// 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;
}
}