namespace ks::lan
+{
+ULONG_PTR remoteInputMarker(){return inputMarker() ^ ULONG_PTR(0x4c414e49);}
+ULONG_PTR cursorWarpMarker(){return inputMarker() ^ ULONG_PTR(0x4c414e57);}
+namespace
+{
+LRESULT CALLBACK controlOverlay(HWND w,UINT message,WPARAM wp,LPARAM lp)
+{
+    if(message==WM_SETCURSOR){SetCursor(nullptr);return TRUE;}
+    if(message==WM_MOUSEACTIVATE)return MA_NOACTIVATE;
+    if(message==WM_PAINT)
+    {
+        PAINTSTRUCT paint{};HDC dc=BeginPaint(w,&paint);RECT r{};GetClientRect(w,&r);
+        FillRect(dc,&r,(HBRUSH)(COLOR_INFOBK+1));SetBkMode(dc,TRANSPARENT);SetTextColor(dc,GetSysColor(COLOR_INFOTEXT));
+        auto previous=SelectObject(dc,GetStockObject(DEFAULT_GUI_FONT));
+        DrawTextW(dc,L"KSwitcher: mouse + keyboard on the other PC\nCtrl+Alt+Esc returns control here",-1,&r,DT_CENTER|DT_WORDBREAK);
+        SelectObject(dc,previous);EndPaint(w,&paint);return 0;
+    }
+    return DefWindowProcW(w,message,wp,lp);
+}
+struct ControlOverlay
+{
+    HWND cover{},notice{};
+    ~ControlOverlay(){hide();}
+    void hide(){if(notice)DestroyWindow(notice);if(cover)DestroyWindow(cover);notice=cover=nullptr;}
+    void show()
+    {
+        if(cover)return;
+        WNDCLASSW cls{};cls.hInstance=GetModuleHandleW(nullptr);cls.lpfnWndProc=controlOverlay;cls.lpszClassName=L"KSwitcher.RemoteControlOverlay";
+        RegisterClassW(&cls);
+        auto style=WS_EX_TOPMOST|WS_EX_TOOLWINDOW|WS_EX_NOACTIVATE;
+        POINT cursor{};GetCursorPos(&cursor);MONITORINFO monitor{sizeof(monitor)};GetMonitorInfoW(MonitorFromPoint(cursor,MONITOR_DEFAULTTONEAREST),&monitor);
+        // Only cover the parked cursor, not a full-screen layered bitmap.
+        int x=(monitor.rcMonitor.left+monitor.rcMonitor.right)/2-16,y=(monitor.rcMonitor.top+monitor.rcMonitor.bottom)/2-16;
+        cover=CreateWindowExW(style|WS_EX_LAYERED,cls.lpszClassName,L"",WS_POPUP,x,y,32,32,nullptr,nullptr,cls.hInstance,nullptr);
+        if(cover){SetLayeredWindowAttributes(cover,0,1,LWA_ALPHA);ShowWindow(cover,SW_SHOWNOACTIVATE);}
+        notice=CreateWindowExW(style,cls.lpszClassName,L"KSwitcher remote control",WS_POPUP,monitor.rcMonitor.left+20,monitor.rcMonitor.top+20,400,48,nullptr,nullptr,cls.hInstance,nullptr);
+        if(notice)ShowWindow(notice,SW_SHOWNOACTIVATE);
+        SetCursor(nullptr);
+    }
+};
+bool ordinaryDesktop()
+{
+    HDESK d=OpenInputDesktop(0,FALSE,DESKTOP_READOBJECTS);if(!d)return false;
+    wchar_t name[256]{};DWORD count{};bool ok=GetUserObjectInformationW(d,UOI_NAME,name,sizeof(name),&count)!=0;
+    CloseDesktop(d);return ok&&_wcsicmp(name,L"Default")==0;
+}
+INPUT button(unsigned index,bool down)
+{
+    INPUT input{};input.type=INPUT_MOUSE;
+    static constexpr DWORD flags[5][2]={{MOUSEEVENTF_LEFTUP,MOUSEEVENTF_LEFTDOWN},{MOUSEEVENTF_RIGHTUP,MOUSEEVENTF_RIGHTDOWN},
+        {MOUSEEVENTF_MIDDLEUP,MOUSEEVENTF_MIDDLEDOWN},{MOUSEEVENTF_XUP,MOUSEEVENTF_XDOWN},{MOUSEEVENTF_XUP,MOUSEEVENTF_XDOWN}};
+    input.mi.dwFlags=flags[index][down];if(index>=3)input.mi.mouseData=index==3?XBUTTON1:XBUTTON2;return input;
+}
+}
+InputEnvironment windowsInputEnvironment()
+{
+    auto overlay=std::make_shared<ControlOverlay>();
+    return {
+        []{LONG x=GetSystemMetrics(SM_XVIRTUALSCREEN),y=GetSystemMetrics(SM_YVIRTUALSCREEN);return RECT{x,y,x+GetSystemMetrics(SM_CXVIRTUALSCREEN),y+GetSystemMetrics(SM_CYVIRTUALSCREEN)};},
+        []{POINT p{};GetCursorPos(&p);return p;},
+        [](const INPUT &i){INPUT input=i;return SendInput(1,&input,sizeof(input))==1;},
+        ordinaryDesktop,
+        []{for(int key=1;key<256;++key)if(GetAsyncKeyState(key)&0x8000)return true;return false;},
+        []{POINT p{};GetCursorPos(&p);MONITORINFO info{sizeof(info)};
+            if(GetMonitorInfoW(MonitorFromPoint(p,MONITOR_DEFAULTTONEAREST),&info))p={(info.rcMonitor.left+info.rcMonitor.right)/2,(info.rcMonitor.top+info.rcMonitor.bottom)/2};
+            return p;},
+        [overlay](ControlMode mode){if(mode==ControlMode::Sending)overlay->show();else overlay->hide();}
+    };
+}
+bool atEdge(POINT p,RECT r,int side)
+{return side==0?p.x<=r.left:side==1?p.x>=r.right-1:side==2?p.y<=r.top:p.y>=r.bottom-1;}
+int edgePosition(POINT p,RECT r,int side)
+{
+    auto length=side<2?r.bottom-r.top:r.right-r.left;
+    auto offset=side<2?p.y-r.top:p.x-r.left;
+    return int(std::clamp<int64_t>(int64_t(offset)*65535/std::max<LONG>(1,length-1),0,65535));
+}
+POINT edgePoint(RECT r,int side,int position,int inset)
+{
+    position=std::clamp(position,0,65535);
+    LONG x=r.left+LONG(int64_t(position)*std::max<LONG>(0,r.right-r.left-1)/65535);
+    LONG y=r.top+LONG(int64_t(position)*std::max<LONG>(0,r.bottom-r.top-1)/65535);
+    POINT p=side==0?POINT{r.left+inset,y}:side==1?POINT{r.right-1-inset,y}:side==2?POINT{x,r.top+inset}:POINT{x,r.bottom-1-inset};
+    p.x=std::clamp(p.x,r.left,r.right-1);p.y=std::clamp(p.y,r.top,r.bottom-1);return p;
+}
+InputRouter::InputRouter(InputEnvironment e,std::function<bool(InputFrame)> s,int side,bool prefer)
+    :env(std::move(e)),send(std::move(s)),edge(side),preferLocal(prefer),nextToken(prefer?1:2)
+{if(side<0||side>3)throw std::runtime_error("Invalid screen position.");}
+InputRouter::~InputRouter(){cancel(GetTickCount64());release();}
+void InputRouter::mode(ControlMode value){if(mode_!=value){mode_=value;++revision_;if(env.modeChanged)env.modeChanged(value);}}
+bool InputRouter::emit(INPUT i)
+{
+    if(i.type==INPUT_KEYBOARD)i.ki.dwExtraInfo=remoteInputMarker();
+    else i.mi.dwExtraInfo=remoteInputMarker();
+    return env.desktop()&&env.inject(i);
+}
+bool InputRouter::move(POINT p,bool warp)
+{
+    auto r=env.bounds();if(r.right<=r.left||r.bottom<=r.top)return false;
+    INPUT input{};input.type=INPUT_MOUSE;input.mi.dwFlags=MOUSEEVENTF_MOVE|MOUSEEVENTF_ABSOLUTE|MOUSEEVENTF_VIRTUALDESK;
+    // Target pixel centres, avoiding a one-pixel bias on every relative mouse event.
+    input.mi.dx=LONG((2*int64_t(std::clamp(p.x,r.left,r.right-1)-r.left)+1)*32768/(r.right-r.left));
+    input.mi.dy=LONG((2*int64_t(std::clamp(p.y,r.top,r.bottom-1)-r.top)+1)*32768/(r.bottom-r.top));
+    input.mi.dwExtraInfo=warp?cursorWarpMarker():remoteInputMarker();return env.desktop()&&env.inject(input);
+}
+bool InputRouter::post(InputFrame f){return connected&&send(f);}
+bool InputRouter::held()const
+{
+    return std::any_of(physical.begin(),physical.end(),[](bool b){return b;})||env.held();
+}
+void InputRouter::release()
+{
+    for(size_t i=0;i<remoteKeys.size();++i)if(remoteKeys[i]&&emit(releases[i]))remoteKeys[i]=false;
+    for(unsigned i=0;i<5;++i)if(remoteButtons[i]&&emit(button(i,false)))remoteButtons[i]=false;
+}
+void InputRouter::local(uint64_t now,int position)
+{
+    bool sending=mode_==ControlMode::Sending;
+    if(position<0)position=edgePosition(returnPoint,env.bounds(),edge);
+    release();mode(ControlMode::Local);cooldown=now+600;token=0;
+    if(sending)move(edgePoint(env.bounds(),edge,position),true);
+}
+void InputRouter::cancel(uint64_t now)
+{
+    if(mode_!=ControlMode::Local)post({InputType::Return,token,edgePosition(env.cursor(),env.bounds(),edge)});
+    local(now);
+}
+void InputRouter::tick(bool ready,uint64_t now)
+{
+    connected=ready;
+    if(!ready||!env.desktop()||(mode_==ControlMode::Requesting&&now-requested>1000))cancel(now);
+    if(mode_==ControlMode::Local)release(); // Retry releases blocked by a temporarily secure desktop.
+}
+void InputRouter::receive(const InputFrame &f,uint64_t now)
+{
+    if(!connected||!env.desktop()){cancel(now);return;}
+    if(f.type==InputType::Enter)
+    {
+        if(!f.token||f.a!=(edge^1)||f.b<0||f.b>65535||held()||
+           mode_==ControlMode::Sending||mode_==ControlMode::Receiving||(mode_==ControlMode::Requesting&&preferLocal))
+        {post({InputType::Return,f.token,32768});return;}
+        if(mode_==ControlMode::Requesting)cancel(now);
+        token=f.token;mode(ControlMode::Receiving);
+        if(!move(edgePoint(env.bounds(),edge,f.b))||!post({InputType::Accept,token}))cancel(now);
+        return;
+    }
+    if(f.type==InputType::Accept)
+    {
+        if(mode_!=ControlMode::Requesting||f.token!=token||held()||!atEdge(env.cursor(),env.bounds(),edge)){post({InputType::Return,f.token,32768});if(f.token==token)cancel(now);return;}
+        auto r=env.bounds();anchor=env.anchor?env.anchor():POINT{(r.left+r.right)/2,(r.top+r.bottom)/2};mode(ControlMode::Sending);
+        if(!move(anchor,true))cancel(now);
+        return;
+    }
+    if(f.token!=token||!token)return;
+    if(f.type==InputType::Return){local(now,std::clamp(f.a,0,65535));return;}
+    if(mode_!=ControlMode::Receiving)return;
+    bool ok=true;
+    if(f.type==InputType::Move)
+    {
+        if(std::abs(int64_t(f.a))>32768||std::abs(int64_t(f.b))>32768){cancel(now);return;}
+        auto p=env.cursor();auto r=env.bounds();p.x=LONG(std::clamp<int64_t>(int64_t(p.x)+f.a,r.left,r.right-1));p.y=LONG(std::clamp<int64_t>(int64_t(p.y)+f.b,r.top,r.bottom-1));
+        if(atEdge(p,r,edge)&&!std::any_of(remoteKeys.begin(),remoteKeys.end(),[](bool b){return b;})&&
+           !std::any_of(remoteButtons.begin(),remoteButtons.end(),[](bool b){return b;}))
+        {post({InputType::Return,token,edgePosition(p,r,edge)});local(now);return;}
+        ok=move(p);
+    }
+    else if(f.type==InputType::Key)
+    {
+        if(f.a<1||f.a>255||f.b<0||f.b>255||f.c<0||f.c>3){cancel(now);return;}
+        INPUT input{};input.type=INPUT_KEYBOARD;input.ki.wVk=WORD(f.a);input.ki.wScan=WORD(f.b);
+        input.ki.dwFlags=(f.c&1?0:KEYEVENTF_KEYUP)|(f.c&2?KEYEVENTF_EXTENDEDKEY:0);
+        if(f.b&&f.a!=VK_PAUSE)input.ki.dwFlags|=KEYEVENTF_SCANCODE;
+        ok=emit(input);if(ok){remoteKeys[size_t(f.a)]=(f.c&1)!=0;input.ki.dwFlags|=KEYEVENTF_KEYUP;releases[size_t(f.a)]=input;}
+    }
+    else if(f.type==InputType::Button)
+    {
+        if(f.a<0||f.a>4||f.b<0||f.b>1){cancel(now);return;}
+        ok=emit(button(unsigned(f.a),f.b!=0));if(ok)remoteButtons[size_t(f.a)]=f.b!=0;
+    }
+    else if(f.type==InputType::Wheel)
+    {
+        if(f.a<-32768||f.a>32767||f.b<0||f.b>1){cancel(now);return;}
+        INPUT input{};input.type=INPUT_MOUSE;input.mi.dwFlags=f.b?MOUSEEVENTF_HWHEEL:MOUSEEVENTF_WHEEL;input.mi.mouseData=DWORD(f.a);ok=emit(input);
+    }
+    if(!ok)cancel(now);
+}
+bool InputRouter::keyboard(const KBDLLHOOKSTRUCT &k,bool down,uint64_t now)
+{
+    if(k.flags&LLKHF_INJECTED||k.vkCode>255||!k.vkCode)return false;
+    auto key=size_t(k.vkCode);physical[key]=down;
+    if(mode_!=ControlMode::Local&&down&&key==VK_ESCAPE&&(physical[VK_LCONTROL]||physical[VK_RCONTROL]||physical[VK_CONTROL])&&
+       (physical[VK_LMENU]||physical[VK_RMENU]||physical[VK_MENU]))
+    {outKeys[key]=true;cancel(now);return true;}
+    if(mode_==ControlMode::Receiving||mode_==ControlMode::Requesting)cancel(now);
+    if(mode_==ControlMode::Sending)
+    {
+        outKeys[key]=down;
+        if(!post({InputType::Key,token,int32_t(k.vkCode),int32_t(k.scanCode),int32_t((down?1:0)|((k.flags&LLKHF_EXTENDED)?2:0))}))cancel(now);
+        return true;
+    }
+    if(outKeys[key]){if(!down)outKeys[key]=false;return true;}
+    return false;
+}
+bool InputRouter::mouse(UINT message,const MSLLHOOKSTRUCT &m,uint64_t now,bool allowEnter)
+{
+    if(m.flags&LLMHF_INJECTED)return false;
+    int index=-1;bool down=false;
+    switch(message){case WM_LBUTTONDOWN:down=true;[[fallthrough]];case WM_LBUTTONUP:index=0;break;
+        case WM_RBUTTONDOWN:down=true;[[fallthrough]];case WM_RBUTTONUP:index=1;break;
+        case WM_MBUTTONDOWN:down=true;[[fallthrough]];case WM_MBUTTONUP:index=2;break;
+        case WM_XBUTTONDOWN:down=true;[[fallthrough]];case WM_XBUTTONUP:index=HIWORD(m.mouseData)==XBUTTON1?3:4;break;}
+    if(mode_==ControlMode::Receiving||(mode_==ControlMode::Requesting&&message!=WM_MOUSEMOVE))cancel(now);
+    if(mode_==ControlMode::Requesting&&message==WM_MOUSEMOVE&&!atEdge(m.pt,env.bounds(),edge))cancel(now);
+    if(mode_==ControlMode::Sending)
+    {
+        bool ok=true;
+        if(message==WM_MOUSEMOVE)
+        {
+            auto dx=m.pt.x-anchor.x,dy=m.pt.y-anchor.y;
+            if(dx||dy)ok=post({InputType::Move,token,dx,dy});
+            ok=move(anchor,true)&&ok;
+        }
+        else if(index>=0){outButtons[size_t(index)]=down;ok=post({InputType::Button,token,index,down?1:0});}
+        else if(message==WM_MOUSEWHEEL||message==WM_MOUSEHWHEEL)ok=post({InputType::Wheel,token,int16_t(HIWORD(m.mouseData)),message==WM_MOUSEHWHEEL?1:0});
+        if(!ok)cancel(now);
+        return true;
+    }
+    if(index>=0&&outButtons[size_t(index)]){if(!down)outButtons[size_t(index)]=false;return true;}
+    if(mode_==ControlMode::Local&&connected&&allowEnter&&message==WM_MOUSEMOVE&&now>=cooldown&&
+       env.desktop()&&!held()&&atEdge(m.pt,env.bounds(),edge))
+    {
+        token=nextToken;nextToken+=2;if(!nextToken)nextToken=preferLocal?1:2;
+        returnPoint=m.pt;requested=now;mode(ControlMode::Requesting);
+        if(!post({InputType::Enter,token,edge,edgePosition(m.pt,env.bounds(),edge)}))cancel(now);
+    }
+    return false;
+}
+}

src/lan_input.h

@@ -0,0 +1,53 @@
+#pragma once
+#include "lan_channel.h"
+#include <array>
+namespace ks::lan
+{
+enum class ControlMode { Local, Requesting, Sending, Receiving };
+struct InputEnvironment
+{
+    std::function<RECT()> bounds;
+    std::function<POINT()> cursor;
+    std::function<bool(const INPUT &)> inject;
+    std::function<bool()> desktop;
+    std::function<bool()> held;
+    std::function<POINT()> anchor;
+    std::function<void(ControlMode)> modeChanged;
+};
+InputEnvironment windowsInputEnvironment();
+ULONG_PTR remoteInputMarker();
+ULONG_PTR cursorWarpMarker();
+bool atEdge(POINT,RECT,int edge);
+int edgePosition(POINT,RECT,int edge);
+POINT edgePoint(RECT,int edge,int position,int inset=8);
+class InputRouter
+{
+    InputEnvironment env;
+    std::function<bool(InputFrame)> send;
+    ControlMode mode_=ControlMode::Local;
+    int edge{};bool preferLocal{},connected{};
+    uint32_t nextToken{},token{};
+    uint64_t cooldown{},requested{},revision_{};
+    POINT anchor{},returnPoint{};
+    std::array<bool,256> physical{},outKeys{},remoteKeys{};
+    std::array<INPUT,256> releases{};
+    std::array<bool,5> outButtons{},remoteButtons{};
+    void mode(ControlMode);
+    bool emit(INPUT);
+    bool move(POINT,bool warp=false);
+    bool post(InputFrame);
+    bool held() const;
+    void release();
+    void local(uint64_t now,int position=-1);
+  public:
+    InputRouter(InputEnvironment,std::function<bool(InputFrame)>,int edge,bool preferLocal);
+    ~InputRouter();
+    ControlMode mode()const{return mode_;}
+    uint64_t revision()const{return revision_;}
+    void tick(bool ready,uint64_t now);
+    void receive(const InputFrame &,uint64_t now);
+    bool keyboard(const KBDLLHOOKSTRUCT &,bool down,uint64_t now);
+    bool mouse(UINT,const MSLLHOOKSTRUCT &,uint64_t now,bool allowEnter=true);
+    void cancel(uint64_t now);
+};
+}

src/lan_pairing.cpp

@@ -0,0 +1,97 @@
+#include "lan_pairing.h"
+#include <bcrypt.h>
+#include <algorithm>
+
+namespace ks::lan
+{
+namespace
+{
+void checked(NTSTATUS s) { if (s < 0) throw std::runtime_error("Windows cryptography failed."); }
+std::string hex(const Bytes &data)
+{
+    std::string out; out.reserve(data.size()*2);
+    for (auto b : data) { out += "0123456789abcdef"[b>>4]; out += "0123456789abcdef"[b&15]; }
+    return out;
+}
+std::string proof(const char *kind, const std::string &from, const std::string &to,
+                  const std::string &a, const std::string &b = {})
+{ return std::string("KSwitcher LAN v1|") + kind + "|" + from + "|" + to + "|" + a + "|" + b; }
+}
+std::string randomHex(size_t size)
+{
+    if (size > 64) throw std::runtime_error("Invalid random size.");
+    Bytes bytes(size); checked(BCryptGenRandom(nullptr, bytes.data(), ULONG(size), BCRYPT_USE_SYSTEM_PREFERRED_RNG));
+    return hex(bytes);
+}
+bool identifier(const std::string &s)
+{ return s.size()==32 && s.find_first_not_of("0123456789abcdef")==s.npos; }
+std::string normalizeCode(const std::string &input)
+{
+    std::string result;
+    for (auto c : input)
+    {
+        if (c=='-' || c==' ') continue;
+        if (c>='A' && c<='F') c+= 'a'-'A';
+        result+=c;
+    }
+    if (!identifier(result)) throw std::runtime_error("Use the same generated 32-character pairing code on both computers.");
+    return result;
+}
+std::string mac(const std::string &key, const std::string &text)
+{
+    BCRYPT_ALG_HANDLE alg{}; BCRYPT_HASH_HANDLE hash{};
+    checked(BCryptOpenAlgorithmProvider(&alg, BCRYPT_SHA256_ALGORITHM, nullptr, BCRYPT_ALG_HANDLE_HMAC_FLAG));
+    struct Close { BCRYPT_ALG_HANDLE a; BCRYPT_HASH_HANDLE &h; ~Close(){if(h) BCryptDestroyHash(h); BCryptCloseAlgorithmProvider(a,0);} } close{alg,hash};
+    checked(BCryptCreateHash(alg,&hash,nullptr,0,(PUCHAR)key.data(),ULONG(key.size()),0));
+    checked(BCryptHashData(hash,(PUCHAR)text.data(),ULONG(text.size()),0));
+    Bytes out(32); checked(BCryptFinishHash(hash,out.data(),ULONG(out.size()),0)); return hex(out);
+}
+bool equal(const std::string &a, const std::string &b)
+{
+    if (a.size()!=b.size()) return false;
+    unsigned diff=0; for(size_t i=0;i<a.size();++i) diff |= unsigned(a[i]^b[i]); return diff==0;
+}
+Json envelope(const std::string &type, const std::string &id)
+{ return {{"app","KSwitcher-LAN"},{"version",1},{"type",type},{"id",id}}; }
+Pairing::Pairing(std::string a,std::string b,const std::string &key,uint64_t now)
+    : local(std::move(a)),peer(std::move(b)),code(normalizeCode(key)),nonce(randomHex(16)),started(now)
+{
+    if(!identifier(local)||!identifier(peer)||local==peer) throw std::runtime_error("Invalid KSwitcher peer.");
+}
+bool Pairing::expired(uint64_t now) const { return now-started >= PairLifetime; }
+Json Pairing::offer() const
+{
+    auto j=envelope("offer",local); j["to"]=peer; j["nonce"]=nonce;
+    j["proof"]=mac(code,proof("offer",local,peer,nonce)); return j;
+}
+std::vector<Json> Pairing::receive(const Json &j,uint64_t now)
+{
+    if(expired(now)||j.value("app","")!="KSwitcher-LAN"||j.value("version",0)!=1||
+       j.value("id","")!=peer||j.value("to","")!=local) return {};
+    auto type=j.value("type",""); auto other=j.value("nonce","");
+    if(!identifier(other)) return {};
+    if(type=="offer")
+    {
+        if(!equal(j.value("proof",""),mac(code,proof("offer",peer,local,other)))) return {};
+        // A new attempt cannot replace a nonce already authenticated in this attempt.
+        if(!remoteNonce.empty() && remoteNonce!=other) return {};
+        remoteNonce=other;
+        derived=local<peer ? mac(code,proof("key",local,peer,nonce,other)) : mac(code,proof("key",peer,local,other,nonce));
+        auto ack=envelope("ack",local); ack["to"]=peer; ack["nonce"]=nonce; ack["echo"]=other;
+        ack["proof"]=mac(code,proof("ack",local,peer,other,nonce)); return {ack};
+    }
+    if(type=="ack" && j.value("echo","")==nonce)
+    {
+        if(!equal(j.value("proof",""),mac(code,proof("ack",peer,local,nonce,other)))) return {};
+        if(!remoteNonce.empty()&&remoteNonce!=other) return {};
+        remoteNonce=other;
+        derived=local<peer ? mac(code,proof("key",local,peer,nonce,other)) : mac(code,proof("key",peer,local,other,nonce));
+        acknowledged=true;
+        auto done=envelope("confirm",local); done["to"]=peer; done["nonce"]=nonce;
+        done["proof"]=mac(derived,proof("confirm",local,peer,nonce,other)); return {done};
+    }
+    if(type=="confirm" && acknowledged && other==remoteNonce &&
+       equal(j.value("proof",""),mac(derived,proof("confirm",peer,local,other,nonce)))) confirmed=true;
+    return {};
+}
+}

src/lan_pairing.h

@@ -0,0 +1,26 @@
+#pragma once
+#include "platform.h"
+#include "../vendor/json.hpp"
+
+namespace ks::lan
+{
+using Json = nlohmann::json;
+inline constexpr unsigned Port = 45883;
+inline constexpr uint64_t PairLifetime = 120000, PeerLifetime = 12000;
+std::string randomHex(size_t bytes);
+std::string normalizeCode(const std::string &);
+std::string mac(const std::string &key, const std::string &text);
+bool equal(const std::string &, const std::string &);
+bool identifier(const std::string &);
+Json envelope(const std::string &type, const std::string &id);
+struct Pairing
+{
+    std::string local, peer, code, nonce, remoteNonce, derived;
+    uint64_t started{};
+    bool acknowledged{}, confirmed{};
+    Pairing(std::string local, std::string peer, const std::string &code, uint64_t now);
+    bool expired(uint64_t now) const;
+    Json offer() const;
+    std::vector<Json> receive(const Json &, uint64_t now);
+};
+}

src/platform.cpp

@@ -435,7 +435,7 @@ bool needsSelectionDelay(HWND target)
 {
     const auto name = lower(processName(target));
     return name == L"ms-teams" || name == L"msedgewebview2" ||
-           name == L"chrome" || name == L"msedge";
+           name == L"chrome" || name == L"msedge" || name == L"chatgpt" || name == L"codex";
 }
 bool selectPrevious(size_t count, const std::function<bool()> &valid)
 {
@@ -733,3 +733,5 @@ void log(const std::wstring &message)
     }
 }
 } // namespace ks
+
+#include "browser_chat.inc"

src/screenshot.cpp

@@ -54,7 +54,7 @@ bool confirmScreenshotClose(HWND owner)
     // If Windows cannot display the confirmation, keep the screenshot open.
     return SUCCEEDED(result) && button==IDYES;
 }
-constexpr int ToolIds[]{27,10,11,22,23,24,25,36,37,21,19,26,20,12,18,13};
+constexpr int ToolIds[]{27,10,11,22,23,24,25,36,37,38,21,19,26,20,12,18,13};
 struct Surface
 {
     HDC dc = CreateCompatibleDC(nullptr);
@@ -124,7 +124,7 @@ bool chooseTextFont(HWND owner,Mark &m)
     m.fontWeight=font.lfWeight; m.fontItalic=font.lfItalic!=0;
     return true;
 }
-constexpr int CursorTools[]{10,11,22,23,24,25,36,37,19};
+constexpr int CursorTools[]{10,11,22,23,24,25,36,37,38,19};
 HCURSOR makeToolCursor(int tool,int size)
 {
     // Monochrome AND/XOR cursor: white outline keeps the glyph visible on dark images.
@@ -148,6 +148,7 @@ HCURSOR makeToolCursor(int tool,int size)
         case 22: line(18,29,29,18); break;
         case 23: Rectangle(dc,x(17),y(18),x(30),y(29)); break;
         case 24: Ellipse(dc,x(17),y(17),x(30),y(30)); break;
+        case 38: Arc(dc,x(16),y(18),x(31),y(38),x(31),y(28),x(16),y(28)); break;
         case 25: Ellipse(dc,x(16),y(20),x(31),y(28)); break;
         case 36: { POINT p[]{{x(23),y(17)},{x(31),y(30)},{x(16),y(30)},{x(23),y(17)}}; Polyline(dc,p,4); break; }
         case 37: { POINT p[]{{x(20),y(18)},{x(27),y(18)},{x(31),y(30)},{x(16),y(30)},{x(20),y(18)}}; Polyline(dc,p,5); break; }
@@ -177,6 +178,8 @@ struct Capture
     Mark textDefaults{};
     ScreenshotShape shape=ScreenshotShape::None;
     LineStyle lineStyle=LineStyle::Solid;
+    int smoothing=25;
+    bool smoothingDrag=false;
     LineEnds arrowEnds=LineEnds::End, freehandEnds=LineEnds::None;
     COLORREF currentColor=RGB(225,42,50);
     COLORREF customColors[16]{};
@@ -268,6 +271,7 @@ void updateStatus(Capture &c)
     else if(c.textTool) text=L"Text (T): click the image to type | Double-click existing text to edit";
     else if(c.highlight) text=L"Highlight (H): drag to paint | Ctrl+drag = paint over an object | V = pointer";
     else if(c.freehand) text=L"Freehand (F): auto-smooth / shapes; Ctrl+Z restores original | Shift = 45-degree steps | Ctrl = draw over objects";
+    else if(c.shape==ScreenshotShape::Arc) text=L"Arc (U): drag to draw a half ellipse | Handles = resize / rotate | V = pointer";
     else if(c.arrow) text=L"Drag to draw | Ctrl+drag over objects = linked connector | V = pointer";
     else text=L"Number (N): click to add | V = select and edit | Ctrl+C = copy screenshot";
     text=L"Zoom: "+std::to_wstring(int(std::lround(100.0*(c.view.right-c.view.left)/c.image->width)))+
@@ -409,6 +413,14 @@ std::vector<POINT> shapeOutline(const Mark &m)
         auto r=region(m.from,m.to);
         if(m.shape==ScreenshotShape::Rectangle)
             points={{r.left,r.top},{r.right,r.top},{r.right,r.bottom},{r.left,r.bottom},{r.left,r.top}};
+        else if(m.shape==ScreenshotShape::Arc) {
+            // An open half ellipse spanning the drag rectangle, with no closing chord.
+            for(int i=0;i<=90;++i) {
+                double a=i*3.141592653589793/90;
+                points.push_back({LONG(std::lround((r.left+r.right)/2.0-(r.right-r.left)/2.0*std::cos(a))),
+                                  LONG(std::lround(r.bottom-(r.bottom-r.top)*std::sin(a)))});
+            }
+        }
         else if(m.shape==ScreenshotShape::Triangle)
             points={{(r.left+r.right)/2,r.top},{r.right,r.bottom},{r.left,r.bottom},{(r.left+r.right)/2,r.top}};
         else if(m.shape==ScreenshotShape::Trapezoid)
@@ -550,7 +562,7 @@ void drawMarks(HDC dc, const std::vector<Mark> &marks, const Mark *preview = nul
             if(m.shape!=ScreenshotShape::None) {
                 auto hollow=SelectObject(dc,GetStockObject(HOLLOW_BRUSH));
                 auto r=region(m.from,m.to);
-                if(!m.points.empty() || m.rotation!=0 || m.shape==ScreenshotShape::Triangle || m.shape==ScreenshotShape::Trapezoid) {
+                if(!m.points.empty() || m.rotation!=0 || m.shape==ScreenshotShape::Triangle || m.shape==ScreenshotShape::Trapezoid || m.shape==ScreenshotShape::Arc) {
                     auto points=shapeOutline(m); Polyline(dc,points.data(),int(points.size()));
                 }
                 else if(m.shape==ScreenshotShape::Rectangle) Rectangle(dc,r.left,r.top,r.right+1,r.bottom+1);
@@ -620,6 +632,13 @@ bool selectedLine(const Capture &c)
 }
 void syncLineOptions(HWND w,const Capture &c)
 {
+    bool pencil=c.selected>=0 && c.marks[c.selected].freehand;
+    int amount=pencil?c.marks[c.selected].smoothing:c.smoothing;
+    SendDlgItemMessageW(w,41,TBM_SETPOS,TRUE,amount);
+    auto smoothingText=L"Smoothing: "+std::to_wstring(amount)+L"%";
+    SetDlgItemTextW(w,42,smoothingText.c_str());
+    SetDlgItemTextW(w,43,pencil?L"Selected stroke":L"New pencil strokes");
+    EnableWindow(GetDlgItem(w,44),std::any_of(c.marks.begin(),c.marks.end(),[](const Mark &m){return m.freehand;}));
     EnableWindow(GetDlgItem(w,34),c.textTool || (c.selected>=0 && (c.marks[c.selected].isText() || !c.marks[c.selected].label.empty())));
     EnableWindow(GetDlgItem(w,35),c.selected>=0 && c.marks[c.selected].isLine());
     bool selected=selectedLine(c),enabled=selected || c.arrow || c.freehand;
@@ -668,7 +687,7 @@ void layout(HWND w, Capture &c)
     RECT statusRect{}; GetWindowRect(status,&statusRect);
     c.statusHeight=statusRect.bottom-statusRect.top;
     r.bottom-=c.statusHeight;
-    const int positions[]{8,44,80,116,152,188,224,260,296,332,368,404,440,488,524,572};
+    const int positions[]{8,44,80,116,152,188,224,260,296,332,368,404,440,476,524,560,608};
     static_assert(std::size(positions)==std::size(ToolIds));
     for (size_t i = 0; i < std::size(ToolIds); ++i)
     {
@@ -677,10 +696,14 @@ void layout(HWND w, Capture &c)
                    MulDiv(32,dpi,96),MulDiv(32,dpi,96),TRUE);
     }
     SendDlgItemMessageW(w,28,WM_SETFONT,(WPARAM)c.font,TRUE);
-    MoveWindow(GetDlgItem(w,28),MulDiv(612,dpi,96),MulDiv(6,dpi,96),
+    MoveWindow(GetDlgItem(w,28),MulDiv(648,dpi,96),MulDiv(6,dpi,96),
                MulDiv(78,dpi,96),MulDiv(32,dpi,96),TRUE);
-    c.panelHeight=c.unit+MulDiv(40,dpi,96);
-    for(int id:{30,31,32,33,34,35}) SendDlgItemMessageW(w,id,WM_SETFONT,(WPARAM)c.font,TRUE);
+    c.panelHeight=c.unit+MulDiv(80,dpi,96);
+    for(int id:{30,31,32,33,34,35,41,42,43,44}) SendDlgItemMessageW(w,id,WM_SETFONT,(WPARAM)c.font,TRUE);
+    MoveWindow(GetDlgItem(w,42),MulDiv(12,dpi,96),c.unit+MulDiv(44,dpi,96),MulDiv(128,dpi,96),MulDiv(24,dpi,96),TRUE);
+    MoveWindow(GetDlgItem(w,41),MulDiv(142,dpi,96),c.unit+MulDiv(40,dpi,96),MulDiv(200,dpi,96),MulDiv(30,dpi,96),TRUE);
+    MoveWindow(GetDlgItem(w,43),MulDiv(350,dpi,96),c.unit+MulDiv(44,dpi,96),MulDiv(150,dpi,96),MulDiv(24,dpi,96),TRUE);
+    MoveWindow(GetDlgItem(w,44),MulDiv(516,dpi,96),c.unit+MulDiv(40,dpi,96),MulDiv(210,dpi,96),MulDiv(30,dpi,96),TRUE);
     MoveWindow(GetDlgItem(w,32),MulDiv(12,dpi,96),c.unit+MulDiv(6,dpi,96),MulDiv(64,dpi,96),MulDiv(24,dpi,96),TRUE);
     MoveWindow(GetDlgItem(w,30),MulDiv(80,dpi,96),c.unit+MulDiv(2,dpi,96),MulDiv(150,dpi,96),MulDiv(180,dpi,96),TRUE);
     MoveWindow(GetDlgItem(w,33),MulDiv(248,dpi,96),c.unit+MulDiv(6,dpi,96),MulDiv(40,dpi,96),MulDiv(24,dpi,96),TRUE);
@@ -771,7 +794,7 @@ HCURSOR toolCursor(const Capture &c)
     if(c.pointer) return LoadCursorW(nullptr,IDC_ARROW);
     if(c.textTool) return LoadCursorW(nullptr,IDC_IBEAM);
     if(c.freehand && c.pencilCursor) return c.pencilCursor;
-    int tool=c.highlight?19:c.straight?22:c.shape==ScreenshotShape::Trapezoid?37:c.shape==ScreenshotShape::Triangle?36:c.shape!=ScreenshotShape::None?22+int(c.shape):c.arrow?11:10;
+    int tool=c.highlight?19:c.straight?22:c.shape==ScreenshotShape::Arc?38:c.shape==ScreenshotShape::Trapezoid?37:c.shape==ScreenshotShape::Triangle?36:c.shape!=ScreenshotShape::None?22+int(c.shape):c.arrow?11:10;
     for(size_t i=0;i<std::size(CursorTools);++i)
         if(CursorTools[i]==tool && c.drawingCursors[i]) return c.drawingCursors[i];
     return LoadCursorW(nullptr,IDC_CROSS);
@@ -883,7 +906,7 @@ void drawTool(const DRAWITEMSTRUCT &item, const Capture &c)
     bool active=(item.CtlID==27 && c.pointer)||(item.CtlID==10 && !c.pointer && !c.arrow && !c.highlight && !c.freehand && !c.textTool)||(item.CtlID==11 && c.arrow && !c.straight && c.shape==ScreenshotShape::None)||
                 (item.CtlID==19 && c.highlight)||(item.CtlID==21 && c.freehand)||
                 (item.CtlID==22 && c.straight)||(item.CtlID>=23 && item.CtlID<=25 && int(c.shape)==int(item.CtlID)-22)||(item.CtlID==26 && c.textTool)||
-                (item.CtlID==36 && c.shape==ScreenshotShape::Triangle)||(item.CtlID==37 && c.shape==ScreenshotShape::Trapezoid);
+                (item.CtlID==36 && c.shape==ScreenshotShape::Triangle)||(item.CtlID==37 && c.shape==ScreenshotShape::Trapezoid)||(item.CtlID==38 && c.shape==ScreenshotShape::Arc);
     bool disabled=item.itemState&ODS_DISABLED;
     POINT mouse; GetCursorPos(&mouse); ScreenToClient(item.hwndItem,&mouse);
     bool hover=PtInRect(&r,mouse) && !disabled;
@@ -897,13 +920,14 @@ void drawTool(const DRAWITEMSTRUCT &item, const Capture &c)
     RoundRect(dc,r.left,r.top,r.right,r.bottom,corner,corner);
     SelectObject(dc,oldPen); SelectObject(dc,oldBrush); DeleteObject(pen); DeleteObject(brush);
     int iconIndex=item.CtlID==35?13:item.CtlID==34?14:item.CtlID>=22?int(item.CtlID)-13:item.CtlID==18?5:item.CtlID==19?6:item.CtlID==20?7:item.CtlID==21?8:item.CtlID-10;
-    auto icon=(item.CtlID==36 || item.CtlID==37)?nullptr:item.CtlID==27?(HICON)LoadCursorW(nullptr,IDC_ARROW):c.toolIcons[disabled?2:active?1:0][iconIndex];
-    if(item.CtlID==36 || item.CtlID==37) {
+    auto icon=(item.CtlID==36 || item.CtlID==37 || item.CtlID==38)?nullptr:item.CtlID==27?(HICON)LoadCursorW(nullptr,IDC_ARROW):c.toolIcons[disabled?2:active?1:0][iconIndex];
+    if(item.CtlID==36 || item.CtlID==37 || item.CtlID==38) {
         int cx=(r.left+r.right)/2,cy=(r.top+r.bottom)/2,s=c.iconSize/2;
         auto trianglePen=CreatePen(PS_SOLID,std::max(1,MulDiv(2,GetDpiForWindow(item.hwndItem),96)),
                                   disabled?RGB(148,163,184):active?RGB(37,99,235):RGB(51,65,85));
         auto previous=SelectObject(dc,trianglePen);
-        if(item.CtlID==36) { POINT vertices[]{{cx,cy-s},{cx+s,cy+s},{cx-s,cy+s},{cx,cy-s}}; Polyline(dc,vertices,4); }
+        if(item.CtlID==38) Arc(dc,cx-s,cy-s,cx+s,cy+3*s,cx+s,cy+s,cx-s,cy+s);
+        else if(item.CtlID==36) { POINT vertices[]{{cx,cy-s},{cx+s,cy+s},{cx-s,cy+s},{cx,cy-s}}; Polyline(dc,vertices,4); }
         else { POINT vertices[]{{cx-s/2,cy-s},{cx+s/2,cy-s},{cx+s,cy+s},{cx-s,cy+s},{cx-s/2,cy-s}}; Polyline(dc,vertices,5); }
         SelectObject(dc,previous); DeleteObject(trianglePen);
     }
@@ -1025,7 +1049,7 @@ void edit(HWND w, Capture &c)
     InitCommonControlsEx(&statusControls);
     CreateWindowExW(0,STATUSCLASSNAMEW,L"",WS_CHILD|WS_VISIBLE|SBARS_TOOLTIPS,
         0,0,0,0,w,(HMENU)50,c.app.instance,nullptr);
-    const wchar_t *labels[]{L"Pointer (V): select and edit objects", L"Number (N)", L"Arrow (A); Ctrl+drag between objects to link", L"Straight line (L); Ctrl+drag between objects to link", L"Rectangle (R)", L"Circle (O)", L"Ellipse (E)", L"Triangle (G): drag to draw; drag each vertex to reshape", L"Trapezoid (B): drag to draw", L"Freehand line (F); Shift for 45-degree steps; move >50 px off line to turn; Ctrl to draw over objects", L"Highlight (H); Ctrl+drag to paint over an object",
+    const wchar_t *labels[]{L"Pointer (V): select and edit objects", L"Number (N)", L"Arrow (A); Ctrl+drag between objects to link", L"Straight line (L); Ctrl+drag between objects to link", L"Rectangle (R)", L"Circle (O)", L"Ellipse (E)", L"Triangle (G): drag to draw; drag each vertex to reshape", L"Trapezoid (B): drag to draw", L"Arc (U): drag to draw a half ellipse; use handles to resize or rotate", L"Freehand line (F); Shift for 45-degree steps; move >50 px off line to turn; Ctrl to draw over objects", L"Highlight (H); Ctrl+drag to paint over an object",
         L"Text (T); double-click or F2 to edit", L"Color — selected object and new objects", L"Undo (Ctrl+Z)", L"Redo (Ctrl+Y / Ctrl+Shift+Z)", L"Copy (Ctrl+C)"};
     static_assert(std::size(labels)==std::size(ToolIds));
     auto saveButton=CreateWindowW(L"BUTTON",L"Save...",WS_CHILD|WS_VISIBLE|WS_TABSTOP|BS_PUSHBUTTON,
@@ -1061,6 +1085,14 @@ void edit(HWND w, Capture &c)
     SetWindowSubclass(labelButton,toolHover,1,0);
     fontTip.uId=(UINT_PTR)labelButton; fontTip.lpszText=const_cast<wchar_t *>(L"Arrow label (F2 / double-click); drag label to reposition");
     SendMessageW(tips,TTM_ADDTOOLW,0,(LPARAM)&fontTip);
+    INITCOMMONCONTROLSEX sliders{sizeof(sliders),ICC_BAR_CLASSES}; InitCommonControlsEx(&sliders);
+    CreateWindowW(TRACKBAR_CLASSW,L"Pencil smoothing",WS_CHILD|WS_VISIBLE|WS_TABSTOP|TBS_NOTICKS,
+                  0,0,0,0,w,(HMENU)41,c.app.instance,nullptr);
+    SendDlgItemMessageW(w,41,TBM_SETRANGE,TRUE,MAKELPARAM(0,100));
+    SendDlgItemMessageW(w,41,TBM_SETPAGESIZE,0,10);
+    for(int id:{42,43}) CreateWindowW(L"STATIC",L"",WS_CHILD|WS_VISIBLE,0,0,0,0,w,(HMENU)(INT_PTR)id,c.app.instance,nullptr);
+    CreateWindowW(L"BUTTON",L"Apply to all strokes",WS_CHILD|WS_VISIBLE|WS_TABSTOP|BS_PUSHBUTTON,
+                  0,0,0,0,w,(HMENU)44,c.app.instance,nullptr);
     c.syncHistory();
     auto work = monitor.rcWork;
     SetWindowPos(w,HWND_NOTOPMOST,work.left+20,work.top+20,
@@ -1120,7 +1152,7 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             }
             break;
         case WM_DRAWITEM:
-            if((wp>=10 && wp<=13) || (wp>=18 && wp<=27) || wp==34 || wp==35 || wp==36 || wp==37) { drawTool(*reinterpret_cast<DRAWITEMSTRUCT *>(lp),*c); return TRUE; }
+            if((wp>=10 && wp<=13) || (wp>=18 && wp<=27) || wp==34 || wp==35 || wp==36 || wp==37 || wp==38) { drawTool(*reinterpret_cast<DRAWITEMSTRUCT *>(lp),*c); return TRUE; }
             break;
         case WM_CTLCOLORSTATIC:
             SetBkColor((HDC)wp,RGB(255,255,255)); SetTextColor((HDC)wp,RGB(51,65,85));
@@ -1129,6 +1161,21 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
         case WM_SETCURSOR:
             if ((HWND)wp==w && LOWORD(lp)==HTCLIENT) { captureCursor(w,*c); return TRUE; }
             break;
+        case WM_HSCROLL:
+            if((HWND)lp==GetDlgItem(w,41) && !c->dragging) {
+                int amount=int(SendDlgItemMessageW(w,41,TBM_GETPOS,0,0));
+                bool pencil=c->selected>=0 && c->marks[c->selected].freehand;
+                if(pencil && c->marks[c->selected].smoothing!=amount) {
+                    if(!c->smoothingDrag) c->remember(c->marks);
+                    setScreenshotSmoothing(c->marks[c->selected],amount);
+                    resolveScreenshotLinks(c->marks);
+                    c->smoothingDrag=LOWORD(wp)==TB_THUMBTRACK;
+                } else if(!pencil) c->smoothing=amount;
+                if(LOWORD(wp)!=TB_THUMBTRACK) c->smoothingDrag=false;
+                syncLineOptions(w,*c); InvalidateRect(w,nullptr,FALSE);
+                return 0;
+            }
+            break;
         case WM_COMMAND:
             if(LOWORD(wp)==40) {
                 if(c->inlineText && HIWORD(wp)==EN_CHANGE) { readInlineText(*c); positionInlineText(*c); }
@@ -1136,6 +1183,17 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 return 0;
             }
             if (c->dragging) return 0;
+            if(LOWORD(wp)==44) {
+                int amount=int(SendDlgItemMessageW(w,41,TBM_GETPOS,0,0));
+                c->smoothing=amount;
+                if(std::any_of(c->marks.begin(),c->marks.end(),[&](const Mark &m){return m.freehand && m.smoothing!=amount;})) {
+                    c->remember(c->marks);
+                    for(auto &mark:c->marks) if(mark.freehand) setScreenshotSmoothing(mark,amount);
+                    resolveScreenshotLinks(c->marks);
+                }
+                c->smoothingDrag=false; syncLineOptions(w,*c); InvalidateRect(w,nullptr,FALSE);
+                return 0;
+            }
             if(LOWORD(wp)==35) {
                 finishInlineText(w,*c,true);
                 if(c->selected>=0 && c->marks[c->selected].isLine()) beginMarkText(w,*c,c->selected);
@@ -1214,13 +1272,13 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 if(changed) { c->copied=false; c->selected=-1; c->selectedLabel=false; c->wheelDelta=0; c->wheelTarget=-1; }
                 c->syncHistory();
             }
-            if (LOWORD(wp)==10 || LOWORD(wp)==11 || LOWORD(wp)==19 || LOWORD(wp)==36 || LOWORD(wp)==37 || (LOWORD(wp)>=21 && LOWORD(wp)<=27))
+            if (LOWORD(wp)==10 || LOWORD(wp)==11 || LOWORD(wp)==19 || LOWORD(wp)==36 || LOWORD(wp)==37 || LOWORD(wp)==38 || (LOWORD(wp)>=21 && LOWORD(wp)<=27))
             {
                 c->pointer=LOWORD(wp)==27;
-                c->arrow = LOWORD(wp)==11 || LOWORD(wp)==36 || LOWORD(wp)==37 || (LOWORD(wp)>=22 && LOWORD(wp)<=25);
+                c->arrow = LOWORD(wp)==11 || LOWORD(wp)==36 || LOWORD(wp)==37 || LOWORD(wp)==38 || (LOWORD(wp)>=22 && LOWORD(wp)<=25);
                 c->straight=LOWORD(wp)==22;
                 c->textTool=LOWORD(wp)==26;
-                c->shape=LOWORD(wp)==37?ScreenshotShape::Trapezoid:LOWORD(wp)==36?ScreenshotShape::Triangle:LOWORD(wp)>=23 && LOWORD(wp)<=25?ScreenshotShape(LOWORD(wp)-22):ScreenshotShape::None;
+                c->shape=LOWORD(wp)==38?ScreenshotShape::Arc:LOWORD(wp)==37?ScreenshotShape::Trapezoid:LOWORD(wp)==36?ScreenshotShape::Triangle:LOWORD(wp)>=23 && LOWORD(wp)<=25?ScreenshotShape(LOWORD(wp)-22):ScreenshotShape::None;
                 c->selected=-1; c->selectedLabel=false;
                 c->highlight=LOWORD(wp)==19;
                 c->freehand=LOWORD(wp)==21;
@@ -1233,6 +1291,7 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 for(int id=22;id<=27;++id) InvalidateRect(GetDlgItem(w,id),nullptr,FALSE);
                 InvalidateRect(GetDlgItem(w,36),nullptr,FALSE);
                 InvalidateRect(GetDlgItem(w,37),nullptr,FALSE);
+                InvalidateRect(GetDlgItem(w,38),nullptr,FALSE);
             }
 
             SetFocus(w); captureCursor(w,*c); InvalidateRect(w,nullptr,FALSE); return 0;
@@ -1293,6 +1352,7 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                     if(wp=='E') SendMessageW(w,WM_COMMAND,25,0);
                     if(wp=='G') SendMessageW(w,WM_COMMAND,36,0);
                     if(wp=='B') SendMessageW(w,WM_COMMAND,37,0);
+                    if(wp=='U') SendMessageW(w,WM_COMMAND,38,0);
                 }
                 if (wp=='N' || wp=='A') SendMessageW(w,WM_COMMAND,wp=='N'?10:11,0);
                 if(wp=='H') SendMessageW(w,WM_COMMAND,19,0);
@@ -1530,6 +1590,7 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                         c->remember(c->marks); c->marks.push_back(std::move(c->stroke));
                         if(c->freehand) {
                             auto &mark=c->marks.back();
+                            mark.rawPoints=mark.points;
                             linkScreenshotEndpoint(mark,true,c->start,c->marks,6);
                             linkScreenshotEndpoint(mark,false,c->end,c->marks,6);
                             resolveScreenshotLinks(c->marks);
@@ -1540,10 +1601,18 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                             ScreenshotShape recognized{};
                             bool straightLine=false;
                             auto improved=improveScreenshotStroke(c->marks.back().points,&recognized,&straightLine);
+                            if(recognized==ScreenshotShape::None && !straightLine) {
+                                improved=smoothScreenshotStroke(c->marks.back().rawPoints,c->smoothing);
+                                const auto &raw=c->marks.back().rawPoints;
+                                if(improved.size()==raw.size() && std::equal(improved.begin(),improved.end(),raw.begin(),
+                                   [](POINT a,POINT b){return a.x==b.x && a.y==b.y;})) improved.clear();
+                            }
                             if(!improved.empty()) {
                                 c->remember(c->marks);
                                 auto &mark=c->marks.back();
-                                mark.points=std::move(improved);
+                                if(recognized==ScreenshotShape::None && !straightLine) {
+                                    setScreenshotSmoothing(mark,c->smoothing);
+                                } else { mark.points=std::move(improved); mark.rawPoints.clear(); }
                                 mark.from=mark.points.front(); mark.to=mark.points.back();
                                 if(straightLine) { mark.points.clear(); mark.freehand=false; }
                                 if(recognized!=ScreenshotShape::None) {
@@ -1563,7 +1632,7 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                         c->marks.back().style=c->lineStyle; c->marks.back().ends=c->straight || c->shape!=ScreenshotShape::None?LineEnds::None:c->arrowEnds;
                         c->marks.back().shape=c->shape;
                         auto &mark=c->marks.back();
-                        if(mark.shape==ScreenshotShape::Triangle || mark.shape==ScreenshotShape::Trapezoid) mark.points=shapeOutline(mark);
+                        if(mark.shape==ScreenshotShape::Triangle || mark.shape==ScreenshotShape::Trapezoid || mark.shape==ScreenshotShape::Arc) mark.points=shapeOutline(mark);
                         linkScreenshotEndpoint(mark,true,c->start,c->marks,6);
                         linkScreenshotEndpoint(mark,false,c->end,c->marks,6);
                         resolveScreenshotLinks(c->marks);
@@ -1586,7 +1655,7 @@ LRESULT CALLBACK captureProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             if (c->editing)
             {
                 auto limits = reinterpret_cast<MINMAXINFO *>(lp);
-                limits->ptMinTrackSize = {MulDiv(730,GetDpiForWindow(w),96),MulDiv(240,GetDpiForWindow(w),96)};
+                limits->ptMinTrackSize = {MulDiv(766,GetDpiForWindow(w),96),MulDiv(240,GetDpiForWindow(w),96)};
                 return 0;
             }
             break;
@@ -1901,7 +1970,14 @@ void resolveScreenshotLinks(std::vector<ScreenshotMark> &marks)
             POINT start=from?from->from:m.from, end=to?to->from:m.to;
             if(from) m.from=rim(*from,end,true);
             if(to) m.to=rim(*to,start,false);
-            if(m.freehand && !m.points.empty()) { m.points.front()=m.from; m.points.back()=m.to; }
+            if(m.freehand && !m.points.empty()) {
+                m.points.front()=m.from; m.points.back()=m.to;
+                if(!m.rawPoints.empty() && (m.rawPoints.front().x!=m.from.x || m.rawPoints.front().y!=m.from.y ||
+                   m.rawPoints.back().x!=m.to.x || m.rawPoints.back().y!=m.to.y)) {
+                    m.rawPoints.front()=m.from; m.rawPoints.back()=m.to;
+                    setScreenshotSmoothing(m,m.smoothing);
+                }
+            }
         }
         state[index]=2;
     };
@@ -2055,10 +2131,15 @@ ScreenshotMark dragScreenshotMark(const ScreenshotMark &original, MarkPart part,
             return low<=high?std::clamp(delta,low,high):0L;
         };
         auto bounds=markBounds(m);
+        for(auto p:m.rawPoints) {
+            bounds.left=std::min(bounds.left,p.x); bounds.right=std::max(bounds.right,p.x);
+            bounds.top=std::min(bounds.top,p.y); bounds.bottom=std::max(bounds.bottom,p.y);
+        }
         LONG dx=shift(position.x-origin.x,bounds.left,bounds.right,width);
         LONG dy=shift(position.y-origin.y,bounds.top,bounds.bottom,height);
         m.from.x+=dx; m.to.x+=dx; m.from.y+=dy; m.to.y+=dy;
         for(auto &point:m.points) { point.x+=dx; point.y+=dy; }
+        for(auto &point:m.rawPoints) { point.x+=dx; point.y+=dy; }
     }
     else if(part==MarkPart::Start || part==MarkPart::End)
     {
@@ -2083,6 +2164,10 @@ ScreenshotMark dragScreenshotMark(const ScreenshotMark &original, MarkPart part,
             }
         }
         if(m.freehand && !m.points.empty()) (part==MarkPart::Start?m.points.front():m.points.back())=endpoint;
+        if(m.freehand && !m.rawPoints.empty()) {
+            (part==MarkPart::Start?m.rawPoints.front():m.rawPoints.back())=endpoint;
+            setScreenshotSmoothing(m,m.smoothing);
+        }
         if(m.shape!=ScreenshotShape::None && m.rotation!=0) {
             auto fixedBefore=rotateShapePoint(original,part==MarkPart::Start?original.to:original.from);
             auto fixedAfter=rotateShapePoint(m,part==MarkPart::Start?m.to:m.from);

src/screenshot.h

@@ -15,7 +15,7 @@ void showScreenshot(ScreenshotHost &);
 void showScreenshotEditor(ScreenshotHost &,const Clip &);
 enum class LineStyle { Solid, Dotted, Dashed, DashDot };
 enum class LineEnds { End, Start, Both, None };
-enum class ScreenshotShape { None, Rectangle, Circle, Ellipse, Triangle, Trapezoid };
+enum class ScreenshotShape { None, Rectangle, Circle, Ellipse, Triangle, Trapezoid, Arc };
 struct ScreenshotOffset { double x, y; };
 struct ScreenshotLink {
     unsigned long long target{};
@@ -39,6 +39,8 @@ struct ScreenshotMark {
     bool labelRotationManual=false;
     unsigned long long id{};
     ScreenshotLink fromLink, toLink;
+    std::vector<POINT> rawPoints; // Original pencil path for reversible smoothing.
+    int smoothing=0; // 0..100; applies only to freehand strokes.
     bool isText() const { return !text.empty(); }
     bool isHighlight() const { return !points.empty() && !freehand && shape==ScreenshotShape::None; }
     bool isLine() const { return !number && !isText() && !isHighlight() && shape==ScreenshotShape::None; }

src/storage.cpp

@@ -61,6 +61,25 @@ bool validId(const std::wstring &id)
 } // namespace
 void validateSettings(const Settings &s)
 {
+    if (s.chatCycles.size() > 1000) throw std::runtime_error("Too many chat language profiles");
+    for (const auto &[key, cycle] : s.chatCycles)
+    {
+        auto separator = key.find(L'\n');
+        if (separator == key.npos || separator + 1 == key.size() || key.size() > 1024 ||
+            key.find(L'\n', separator + 1) != key.npos || key.find(L'\r') != key.npos ||
+            (key.substr(0, separator) != L"telegram" && key.substr(0, separator) != L"ms-teams" && key.substr(0, separator) != L"viber" && key.substr(0, separator) != L"telegram-web"))
+            throw std::runtime_error("Invalid chat language profile");
+        if (cycle.empty() || cycle.size() > 64) throw std::runtime_error("Select at least one chat language");
+        std::vector<std::wstring> seen;
+        for (const auto &id : cycle)
+        {
+            if (id.size() != 12 || !id.starts_with(L"win:") ||
+                id.find_first_not_of(L"0123456789abcdefABCDEF", 4) != id.npos ||
+                std::find(seen.begin(), seen.end(), id) != seen.end())
+                throw std::runtime_error("Invalid or duplicate chat layout");
+            seen.push_back(id);
+        }
+    }
     if (s.tesseractPath.size() > 32700 || s.tesseractPath.find_first_of(L"\r\n\"") != s.tesseractPath.npos)
         throw std::runtime_error("Invalid Tesseract executable path");
     if (s.tesseractLanguages.empty() || s.tesseractLanguages.size() > 128 ||
@@ -118,9 +137,11 @@ void validateSettings(const Settings &s)
                               L"абвгдеёжзийклмнопрстуфхцчшщъыьэюя"})
             valid |= !from.empty() && !to.empty() && from.size() <= 32 && to.size() <= 32 &&
                      from == lower(from) && to == lower(to) && from != to &&
-                     from.find_first_not_of(alphabet) == from.npos && to.find_first_not_of(alphabet) == to.npos;
+                     from.find_first_not_of(alphabet) == from.npos &&
+                     to.find_first_not_of(std::wstring(alphabet) + L" ") == to.npos &&
+                     to.front() != L' ' && to.back() != L' ' && to.find(L"  ") == to.npos;
         if (!valid)
-            throw std::runtime_error("Replacement pairs must be different lowercase words of 1-32 letters in the same language");
+            throw std::runtime_error("Use a lowercase typo of 1-32 letters and a different correction of 1-32 characters in the same language. Single spaces between correction words are allowed.");
     }
     for (const auto &[language, words] : s.autoWords)
     {
@@ -148,8 +169,19 @@ void validateSettings(const Settings &s)
         if (snippet.trigger.size() < 2 || snippet.trigger.size() > 64 ||
             snippet.trigger.find_first_of(L"\r\n\t ") != snippet.trigger.npos)
             throw std::runtime_error("Snippet triggers must contain 2–64 characters without whitespace");
-        if (!seen.insert(lower(snippet.trigger)).second)
-            throw std::runtime_error("Duplicate snippet trigger");
+        if (snippet.apps.size() > 64) throw std::runtime_error("Too many snippet applications");
+        std::vector<std::wstring> scopes;
+        for (const auto &app : snippet.apps)
+        {
+            auto normalized = snippetAppName(app);
+            if (normalized.empty() || normalized.size() > 250 || normalized.find_first_of(L"\\/:*?\"<>|,\r\n\t") != normalized.npos)
+                throw std::runtime_error("Use application names such as chrome.exe, not paths or wildcards");
+            scopes.push_back(normalized);
+        }
+        if (scopes.empty()) scopes.push_back(L"");
+        for (const auto &scope : scopes)
+            if (!seen.insert(lower(snippet.trigger) + L"\n" + scope).second)
+                throw std::runtime_error("Duplicate snippet trigger for the same application or global scope");
         auto t = parseTemplate(snippet.text);
         if (t.text.empty() || t.cursors > 1)
             throw std::runtime_error("Each snippet needs text and at most one {cursor} marker");
@@ -232,6 +264,16 @@ Settings decodeSettings(const Bytes &bytes, const std::vector<Layout> &layouts)
                 s.cycle.push_back(w);
         }
     }
+    if (j.contains("chatCycles"))
+    {
+        if (!j.at("chatCycles").is_object()) throw std::runtime_error("Invalid chat profiles object");
+        for (const auto &[key, cycle] : j.at("chatCycles").items())
+        {
+            if (!cycle.is_array() || cycle.empty()) throw std::runtime_error("Empty chat language profile");
+            for (const auto &id : cycle)
+                s.chatCycles[wide(key)].push_back(wide(id.get<std::string>()));
+        }
+    }
     if (j.contains("layoutHotkeys"))
     {
         std::fill(s.direct.begin(), s.direct.end(), L"");
@@ -250,6 +292,12 @@ Settings decodeSettings(const Bytes &bytes, const std::vector<Layout> &layouts)
         for (auto &sn : j.at("snippets"))
         {
             Snippet item{str(sn, "trigger"), str(sn, "text"), str(sn, "id")};
+            if (sn.contains("apps"))
+            {
+                if (!sn.at("apps").is_array()) throw std::runtime_error("Snippet apps must be a list");
+                for (const auto &app : sn.at("apps")) item.apps.push_back(snippetAppName(wide(app.get<std::string>())));
+            }
+            if (item.id.empty() && !item.apps.empty()) item.id = newSnippetId();
             item.id = snippetId(item);
             s.snippets.push_back(std::move(item));
         }
@@ -288,6 +336,9 @@ Bytes encodeSettings(const Settings &s)
               {"screenshotHotkey", utf8(s.screenshot)},
               {"screenshotAutoOpenEditor", s.screenshotAutoOpenEditor}};
     j["layouts"] = Json::array();
+    j["chatCycles"] = Json::object();
+    for (const auto &[key, cycle] : s.chatCycles)
+        for (const auto &id : cycle) j["chatCycles"][utf8(key)].push_back(utf8(id));
     for (auto &id : s.cycle)
         j["layouts"].push_back(utf8(id));
     j["autoCorrectLayout"] = s.autoCorrect;
@@ -320,7 +371,15 @@ Bytes encodeSettings(const Settings &s)
         j["layoutHotkeys"].push_back({{"layoutId", utf8(s.directIds[i])}, {"hotkey", utf8(s.direct[i])}});
     j["snippets"] = Json::array();
     for (auto &sn : s.snippets)
-        j["snippets"].push_back({{"trigger", utf8(sn.trigger)}, {"text", utf8(sn.text)}, {"id", utf8(snippetId(sn))}});
+    {
+        Json item{{"trigger", utf8(sn.trigger)}, {"text", utf8(sn.text)}, {"id", utf8(snippetId(sn))}};
+        if (!sn.apps.empty())
+        {
+            item["apps"] = Json::array();
+            for (const auto &app : sn.apps) item["apps"].push_back(utf8(snippetAppName(app)));
+        }
+        j["snippets"].push_back(std::move(item));
+    }
     j["snippetTombstones"] = Json::array();
     for (const auto &id : s.snippetTombstones) j["snippetTombstones"].push_back(utf8(id));
     j["excludedApps"] = Json::array();

src/stroke_improvement.h

@@ -38,6 +38,42 @@ inline double cross(Point a, Point b, Point c) { return (b.x-a.x)*(c.y-a.y)-(b.y
 }
 
 namespace ks {
+// Filter by distance along the path, not mouse-event count. Always start from
+// the original path so lowering the amount restores detail without drift.
+inline std::vector<POINT> smoothScreenshotStroke(const std::vector<POINT> &input, int amount) {
+    amount=std::clamp(amount,0,100);
+    if(!amount || input.size()<5) return input;
+    using namespace stroke_detail;
+    std::vector<Point> raw;
+    for(auto p:input) if(raw.empty() || distance(raw.back(),{double(p.x),double(p.y)})>0)
+        raw.push_back({double(p.x),double(p.y)});
+    double total=length(raw);
+    if(raw.size()<5 || total<16) return input;
+    auto points=sample(raw,size_t(std::clamp(std::ceil(total/2)+1,3.0,4096.0)));
+    double step=total/(points.size()-1),radius=0.5+32*std::pow(amount/100.0,2);
+    int reach=std::max(1,int(std::ceil(radius/step)));
+    std::vector<POINT> result;
+    for(size_t i=0;i<points.size();++i) {
+        Point sum{}; double weights=0;
+        for(int j=std::max(0,int(i)-reach);j<=std::min(int(points.size())-1,int(i)+reach);++j) {
+            double d=(j-double(i))*step,weight=std::exp(-2*d*d/(radius*radius));
+            sum.x+=points[j].x*weight; sum.y+=points[j].y*weight; weights+=weight;
+        }
+        double blend=std::min(1.0,std::min(i,points.size()-1-i)*step/radius);
+        POINT p{LONG(std::lround(points[i].x+blend*(sum.x/weights-points[i].x))),
+                LONG(std::lround(points[i].y+blend*(sum.y/weights-points[i].y)))};
+        if(result.empty() || p.x!=result.back().x || p.y!=result.back().y) result.push_back(p);
+    }
+    result.front()=input.front(); result.back()=input.back();
+    return result;
+}
+inline void setScreenshotSmoothing(ScreenshotMark &mark,int amount) {
+    if(!mark.freehand || mark.shape!=ScreenshotShape::None || mark.points.empty()) return;
+    if(mark.rawPoints.empty()) mark.rawPoints=mark.points;
+    mark.smoothing=std::clamp(amount,0,100);
+    mark.points=smoothScreenshotStroke(mark.rawPoints,mark.smoothing);
+    mark.from=mark.points.front(); mark.to=mark.points.back();
+}
 // Returns a replacement path; an empty result means no visible improvement.
 // Report recognized geometry separately from a smoothed freehand path.
 inline std::vector<POINT> improveScreenshotStroke(const std::vector<POINT> &input, ScreenshotShape *shape=nullptr,

src/sync.cpp

@@ -229,6 +229,9 @@ Settings restoreSyncSettings(const Bytes &shared, const Settings &local, const s
     if (!j.contains("autoCorrectReplace")) j["autoCorrectReplace"] = false;
     if (!j.contains("autoCorrectTypos")) j["autoCorrectTypos"] = false;
     if (!j.contains("autoCorrectReplacements")) j["autoCorrectReplacements"] = Json::object();
+    // Profiles uploaded before v0.6.53 do not participate in chat synchronization.
+    // An explicit empty object from a newer client does mean remove all profiles.
+    if (!j.contains("chatCycles")) j["chatCycles"] = original.at("chatCycles");
     auto allowed = parse(sharedSyncSettings(local));
     if (!j.is_object() || j.value("format", "") != "kswitcher-settings" || j.value("schemaVersion", 0) != 1)
         throw std::runtime_error("Unsupported synchronized settings format.");
@@ -294,7 +297,9 @@ SyncResult synchronize(SyncProvider &provider, const Bytes &base, const Bytes &l
     if (action == SyncAction::Automatic) merged = mergeSyncProfile(mergeBase, mergeLocal, remote.settings, choices);
     else
     {
-        auto selected = bytes(normalizeProfile(parse(action == SyncAction::Download ? remote.settings : mergeLocal)));
+        auto profile = parse(action == SyncAction::Download ? remote.settings : mergeLocal);
+        if (!profile.contains("chatCycles")) profile["chatCycles"] = parse(local).value("chatCycles", Json::object());
+        auto selected = bytes(normalizeProfile(profile));
         merged = {selected, selected, selected, {}};
     }
     if (validate) { validate(merged.local); validate(merged.remote); }

src/sync_merge.inl

@@ -8,6 +8,7 @@ Json normalizeProfile(Json j)
     if (!j.contains("autoCorrectTypos")) j["autoCorrectTypos"] = false;
     if (!j.contains("autoCorrectReplacements")) j["autoCorrectReplacements"] = Json::object();
     if (!j.contains("snippetTombstones")) j["snippetTombstones"] = Json::array();
+    if (!j.contains("chatCycles")) j["chatCycles"] = Json::object();
     for (auto &sn : j.at("snippets"))
         if (!sn.contains("id")) sn["id"] = utf8(snippetId({wide(sn.at("trigger").get<std::string>()), L""}));
     return j;
@@ -53,6 +54,10 @@ Json flatProfile(Json j)
     for (auto it = replacements.begin(); it != replacements.end();)
         if (it.value().is_null()) it = replacements.erase(it);
         else ++it;
+    auto &chats = j["chatCycles"];
+    for (auto it = chats.begin(); it != chats.end();)
+        if (it.value().is_null()) it = chats.erase(it);
+        else ++it;
     Json snippets = Json::array(), deleted = Json::array();
     for (const auto &[id, item] : j.at("snippets").items())
     {
@@ -94,6 +99,7 @@ std::wstring fieldLabel(const std::string &key)
         {"translitHotkey", L"Transliteration shortcut"}, {"undoHotkey", L"Undo shortcut"},
         {"clipboardHotkey", L"Clipboard shortcut"}, {"screenshotHotkey", L"Screenshot shortcut"},
         {"layouts", L"Layout cycle order"}, {"layoutHotkeys", L"Layout shortcuts"},
+        {"chatCycles", L"Chat languages"},
         {"convertLastWord", L"Convert recent word"}, {"switchSystemLayout", L"Switch system layout"},
         {"autoCorrectMinLength", L"Minimum word length"}, {"autoCorrectMaxRank", L"Maximum word rank"},
         {"autoCorrectLayout", L"Automatic layout correction"}, {"autoCorrectLanguages", L"Dictionary languages"},
@@ -141,6 +147,11 @@ MergeNode mergeNode(const Json &b, const Json &l, const Json &r, const std::stri
                 auto item = get(l); if (item.is_null() || tombstone(item)) item = get(r);
                 childLabel = L"Snippet: " + wide(item.is_object() ? item.value("trigger", key) : key);
             }
+            if (path == "/chatCycles") {
+                auto name = key;
+                if (auto separator = name.find('\n'); separator != name.npos) name.replace(separator, 1, " / ");
+                childLabel = L"Chat languages: " + wide(name);
+            }
             auto child = mergeNode(get(b), get(l), get(r), path + "/" + pointerKey(key), childLabel, choices, conflicts, forced);
             // Keep nulls in the ancestor so deletion conflicts survive restarts.
             out.local[key] = child.local; out.remote[key] = child.remote; out.base[key] = child.base;
@@ -158,8 +169,14 @@ void collisionPaths(const Json &j, std::set<std::string> &paths)
         if (sn.is_null() || tombstone(sn)) continue;
         auto path = "/snippets/" + pointerKey(id);
         auto key = lower(wide(sn.at("trigger").get<std::string>()));
-        auto [it, inserted] = triggers.emplace(key, path);
-        if (!inserted) { paths.insert(path); paths.insert(it->second); }
+        std::vector<std::wstring> scopes;
+        if (sn.contains("apps")) for (const auto &app : sn.at("apps")) scopes.push_back(snippetAppName(wide(app.get<std::string>())));
+        if (scopes.empty()) scopes.push_back(L"");
+        for (const auto &scope : scopes)
+        {
+            auto [it, inserted] = triggers.emplace(key + L"\n" + scope, path);
+            if (!inserted) { paths.insert(path); paths.insert(it->second); }
+        }
     }
     std::map<std::pair<UINT, UINT>, std::string> shortcuts;
     auto add = [&](const Json &text, const std::string &path) {
@@ -175,7 +192,12 @@ void collisionPaths(const Json &j, std::set<std::string> &paths)
 }
 SyncMerge mergeSyncProfile(const Bytes &base, const Bytes &local, const Bytes &remote, const std::vector<SyncChoice> &choices)
 {
-    auto l = treeProfile(parse(local)), r = treeProfile(parse(remote));
+    auto localProfile = parse(local), remoteProfile = parse(remote);
+    // Absence in an older client is not a deletion. Preserve the participating
+    // client's chat profiles until both copies understand this field.
+    if (!remoteProfile.contains("chatCycles")) remoteProfile["chatCycles"] = localProfile.value("chatCycles", Json::object());
+    if (!localProfile.contains("chatCycles")) localProfile["chatCycles"] = remoteProfile.at("chatCycles");
+    auto l = treeProfile(localProfile), r = treeProfile(remoteProfile);
     // With no common history, union independent entries; differing scalar values
     // remain on their respective devices until the user resolves the conflict.
     auto b = base.empty() ? Json::object() : treeProfile(parse(base));

src/ui.cpp

@@ -967,7 +967,131 @@ struct SettingsView
     std::vector<int> order;
     int selection = -1;
     bool filling{};
+    std::vector<std::vector<HWND>> pages;
+    bool ready{}, refreshing{};
 };
+void updateSettingsState(HWND w, SettingsView *v);
+void selectSettingsPage(HWND w, SettingsView *v)
+{
+    int selected = TabCtrl_GetCurSel(GetDlgItem(w, 260));
+    for (size_t page = 0; page < v->pages.size(); ++page)
+        for (HWND child : v->pages[page]) ShowWindow(child, (int)page == selected ? SW_SHOWNA : SW_HIDE);
+    InvalidateRect(w, nullptr, TRUE);
+}
+struct ChatLanguagesView
+{
+    HWND parent{};
+    SettingsView *settings{};
+    std::vector<std::wstring> keys;
+};
+void fillChatLanguages(HWND w, ChatLanguagesView *v)
+{
+    int index = (int)SendDlgItemMessageW(w, 710, LB_GETCURSEL, 0, 0);
+    if (index < 0 || index >= (int)v->keys.size()) return;
+    const auto &draft = v->settings->draft;
+    auto saved = draft.chatCycles.find(v->keys[index]);
+    const auto &cycle = saved == draft.chatCycles.end() ? draft.cycle : saved->second;
+    for (size_t i = 0; i < v->settings->order.size(); ++i)
+    {
+        auto &layout = v->settings->app->layouts[v->settings->order[i]];
+        SendDlgItemMessageW(w, 711, LB_SETSEL,
+            std::find(cycle.begin(), cycle.end(), layout.id) != cycle.end(), i);
+    }
+    value(w, 712, saved == draft.chatCycles.end() ? L"No profile yet. Select the languages for this chat." :
+        L"Saved profile. Select languages, or remove it to use the defaults.");
+    EnableWindow(GetDlgItem(w, 713), saved != draft.chatCycles.end());
+}
+LRESULT CALLBACK chatLanguagesProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
+{
+    auto *v = (ChatLanguagesView *)GetWindowLongPtrW(w, GWLP_USERDATA);
+    if (!v) return DefWindowProcW(w, msg, wp, lp);
+    try
+    {
+        if (msg == WM_COMMAND)
+        {
+            int id = LOWORD(wp);
+            if (id == 710 && HIWORD(wp) == LBN_SELCHANGE) { fillChatLanguages(w, v); return 0; }
+            if (id == IDOK || id == 713)
+            {
+                int selected = (int)SendDlgItemMessageW(w, 710, LB_GETCURSEL, 0, 0);
+                if (selected < 0 || selected >= (int)v->keys.size())
+                    throw std::runtime_error("Open Telegram, Telegram Web K in Chrome, or Teams, then reopen this dialog. Viber OCR is disabled.");
+                auto next = v->settings->draft;
+                if (id == 713) next.chatCycles.erase(v->keys[selected]);
+                else
+                {
+                    std::vector<std::wstring> cycle;
+                    for (size_t i = 0; i < v->settings->order.size(); ++i)
+                        if (SendDlgItemMessageW(w, 711, LB_GETSEL, i, 0) > 0)
+                            cycle.push_back(v->settings->app->layouts[v->settings->order[i]].id);
+                    if (cycle.empty()) throw std::runtime_error("Select at least one language.");
+                    next.chatCycles[v->keys[selected]] = std::move(cycle);
+                }
+                validateSettings(next);
+                v->settings->draft.chatCycles = std::move(next.chatCycles);
+                DestroyWindow(w);
+                return 0;
+            }
+            if (id == IDCANCEL) { DestroyWindow(w); return 0; }
+        }
+        if (msg == WM_CLOSE) { DestroyWindow(w); return 0; }
+        if (msg == WM_DPICHANGED) { resizeForDpi(w, wp, lp); return 0; }
+        if (msg == WM_NCDESTROY)
+        {
+            EnableWindow(v->parent, TRUE);
+            SetForegroundWindow(v->parent);
+            disposeFont(w);
+            delete v;
+            SetWindowLongPtrW(w, GWLP_USERDATA, 0);
+        }
+    }
+    catch (const std::exception &e) { error(w, e); }
+    return DefWindowProcW(w, msg, wp, lp);
+}
+void showChatLanguages(HWND parent, SettingsView *settings)
+{
+    std::set<std::wstring> keys;
+    for (const auto &[key, cycle] : settings->draft.chatCycles) keys.insert(key);
+    struct Context { std::set<std::wstring> &keys; const Settings &settings; } context{keys, settings->draft};
+    EnumWindows([](HWND candidate, LPARAM context) -> BOOL
+    {
+        if (!IsWindowVisible(candidate)) return TRUE;
+        auto &data = *(Context *)context;
+        auto key = lower(processName(candidate)) == L"chrome" ? readChromeChat(candidate) : windowChatKey(candidate);
+        if (!key.empty()) data.keys.insert(std::move(key));
+        return TRUE;
+    }, (LPARAM)&context);
+    HWND w = makeWindow(*settings->app, L"KSwitcher.ChatLanguages", L"Languages for a chat", chatLanguagesProc, 640, 524);
+    auto *v = new ChatLanguagesView{parent, settings, {keys.begin(), keys.end()}};
+    SetWindowLongPtrW(w, GWLP_HWNDPARENT, (LONG_PTR)parent);
+    SetWindowLongPtrW(w, GWLP_USERDATA, (LONG_PTR)v);
+    label(w, L"Telegram / Telegram Web (Chrome) / Teams; Viber inactive", 18, 16, 604);
+    control(w, L"LISTBOX", L"", WS_TABSTOP | WS_VSCROLL | LBS_NOTIFY | LBS_NOINTEGRALHEIGHT | WS_BORDER,
+            710, 18, 44, 604, 140);
+    for (const auto &key : v->keys)
+    {
+        auto split = key.find(L'\n');
+        auto name = std::wstring(key.starts_with(L"telegram\n") ? L"Telegram: " : key.starts_with(L"telegram-web\n") ? L"Telegram Web: " : key.starts_with(L"viber\n") ? L"Viber (inactive): " : L"Teams: ") + key.substr(split + 1);
+        SendDlgItemMessageW(w, 710, LB_ADDSTRING, 0, (LPARAM)name.c_str());
+    }
+    control(w, L"STATIC", L"Open a chat, then reopen this dialog to add it.", 0, 712, 18, 194, 604, 26);
+    label(w, L"Click languages to include (saved in the order shown)", 18, 228, 604);
+    control(w, L"LISTBOX", L"", WS_TABSTOP | WS_VSCROLL | LBS_MULTIPLESEL | LBS_NOINTEGRALHEIGHT | WS_BORDER,
+            711, 18, 256, 604, 132);
+    for (int i : settings->order)
+        SendDlgItemMessageW(w, 711, LB_ADDSTRING, 0, (LPARAM)settings->app->layouts[i].name.c_str());
+    label(w, L"Applies to Alt+Shift, Win+Space and KSwitcher Next layout.", 18, 402, 604);
+    label(w, L"Matched by chat name. Identical names share a profile. Then Save settings.", 18, 430, 604);
+    button(w, L"&Remove profile", 713, 18, 476, 170);
+    button(w, L"&Use languages", IDOK, 300, 476, 170);
+    button(w, L"&Cancel", IDCANCEL, 486, 476, 136);
+    EnableWindow(GetDlgItem(w, IDOK), !keys.empty());
+    EnableWindow(GetDlgItem(w, 713), FALSE);
+    if (!keys.empty()) { SendDlgItemMessageW(w, 710, LB_SETCURSEL, 0, 0); fillChatLanguages(w, v); }
+    EnableWindow(parent, FALSE);
+    showRequestedWindow(w);
+    SetFocus(GetDlgItem(w, 710));
+}
 void collectLayout(HWND w, SettingsView *v)
 {
     if (v->selection < 0 || v->selection >= (int)v->order.size())
@@ -1047,6 +1171,7 @@ void fillSettings(HWND w, SettingsView *v)
     v->selection = 0;
     fillLayouts(w, v);
     v->filling = false;
+    updateSettingsState(w, v);
 }
 int integer(HWND w, int id)
 {
@@ -1176,7 +1301,10 @@ LRESULT CALLBACK autoOptionsProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 auto words = parseCommaList(text);
                 std::sort(words.begin(), words.end());
                 words.erase(std::unique(words.begin(), words.end()), words.end());
-                draft.autoWords[language] = std::move(words);
+                // Opening and accepting an untouched empty dictionary must not
+                // introduce a new entry and mark Settings as changed.
+                if (!words.empty() || draft.autoWords.contains(language))
+                    draft.autoWords[language] = std::move(words);
             }
             draft.autoExcluded = parseCommaList(value(w, 404));
             draft.autoPrefixChars = value(w, 408);
@@ -1285,7 +1413,7 @@ void showAutoOptions(HWND parent, SettingsView *v)
     label(w, L"Enter punctuation without spaces or separators. These characters are kept.", 18, 530, 525);
     checkbox(w, L"Use custom &replacements (take priority over dictionaries)", 414, 18, 562, 524);
     check(w, 414, v->draft.autoReplace);
-    label(w, L"One pair per line: typo=correction (same language, letters only)", 18, 592, 525);
+    label(w, L"One pair per line: typo=correction (same language; correction may contain spaces)", 18, 592, 525);
     edit(w, 416, 18, 618, 524, 70, ES_MULTILINE | WS_VSCROLL | ES_AUTOVSCROLL | ES_WANTRETURN);
     std::wstring pairs;
     for (const auto &[from, to] : v->draft.autoReplacements) pairs += from + L"=" + to + L"\r\n";
@@ -1400,6 +1528,7 @@ void showOcrOptions(HWND parent, SettingsView *v)
     showRequestedWindow(w); SetForegroundWindow(w);
 }
 #include "ui_sync.inl"
+#include "ui_lan.inl"
 bool settingsChanged(HWND w, SettingsView *v)
 {
     try
@@ -1413,6 +1542,27 @@ bool settingsChanged(HWND w, SettingsView *v)
         return true;
     }
 }
+void updateSettingsState(HWND w, SettingsView *v)
+{
+    if (!v || !v->ready || v->filling || v->refreshing) return;
+    v->refreshing = true;
+    bool changed = settingsChanged(w, v);
+    EnableWindow(GetDlgItem(w, IDOK), changed);
+    const wchar_t *text = changed ? L"Unsaved changes — click Save to apply." : L"No unsaved changes.";
+    if (value(w, 261) != text) value(w, 261, text);
+    v->refreshing = false;
+}
+// Refresh after commands have updated controls/drafts, including early returns.
+// Saving can destroy Settings, so retrieve its state only if it still exists.
+struct SettingsStateRefresh
+{
+    HWND window;
+    ~SettingsStateRefresh()
+    {
+        if (IsWindow(window))
+            updateSettingsState(window, reinterpret_cast<SettingsView *>(GetWindowLongPtrW(window, GWLP_USERDATA)));
+    }
+};
 void closeSettings(HWND w, SettingsView *v)
 {
     if (settingsChanged(w, v))
@@ -1461,8 +1611,22 @@ LRESULT CALLBACK settingsProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
     {
         switch (msg)
         {
+        case WM_ENABLE:
+            if (wp) updateSettingsState(w, v);
+            break;
+        case WM_ACTIVATE:
+            if (LOWORD(wp) != WA_INACTIVE) updateSettingsState(w, v);
+            break;
+        case WM_NOTIFY:
+            if (((NMHDR *)lp)->idFrom == 260 && ((NMHDR *)lp)->code == TCN_SELCHANGE)
+            {
+                selectSettingsPage(w, v);
+                return 0;
+            }
+            break;
         case WM_COMMAND:
         {
+            SettingsStateRefresh refresh{w};
             int id = LOWORD(wp);
             if (id == 220 && HIWORD(wp) == LBN_SELCHANGE && !v->filling)
             {
@@ -1477,6 +1641,8 @@ LRESULT CALLBACK settingsProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             }
             if (id == 257) { showOcrOptions(w, v); return 0; }
             if (id == 258) { showSyncOptions(w, *v->app); return 0; }
+            if (id == 262) { showLan(w, *v->app); return 0; }
+            if (id == 259) { collectLayout(w, v); showChatLanguages(w, v); return 0; }
             if (id == 230)
             {
                 collectLayout(w, v);
@@ -1497,6 +1663,7 @@ LRESULT CALLBACK settingsProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             }
             if (id == IDOK)
             {
+                if (!settingsChanged(w, v)) return 0;
                 if (v->app->busy)
                     throw std::runtime_error("Wait for the current text operation to finish");
                 v->app->applySettings(collectSettings(w, v));
@@ -1582,14 +1749,27 @@ void updateSnippetEditor(HWND w, SnippetView *v)
     bool selected = v->selection >= 0 && v->selection < (int)v->snippets.size();
     value(w, 302, selected ? v->snippets[v->selection].trigger : L"");
     value(w, 303, selected ? v->snippets[v->selection].text : L"");
-    for (int id : {302, 303, 311, 312, 313})
+    std::wstring apps;
+    if (selected) for (const auto &app : v->snippets[v->selection].apps)
+    {
+        if (!apps.empty()) apps += L", ";
+        if (!app.empty()) apps += app + L".exe";
+    }
+    value(w, 315, apps);
+    bool restricted = selected && !v->snippets[v->selection].apps.empty();
+    CheckDlgButton(w, 314, restricted ? BST_CHECKED : BST_UNCHECKED);
+    for (int id : {302, 303, 311, 312, 313, 314})
         EnableWindow(GetDlgItem(w, id), selected);
+    for (int id : {315, 316, 317}) EnableWindow(GetDlgItem(w, id), selected && restricted);
 }
 void fillSnippets(HWND w, SnippetView *v)
 {
     SendDlgItemMessageW(w, 301, LB_RESETCONTENT, 0, 0);
     for (auto &sn : v->snippets)
-        SendDlgItemMessageW(w, 301, LB_ADDSTRING, 0, (LPARAM)sn.trigger.c_str());
+    {
+        auto label = sn.trigger + (sn.apps.empty() ? L" [All apps]" : L" [" + sn.apps.front() + (sn.apps.size() > 1 ? L", ...]" : L"]"));
+        SendDlgItemMessageW(w, 301, LB_ADDSTRING, 0, (LPARAM)label.c_str());
+    }
     if (v->selection >= 0)
         SendDlgItemMessageW(w, 301, LB_SETCURSEL, v->selection, 0);
     updateSnippetEditor(w, v);
@@ -1602,6 +1782,18 @@ void collectSnippet(HWND w, SnippetView *v)
         if (snippet.id.empty()) snippet.id = snippetId(snippet);
         snippet.trigger = value(w, 302);
         snippet.text = value(w, 303);
+        snippet.apps.clear();
+        if (IsDlgButtonChecked(w, 314) == BST_CHECKED)
+        {
+            std::wistringstream input(value(w, 315)); std::wstring item;
+            while (std::getline(input, item, L','))
+            {
+                auto app = snippetAppName(item);
+                if (!app.empty()) snippet.apps.push_back(app);
+            }
+            // An explicitly restricted but empty list must not become global.
+            if (snippet.apps.empty()) snippet.apps.push_back(L"");
+        }
     }
 }
 LRESULT CALLBACK snippetProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
@@ -1628,6 +1820,24 @@ LRESULT CALLBACK snippetProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
         case WM_COMMAND:
         {
             int id = LOWORD(wp);
+            if (id == 314)
+            {
+                bool restricted = IsDlgButtonChecked(w, 314) == BST_CHECKED;
+                for (int field : {315, 316, 317}) EnableWindow(GetDlgItem(w, field), restricted);
+                return 0;
+            }
+            if (id == 317)
+            {
+                auto app = value(w, 316);
+                if (!app.empty())
+                {
+                    auto current = value(w, 315);
+                    std::wistringstream input(current); std::wstring entry;
+                    while (std::getline(input, entry, L',')) if (snippetAppName(entry) == snippetAppName(app)) return 0;
+                    value(w, 315, current.empty() ? app : current + L", " + app);
+                }
+                return 0;
+            }
             if (id == 301 && HIWORD(wp) == LBN_SELCHANGE)
             {
                 collectSnippet(w, v);
@@ -1673,6 +1883,7 @@ LRESULT CALLBACK snippetProc(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 {
                     auto *parent = (SettingsView *)GetWindowLongPtrW(v->app->settingsWindow, GWLP_USERDATA);
                     parent->draft.snippets = s.snippets;
+                    updateSettingsState(v->app->settingsWindow, parent);
                 }
                 DestroyWindow(w);
                 return 0;
@@ -1815,56 +2026,98 @@ void showSettings(App &app, bool visible)
         activateWindow(target);
         return;
     }
-    HWND w = makeWindow(app, L"KSwitcher.Settings", L"KSwitcher settings", settingsProc, 780, 660, 0, false);
+    HWND w = makeWindow(app, L"KSwitcher.Settings", L"KSwitcher settings", settingsProc, 720, 510, 0, false);
     app.settingsWindow = w;
-    label(w, L"Text conversion", 18, 16);
-    checkbox(w, L"Con&vert recently typed text when nothing is selected", 201, 18, 43, 390);
-    checkbox(w, L"Switch Windows input &layout after conversion", 202, 18, 70, 390);
-    checkbox(w, L"Record clip&board history", 203, 18, 106);
-    checkbox(w, L"Start with &Windows", 204, 18, 133);
-    checkbox(w, L"Start with Windows as ad&ministrator", 206, 18, 160, 395);
-    checkbox(w, L"&Keep screen awake", 205, 18, 184, 210);
-    checkbox(w, L"Write lo&g", 208, 240, 184, 160);
-    label(w, L"Click a shortcut and press the desired keys", 420, 16, 350);
-    const wchar_t *names[] = {L"Next layout", L"Change case", L"Transliterate", L"Undo",
-                              L"Clipboard history", L"Screen capture"};
+    auto *v = (SettingsView *)GetWindowLongPtrW(w, GWLP_USERDATA);
+    INITCOMMONCONTROLSEX tabsInit{sizeof(tabsInit), ICC_TAB_CLASSES};
+    InitCommonControlsEx(&tabsInit);
+    HWND tabs = control(w, WC_TABCONTROLW, L"", WS_TABSTOP, 260, 18, 16, 684, 32);
+    const wchar_t *tabNames[] = {L"General", L"Languages", L"Shortcuts", L"Clipboard", L"Tools"};
+    for (int i = 0; i < 5; ++i)
+    {
+        TCITEMW item{}; item.mask = TCIF_TEXT; item.pszText = const_cast<wchar_t *>(tabNames[i]);
+        TabCtrl_InsertItem(tabs, i, &item);
+    }
+    size_t start = windowLayoutState(w)->controls.size();
+    auto page = [&]
+    {
+        std::vector<HWND> children;
+        const auto &controls = windowLayoutState(w)->controls;
+        for (size_t i = start; i < controls.size(); ++i) children.push_back(controls[i].first);
+        v->pages.push_back(std::move(children));
+        start = controls.size();
+    };
+    label(w, L"Text conversion", 24, 76, 650);
+    checkbox(w, L"Con&vert recently typed text when nothing is selected", 201, 24, 110, 660);
+    checkbox(w, L"Switch Windows input &layout after conversion", 202, 24, 146, 660);
+    checkbox(w, L"Automatic correction (e&xperimental)", 207, 24, 182, 390);
+    button(w, L"&Correction options...", 255, 454, 180, 230);
+    label(w, L"Windows integration", 24, 254, 650);
+    checkbox(w, L"Start with &Windows", 204, 24, 288, 660);
+    checkbox(w, L"Start with Windows as ad&ministrator", 206, 24, 324, 660);
+    checkbox(w, L"&Keep screen awake", 205, 24, 360, 660);
+    page();
+
+    label(w, L"Default language cycle — top to bottom", 24, 76, 650);
+    control(w, L"LISTBOX", L"", WS_TABSTOP | WS_VSCROLL | LBS_NOTIFY | LBS_NOINTEGRALHEIGHT | WS_BORDER,
+            220, 24, 108, 410, 240);
+    button(w, L"Move u&p", 232, 454, 108, 110);
+    button(w, L"Move &down", 233, 574, 108, 110);
+    checkbox(w, L"&Include in cycle", 230, 454, 154, 230);
+    label(w, L"Direct layout shortcut", 454, 206, 230);
+    hotkeyEdit(app, w, 231, 454, 234, 230);
+    label(w, L"Backspace / Delete clears it", 454, 270, 230);
+    button(w, L"Re&fresh layouts", 253, 454, 322, 230);
+    button(w, L"Languages for a &chat...", 259, 24, 378, 230);
+    label(w, L"Telegram / Telegram Web (Chrome) / Teams", 272, 382, 412);
+    page();
+
+    label(w, L"Click a shortcut field and press the desired keys", 24, 76, 660);
+    const wchar_t *names[] = {L"Next layout", L"Change case", L"Transliterate", L"Undo", L"Clipboard history", L"Screen capture"};
     for (int i = 0; i < 6; ++i)
     {
-        label(w, names[i], 420, 48 + i * 30, 115);
-        hotkeyEdit(app, w, 210 + i, 540, 44 + i * 30, 220);
+        label(w, names[i], 24, 116 + i * 40, 180);
+        hotkeyEdit(app, w, 210 + i, 230, 112 + i * 40, 454);
     }
-    checkbox(w, L"Open editor after screen capt&ure", 209, 420, 224, 340);
-    checkbox(w, L"Automatic correction (e&xperimental)", 207, 18, 210, 395);
-    label(w, L"Layout cycle — top to bottom", 18, 240, 400);
-    control(w, L"LISTBOX", L"", WS_TABSTOP | WS_VSCROLL | LBS_NOTIFY | LBS_NOINTEGRALHEIGHT | WS_BORDER, 220,
-            18, 262, 470, 172);
-    button(w, L"Move u&p", 232, 504, 262, 120);
-    button(w, L"Move &down", 233, 632, 262, 128);
-    checkbox(w, L"&Include in cycle", 230, 504, 300, 240);
-    label(w, L"Direct layout shortcut", 504, 332, 240);
-    hotkeyEdit(app, w, 231, 504, 356, 256);
-    label(w, L"Backspace / Delete clears a shortcut", 504, 382, 256);
-    button(w, L"Re&fresh layouts", 253, 504, 408, 150);
-    label(w, L"History limits", 18, 444);
-    label(w, L"Items", 18, 478, 50);
-    edit(w, 240, 70, 474, 90);
-    label(w, L"Total MiB", 180, 478, 75);
-    edit(w, 241, 260, 474, 90);
-    label(w, L"Per item MiB", 370, 478, 100);
-    edit(w, 242, 475, 474, 80);
-    button(w, L"Clear &history…", 254, 580, 474, 180);
-    label(w, L"Exclude applications (process names, comma-separated)", 18, 516, 700);
-    edit(w, 243, 18, 544, 742);
-    button(w, L"&Auto-correction options…", 255, 18, 575, 240);
-    button(w, L"View l&og…", 256, 278, 575, 220);
-    button(w, L"OCR op&tions…", 257, 518, 575, 242);
-    button(w, L"Impo&rt settings…", 250, 18, 606, 145);
-    button(w, L"&Export settings…", 251, 173, 606, 145);
-    button(w, L"S&nippets…", 252, 328, 606, 110);
-    button(w, L"S&ync...", 258, 448, 606, 90);
-    button(w, L"&Save", IDOK, 548, 606, 100);
-    button(w, L"&Cancel", IDCANCEL, 660, 606, 100);
-    fillSettings(w, (SettingsView *)GetWindowLongPtrW(w, GWLP_USERDATA));
+    checkbox(w, L"Open editor after screen capt&ure", 209, 24, 378, 660);
+    page();
+
+    checkbox(w, L"Record clip&board history", 203, 24, 80, 660);
+    label(w, L"History limits", 24, 140, 660);
+    label(w, L"Items", 24, 176, 180);
+    label(w, L"Total MiB", 254, 176, 180);
+    label(w, L"Per item MiB", 484, 176, 180);
+    edit(w, 240, 24, 204, 200);
+    edit(w, 241, 254, 204, 200);
+    edit(w, 242, 484, 204, 200);
+    button(w, L"Clear &history...", 254, 24, 258, 200);
+    label(w, L"Exclude applications (process names, comma-separated)", 24, 330, 660);
+    edit(w, 243, 24, 362, 660);
+    page();
+
+    label(w, L"Additional tools and preferences", 24, 76, 660);
+    button(w, L"S&nippets...", 252, 24, 116, 210);
+    label(w, L"Manage reusable text and expansion triggers.", 254, 120, 430);
+    button(w, L"OCR op&tions...", 257, 24, 180, 210);
+    label(w, L"Configure text recognition from images.", 254, 184, 430);
+    button(w, L"S&ync...", 258, 24, 244, 210);
+    label(w, L"Synchronize preferences between computers.", 254, 248, 430);
+    button(w, L"View l&og...", 256, 24, 308, 210);
+    label(w, L"Inspect recent operations and diagnostics.", 254, 312, 430);
+    checkbox(w, L"Write lo&g", 208, 24, 378, 210);
+    button(w, L"KSwitcher &computers...", 262, 254, 374, 260);
+    page();
+
+    control(w, L"STATIC", L"No unsaved changes.", 0, 261, 18, 430, 684, 24);
+    button(w, L"Impo&rt...", 250, 18, 466, 125);
+    button(w, L"&Export...", 251, 155, 466, 125);
+    button(w, L"&Save", IDOK, 490, 466, 100);
+    button(w, L"&Cancel", IDCANCEL, 602, 466, 100);
+    fillSettings(w, v);
+    v->ready = true;
+    updateSettingsState(w, v);
+    TabCtrl_SetCurSel(tabs, 0);
+    selectSettingsPage(w, v);
     if (visible)
     {
         showRequestedWindow(w);
@@ -1878,22 +2131,34 @@ void showSnippets(App &app)
         SetForegroundWindow(app.snippetsWindow);
         return;
     }
-    HWND w = makeWindow(app, L"KSwitcher.Snippets", L"Text snippets", snippetProc, 740, 520);
+    HWND w = makeWindow(app, L"KSwitcher.Snippets", L"Text snippets", snippetProc, 740, 620);
     app.snippetsWindow = w;
     label(w, L"Triggers", 16, 16);
     control(w, L"LISTBOX", L"", WS_TABSTOP | WS_VSCROLL | LBS_NOTIFY | LBS_NOINTEGRALHEIGHT | WS_BORDER, 301,
-            16, 44, 200, 380);
-    button(w, L"&Add", 310, 16, 438, 90);
-    button(w, L"&Delete", 311, 116, 438, 100);
+            16, 44, 200, 480);
+    button(w, L"&Add", 310, 16, 538, 90);
+    button(w, L"&Delete", 311, 116, 538, 100);
     label(w, L"&Trigger (for example ;addr)", 236, 16, 470);
     edit(w, 302, 236, 44, 488);
-    label(w, L"&Replacement text", 236, 82, 480);
-    edit(w, 303, 236, 110, 488, 270, ES_MULTILINE | ES_WANTRETURN | ES_AUTOVSCROLL | WS_VSCROLL);
-    control(w, L"STATIC", L"{cursor}: caret; {enter}: press Enter after insertion.\nUse {{cursor}} / {{enter}} for literal markers.", 0, 0, 236, 392, 488, 36);
-    button(w, L"Insert cursor &marker", 312, 236, 430, 190);
-    button(w, L"Insert &Enter marker", 313, 436, 430, 190);
-    button(w, L"&Save", IDOK, 510, 478, 100);
-    button(w, L"&Cancel", IDCANCEL, 624, 478, 100);
+    control(w, L"BUTTON", L"Only in these &applications (unchecked: everywhere)", WS_TABSTOP | BS_AUTOCHECKBOX, 314, 236, 82, 488, 24);
+    edit(w, 315, 236, 112, 488);
+    control(w, L"COMBOBOX", L"", WS_TABSTOP | CBS_DROPDOWNLIST | WS_VSCROLL, 316, 236, 148, 364, 200);
+    button(w, L"Add a&pp", 317, 612, 145, 112);
+    std::set<std::wstring> apps;
+    EnumWindows([](HWND candidate, LPARAM context)->BOOL {
+        if (IsWindowVisible(candidate)) { auto name = processName(candidate); if (!name.empty()) ((std::set<std::wstring>*)context)->insert(lower(name) + L".exe"); }
+        return TRUE;
+    }, (LPARAM)&apps);
+    for (const auto &name : apps) SendDlgItemMessageW(w, 316, CB_ADDSTRING, 0, (LPARAM)name.c_str());
+    SendDlgItemMessageW(w, 316, CB_SETCURSEL, 0, 0);
+    label(w, L"Process names, comma-separated; e.g. chrome.exe, ms-teams.exe", 236, 182, 488);
+    label(w, L"&Replacement text", 236, 212, 480);
+    edit(w, 303, 236, 240, 488, 240, ES_MULTILINE | ES_WANTRETURN | ES_AUTOVSCROLL | WS_VSCROLL);
+    control(w, L"STATIC", L"{cursor}: caret; {enter}: press Enter after insertion.\nUse {{cursor}} / {{enter}} for literal markers.", 0, 0, 236, 492, 488, 36);
+    button(w, L"Insert cursor &marker", 312, 236, 530, 190);
+    button(w, L"Insert &Enter marker", 313, 436, 530, 190);
+    button(w, L"&Save", IDOK, 510, 578, 100);
+    button(w, L"&Cancel", IDCANCEL, 624, 578, 100);
     fillSnippets(w, (SnippetView *)GetWindowLongPtrW(w, GWLP_USERDATA));
     showRequestedWindow(w);
     SetForegroundWindow(w);

src/ui_lan.inl

@@ -0,0 +1,133 @@
+// Uses the resident service; the configurator never opens a discovery socket.
+struct LanView
+{
+    HWND parent{};
+    App *app{};
+    nlohmann::json snapshot;
+    std::vector<std::string> ids;
+    std::wstring error;
+    bool positionEdited{};
+};
+nlohmann::json lanRequest(App &app,const nlohmann::json &request)
+{
+    auto text=request.dump(); auto reply=app.lanCommand(Bytes(text.begin(),text.end()));
+    return nlohmann::json::parse(reply);
+}
+std::string selectedLan(HWND w,LanView &v)
+{
+    auto index=SendDlgItemMessageW(w,702,LB_GETCURSEL,0,0);
+    return index>=0 && size_t(index)<v.ids.size() ? v.ids[size_t(index)] : "";
+}
+void refreshLan(HWND w,LanView &v)
+{
+    auto selected=selectedLan(w,v);
+    auto next=lanRequest(*v.app,{{"action","status"}});
+    if(v.snapshot.is_null()||v.snapshot["peers"]!=next["peers"])
+    {
+        SendDlgItemMessageW(w,702,WM_SETREDRAW,FALSE,0);
+        SendDlgItemMessageW(w,702,LB_RESETCONTENT,0,0); v.ids.clear();
+        for(const auto &peer:next["peers"])
+        {
+            auto id=peer.at("id").get<std::string>(); v.ids.push_back(id);
+            std::wstring state=!peer.at("online").get<bool>() ? L"Offline" : peer.at("verified").get<bool>() ? L"Paired / verified" :
+                peer.at("paired").get<bool>() ? L"Paired / checking identity" : L"Available / not paired";
+            auto text=wide(peer.at("name").get<std::string>())+L"  ["+wide(id.substr(0,8))+L"]  — "+state;
+            auto row=SendDlgItemMessageW(w,702,LB_ADDSTRING,0,(LPARAM)text.c_str());
+            if(id==selected) SendDlgItemMessageW(w,702,LB_SETCURSEL,row,0);
+        }
+        SendDlgItemMessageW(w,702,WM_SETREDRAW,TRUE,0); InvalidateRect(GetDlgItem(w,702),nullptr,TRUE);
+    }
+    v.snapshot=std::move(next);
+    bool enabled=v.snapshot.at("enabled"), pending=v.snapshot.at("pending"), online=false, paired=false;
+    for(const auto &peer:v.snapshot["peers"]) if(peer.at("id")==selected) {online=peer.at("online");paired=peer.at("paired");}
+    value(w,701,enabled ? L"&Disable discovery" : L"&Enable discovery");
+    value(w,709,L"This KSwitcher: "+wide(v.snapshot.at("name").get<std::string>())+L"  ["+wide(v.snapshot.at("id").get<std::string>().substr(0,8))+L"]");
+    value(w,708,v.error.empty() ? wide(v.snapshot.at("status").get<std::string>()) : v.error);
+    value(w,710,v.ids.empty() ? (enabled ? L"No KSwitcher found. Enable discovery on the other PC too. UDP 45883 must be allowed on your private network." : L"Discovery is disabled on this computer.") : L"Select the matching KSwitcher name and ID shown on the other computer.");
+    EnableWindow(GetDlgItem(w,705),enabled&&online&&!pending);
+    EnableWindow(GetDlgItem(w,706),pending);
+    EnableWindow(GetDlgItem(w,707),paired);
+    for(int id:{703,704}) EnableWindow(GetDlgItem(w,id),enabled&&!pending);
+    EnableWindow(GetDlgItem(w,715),enabled&&paired);
+    EnableWindow(GetDlgItem(w,716),v.snapshot.value("shareInput",false));
+    for(int id:{711,712,713,714})EnableWindow(GetDlgItem(w,id),paired);
+    if(!v.positionEdited)CheckRadioButton(w,711,714,711+v.snapshot.value("inputEdge",1));
+    int position=1;for(int i=0;i<4;++i)if(checked(w,711+i))position=i;
+    const wchar_t *diagrams[]={L"[ Other PC ]  ←  [ This PC ]",L"[ This PC ]  →  [ Other PC ]",L"Other PC is ABOVE this PC",L"Other PC is BELOW this PC"};
+    value(w,719,diagrams[position]);
+    auto inputStatus=wide(v.snapshot.value("inputStatus",std::string("Input sharing disabled.")));
+    auto mode=v.snapshot.value("controlMode",0);
+    if(mode==2)inputStatus=L"Mouse and keyboard control the OTHER PC. Ctrl+Alt+Esc returns here.";
+    else if(mode==3)inputStatus=L"This PC is controlled remotely. Local physical input takes control back.";
+    value(w,718,inputStatus);
+}
+LRESULT CALLBACK lanProc(HWND w,UINT msg,WPARAM wp,LPARAM lp)
+{
+    if(msg==WM_DPICHANGED) {resizeForDpi(w,wp,lp);return 0;}
+    auto v=(LanView*)GetWindowLongPtrW(w,GWLP_USERDATA);
+    if(!v) return DefWindowProcW(w,msg,wp,lp);
+    if(msg==WM_DESTROY) {KillTimer(w,1);EnableWindow(v->parent,TRUE);SetForegroundWindow(v->parent);delete v;SetWindowLongPtrW(w,GWLP_USERDATA,0);return 0;}
+    if(msg==WM_CLOSE||(msg==WM_COMMAND&&LOWORD(wp)==IDCANCEL)) {DestroyWindow(w);return 0;}
+    try
+    {
+        if(msg==WM_TIMER) {refreshLan(w,*v);return 0;}
+        if(msg==WM_COMMAND)
+        {
+            int id=LOWORD(wp); auto peer=selectedLan(w,*v);
+            if(id==702&&HIWORD(wp)==LBN_SELCHANGE) {v->positionEdited=false;refreshLan(w,*v);return 0;}
+            if(HIWORD(wp)!=BN_CLICKED) return DefWindowProcW(w,msg,wp,lp);
+            v->error.clear();
+            if(id==701) lanRequest(*v->app,{{"action","enable"},{"enabled",!v->snapshot.value("enabled",false)}});
+            if(id==704)
+            {
+                auto code=lanRequest(*v->app,{{"action","code"}}).at("code").get<std::string>();
+                std::string grouped; for(size_t i=0;i<code.size();++i) {if(i&&i%4==0) grouped+='-';grouped+=code[i];}
+                value(w,703,wide(grouped)); SetFocus(GetDlgItem(w,703)); SendDlgItemMessageW(w,703,EM_SETSEL,0,-1);
+            }
+            if(id==705) {lanRequest(*v->app,{{"action","pair"},{"peer",peer},{"code",utf8(value(w,703))}});value(w,703,L"");}
+            if(id==706) lanRequest(*v->app,{{"action","cancel"}});
+            if(id==707) lanRequest(*v->app,{{"action","forget"},{"peer",peer}});
+            if(id>=711&&id<=714) v->positionEdited=true;
+            if(id==715)
+            {
+                int position=1;for(int i=0;i<4;++i)if(checked(w,711+i))position=i;
+                lanRequest(*v->app,{{"action","input"},{"enabled",true},{"peer",peer},{"edge",position}});
+                v->positionEdited=false;
+            }
+            if(id==716)lanRequest(*v->app,{{"action","input"},{"enabled",false}});
+            refreshLan(w,*v); return 0;
+        }
+    }
+    catch(const std::exception &e) {v->error=wide(e.what());value(w,708,v->error);}
+    return DefWindowProcW(w,msg,wp,lp);
+}
+void showLan(HWND parent,App &app)
+{
+    HWND w=makeWindow(app,L"KSwitcher.LAN",L"KSwitcher computers — mouse and keyboard",lanProc,740,790);
+    SetWindowLongPtrW(w,GWLP_HWNDPARENT,(LONG_PTR)parent);
+    auto v=new LanView{parent,&app};SetWindowLongPtrW(w,GWLP_USERDATA,(LONG_PTR)v);
+    label(w,L"Find running KSwitcher instances on your local network and pair them.",18,16,700);
+    control(w,L"STATIC",L"",0,709,18,45,700,24);
+    button(w,L"&Enable discovery",701,18,78,210);
+    label(w,L"Only enabled KSwitcher instances announce themselves.",244,82,470);
+    control(w,L"LISTBOX",L"",WS_TABSTOP|WS_VSCROLL|WS_BORDER|LBS_NOTIFY|LBS_NOINTEGRALHEIGHT,702,18,120,700,150);
+    control(w,L"STATIC",L"",0,710,18,278,700,40);
+    label(w,L"Same pairing c&ode on both computers",18,327,700);
+    edit(w,703,18,355,470);SendDlgItemMessageW(w,703,EM_SETLIMITTEXT,80,0);
+    button(w,L"&Generate code",704,504,354,214);
+    label(w,L"Generate once, enter that code on both PCs, select each other, then click Pair on both.",18,392,700);
+    button(w,L"&Pair",705,18,424,140);button(w,L"Cancel &pairing",706,174,424,160);button(w,L"&Forget pair",707,350,424,160);
+    control(w,L"STATIC",L"",0,708,18,466,700,40);
+    label(w,L"Selected paired computer stands relative to this PC:",18,512,700);
+    const wchar_t *positions[]={L"← &Left",L"&Right →",L"↑ &Above",L"↓ &Below"};
+    for(int i=0;i<4;++i)control(w,L"BUTTON",positions[i],WS_TABSTOP|BS_AUTORADIOBUTTON|(i==0?WS_GROUP:0),711+i,18+i*175,540,166,28);
+    control(w,L"STATIC",L"",SS_CENTER,719,18,578,700,28);
+    button(w,L"Apply position / enable &input",715,18,620,330);
+    button(w,L"&Stop input sharing",716,370,620,240);
+    control(w,L"STATIC",L"",0,718,18,660,700,40);
+    control(w,L"STATIC",L"Choose opposite sides on the two PCs (right ↔ left, above ↔ below). Changes apply immediately. Keyboard follows the mouse. Clipboard sharing is not included yet.",0,720,18,706,700,36);
+    button(w,L"&Close",IDCANCEL,618,748,100);
+    EnableWindow(parent,FALSE);showRequestedWindow(w);SetForegroundWindow(w);
+    SetTimer(w,1,1000,nullptr);
+    try {refreshLan(w,*v);} catch(const std::exception &e){v->error=wide(e.what());value(w,708,v->error);}
+}

src/update.h

@@ -2,7 +2,7 @@
 #include "platform.h"
 namespace ks
 {
-inline constexpr wchar_t AppVersion[] = L"0.6.46";
+inline constexpr wchar_t AppVersion[] = L"0.6.56";
 inline constexpr UINT UpdateMessage = WM_APP + 7;
 inline constexpr UINT UpdateCheckIntervalMs = 6 * 60 * 60 * 1000;
 inline constexpr UINT UpdateNotificationRetryMs = 5 * 60 * 1000;

src/viber_ocr.inc

@@ -0,0 +1,82 @@
+// Experimental Viber header OCR; never called on the keyboard hook thread.
+#include <uiautomation.h>
+#include <mutex>
+namespace ks {
+namespace {
+std::mutex viberMutex;
+HWND viberWindow{};
+std::wstring viberKey;
+ULONGLONG viberTime{};
+std::wstring elementClass(IUIAutomationElement *e) {
+ BSTR s{}; e->get_CurrentClassName(&s); std::wstring out=s?s:L""; SysFreeString(s); return out;
+}
+bool findViberHeader(IUIAutomationTreeWalker *walker,IUIAutomationElement *e,RECT &pane,RECT &search,int depth,int &budget) {
+ if(depth>5 || --budget<0) return false;
+ bool stack=elementClass(e).starts_with(L"StackView_");
+ Com<IUIAutomationElement> child;walker->GetFirstChildElement(e,child.out());
+ bool found=false,info=false;
+ while(child.p && --budget>0) {
+  if(stack) {
+   auto name=elementClass(child.p);
+   if(name.starts_with(L"SearchButton_")){child->get_CurrentBoundingRectangle(&search);found=true;}
+   if(name.starts_with(L"InfoButton_")) info=true;
+  } else if(findViberHeader(walker,child.p,pane,search,depth+1,budget)) return true;
+  Com<IUIAutomationElement> next;walker->GetNextSiblingElement(child.p,next.out());
+  child.p->Release();child.p=next.p;next.p=nullptr;
+ }
+ if(found && info){e->get_CurrentBoundingRectangle(&pane);return true;}
+ return false;
+}
+Pixels viberHeader(HWND window) {
+ if(!IsWindow(window)||IsIconic(window)) return {};
+ Com<IUIAutomation2> automation;
+ check(CoCreateInstance(CLSID_CUIAutomation8,nullptr,CLSCTX_INPROC_SERVER,IID_IUIAutomation2,(void**)automation.out()));
+ automation->put_ConnectionTimeout(200);automation->put_TransactionTimeout(200);
+ Com<IUIAutomationElement> root;check(automation->ElementFromHandle(window,root.out()));
+ Com<IUIAutomationTreeWalker> walker;check(automation->get_RawViewWalker(walker.out()));
+ RECT pane{},search{},rect{};int budget=160;
+ if(!findViberHeader(walker.p,root.p,pane,search,0,budget)||!GetWindowRect(window,&rect)) return {};
+ double scale=GetDpiForWindow(window)/96.0;
+ int x=pane.left+int(76*scale)-rect.left,y=search.top-int(12*scale)-rect.top;
+ int width=search.left-int(12*scale)-rect.left-x,height=int(28*scale);
+ int ww=rect.right-rect.left,wh=rect.bottom-rect.top;
+ if(width<30||height<10||x<0||y<0||x+width>ww||y+height>wh||uint64_t(ww)*wh>16000000) return {};
+ HDC dc=CreateCompatibleDC(nullptr);BITMAPINFO bi{};bi.bmiHeader.biSize=sizeof(BITMAPINFOHEADER);
+ bi.bmiHeader.biWidth=ww;bi.bmiHeader.biHeight=-wh;bi.bmiHeader.biPlanes=1;bi.bmiHeader.biBitCount=32;
+ void *bits{};HBITMAP bitmap=CreateDIBSection(dc,&bi,DIB_RGB_COLORS,&bits,nullptr,0);
+ if(!bitmap){DeleteDC(dc);return {};}
+ auto old=SelectObject(dc,bitmap);Pixels p;
+ if(PrintWindow(window,dc,2)) {
+  p.width=width;p.height=height;p.bgra.resize(size_t(width)*height*4);
+  for(int row=0;row<height;++row) memcpy(p.bgra.data()+size_t(row)*width*4,(BYTE*)bits+(size_t(y+row)*ww+x)*4,size_t(width)*4);
+ }
+ SelectObject(dc,old);DeleteObject(bitmap);DeleteDC(dc);return p;
+}
+}
+std::wstring cachedViberChat(HWND window) {
+ std::lock_guard lock(viberMutex);
+ return window==viberWindow && GetTickCount64()-viberTime<2000 ? viberKey : L"";
+}
+std::wstring recognizeViberChat(HWND window,const Settings &settings) {
+ std::wstring key;
+ try {
+  auto hr=CoInitializeEx(nullptr,COINIT_MULTITHREADED);
+  struct Apartment {bool owned;~Apartment(){if(owned)CoUninitialize();}} apartment{SUCCEEDED(hr)};
+  auto context=SetThreadDpiAwarenessContext(DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2);
+  struct Dpi {DPI_AWARENESS_CONTEXT old;~Dpi(){if(old)SetThreadDpiAwarenessContext(old);}} dpi{context};
+  auto before=viberHeader(window);
+  if(!before.bgra.empty()) {
+   Settings options=settings;options.useTesseract=true;
+   Clip clip;clip.formats.push_back(imageDib(before));
+   auto title=recognizeText(clip,options);
+   while(!title.empty() && iswspace(title.back())) title.pop_back();
+   while(!title.empty() && iswspace(title.front())) title.erase(0,1);
+   auto after=viberHeader(window);
+   if(!title.empty() && title.size()<512 && title.find_first_of(L"\r\n")==title.npos && before.width==after.width && before.height==after.height && before.bgra==after.bgra)
+    key=L"viber\n"+title;
+  }
+ } catch(...) {}
+ {std::lock_guard lock(viberMutex);viberWindow=window;viberKey=key;viberTime=GetTickCount64();}
+ return key;
+}
+}

tests/chat_profiles.cpp

@@ -0,0 +1,343 @@
+#include "app.h"
+#include "ocr.h"
+#include "screenshot.h"
+#include "lan_pairing.h"
+#include <iostream>
+#include <commctrl.h>
+
+namespace
+{
+int passed{};
+void require(bool ok, const char *message)
+{
+    if (!ok) throw std::runtime_error(message);
+    ++passed;
+}
+void contextChecks()
+{
+    ks::Settings scoped;
+    scoped.snippets = {{L";sig", L"Global", L"global"},
+        {L";sig", L"Work", L"teams", {L"MS-Teams.EXE", L"OUTLOOK.exe"}},
+        {L";sig", L"Personal", L"telegram", {L"telegram"}}};
+    ks::validateSettings(scoped);
+    require(ks::snippetAppPriority(scoped.snippets[1], L"ms-teams") > ks::snippetAppPriority(scoped.snippets[0], L"ms-teams"), "app snippet precedes global regardless of list order");
+    require(ks::snippetAppPriority(scoped.snippets[1], L"Telegram.exe") == 0, "restricted snippet cannot run in another app");
+    require(ks::snippetAppPriority(scoped.snippets[1], L"Outlook.EXE") == 2, "restricted snippet also runs in its second application");
+    require(ks::snippetAppPriority(scoped.snippets[0], L"") == 1, "legacy/global snippets remain available");
+    auto scopedRoundtrip = ks::decodeSettings(ks::encodeSettings(scoped), {});
+    require(scopedRoundtrip.snippets[1].apps == std::vector<std::wstring>{L"ms-teams", L"outlook"}, "scopes normalize and persist");
+    require(scopedRoundtrip.snippets[0].apps.empty(), "absent scope remains global");
+    auto collision = scoped; collision.snippets.push_back({L";SIG", L"Ambiguous", L"other", {L"outlook.exe"}});
+    bool collisionRejected=false;try { ks::validateSettings(collision); } catch(...) { collisionRejected=true; }
+    require(collisionRejected, "overlapping app lists with same trigger rejected");
+    auto emptyScope = scoped; emptyScope.snippets[1].apps={L""};
+    bool emptyRejected=false;try { ks::validateSettings(emptyScope); } catch(...) { emptyRejected=true; }
+    require(emptyRejected, "empty explicit restriction cannot become global");
+    require(ks::telegramWebKey(L"https://web.telegram.org/k/#@Example") == L"telegram-web\n@example", "Telegram Web username normalized");
+    require(ks::telegramWebKey(L"web.telegram.org/a/#-123456") == L"telegram-web\n-123456", "Telegram Web numeric peer");
+    for (const auto *url : {L"https://web.telegram.org/k/", L"https://web.telegram.org.evil/k/#@example",
+         L"http://web.telegram.org/k/#@example", L"https://evil/web.telegram.org/k/#@example",
+         L"https://web.telegram.org/k/#@example?foo", L"https://web.telegram.org/k/#@",
+         L"https://web.telegram.org/k/#-", L"https://web.telegram.org/k/#settings"})
+        require(ks::telegramWebKey(url).empty(), "Reject non-chat or untrusted Telegram Web URL");
+    const auto key = ks::chatKey(L"Telegram.exe", L"\u200eТестовий чат \u2013 (12)");
+    require(key == L"telegram\nТестовий чат", "Telegram unread suffix");
+    require(ks::chatKey(L"Telegram", L"Тестовий чат") == key, "stable unread profile");
+    require(ks::chatKey(L"Telegram", L"Team (2026)") == L"telegram\nTeam (2026)", "preserve parentheses");
+    require(ks::chatKey(L"Telegram", L"Telegram").empty(), "no profile on home");
+    require(ks::chatKey(L"Viber", L"Rakuten Viber").empty(), "Viber generic window title is not a chat");
+    require(ks::chatKey(L"ms-teams", L"Chat | Alice | Microsoft Teams") == L"ms-teams\nAlice", "Teams chat");
+    require(ks::chatKey(L"ms-teams", L"Calendar | Alice | Microsoft Teams").empty(), "Teams calendar excluded");
+    require(ks::chatKey(L"ms-teams", L"Chat | Microsoft Teams").empty(), "Teams chat home excluded");
+    require(ks::chatKey(L"other", L"Chat | Alice | Microsoft Teams").empty(), "app identity required");
+    ks::Settings settings;
+    settings.cycle = {L"win:04090409", L"win:04220422", L"win:04190419"};
+    settings.chatCycles[key] = {settings.cycle[1], settings.cycle[0]};
+    settings.chatCycles[L"viber\nТестовий контакт"] = {settings.cycle[1], settings.cycle[0]};
+    settings.chatCycles[L"telegram-web\n@example"] = {settings.cycle[0], settings.cycle[1]};
+    std::vector<ks::Layout> installed(3);
+    for (size_t i = 0; i < installed.size(); ++i)
+    {
+        installed[i].id = settings.cycle[i];
+        installed[i].handle = (HKL)(uintptr_t)(i + 1);
+    }
+    auto subset = settings.chatCycles[key];
+    require(ks::nextChatLayout(subset, installed, installed[1].handle, false) == installed[0].handle, "cycle within subset");
+    require(ks::nextChatLayout(subset, installed, installed[0].handle, false) == installed[1].handle, "wrap skips excluded language");
+    require(ks::nextChatLayout(subset, installed, installed[2].handle, false) == installed[1].handle, "outside subset enters first language");
+    require(ks::nextChatLayout(settings.cycle, installed, installed[0].handle, true) == installed[2].handle, "reverse wraps");
+    require(ks::nextChatLayout({settings.cycle[1]}, installed, installed[0].handle, false) == installed[1].handle, "single language selects allowed layout");
+    require(!ks::nextChatLayout({L"win:04070407"}, installed, installed[0].handle, false), "missing layout is not activated");
+    require(ks::nextConversionLayout(L"", installed, {1}, 0) == 1, "conversion uses single allowed language");
+    require(ks::chatCycle(settings, key, installed) == settings.chatCycles[key], "profile order");
+    require(ks::chatCycle(settings, L"telegram\nOther", installed) == settings.cycle, "unknown fallback");
+    require(ks::decodeSettings(ks::encodeSettings(settings), installed).chatCycles == settings.chatCycles, "Unicode roundtrip");
+    require(ks::decodeSettings({}, installed).chatCycles.empty(), "old defaults without profiles");
+    auto withoutProfiles = settings;
+    withoutProfiles.chatCycles.clear();
+    require(ks::sharedSyncSettings(settings) != ks::sharedSyncSettings(withoutProfiles), "profiles included in sync");
+    auto restored = ks::restoreSyncSettings(ks::sharedSyncSettings(settings), withoutProfiles, installed, false);
+    require(restored.chatCycles == settings.chatCycles, "sync transfers chat profiles to another PC");
+    settings.chatCycles[key] = {settings.cycle[1]};
+    require(ks::chatCycle(settings, key, installed).size() == 1, "one-language profile");
+    settings.chatCycles[key] = {L"win:04070407"};
+    require(ks::chatCycle(settings, key, installed) == settings.cycle, "missing layouts fallback");
+    settings.chatCycles[key] = {};
+    bool rejected = false;
+    try { ks::encodeSettings(settings); } catch (...) { rejected = true; }
+    require(rejected, "empty profile rejected");
+    settings.chatCycles[key] = {settings.cycle[0], settings.cycle[0]};
+    rejected = false;
+    try { ks::encodeSettings(settings); } catch (...) { rejected = true; }
+    require(rejected, "duplicate profile layout rejected");
+    ks::ChatSwitchHook hook;
+    require(hook.update(VK_SPACE, true, MOD_WIN, false) == 0, "unprofiled Win+Space passes");
+    require(hook.update(VK_SPACE, true, MOD_WIN, true) == 1, "Win+Space forward");
+    require(hook.update(VK_SPACE, true, MOD_WIN, true) == -1, "consume repeat");
+    require(hook.update(VK_SPACE, false, 0, false) == -1, "release after profile change");
+    require(hook.update(VK_SPACE, true, MOD_WIN | MOD_SHIFT, true) == 2, "reverse cycle");
+    hook.update(VK_SPACE, false, 0, true);
+    require(hook.update(VK_LSHIFT, true, MOD_ALT, true) == 1, "Alt then Shift");
+    hook.update(VK_LSHIFT, false, 0, true);
+    require(hook.update(VK_LMENU, true, MOD_SHIFT, true) == 1, "Shift then Alt");
+    hook.update(VK_LMENU, false, 0, true);
+    require(hook.update(VK_LSHIFT, true, MOD_ALT | MOD_CONTROL, true) == 0, "do not consume Ctrl+Alt+Shift");
+    require(hook.update('A', true, MOD_ALT, true) == 0, "ordinary keys pass");
+}
+}
+int main()
+{
+    CoInitializeEx(nullptr, COINIT_APARTMENTTHREADED);
+    auto root = std::filesystem::temp_directory_path() / (L"KSwitcher-chat-tests-" + std::to_wstring(GetCurrentProcessId()));
+    try
+    {
+        contextChecks();
+        {
+            ks::App app(GetModuleHandleW(nullptr), true, root);
+            require(!app.layouts.empty(), "installed layouts available");
+            app.settings.toggle = app.settings.casing = app.settings.translit = app.settings.undo = L"";
+            app.settings.clipboard = app.settings.screenshot = L"";
+            app.settings.direct.assign(app.layouts.size(), L"");
+            app.settings.history = app.settings.autoCorrect = false;
+            const std::wstring key = L"telegram\n! Fixture chat";
+            app.settings.chatCycles[key] = {app.layouts[0].id};
+            ks::showSettings(app);
+            HWND parent = app.settingsWindow;
+            auto saveEnabled=[&] { return IsWindowEnabled(GetDlgItem(parent,IDOK))!=FALSE; };
+            auto status=[&] { wchar_t text[256]{}; GetDlgItemTextW(parent,261,text,256); return std::wstring(text); };
+            require(!saveEnabled() && status()==L"No unsaved changes.","new Settings shows clean state with Save disabled");
+            SendMessageW(parent,WM_COMMAND,IDOK,0);
+            require(IsWindow(parent),"Save command with no changes does not apply or close Settings");
+            bool originalLog=IsDlgButtonChecked(parent,208)==BST_CHECKED;
+            CheckDlgButton(parent,208,originalLog?BST_UNCHECKED:BST_CHECKED);
+            SendMessageW(parent,WM_COMMAND,MAKEWPARAM(208,BN_CLICKED),0);
+            require(saveEnabled() && status().find(L"Unsaved changes") == 0,"checkbox edit immediately marks Settings dirty");
+            CheckDlgButton(parent,208,originalLog?BST_CHECKED:BST_UNCHECKED);
+            SendMessageW(parent,WM_COMMAND,MAKEWPARAM(208,BN_CLICKED),0);
+            require(!saveEnabled(),"reverting checkbox disables Save again");
+            wchar_t originalLimit[32]{}; GetDlgItemTextW(parent,240,originalLimit,32);
+            SetDlgItemTextW(parent,240,L"invalid");
+            require(saveEnabled(),"invalid text remains an unsaved edit");
+            SetDlgItemTextW(parent,240,originalLimit);
+            require(!saveEnabled(),"restoring valid original text clears dirty state");
+            SendMessageW(parent,WM_COMMAND,257,0);
+            HWND ocr=FindWindowW(L"KSwitcher.OcrOptions",nullptr);
+            require(ocr!=nullptr,"OCR preferences open");
+            wchar_t languages[128]{}; GetDlgItemTextW(ocr,503,languages,128);
+            SetDlgItemTextW(ocr,503,L"eng");
+            SendMessageW(ocr,WM_COMMAND,IDCANCEL,0);
+            require(!saveEnabled(),"cancelled child changes leave Settings clean");
+            SendMessageW(parent,WM_COMMAND,257,0);
+            ocr=FindWindowW(L"KSwitcher.OcrOptions",nullptr);
+            SetDlgItemTextW(ocr,503,std::wstring(languages)==L"eng"?L"ukr":L"eng");
+            SendMessageW(ocr,WM_COMMAND,IDOK,0);
+            require(!IsWindow(ocr) && saveEnabled(),"accepted OCR edits enable parent Save");
+            SendMessageW(parent,WM_COMMAND,257,0);
+            ocr=FindWindowW(L"KSwitcher.OcrOptions",nullptr);
+            SetDlgItemTextW(ocr,503,languages);
+            SendMessageW(ocr,WM_COMMAND,IDOK,0);
+            require(!saveEnabled(),"reverting OCR draft in child clears parent dirty state");
+            SendMessageW(parent,WM_COMMAND,255,0);
+            HWND automatic=FindWindowW(L"KSwitcher.AutoOptions",nullptr);
+            require(automatic!=nullptr,"automatic correction preferences open");
+            bool replace=IsDlgButtonChecked(automatic,414)==BST_CHECKED;
+            CheckDlgButton(automatic,414,replace?BST_UNCHECKED:BST_CHECKED);
+            SendMessageW(automatic,WM_COMMAND,IDOK,0);
+            require(!IsWindow(automatic) && saveEnabled(),"accepted auto-correction edits enable Save");
+            SendMessageW(parent,WM_COMMAND,255,0);
+            automatic=FindWindowW(L"KSwitcher.AutoOptions",nullptr);
+            CheckDlgButton(automatic,414,replace?BST_CHECKED:BST_UNCHECKED);
+            SendMessageW(automatic,WM_COMMAND,IDOK,0);
+            require(!saveEnabled(),"reverting auto-correction draft disables Save");
+            HWND tabs = GetDlgItem(parent, 260);
+            require(tabs && TabCtrl_GetItemCount(tabs) == 5, "five settings categories");
+            for (int page = 0; page < 5; ++page)
+            {
+                TabCtrl_SetCurSel(tabs, page);
+                NMHDR notification{tabs, 260, TCN_SELCHANGE};
+                SendMessageW(parent, WM_NOTIFY, 260, (LPARAM)&notification);
+                std::vector<RECT> boxes;
+                for (HWND child = GetWindow(parent, GW_CHILD); child; child = GetWindow(child, GW_HWNDNEXT))
+                {
+                    if (!(GetWindowLongPtrW(child, GWL_STYLE) & WS_VISIBLE)) continue;
+                    RECT rect{}; GetWindowRect(child, &rect);
+                    for (const auto &other : boxes)
+                    {
+                        RECT overlap{};
+                        require(!IntersectRect(&overlap, &rect, &other), "visible settings controls never overlap");
+                    }
+                    boxes.push_back(rect);
+                }
+                RedrawWindow(parent, nullptr, nullptr, RDW_INVALIDATE | RDW_UPDATENOW | RDW_ALLCHILDREN);
+                RECT rect{}; GetClientRect(parent, &rect);
+                HDC dc = GetDC(parent);
+                auto clip = ks::screenshotClip(dc, rect.right, rect.bottom, {});
+                ReleaseDC(parent, dc);
+                ks::atomicWrite(std::filesystem::path(ks::executable()).parent_path() / (L"settings-tab-" + std::to_wstring(page) + L".png"),
+                                ks::encodePng(ks::decodeImage(clip)));
+            }
+            TabCtrl_SetCurSel(tabs, 1);
+            NMHDR notification{tabs, 260, TCN_SELCHANGE};
+            SendMessageW(parent, WM_NOTIFY, 260, (LPARAM)&notification);
+            require(!saveEnabled(),"changing tabs leaves Settings clean");
+            SendMessageW(parent, WM_COMMAND, 259, 0);
+            HWND dialog = FindWindowW(L"KSwitcher.ChatLanguages", nullptr);
+            require(dialog && !IsWindowEnabled(parent), "chat dialog opens with disabled parent");
+            int index = (int)SendDlgItemMessageW(dialog, 710, LB_FINDSTRINGEXACT, -1, (LPARAM)L"Telegram: ! Fixture chat");
+            require(index >= 0, "saved chat listed");
+            SendDlgItemMessageW(dialog, 710, LB_SETCURSEL, index, 0);
+            SendMessageW(dialog, WM_COMMAND, MAKEWPARAM(710, LBN_SELCHANGE), 0);
+            require(SendDlgItemMessageW(dialog, 711, LB_GETSELCOUNT, 0, 0) == 1, "saved single language selected");
+            RedrawWindow(dialog, nullptr, nullptr, RDW_INVALIDATE | RDW_UPDATENOW | RDW_ALLCHILDREN);
+            RECT rect{}; GetClientRect(dialog, &rect);
+            HDC dc = GetDC(dialog);
+            auto clip = ks::screenshotClip(dc, rect.right, rect.bottom, {});
+            ReleaseDC(dialog, dc);
+            ks::atomicWrite(std::filesystem::path(ks::executable()).parent_path() / L"chat-languages.png",
+                            ks::encodePng(ks::decodeImage(clip)));
+            SendDlgItemMessageW(dialog, 711, LB_SETSEL, TRUE, -1);
+            SendMessageW(dialog, WM_COMMAND, IDCANCEL, 0);
+            require(!IsWindow(dialog) && IsWindowEnabled(parent), "cancel closes dialog");
+            require(!saveEnabled(),"cancelled chat edits do not enable Save");
+            SendMessageW(parent, WM_COMMAND, 259, 0);
+            dialog = FindWindowW(L"KSwitcher.ChatLanguages", nullptr);
+            index = (int)SendDlgItemMessageW(dialog, 710, LB_FINDSTRINGEXACT, -1, (LPARAM)L"Telegram: ! Fixture chat");
+            SendDlgItemMessageW(dialog, 710, LB_SETCURSEL, index, 0);
+            SendMessageW(dialog, WM_COMMAND, MAKEWPARAM(710, LBN_SELCHANGE), 0);
+            require(SendDlgItemMessageW(dialog, 711, LB_GETSELCOUNT, 0, 0) == 1, "cancel discards language edits");
+            SendDlgItemMessageW(dialog, 711, LB_SETSEL, TRUE, -1);
+            SendMessageW(dialog, WM_COMMAND, IDOK, 0);
+            require(!IsWindow(dialog) && IsWindowEnabled(parent), "profile applies to settings draft");
+            require(saveEnabled() == (app.layouts.size()>1),"accepted chat edits refresh Save immediately");
+            SendMessageW(parent, WM_COMMAND, IDOK, 0);
+            require(!app.settingsWindow && app.settings.chatCycles.at(key).size() == app.layouts.size(), "settings saves selected languages");
+            require(ks::loadSettings(root / L"settings.json", app.layouts).chatCycles == app.settings.chatCycles, "profile saved to disk");
+            ks::showSettings(app);
+            parent = app.settingsWindow;
+            require(!saveEnabled(),"reopened saved Settings is clean");
+            SendMessageW(parent, WM_COMMAND, 259, 0);
+            dialog = FindWindowW(L"KSwitcher.ChatLanguages", nullptr);
+            index = (int)SendDlgItemMessageW(dialog, 710, LB_FINDSTRINGEXACT, -1, (LPARAM)L"Telegram: ! Fixture chat");
+            SendDlgItemMessageW(dialog, 710, LB_SETCURSEL, index, 0);
+            SendMessageW(dialog, WM_COMMAND, MAKEWPARAM(710, LBN_SELCHANGE), 0);
+            SendMessageW(dialog, WM_COMMAND, 713, 0);
+            require(saveEnabled() && status().find(L"Unsaved changes")==0,"removing child profile immediately marks parent dirty");
+            RedrawWindow(parent,nullptr,nullptr,RDW_INVALIDATE|RDW_UPDATENOW|RDW_ALLCHILDREN);
+            GetClientRect(parent,&rect); dc=GetDC(parent);
+            clip=ks::screenshotClip(dc,rect.right,rect.bottom,{}); ReleaseDC(parent,dc);
+            ks::atomicWrite(std::filesystem::path(ks::executable()).parent_path()/L"settings-unsaved.png",
+                            ks::encodePng(ks::decodeImage(clip)));
+            SendMessageW(parent, WM_COMMAND, IDOK, 0);
+            require(!app.settings.chatCycles.contains(key), "remove profile restores default");
+            app.settings.snippets = {{L";scope", L"Example", L"scope-fixture"}};
+            ks::showSettings(app); parent=app.settingsWindow;
+            require(!saveEnabled(),"Settings starts clean before separately saved snippet edit");
+            ks::showSnippets(app);
+            HWND snippets = app.snippetsWindow;
+            SendDlgItemMessageW(snippets,301,LB_SETCURSEL,0,0);
+            SendMessageW(snippets,WM_COMMAND,MAKEWPARAM(301,LBN_SELCHANGE),0);
+            require(IsDlgButtonChecked(snippets,314)==BST_UNCHECKED, "old snippet shows everywhere");
+            CheckDlgButton(snippets,314,BST_CHECKED);
+            SendMessageW(snippets,WM_COMMAND,314,0);
+            SetDlgItemTextW(snippets,315,L"Notepad.exe");
+            auto secondApp = SendDlgItemMessageW(snippets,316,CB_ADDSTRING,0,(LPARAM)L"MS-Teams.EXE");
+            SendDlgItemMessageW(snippets,316,CB_SETCURSEL,secondApp,0);
+            SendMessageW(snippets,WM_COMMAND,317,0);
+            SendMessageW(snippets,WM_COMMAND,317,0);
+            wchar_t appList[128]{};
+            GetDlgItemTextW(snippets,315,appList,128);
+            require(std::wstring(appList)==L"Notepad.exe, MS-Teams.EXE", "Add app appends a second application without duplicates");
+            SendMessageW(snippets,WM_COMMAND,IDOK,0);
+            require(!app.snippetsWindow && app.settings.snippets[0].apps==std::vector<std::wstring>{L"notepad",L"ms-teams"}, "snippet editor saves selected applications");
+            require(!saveEnabled() && status()==L"No unsaved changes.","separately saved snippet edit leaves Settings clean");
+            SendMessageW(parent,WM_COMMAND,IDCANCEL,0);
+            ks::showSnippets(app);snippets=app.snippetsWindow;
+            SendDlgItemMessageW(snippets,301,LB_SETCURSEL,0,0);
+            SendMessageW(snippets,WM_COMMAND,MAKEWPARAM(301,LBN_SELCHANGE),0);
+            require(IsDlgButtonChecked(snippets,314)==BST_CHECKED, "scope restored when reopening editor");
+            RedrawWindow(snippets,nullptr,nullptr,RDW_INVALIDATE|RDW_UPDATENOW|RDW_ALLCHILDREN);
+            RECT snippetRect{};GetClientRect(snippets,&snippetRect);
+            HDC snippetDc=GetDC(snippets);
+            auto snippetImage=ks::screenshotClip(snippetDc,snippetRect.right,snippetRect.bottom,{});
+            ReleaseDC(snippets,snippetDc);
+            ks::atomicWrite(std::filesystem::path(ks::executable()).parent_path()/L"snippet-scopes.png",ks::encodePng(ks::decodeImage(snippetImage)));
+            SetDlgItemTextW(snippets,315,L"chrome.exe");
+            SendMessageW(snippets,WM_COMMAND,IDCANCEL,0);
+            require(app.settings.snippets[0].apps==std::vector<std::wstring>{L"notepad",L"ms-teams"}, "cancel preserves existing scope");
+            ks::showSettings(app);parent=app.settingsWindow;
+            SendMessageW(parent,WM_COMMAND,262,0);
+            HWND lan=FindWindowW(L"KSwitcher.LAN",nullptr);
+            require(lan && !IsWindowEnabled(parent),"LAN pairing opens a native child window");
+            require(!IsWindowEnabled(GetDlgItem(lan,705)),"pairing disabled without discovered peer");
+            require(!IsWindowEnabled(GetDlgItem(lan,706)),"no cancellation without pending pairing");
+            require(!IsWindowEnabled(GetDlgItem(lan,707)),"cannot forget nonexistent pair");
+            require(!IsWindowEnabled(GetDlgItem(lan,715)),"input sharing requires a paired computer");
+            require(!IsWindowEnabled(GetDlgItem(lan,716)),"stop input disabled when sharing is off");
+            for(int id:{711,712,713,714}) require(!IsWindowEnabled(GetDlgItem(lan,id)),"screen positions unavailable until peer selected");
+            require(IsDlgButtonChecked(lan,712)==BST_CHECKED,"default screen position is Right");
+            require(SendDlgItemMessageW(lan,702,LB_GETCOUNT,0,0)==0,"disabled discovery lists no generic network devices");
+            require(!std::filesystem::exists(root/L"lan-pairing.bin"),"opening LAN settings does not enable or save discovery");
+            RedrawWindow(lan,nullptr,nullptr,RDW_INVALIDATE|RDW_UPDATENOW|RDW_ALLCHILDREN);
+            RECT lanRect{};GetClientRect(lan,&lanRect);HDC lanDc=GetDC(lan);
+            auto lanImage=ks::screenshotClip(lanDc,lanRect.right,lanRect.bottom,{});ReleaseDC(lan,lanDc);
+            ks::atomicWrite(std::filesystem::path(ks::executable()).parent_path()/L"lan-pairing.png",ks::encodePng(ks::decodeImage(lanImage)));
+            SendMessageW(lan,WM_COMMAND,IDCANCEL,0);
+            require(IsWindowEnabled(parent)&&!saveEnabled(),"closing discovery restores Settings without false unsaved state");
+            SendMessageW(parent,WM_COMMAND,IDCANCEL,0);
+        }
+        {
+            ks::lan::Json fixture={{"version",1},{"id",std::string(32,'a')},{"enabled",false},
+                {"trusted",{{std::string(32,'b'),{{"name","Test paired KSwitcher"},{"key",std::string(64,'f')}}}}}};
+            auto text=fixture.dump();ks::atomicWrite(root/L"lan-pairing.bin",ks::protect(ks::Bytes(text.begin(),text.end())));
+            ks::App pairedApp(GetModuleHandleW(nullptr),true,root);ks::showSettings(pairedApp);
+            SendMessageW(pairedApp.settingsWindow,WM_COMMAND,262,0);
+            HWND lan=FindWindowW(L"KSwitcher.LAN",nullptr);
+            SendDlgItemMessageW(lan,702,LB_SETCURSEL,0,0);
+            SendMessageW(lan,WM_COMMAND,MAKEWPARAM(702,LBN_SELCHANGE),0);
+            for(int id:{711,712,713,714})require(IsWindowEnabled(GetDlgItem(lan,id)),"paired computer exposes all four layout positions");
+            SendDlgItemMessageW(lan,713,BM_CLICK,0,0);
+            require(IsDlgButtonChecked(lan,713)==BST_CHECKED&&IsDlgButtonChecked(lan,712)==BST_UNCHECKED,"Above selection changes radio group");
+            SendMessageW(lan,WM_TIMER,1,0);
+            require(IsDlgButtonChecked(lan,713)==BST_CHECKED,"status refresh preserves unsaved position choice");
+            require(!IsWindowEnabled(GetDlgItem(lan,715)),"input cannot start while discovery is disabled");
+            // Let the native radio-button theme animation finish before visual capture.
+            auto repaintUntil=GetTickCount64()+200;
+            while(GetTickCount64()<repaintUntil)
+            {
+                MSG message{};
+                while(PeekMessageW(&message,nullptr,0,0,PM_REMOVE)){TranslateMessage(&message);DispatchMessageW(&message);}
+                Sleep(10);
+            }
+            RedrawWindow(lan,nullptr,nullptr,RDW_INVALIDATE|RDW_UPDATENOW|RDW_ALLCHILDREN);
+            RECT r{};GetClientRect(lan,&r);HDC dc=GetDC(lan);auto screenshot=ks::screenshotClip(dc,r.right,r.bottom,{});ReleaseDC(lan,dc);
+            ks::atomicWrite(std::filesystem::path(ks::executable()).parent_path()/L"lan-screen-layout.png",ks::encodePng(ks::decodeImage(screenshot)));
+            SendMessageW(lan,WM_COMMAND,IDCANCEL,0);
+            SendMessageW(pairedApp.settingsWindow,WM_COMMAND,IDCANCEL,0);
+        }
+        std::filesystem::remove_all(root);
+        std::cout << "Passed " << passed << " chat profile checks\n";
+        CoUninitialize();
+        return 0;
+    }
+    catch (const std::exception &e) { std::cerr << "FAIL: " << e.what() << '\n'; CoUninitialize(); return 1; }
+}

tests/input.cpp

@@ -26,6 +26,17 @@ LRESULT CALLBACK countControlMoves(HWND w, UINT message, WPARAM wp, LPARAM lp, U
 }
 namespace ks {
 struct InputRegressionAccess {
+    static int snippetChoice(App &a, const std::vector<Snippet> &snippets) {
+        a.settings.snippets=snippets; a.settings.autoCorrect=false; a.busy=false;
+        a.snippetPending=-1; a.typingTarget=nullptr; a.snippetTyping=false;
+        auto target=GetForegroundWindow();
+        a.run.keys=L";si"; a.run.window=target; a.run.layout=windowLayout(target); a.run.at=GetTickCount64();
+        KBDLLHOOKSTRUCT key{};key.vkCode='G';key.scanCode=0x22;
+        a.keyboard(key,0);
+        int chosen=a.snippetPending;
+        a.busy=false;a.snippetPending=-1;a.typingTarget=nullptr;a.snippetTyping=false;
+        return chosen;
+    }
     static bool idleUndo(App &a) {
         a.last=LastTransform{}; a.last->at=100;
         a.releaseIdleMemory(120100);
@@ -130,6 +141,19 @@ int main(int argc, char **argv) {
     try {
         INITCOMMONCONTROLSEX controls{sizeof(controls),ICC_STANDARD_CLASSES|ICC_LISTVIEW_CLASSES};
         InitCommonControlsEx(&controls);
+        {
+            ks::App app(GetModuleHandleW(nullptr),true,temp/L"snippet-scopes");
+            app.window=CreateWindowExW(0,L"STATIC",L"Snippet scope test",0,0,0,0,0,HWND_MESSAGE,nullptr,GetModuleHandleW(nullptr),nullptr);
+            auto process=ks::processName(GetForegroundWindow());
+            require(!process.empty(),"scope test has foreground process");
+            std::vector<ks::Snippet> snippets{{L";sig",L"global",L"global"},{L";sig",L"scoped",L"scoped",{process}}};
+            require(ks::InputRegressionAccess::snippetChoice(app,snippets)==1,"app-specific trigger wins even when global is first");
+            snippets[1].apps={L"kswitcher-no-such-process"};
+            require(ks::InputRegressionAccess::snippetChoice(app,snippets)==0,"unmatched app falls back to global snippet");
+            snippets.erase(snippets.begin());
+            require(ks::InputRegressionAccess::snippetChoice(app,snippets)==-1,"scoped snippet is not queued in another application");
+            DestroyWindow(app.window);app.window=nullptr;
+        }
         {
             HMENU menu = CreatePopupMenu(), child = CreatePopupMenu();
             AppendMenuW(menu,MF_STRING | MF_CHECKED,1,L"&Settings…");
@@ -901,7 +925,7 @@ int main(int argc, char **argv) {
                         "personal dictionary field fits options window");
             }
             SetDlgItemTextW(autoOptions,412,L"Релізик\r\nрелізик, словечко");
-            SetDlgItemTextW(autoOptions,416,L" Првиіт = Привіт\r\nhelo=hello");
+            SetDlgItemTextW(autoOptions,416,L" Првиіт = Привіт\r\nhelo=hello\r\n Мамамила = Мама мила ");
             SendDlgItemMessageW(autoOptions,414,BM_SETCHECK,BST_CHECKED,0);
             SendDlgItemMessageW(autoOptions,415,BM_SETCHECK,BST_CHECKED,0);
             SendMessageW(autoOptions,WM_COMMAND,IDOK,0);
@@ -923,7 +947,7 @@ int main(int argc, char **argv) {
                     "personal dictionary normalizes case, newlines and duplicate words");
             wchar_t pairs[128]{};
             GetDlgItemTextW(autoOptions,416,pairs,128);
-            require(std::wstring(pairs)==L"helo=hello\r\nпрвиіт=привіт\r\n" &&
+            require(std::wstring(pairs)==L"helo=hello\r\nмамамила=мама мила\r\nпрвиіт=привіт\r\n" &&
                     SendDlgItemMessageW(autoOptions,414,BM_GETCHECK,0,0)==BST_CHECKED &&
                     SendDlgItemMessageW(autoOptions,415,BM_GETCHECK,0,0)==BST_CHECKED,
                     "typo options and normalized replacement pairs survive reopening");
@@ -1021,6 +1045,9 @@ int main(int argc, char **argv) {
             require(SendDlgItemMessageW(settings,209,BM_GETCHECK,0,0)==BST_UNCHECKED,"automatic screenshot editor checkbox defaults off");
             require(settings&&!IsWindowVisible(settings),"settings layout tested without changing user focus");
             for(auto pair:{std::pair{209,215},std::pair{209,207},std::pair{209,220},std::pair{209,232},std::pair{207,215},std::pair{207,232},std::pair{207,220},std::pair{232,230},std::pair{230,231},std::pair{231,253}}) {
+                // Controls on different settings tabs intentionally share the page area.
+                if (!(GetWindowLongPtrW(GetDlgItem(settings,pair.first),GWL_STYLE)&WS_VISIBLE) ||
+                    !(GetWindowLongPtrW(GetDlgItem(settings,pair.second),GWL_STYLE)&WS_VISIBLE)) continue;
                 RECT first{},second{},overlap{};
                 GetWindowRect(GetDlgItem(settings,pair.first),&first); GetWindowRect(GetDlgItem(settings,pair.second),&second);
                 require(!IntersectRect(&overlap,&first,&second),"capture hotkey and layout controls do not overlap");

tests/integration.cpp

@@ -22,6 +22,7 @@ namespace
 ks::App *app{};
 HWND host{}, field{};
 ks::Clip saved;
+bool snippetRecoveryOnly = false;
 bool captured = false, failed = false;
 bool conversionOnly = false;
 bool typosOnly = false;
@@ -588,10 +589,29 @@ LRESULT CALLBACK procedure(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 require(ks::readClipboard(app->window).text() == sentinel, "selected and repeated conversions restore clipboard");
                 finish();
                 break;
-            case 62:
+            case 64:
                 saved = ks::readClipboard(app->window, 64 * 1024 * 1024);
                 captured = true;
                 app->ownSequence = ks::writeClipboard(app->window, ks::textClip(sentinel));
+                app->settings.snippets = {{L";repo-changes-jira", L"expanded{cursor}"}};
+                ActivateKeyboardLayout(app->layouts[en].handle, 0);
+                prepare(L"prefix ;repo-changes-jira", false);
+                record(L";repo-changes-jira");
+                droppedSelectionKeys = 10;
+                enterPresses = 0;
+                app->transform(0, 0);
+                break;
+            case 65:
+                require(text() == L"prefix expanded", "long snippet recovers partial selection and preserves prefix");
+                require(droppedSelectionKeys == 0 && enterPresses == 0, "snippet recovery consumes missing arrows without Enter");
+                require(ks::readClipboard(app->window).text() == sentinel, "snippet recovery restores clipboard");
+                if (snippetRecoveryOnly) { finish(); break; }
+                stage = 62;
+                break;
+            case 62:
+                if (!captured) saved = ks::readClipboard(app->window, 64 * 1024 * 1024);
+                captured = true;
+                app->ownSequence = ks::writeClipboard(app->window, ks::textClip(sentinel));
                 app->settings.snippets = {{L";r", L"unexpected{enter}"}};
                 ActivateKeyboardLayout(app->layouts[en].handle, 0);
                 prepare(L"prefix ", false);
@@ -802,14 +822,14 @@ LRESULT CALLBACK procedure(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             case 22:
                 require(text() == L"робить ", "automatic correction selects and converts the whole word across an internal comma");
                 app->settings.autoReplace = true;
-                app->settings.autoReplacements = {{L"helo", L"hello"}};
+                app->settings.autoReplacements = {{L"helo", L"hello world"}};
                 ActivateKeyboardLayout(app->layouts[en].handle, 0);
                 prepare(L"(Helo)! ", false);
                 record(L"(Helo)! ");
                 app->transform(ks::AutoCorrect);
                 break;
             case 23:
-                require(text() == L"(Hello)! ", "explicit typo pair replaces verified text with punctuation and capital");
+                require(text() == L"(Hello world)! ", "explicit phrase pair replaces verified text with punctuation and capital");
                 app->transform(ks::Undo);
                 break;
             case 24:
@@ -835,7 +855,7 @@ LRESULT CALLBACK procedure(HWND w, UINT msg, WPARAM wp, LPARAM lp)
             case 27:
                 require(text() == L"kswithcer ", "Undo suppresses the rejected spelling correction");
                 app->settings.autoReplace = true;
-                app->settings.autoReplacements = {{L"tehh", L"the"}};
+                app->settings.autoReplacements = {{L"tehh", L"the word"}};
                 app->autoPredictor.configure(L"dictionaries", app->settings.autoLanguages);
                 prepare(L"", false);
                 {
@@ -852,7 +872,7 @@ LRESULT CALLBACK procedure(HWND w, UINT msg, WPARAM wp, LPARAM lp)
                 }
                 break;
             case 28:
-                require(text() == L"the x", "custom replacement through keyboard hook preserves subsequent typing");
+                require(text() == L"the word x", "custom phrase replacement through keyboard hook preserves subsequent typing");
                 app->settings.autoReplace = false;
                 app->settings.autoTypos = false;
                 if (typosOnly) { finish(); break; }
@@ -1038,8 +1058,9 @@ int main(int argc, char **argv)
             SetWindowSubclass(field, observeEnter, 1, 0);
             if (typosOnly || (argc > 1 && std::string(argv[1]) == "--typing-only"))
                 stage = 20;
-            if (argc > 1 && std::string(argv[1]) == "--snippets-only")
-                stage = 62;
+            snippetRecoveryOnly = argc > 1 && std::string(argv[1]) == "--snippet-recovery-only";
+            if (snippetRecoveryOnly || (argc > 1 && std::string(argv[1]) == "--snippets-only"))
+                stage = 64;
             SetTimer(host, 1, 100, nullptr);
             auto forwarding = SetWindowsHookExW(WH_KEYBOARD_LL,forwardingHook,GetModuleHandleW(nullptr),0);
             require(forwarding!=nullptr,"downstream forwarding fixture installed before application hook");

tests/lan.cpp

@@ -0,0 +1,120 @@
+#include "lan.h"
+#include "lan_pairing.h"
+#include <iostream>
+#include <tlhelp32.h>
+
+namespace
+{
+int passed{};
+void check(bool ok,const char *name) {if(!ok) throw std::runtime_error(name);++passed;}
+template<class F> void rejects(F f,const char *name) {bool failed=false;try{f();}catch(...){failed=true;}check(failed,name);}
+unsigned threads()
+{
+    HANDLE snapshot=CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD,0);
+    if(snapshot==INVALID_HANDLE_VALUE) throw std::runtime_error("Cannot inspect test threads");
+    THREADENTRY32 entry{sizeof(entry)};unsigned count=0;
+    if(Thread32First(snapshot,&entry)) do {if(entry.th32OwnerProcessID==GetCurrentProcessId()) ++count;} while(Thread32Next(snapshot,&entry));
+    CloseHandle(snapshot);return count;
+}
+}
+int main(int argc,char **argv)
+{
+    using namespace ks;using namespace ks::lan;
+    try
+    {
+        const std::string a(32,'a'),b(32,'b'),c(32,'c'),code="0123456789abcdef0123456789abcdef";
+        check(normalizeCode("0123-4567-89AB-CDEF-0123-4567-89ab-cdef")==code,"code accepts groups and case");
+        rejects([]{normalizeCode("123456");},"short guessable codes rejected");
+        rejects([]{normalizeCode(std::string(32,'x'));},"invalid code rejected");
+        check(identifier(randomHex(16)),"cryptographic instance ID");
+        check(mac("key","The quick brown fox jumps over the lazy dog")=="f7bc83f430538424b13298e6aa6fb143ef4d59a14946175997479dbc2d1a3cd8", "HMAC SHA256 known vector");
+        check(equal("abc","abc")&&!equal("abc","abd")&&!equal("abc","ab"),"proof comparison");
+        Pairing left(a,b,code,100),right(b,a,code,100),wrong(b,a,std::string(32,'f'),100);
+        check(wrong.receive(left.offer(),101).empty(),"different code cannot acknowledge");
+        auto forged=left.offer();forged["id"]=c;
+        check(right.receive(forged,101).empty(),"identity substitution rejected");
+        forged=left.offer();forged["version"]=2;
+        check(right.receive(forged,101).empty(),"unsupported protocol rejected");
+        forged=left.offer();forged["to"]=c;
+        check(right.receive(forged,101).empty(),"wrong destination rejected");
+        auto ackR=right.receive(left.offer(),101),ackL=left.receive(right.offer(),101);
+        check(ackR.size()==1&&ackL.size()==1,"mutual offers acknowledged");
+        check(!left.confirmed&&!right.confirmed,"discovery and offers are not trust");
+        auto confirmL=left.receive(ackR[0],102),confirmR=right.receive(ackL[0],102);
+        check(confirmL.size()==1&&confirmR.size()==1,"authenticated challenges confirmed");
+        left.receive(confirmR[0],103);right.receive(confirmL[0],103);
+        check(left.confirmed&&right.confirmed&&left.derived==right.derived,"both endpoints derive same pair key");
+        check(left.derived!=code&&left.derived.size()==64,"pair key separate from setup code");
+        Pairing retry(a,b,code,200);
+        check(retry.receive(ackR[0],201).empty()&&!retry.confirmed,"old ACK cannot pair new attempt");
+        check(retry.receive(confirmR[0],201).empty()&&!retry.confirmed,"old confirmation cannot pair new attempt");
+        Pairing expired(b,a,code,100);
+        check(expired.receive(left.offer(),100+PairLifetime).empty(),"pairing window expires");
+        check(left.receive(right.offer(),104).size()==1,"duplicate UDP offer is safely acknowledged");
+        rejects([&]{Pairing self(a,a,code,0);},"self-pair rejected");
+        auto root=std::filesystem::temp_directory_path()/wide("ks-lan-test-"+randomHex(16));
+        std::filesystem::create_directory(root);
+        struct Cleanup{std::filesystem::path p;~Cleanup(){std::error_code ec;std::filesystem::remove_all(p,ec);}} cleanup{root};
+        auto request=[](LanService &service,Json j){auto s=j.dump();return Json::parse(service.command(Bytes(s.begin(),s.end())));};
+        std::string identity;
+        {
+            auto idleThreads=threads();
+            LanService service(root);
+            check(threads()==idleThreads,"disabled LAN creates no worker thread");
+            auto state=request(service,{{"action","status"}});
+            check(!state.at("enabled").get<bool>()&&state.at("peers").empty(),"disabled by default");
+            identity=state.at("id");
+            check(!std::filesystem::exists(root/L"lan-pairing.bin"),"viewing disabled status does not create config");
+            auto generated=request(service,{{"action","code"}}).at("code").get<std::string>();
+            check(identifier(generated),"generated pairing code has 128 bits");
+            rejects([&]{request(service,{{"action","pair"},{"peer",b},{"code",code}});},"cannot pair undiscovered peer while disabled");
+            request(service,{{"action","enable"},{"enabled",false}});
+            auto sealed=readFile(root/L"lan-pairing.bin",256*1024);
+            check(std::string(sealed.begin(),sealed.end()).find(identity)==std::string::npos,"local configuration protected by DPAPI");
+            if(argc>1&&std::string(argv[1])=="--network")
+            {
+                request(service,{{"action","enable"},{"enabled",true}});
+                Sleep(400);
+                auto active=request(service,{{"action","status"}});
+                check(active.at("enabled").get<bool>() && active.at("status").get<std::string>().find("LAN stopped:")==std::string::npos,"opt-in discovery starts successfully");
+                check(threads()>idleThreads,"enabled discovery has a worker");
+                request(service,{{"action","enable"},{"enabled",false}});
+                check(threads()==idleThreads,"disabling discovery joins its worker");
+                // Reopening immediately exercises socket cleanup and exclusive bind.
+                request(service,{{"action","enable"},{"enabled",true}});Sleep(200);
+                check(request(service,{{"action","status"}}).at("status").get<std::string>().find("LAN stopped:")==std::string::npos,"discovery port released and reusable");
+                request(service,{{"action","enable"},{"enabled",false}});
+            }
+        }
+        {
+            LanService restored(root);auto state=request(restored,{{"action","status"}});
+            check(state.at("id")==identity&&!state.at("enabled").get<bool>(),"stable local instance ID and disabled state restored");
+        }
+        {
+            auto saved=Json::parse(unprotect(readFile(root/L"lan-pairing.bin",256*1024)));
+            saved["trusted"][b]={{"name","Other KSwitcher"},{"key",left.derived}};
+            auto json=saved.dump();atomicWrite(root/L"lan-pairing.bin",protect(Bytes(json.begin(),json.end())));
+            LanService restored(root);auto state=request(restored,{{"action","status"}});
+            check(state["peers"].size()==1 && state["peers"][0].at("paired").get<bool>() && !state["peers"][0].at("online").get<bool>(),"saved pair remains visible offline");
+            check(state.dump().find(left.derived)==std::string::npos,"status never exposes stored pair keys");
+            rejects([&]{request(restored,{{"action","input"},{"enabled",true},{"peer",b},{"edge",1}});},"input cannot be enabled without discovery");
+            rejects([&]{request(restored,{{"action","input"},{"enabled",false},{"edge",4}});},"invalid screen edge rejected");
+            auto position=request(restored,{{"action","input"},{"enabled",false},{"peer",b},{"edge",2}});
+            check(position.at("inputEdge")==2&&!restored.inputEnabled(),"screen position saved without enabling input");
+            if(argc>1&&std::string(argv[1])=="--network")
+            {
+                request(restored,{{"action","enable"},{"enabled",true}});
+                rejects([&]{request(restored,{{"action","input"},{"enabled",true},{"peer",c},{"edge",1}});},"discovered but unpaired peer cannot receive input");
+                request(restored,{{"action","input"},{"enabled",true},{"peer",b},{"edge",2}});
+                check(restored.inputEnabled(),"paired input enabled with explicit screen position");
+                request(restored,{{"action","enable"},{"enabled",false}});
+                check(!restored.inputEnabled(),"disabling discovery also stops input runtime");
+            }
+            request(restored,{{"action","forget"},{"peer",b}});
+            check(request(restored,{{"action","status"}})["peers"].empty(),"forget removes offline pair");
+            check(!request(restored,{{"action","status"}}).at("shareInput").get<bool>(),"forgetting the input peer revokes persisted input permission");
+        }
+        std::cout<<"Passed "<<passed<<" LAN discovery/pairing checks\n";
+    }
+    catch(const std::exception &e){std::cerr<<"FAIL: "<<e.what()<<'\n';return 1;}
+}

tests/lan_input.cpp

@@ -0,0 +1,206 @@
+#include <winsock2.h>
+#include "lan_input.h"
+#include <iostream>
+#include <deque>
+
+using namespace ks;using namespace ks::lan;
+namespace
+{
+int passed{};
+void check(bool value,const char *text){if(!value)throw std::runtime_error(text);++passed;}
+template<class F>void rejects(F f,const char *text){bool failed=false;try{f();}catch(...){failed=true;}check(failed,text);}
+struct Desktop
+{
+    RECT rect{-1920,-200,0,880};POINT point{-1000,300};bool available=true,physicalHeld=false,allow=true;
+    std::vector<INPUT> events;
+    InputEnvironment environment()
+    {
+        return {[this]{return rect;},[this]{return point;},[this](const INPUT &i){
+            if(!allow)return false;
+            events.push_back(i);
+            if(i.type==INPUT_MOUSE&&(i.mi.dwFlags&MOUSEEVENTF_MOVE))
+                point={rect.left+LONG(int64_t(i.mi.dx)*(rect.right-rect.left)/65536),rect.top+LONG(int64_t(i.mi.dy)*(rect.bottom-rect.top)/65536)};
+            return true;
+        },[this]{return available;},[this]{return physicalHeld;}};
+    }
+    unsigned keyEvents(bool down)const
+    {return unsigned(std::count_if(events.begin(),events.end(),[down](auto &i){return i.type==INPUT_KEYBOARD&&bool(i.ki.dwFlags&KEYEVENTF_KEYUP)!=down;}));}
+};
+KBDLLHOOKSTRUCT key(unsigned vk,unsigned scan=0){KBDLLHOOKSTRUCT k{};k.vkCode=vk;k.scanCode=scan;return k;}
+bool motion(InputRouter &router,Desktop &desktop,POINT p,uint64_t now)
+{desktop.point=p;MSLLHOOKSTRUCT m{};m.pt=p;return router.mouse(WM_MOUSEMOVE,m,now);}
+void exchange(InputRouter &source,InputRouter &target,std::deque<InputFrame> &out,uint64_t now)
+{(void)source;while(!out.empty()){auto f=out.front();out.pop_front();target.receive(f,now);}}
+struct Pair
+{
+    Desktop a,b;std::deque<InputFrame> ab,ba;
+    InputRouter left,right;
+    explicit Pair(int side):left(a.environment(),[this](auto f){ab.push_back(f);return true;},side,true),
+        right(b.environment(),[this](auto f){ba.push_back(f);return true;},side^1,false)
+    {b.rect={0,0,1600,900};b.point={600,400};left.tick(true,1000);right.tick(true,1000);}
+    void deliver(uint64_t now=1100){exchange(left,right,ab,now);exchange(right,left,ba,now);}
+    void enter(int edge)
+    {
+        motion(left,a,edgePoint(a.rect,edge,30000,0),1000);
+        check(left.mode()==ControlMode::Requesting,"crossing edge requests ownership, not immediate suppression");
+        deliver();check(left.mode()==ControlMode::Sending&&right.mode()==ControlMode::Receiving,"mouse and keyboard ownership acknowledged together");
+    }
+};
+void routerChecks()
+{
+    for(int side=0;side<4;++side)
+    {
+        Pair p(side);auto middle=edgePoint(p.a.rect,side,32768,0);
+        check(atEdge(middle,p.a.rect,side),"all four virtual-screen edges supported");
+        check(std::abs(edgePosition(middle,p.a.rect,side)-32768)<100,"negative monitor coordinates normalize");
+        p.enter(side);
+        auto old=p.b.point;
+        for(int step=0;step<20;++step)
+        {
+            auto point=p.a.point;if(side==0)--point.x;else if(side==1)++point.x;else if(side==2)--point.y;else ++point.y;
+            motion(p.left,p.a,point,1110+step);p.deliver(1110+step);
+        }
+        check(side<2 ? std::abs(p.b.point.x-old.x)==20 : std::abs(p.b.point.y-old.y)==20,"one-pixel mouse movements have no accumulating warp bias");
+        check(p.left.keyboard(key('A',0x1e),true,1200),"source key down suppressed");p.deliver(1200);
+        check(p.a.keyEvents(true)==0&&p.b.keyEvents(true)==1,"key only injected on computer with cursor");
+        check(p.b.events.back().ki.dwFlags&KEYEVENTF_SCANCODE,"physical scan code preserved across layouts");
+        check(p.left.keyboard(key('A',0x1e),false,1210),"source key up suppressed");p.deliver(1210);
+        check(p.b.keyEvents(false)==1,"remote key released");
+        auto injected=key('A',0x1e);injected.flags=LLKHF_INJECTED;injected.dwExtraInfo=remoteInputMarker();
+        check(!p.right.keyboard(injected,true,1220),"received input continues to destination hotkeys/snippets, no routing loop");
+        MSLLHOOKSTRUCT click{};check(p.left.mouse(WM_LBUTTONDOWN,click,1230),"source click suppressed");p.deliver(1230);
+        check(p.b.events.back().mi.dwFlags==MOUSEEVENTF_LEFTDOWN,"remote left button pressed");
+        p.left.mouse(WM_LBUTTONUP,click,1240);p.deliver(1240);
+        check(p.b.events.back().mi.dwFlags==MOUSEEVENTF_LEFTUP,"remote left button released");
+        click.mouseData=DWORD(120)<<16;p.left.mouse(WM_MOUSEWHEEL,click,1250);p.deliver(1250);
+        check(p.b.events.back().mi.dwFlags==MOUSEEVENTF_WHEEL&&p.b.events.back().mi.mouseData==120,"wheel delta forwarded");
+        auto centre=p.a.point;POINT moved=centre;
+        if(side==0)moved.x-=30;else if(side==1)moved.x+=30;else if(side==2)moved.y-=30;else moved.y+=30;
+        check(motion(p.left,p.a,moved,1300),"remote mouse move suppressed locally");p.deliver(1300);
+        check(p.b.point.x!=old.x||p.b.point.y!=old.y,"cursor moves on target");
+        // Repeated source movement towards the return edge.
+        for(int n=0;n<5&&p.left.mode()==ControlMode::Sending;++n)
+        {
+            moved=p.a.point;if(side==0)moved.x+=400;else if(side==1)moved.x-=400;else if(side==2)moved.y+=400;else moved.y-=400;
+            motion(p.left,p.a,moved,1400+n);p.deliver(1400+n);
+        }
+        check(p.left.mode()==ControlMode::Local&&p.right.mode()==ControlMode::Local,"crossing target return edge restores local ownership");
+        check(!atEdge(p.a.point,p.a.rect,side),"return cursor inset avoids immediate bounce");
+        check(!p.left.keyboard(key('B'),true,1500),"normal local typing resumes");p.left.keyboard(key('B'),false,1501);
+    }
+    {
+        Pair p(1);p.enter(1);p.left.keyboard(key(VK_LCONTROL),true,1200);p.left.keyboard(key(VK_LMENU),true,1201);p.deliver();
+        check(p.left.keyboard(key(VK_ESCAPE),true,1202),"emergency return chord consumed");p.deliver();
+        check(p.left.mode()==ControlMode::Local&&p.right.mode()==ControlMode::Local,"emergency chord returns both sides");
+        check(p.b.keyEvents(false)==2,"emergency return releases remote modifiers");
+        check(p.left.keyboard(key(VK_LCONTROL),false,1203)&&p.left.keyboard(key(VK_LMENU),false,1204),"stray source modifier releases consumed after return");
+    }
+    {
+        Pair p(1);p.enter(1);p.left.keyboard(key('A'),true,1200);p.deliver();
+        p.left.tick(false,1300);p.right.tick(false,1300);
+        check(p.b.keyEvents(false)==1&&p.left.mode()==ControlMode::Local,"disconnect releases held remote key");
+        check(p.left.keyboard(key('A'),false,1400),"source does not leak orphaned key-up after disconnect");
+    }
+    {
+        Pair p(1);p.enter(1);p.left.keyboard(key('A'),true,1200);p.deliver();p.b.available=false;p.right.tick(true,1300);
+        check(p.right.mode()==ControlMode::Local&&p.b.keyEvents(false)==0,"secure desktop stops ownership without injecting there");
+        p.b.available=true;p.right.tick(true,1400);check(p.b.keyEvents(false)==1,"blocked release retried when normal desktop returns");
+    }
+    {
+        Pair p(1);p.a.physicalHeld=true;motion(p.left,p.a,edgePoint(p.a.rect,1,30000,0),1000);
+        check(p.left.mode()==ControlMode::Local,"no cross-screen handoff with physically held key/button");
+        p.a.physicalHeld=false;motion(p.left,p.a,edgePoint(p.a.rect,1,30000,0),1100);
+        p.left.keyboard(key('X'),true,1101);p.deliver(1200);
+        check(p.left.mode()==ControlMode::Local&&p.right.mode()==ControlMode::Local,"typing during handoff cancels stale accept");
+    }
+    {
+        Pair p(1);motion(p.left,p.a,edgePoint(p.a.rect,1,30000,0),1000);motion(p.right,p.b,edgePoint(p.b.rect,0,30000,0),1000);
+        p.deliver();p.deliver();check(p.left.mode()==ControlMode::Sending&&p.right.mode()==ControlMode::Receiving,"simultaneous crossing has deterministic ownership");
+    }
+    {
+        Pair p(1);p.enter(1);p.left.keyboard(key('A'),true,1200);p.deliver();
+        check(!p.right.keyboard(key('B'),true,1300),"local physical keyboard takes over target");p.deliver();
+        check(p.left.mode()==ControlMode::Local&&p.b.keyEvents(false)==1,"local takeover returns source and releases remote keys");
+    }
+    {
+        Pair p(1);p.b.allow=false;motion(p.left,p.a,edgePoint(p.a.rect,1,30000,0),1000);p.deliver();
+        check(p.left.mode()==ControlMode::Local&&p.right.mode()==ControlMode::Local,"blocked SendInput fails closed without capturing source");
+    }
+    {
+        Pair p(1);p.enter(1);MSLLHOOKSTRUCT m{};m.mouseData=DWORD(XBUTTON2)<<16;
+        p.left.mouse(WM_XBUTTONDOWN,m,1200);p.deliver();p.right.tick(false,1300);
+        check(p.b.events.back().mi.dwFlags==MOUSEEVENTF_XUP&&p.b.events.back().mi.mouseData==XBUTTON2,"disconnect releases held extra mouse button");
+    }
+    {
+        Pair p(1);motion(p.left,p.a,edgePoint(p.a.rect,1,30000,0),1000);p.left.tick(true,2101);
+        check(p.left.mode()==ControlMode::Local,"unanswered ownership request times out locally");p.deliver(2200);p.deliver(2200);
+        check(p.left.mode()==ControlMode::Local&&p.right.mode()==ControlMode::Local,"late handoff acknowledgement cannot steal control");
+    }
+    {
+        Desktop d;bool accept=true;std::deque<InputFrame> frames;
+        InputRouter router(d.environment(),[&](auto f){frames.push_back(f);return accept;},1,true);
+        router.tick(true,1000);motion(router,d,edgePoint(d.rect,1,30000,0),1000);
+        auto token=frames.front().token;router.receive({InputType::Accept,token},1100);
+        accept=false;check(router.keyboard(key('Q'),true,1200),"failed queue still consumes the key rather than typing locally");
+        check(router.mode()==ControlMode::Local&&router.keyboard(key('Q'),false,1300),"queue failure returns control and consumes orphan release");
+    }
+}
+uint16_t freePort()
+{
+    SOCKET s=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);if(s==INVALID_SOCKET)throw std::runtime_error("test socket");
+    sockaddr_in a{};a.sin_family=AF_INET;a.sin_addr.s_addr=htonl(INADDR_LOOPBACK);
+    if(bind(s,(sockaddr*)&a,sizeof(a))){closesocket(s);throw std::runtime_error("test bind");}
+    int size=sizeof(a);getsockname(s,(sockaddr*)&a,&size);auto port=ntohs(a.sin_port);closesocket(s);return port;
+}
+void channelChecks()
+{
+    std::string a(32,'a'),b(32,'b'),secret(64,'f');auto na=randomHex(16),nb=randomHex(16);
+    auto k=inputSessionKey(secret,a,b,na,nb);check(k!=inputSessionKey(secret,b,a,nb,na),"directional session keys differ");
+    check(inputSessionKey(secret,a,b,na,nb,0)!=inputSessionKey(secret,a,b,na,nb,1),"screen geometry bound into authenticated session");
+    InputCipher tx(k),rx(k);InputFrame f{InputType::Key,37,'A',0x1e,1};auto packet=tx.encrypt(f);
+    check(packet.size()==36&&rx.decrypt(packet)==f,"AES-GCM authenticated input roundtrip");
+    rejects([&]{rx.decrypt(packet);},"encrypted frame replay rejected");
+    auto next=tx.encrypt({InputType::Move,37,-12,400});auto tampered=next;tampered[4]^=1;
+    rejects([&]{rx.decrypt(tampered);},"ciphertext modification rejected");
+    check(rx.decrypt(next)==InputFrame{InputType::Move,37,-12,400},"failed authentication does not expose or advance data");
+    InputCipher wrong(inputSessionKey(secret,b,a,nb,na));rejects([&]{wrong.decrypt(packet);},"reflection across directions rejected");
+    InputCipher otherSession(inputSessionKey(secret,a,b,randomHex(16),nb));rejects([&]{otherSession.decrypt(packet);},"old-session input rejected");
+    WSADATA data{};if(WSAStartup(MAKEWORD(2,2),&data))throw std::runtime_error("WSAStartup");
+    struct Close{~Close(){WSACleanup();}} close;
+    {
+        auto port=freePort();InputChannel client(a,b,secret,1,port),server(b,a,secret,0,port);
+        auto deadline=GetTickCount64()+5000;std::vector<InputFrame> received;
+        while((!client.ready()||!server.ready())&&GetTickCount64()<deadline)
+        {
+            server.poll(htonl(INADDR_LOOPBACK),{},received,GetTickCount64());client.poll(htonl(INADDR_LOOPBACK),{},received,GetTickCount64());Sleep(1);
+        }
+        check(client.ready()&&server.ready(),"real TCP peers mutually authenticate with paired key");
+        check(received.empty(),"handshake produces no input events");
+        client.poll(htonl(INADDR_LOOPBACK),{f},received,GetTickCount64());
+        for(int n=0;n<100&&received.empty();++n){server.poll(htonl(INADDR_LOOPBACK),{},received,GetTickCount64());client.poll(htonl(INADDR_LOOPBACK),{},received,GetTickCount64());Sleep(1);}
+        check(received.size()==1&&received[0]==f,"real TCP channel delivers one ordered authenticated key");received.clear();
+        InputFrame reverse{InputType::Wheel,37,-120,1};server.poll(htonl(INADDR_LOOPBACK),{reverse},received,GetTickCount64());
+        for(int n=0;n<100&&received.empty();++n){client.poll(htonl(INADDR_LOOPBACK),{},received,GetTickCount64());Sleep(1);}
+        check(received.size()==1&&received[0]==reverse,"real input channel is bidirectional");
+        auto generation=client.generation();client.poll(htonl(INADDR_LOOPBACK),{},received,GetTickCount64()+3000);
+        check(!client.ready()&&client.generation()!=generation,"heartbeat timeout closes channel and changes generation");
+    }
+    {
+        auto port=freePort();InputChannel client(a,b,secret,1,port),server(b,a,std::string(64,'e'),0,port);
+        std::vector<InputFrame> received;auto start=GetTickCount64();
+        while(GetTickCount64()-start<400){server.poll(htonl(INADDR_LOOPBACK),{},received,GetTickCount64());client.poll(htonl(INADDR_LOOPBACK),{},received,GetTickCount64());Sleep(1);}
+        check(!client.ready()&&!server.ready()&&received.empty(),"wrong saved pair key never authorizes input");
+    }
+    {
+        auto port=freePort();InputChannel client(a,b,secret,1,port),server(b,a,secret,1,port);
+        std::vector<InputFrame> received;auto start=GetTickCount64();
+        while(GetTickCount64()-start<400){server.poll(htonl(INADDR_LOOPBACK),{},received,GetTickCount64());client.poll(htonl(INADDR_LOOPBACK),{},received,GetTickCount64());Sleep(1);}
+        check(!client.ready()&&!server.ready()&&received.empty(),"conflicting screen arrangement rejected before input");
+    }
+}
+}
+int main()
+{
+    try{channelChecks();routerChecks();std::cout<<"Passed "<<passed<<" LAN input checks\n";}
+    catch(const std::exception &e){std::cerr<<"FAIL: "<<e.what()<<'\n';return 1;}
+}

tests/screenshot_ui.cpp

@@ -83,6 +83,53 @@ int main(int argc, char **argv)
         require(c.pencilCursor!=nullptr,"pencil drawing cursor loads");
         require(c.freehand && !c.pointer && ks::toolCursor(c)==c.pencilCursor,
                 "new screenshot editor starts with the pencil tool");
+        {
+            require(GetDlgItem(window,41) && GetDlgItem(window,44),"smoothing slider and Apply to all exist");
+            auto adjust=[&](int value,int code=TB_THUMBPOSITION) {
+                SendDlgItemMessageW(window,41,TBM_SETPOS,TRUE,value);
+                SendMessageW(window,WM_HSCROLL,MAKEWPARAM(code,0),(LPARAM)GetDlgItem(window,41));
+            };
+            adjust(70); require(c.smoothing==70 && c.marks.empty(),"no selection changes default smoothing");
+            ks::Mark pencil{{40,80},{240,80},0}; pencil.freehand=true;
+            for(int i=0;i<=100;++i) pencil.points.push_back({40+i*2,80+(i%2?5:0)});
+            ks::Mark rectangle{{40,130},{240,210},0}; rectangle.shape=ks::ScreenshotShape::Rectangle;
+            c.marks={pencil,pencil,rectangle}; c.selected=0;
+            auto rawImage=ks::decodeImage(ks::screenshotClip(c.image->dc,320,240,c.marks)).bgra;
+            adjust(40,TB_THUMBTRACK); adjust(90,TB_THUMBTRACK); adjust(90,TB_ENDTRACK);
+            require(c.marks[0].smoothing==90 && c.marks[1].smoothing==0 && c.smoothing==70,
+                    "selected stroke smoothing leaves other objects and default alone");
+            SendMessageW(window,WM_COMMAND,12,0);
+            require(c.marks[0].smoothing==0,"one undo reverses an entire slider drag");
+            SendMessageW(window,WM_COMMAND,18,0);
+            require(c.marks[0].smoothing==90,"redo restores smoothing amount and path");
+            c.selected=0; ks::syncLineOptions(window,c);
+            SendMessageW(window,WM_COMMAND,44,0);
+            require(c.marks[0].smoothing==90 && c.marks[1].smoothing==90 && c.smoothing==90 &&
+                    c.marks[2].shape==ks::ScreenshotShape::Rectangle && c.marks[2].rawPoints.empty(),
+                    "Apply to all updates pencil strokes and default without changing shapes");
+            require(ks::decodeImage(ks::screenshotClip(c.image->dc,320,240,c.marks)).bgra!=rawImage,
+                    "PNG export uses the smoothed geometry");
+            SendMessageW(window,WM_COMMAND,12,0);
+            require(c.marks[0].smoothing==90 && c.marks[1].smoothing==0,"bulk smoothing is one undo step");
+            c.selected=0; adjust(0);
+            require(c.marks[0].points.size()==pencil.points.size() && c.marks[0].points[1].y==85,
+                    "selected zero smoothing restores exact original path");
+            require(ks::decodeImage(ks::screenshotClip(c.image->dc,320,240,c.marks)).bgra==rawImage,
+                    "restoring zero smoothing restores the exact original exported pixels");
+            c.marks.clear(); c.selected=-1; c.history=ks::ScreenshotHistory{};
+            adjust(75);
+            auto mouse=[&](UINT message,POINT p) {
+                int x=c.view.left+MulDiv(p.x,c.view.right-c.view.left,c.image->width);
+                int y=c.view.top+MulDiv(p.y,c.view.bottom-c.view.top,c.image->height);
+                SendMessageW(window,message,message==WM_LBUTTONUP?0:MK_LBUTTON,MAKELPARAM(x,y));
+            };
+            mouse(WM_LBUTTONDOWN,{40,90});
+            for(int i=1;i<=100;++i) mouse(WM_MOUSEMOVE,{40+i*2,90+LONG(std::lround(35*std::sin(i*.04)+3*std::sin(i*1.7)))});
+            mouse(WM_LBUTTONUP,{240,64});
+            require(c.marks.size()==1 && c.marks[0].freehand && c.marks[0].smoothing==75 && !c.marks[0].rawPoints.empty(),
+                    "new curved pencil stroke uses toolbar default and retains original samples");
+            c.marks.clear(); c.selected=-1; c.history=ks::ScreenshotHistory{}; c.smoothing=25;
+        }
         {
             require(GetDlgItem(window,36)!=nullptr,"triangle has a dedicated toolbar button");
             SendMessageW(window,WM_KEYDOWN,'G',0);
@@ -141,6 +188,38 @@ int main(int argc, char **argv)
             SendMessageW(window,WM_COMMAND,12,0); require(c.marks.empty(),"undo trapezoid creation");
             SendMessageW(window,WM_COMMAND,18,0); require(c.marks[0].shape==ks::ScreenshotShape::Trapezoid,"redo trapezoid creation");
             c.marks.clear(); c.selected=-1; c.history=ks::ScreenshotHistory{};
+            require(GetDlgItem(window,38)!=nullptr,"arc has a dedicated toolbar button");
+            SendMessageW(window,WM_KEYDOWN,'U',0);
+            require(c.shape==ks::ScreenshotShape::Arc && c.arrow && !c.freehand,"U selects arc tool");
+            mouse(WM_LBUTTONDOWN,{60,70}); mouse(WM_LBUTTONUP,{240,180});
+            require(c.marks.size()==1 && c.marks[0].shape==ks::ScreenshotShape::Arc && !c.marks[0].isHighlight(),
+                    "arc tool creates an editable shape");
+            auto arc=c.marks[0];
+            require(ks::hitScreenshotMark(arc,{150,70},3)==ks::MarkPart::Body &&
+                    ks::hitScreenshotMark(arc,{150,180},3)==ks::MarkPart::None,
+                    "arc selects its curve but has no closing chord");
+            ks::Surface rendered(320,240); PatBlt(rendered.dc,0,0,320,240,WHITENESS);
+            ks::drawMarks(rendered.dc,{arc});
+            require(GetPixel(rendered.dc,150,70)==arc.color && GetPixel(rendered.dc,150,180)==RGB(255,255,255),
+                    "arc renders an open curve without a closing chord");
+            auto exported=ks::decodeImage(ks::screenshotClip(c.image->dc,320,240,{arc}));
+            auto channel=[&](int x,int y,int component){return exported.bgra[(y*exported.width+x)*4+component];};
+            require(channel(150,70,2)==GetRValue(arc.color) && channel(150,70,1)==GetGValue(arc.color) &&
+                    channel(150,180,0)==255 && channel(150,180,1)==255 && channel(150,180,2)==255,
+                    "PNG export preserves the arc and its open chord");
+            mouse(WM_LBUTTONDOWN,arc.to); mouse(WM_LBUTTONUP,{260,200});
+            require(c.marks[0].to.x==260 && c.marks[0].points.back().y==200,"arc resizes with its bounds");
+            auto arcGrip=ks::screenshotShapeRotationHandle(arc);
+            auto turned=ks::dragScreenshotMark(arc,ks::MarkPart::Rotation,arcGrip,{280,135},320,240);
+            require(turned.rotation!=0 && ks::hitScreenshotMark(turned,ks::rotateShapePoint(turned,{150,70}),3)==ks::MarkPart::Body,
+                    "rotated arc remains selectable");
+            std::vector<ks::Mark> linked{arc}; ks::Mark connector{{10,10},{150,70},0};
+            ks::linkScreenshotEndpoint(connector,false,{150,70},linked,4);
+            require(connector.toLink.target!=0,"connector can attach to the arc curve");
+            SendMessageW(window,WM_COMMAND,12,0); require(c.marks[0].to.x==240,"undo arc resize");
+            SendMessageW(window,WM_COMMAND,12,0); require(c.marks.empty(),"undo arc creation");
+            SendMessageW(window,WM_COMMAND,18,0); require(c.marks[0].shape==ks::ScreenshotShape::Arc,"redo arc creation");
+            c.marks.clear(); c.selected=-1; c.history=ks::ScreenshotHistory{};
             SendMessageW(window,WM_COMMAND,21,0);
         }
         {

tests/stroke_improvement.h

@@ -122,4 +122,31 @@ inline void testStrokeImprovement() {
     double deviation=0; for(auto p:smooth) deviation+=std::abs(p.y-100);
     require(deviation/smooth.size()<1.5 && smooth.front().y==jitter.front().y && smooth.back().y==jitter.back().y,
             "smoothing reduces jitter and preserves endpoints");
+    auto equal=[](const auto &a,const auto &b){return a.size()==b.size() && std::equal(a.begin(),a.end(),b.begin(),
+        [](POINT x,POINT y){return x.x==y.x && x.y==y.y;});};
+    require(equal(ks::smoothScreenshotStroke(jitter,0),jitter),"zero smoothing preserves exact mouse samples");
+    std::vector<POINT> waves;
+    for(int i=0;i<=200;++i) waves.push_back({30+i,100+LONG(std::lround(6*std::sin(i*.5)))});
+    auto roughness=[](const auto &p){double total=0; for(size_t i=1;i<p.size();++i) total+=std::abs(p[i].y-p[i-1].y); return total;};
+    auto low=ks::smoothScreenshotStroke(waves,25),high=ks::smoothScreenshotStroke(waves,100);
+    require(roughness(high)<roughness(low) && roughness(low)<roughness(waves),"higher smoothing removes more jitter");
+    require(high.front().x==waves.front().x && high.front().y==waves.front().y &&
+            high.back().x==waves.back().x && high.back().y==waves.back().y,"smoothing preserves both endpoints");
+    ks::ScreenshotMark mark{waves.front(),waves.back(),0}; mark.freehand=true; mark.points=waves;
+    ks::setScreenshotSmoothing(mark,100); ks::setScreenshotSmoothing(mark,25);
+    require(equal(mark.points,low),"lowering smoothing recomputes from original instead of accumulating filters");
+    ks::setScreenshotSmoothing(mark,0);
+    require(equal(mark.points,waves),"zero restores original after multiple adjustments");
+    ks::setScreenshotSmoothing(mark,100);
+    auto moved=ks::dragScreenshotMark(mark,ks::MarkPart::Body,{0,0},{10,15},500,500);
+    ks::setScreenshotSmoothing(moved,0);
+    require(moved.points[40].x==waves[40].x+10 && moved.points[40].y==waves[40].y+15,
+            "moving preserves the original path in moved coordinates");
+    auto resized=ks::dragScreenshotMark(mark,ks::MarkPart::End,mark.to,{260,130},500,500);
+    ks::setScreenshotSmoothing(resized,0);
+    require(resized.points.back().x==260 && resized.points.back().y==130,"endpoint editing survives smoothing changes");
+    auto duplicate=ks::cloneScreenshotMark(mark,{mark},500,500);
+    ks::setScreenshotSmoothing(duplicate,0);
+    require(duplicate.points[40].x==waves[40].x+16 && duplicate.points[40].y==waves[40].y+16,
+            "cloning retains independent original geometry");
 }

tests/sync.cpp

@@ -70,6 +70,91 @@ int main()
         reordered.directIds = {L"00000422", L"00000409"}; reordered.direct = {L"Ctrl+2", L"Ctrl+1"};
         require(sharedSyncSettings(ordered) == sharedSyncSettings(reordered), "layout enumeration does not cause sync churn");
         auto j = parse(base);
+        {
+            const std::wstring chat=L"telegram\nРобота / ~test";
+            const auto chatKey=utf8(chat);
+            Settings chats=local;
+            chats.chatCycles[chat]={L"win:00000422",L"win:00000409"};
+            chats.chatCycles[L"telegram-web\nРобота / ~test"]={L"win:00000409"};
+            chats.chatCycles[L"ms-teams\nTeam"]={L"win:00000422"};
+            chats.chatCycles[L"viber\nSaved inactive"]={L"win:00000409"};
+            auto shared=sharedSyncSettings(chats);
+            require(restoreSyncSettings(shared,local,{},true).chatCycles==chats.chatCycles,
+                    "sync transfers all chat applications, Unicode names and ordered layout IDs even when not installed");
+            auto legacy=j; legacy.erase("chatCycles");
+            require(restoreSyncSettings(bytes(legacy),chats,{},true).chatCycles==chats.chatCycles,
+                    "legacy profile without chat field preserves existing profiles");
+            require(restoreSyncSettings(base,chats,{},true).chatCycles.empty(),
+                    "explicit empty chat map clears synchronized profiles");
+            auto l=j,r=j;
+            l["chatCycles"][chatKey]=Json::array({"win:00000422","win:00000409"});
+            r["chatCycles"]["ms-teams\nOther"]=Json::array({"win:00000409"});
+            auto first=mergeSyncProfile({},bytes(l),bytes(r));
+            require(first.conflicts.empty() && parse(first.local)["chatCycles"].size()==2 && first.local==first.remote,
+                    "first sync unions profiles for different chats");
+            auto ancestor=first.local;
+            l=r=parse(ancestor);
+            l["chatCycles"][chatKey]=Json::array({"win:00000409","win:00000422"});
+            r["chatCycles"]["ms-teams\nOther"]=Json::array({"win:00000422"});
+            auto independent=mergeSyncProfile(ancestor,bytes(l),bytes(r));
+            require(independent.conflicts.empty() && parse(independent.local)["chatCycles"]==
+                    Json({{chatKey,l["chatCycles"][chatKey]},{"ms-teams\nOther",r["chatCycles"]["ms-teams\nOther"]}}),
+                    "independent chat edits merge without losing language order");
+            r["chatCycles"][chatKey]=Json::array({"win:00000422"});
+            auto conflict=mergeSyncProfile(ancestor,bytes(l),bytes(r));
+            require(conflict.conflicts.size()==1 && conflict.conflicts[0].key.find("~1")!=std::string::npos &&
+                    conflict.conflicts[0].label.find(L"Chat languages: telegram / ")==0,
+                    "same-chat edit conflict has readable name and escaped pointer");
+            auto again=mergeSyncProfile(conflict.base,conflict.local,conflict.remote);
+            require(again.conflicts.size()==1,"chat conflict survives persisted merge ancestor");
+            auto resolved=mergeSyncProfile(again.base,again.local,again.remote,{{again.conflicts[0],false}});
+            require(resolved.conflicts.empty() && parse(resolved.local)["chatCycles"][chatKey]==r["chatCycles"][chatKey],
+                    "choose remote languages for one chat");
+            l=r=parse(ancestor); l["chatCycles"].erase(chatKey);
+            auto removed=mergeSyncProfile(ancestor,bytes(l),bytes(r));
+            require(removed.conflicts.empty() && !restoreSyncSettings(removed.local,local,{},true).chatCycles.contains(chat),
+                    "chat deletion propagates and merged profile remains loadable");
+            r["chatCycles"][chatKey]=Json::array({"win:00000409"});
+            auto deletion=mergeSyncProfile(ancestor,bytes(l),bytes(r));
+            require(deletion.conflicts.size()==1,"chat deletion versus edit requires a choice");
+            auto erase=mergeSyncProfile(deletion.base,deletion.local,deletion.remote,{{deletion.conflicts[0],true}});
+            require(erase.conflicts.empty() && !parse(erase.remote)["chatCycles"].contains(chatKey),
+                    "choosing deletion removes chat without leaving null entries");
+            auto stale=mergeSyncProfile(ancestor,bytes(l),bytes(legacy));
+            require(stale.conflicts.empty() && parse(stale.local)["chatCycles"]==l["chatCycles"],
+                    "older remote missing chat field cannot delete or resurrect local chat profiles");
+            auto validate=[&](const Bytes &value){restoreSyncSettings(value,chats,{},true);};
+            FakeProvider provider; provider.remote={1,bytes(legacy)};
+            auto download=synchronize(provider,{},shared,SyncAction::Download,validate,{},true);
+            require(provider.writes==0 && restoreSyncSettings(download.settings,local,{},true).chatCycles==chats.chatCycles,
+                    "download from older server profile preserves chat settings");
+            provider.remote={1,base};
+            download=synchronize(provider,{},shared,SyncAction::Download,validate,{},true);
+            require(restoreSyncSettings(download.settings,local,{},true).chatCycles.empty(),
+                    "download explicit empty chat map removes local profiles");
+            provider.remote={1,bytes(legacy)};
+            auto upload=synchronize(provider,{},shared,SyncAction::Upload,validate,{},true);
+            require(provider.writes==1 && restoreSyncSettings(provider.remote.settings,local,{},true).chatCycles==chats.chatCycles,
+                    "upload publishes chat profiles while keeping PC layout settings separate");
+            auto invalid=j; invalid["chatCycles"][chatKey]=Json::array();
+            rejects([&]{restoreSyncSettings(bytes(invalid),local,{},true);},"reject empty synchronized chat cycle");
+            invalid["chatCycles"][chatKey]=Json::array({"not-a-layout"});
+            rejects([&]{restoreSyncSettings(bytes(invalid),local,{},true);},"reject invalid synchronized layout ID");
+            invalid["chatCycles"]=Json::object({{"unknown\nChat",Json::array({"win:00000409"})}});
+            rejects([&]{restoreSyncSettings(bytes(invalid),local,{},true);},"reject unknown synchronized chat application");
+        }
+        {
+            Settings scoped = local;
+            scoped.snippets.push_back({L"test", L"Work apps", L"teams-scope", {L"ms-teams", L"outlook"}});
+            auto wire=sharedSyncSettings(scoped);
+            require(restoreSyncSettings(wire, local, {}).snippets[1].apps==std::vector<std::wstring>{L"ms-teams", L"outlook"}, "sync preserves multiple app scopes");
+            auto leftScope=j,rightScope=j;
+            leftScope["snippets"].push_back({{"id","left-scope"},{"trigger","same"},{"text","left"},{"apps",Json::array({"notepad"})}});
+            rightScope["snippets"].push_back({{"id","right-scope"},{"trigger","same"},{"text","right"},{"apps",Json::array({"ms-teams"})}});
+            require(parse(mergeSyncSettings(base,bytes(leftScope),bytes(rightScope)))["snippets"].size()==3, "same trigger in different apps merges");
+            rightScope["snippets"].back()["apps"]=Json::array({"NOTEPAD.exe"});
+            rejects([&]{mergeSyncSettings(base,bytes(leftScope),bytes(rightScope));}, "sync detects overlapping application scopes");
+        }
         require(!j.contains("startWithSystem") && !j.contains("tesseractPath") && !j.contains("historyEnabled"), "local-only fields excluded");
         auto restored = restoreSyncSettings(base, local, {});
         require(restored.autostart && restored.elevatedAutostart && !restored.history && restored.tesseractPath == local.tesseractPath, "preserve device settings");

tests/tests.cpp

@@ -590,6 +590,12 @@ int main(int argc, char **argv)
             options.autoNever = {L"hlelo"};
             require(!edited.suggest(L"hlelo ", 0, layouts, options), "never-correct overrides explicit pairs");
             options.autoNever.clear();
+            options.autoReplacements[L"мамамила"] = L"мама мила";
+            correction = edited.suggest(L"(Мамамила)! ", 2, layouts, options);
+            require(correction && correction->text == L"(Мама мила)! " && correction->target == 2,
+                    "joined words split while preserving capitalization, punctuation and layout");
+            edited.reject(L"мамамила ", options);
+            require(!edited.suggest(L"мамамила ", 2, layouts, options), "undo suppresses phrase replacements");
             edited.reject(L"(Hlelo)! ", options);
             require(!edited.suggest(L"hlelo ", 0, layouts, options), "undo rejection suppresses custom replacements");
             options.autoReplace = false;
@@ -711,7 +717,7 @@ int main(int argc, char **argv)
         settings.elevatedAutostart = true;
         settings.autoCorrect = true;
         settings.autoReplace = settings.autoTypos = true;
-        settings.autoReplacements = {{L"првиіт", L"привіт"}, {L"helo", L"hello"}};
+        settings.autoReplacements = {{L"првиіт", L"привіт"}, {L"helo", L"hello"}, {L"мамамила", L"мама мила"}};
         settings.autoMaxRank = 10000;
         settings.autoMinLength = 5;
         settings.autoPrefixChars = L"(#";
@@ -726,7 +732,13 @@ int main(int argc, char **argv)
         require(restored.autoWords == settings.autoWords, "personal dictionaries survive settings roundtrip");
         require(restored.autoReplace && restored.autoTypos && restored.autoReplacements == settings.autoReplacements,
                 "typo options and Unicode pairs survive settings roundtrip");
-        for (const auto &pair : {std::pair{L"hello", L"привіт"}, {L"hello", L"hello"}, {L"hi!", L"hello"}})
+        for (const auto &pair : {std::pair{L"hello", L"привіт"}, {L"hello", L"hello"}, {L"hi!", L"hello"},
+                                {L"helloworld", L" hello world"}, {L"helloworld", L"hello world "},
+                                {L"helloworld", L"hello  world"}, {L"helloworld", L"hello\tworld"},
+                                {L"helloworld", L"hello\nworld"}, {L"hello world", L"helloworld"},
+                                {L"helloworld", L"hello світ"}, {L"helloworld", L"hello world!"},
+                                {L"helloworld", L"hello Hello"}, {L"helloworld", L""},
+                                {L"helloworld", L"abcdefghijklmnopqrstuvwxyz abcdef"}})
         {
             auto invalid = settings;
             invalid.autoReplacements = {{pair.first, pair.second}};

utilities/StayHere/README.md

@@ -2,7 +2,7 @@
 
 Маленька портативна утиліта для Windows, без .NET та інсталяції.
 
-У KSwitcher v0.6.46 і новіших виберіть **Utilities → StayHere** у меню трея
+Виберіть **Tools → StayHere** у меню трея (у v0.6.46 цей пункт називається Utilities)
 або запустіть `tools/StayHere.exe` поруч із KSwitcher.exe.
 Зелена крапка в треї означає, що підтримка активності ввімкнена.
 Клацання лівою кнопкою перемикає режим; правою — відкриває меню з перемикачем і виходом.