#!/usr/bin/env python3
"""Owner-run provisioning/verification of Notification Service storage. No deletion."""

import json
import os
from pathlib import Path
import stat
import subprocess
import sys

BASE = Path("/mnt/shared/notification-service")
UUID = "c2c31640-a247-4988-bc7b-9ee9789464d1"
DIRECTORIES = (("postgres", 999, 999), ("rabbitmq", 100, 101))


def main():
    if sys.platform != "linux" or os.geteuid() != 0:
        raise RuntimeError("run this script as root on mini-pc-2")
    for location in (Path("/mnt/files"), Path("/mnt/shared")):
        if not location.is_dir() or location.is_symlink():
            raise RuntimeError("expected real storage mount directory is missing")
        result = subprocess.run(["findmnt", "--json", "--target", str(location), "--output", "TARGET,FSTYPE,UUID"],
                                check=True, capture_output=True, timeout=20)
        filesystems = json.loads(result.stdout)["filesystems"]
        if len(filesystems) != 1 or filesystems[0]["target"] != str(location) or filesystems[0]["fstype"] != "xfs" or filesystems[0]["uuid"] != UUID:
            raise RuntimeError("storage mount/UUID/XFS verification failed; no directories created")
    if BASE.is_symlink():
        raise RuntimeError("notification-service path must not be a symlink")
    if BASE.exists():
        info = BASE.stat()
        if not BASE.is_dir() or (info.st_uid, info.st_gid, stat.S_IMODE(info.st_mode)) != (0, 0, 0o755):
            raise RuntimeError("existing parent path has unexpected type/ownership/permissions")
        if set(child.name for child in BASE.iterdir()) - {name for name, _, _ in DIRECTORIES}:
            raise RuntimeError("unexpected contents in notification-service parent")
    # Inspect both directories before creating anything. Never adopt arbitrary data.
    for name, uid, gid in DIRECTORIES:
        path = BASE / name
        if path.is_symlink():
            raise RuntimeError("service data path must not be a symlink")
        if not path.exists():
            continue
        info = path.stat()
        if not path.is_dir() or (info.st_uid, info.st_gid, stat.S_IMODE(info.st_mode)) != (uid, gid, 0o700):
            raise RuntimeError("existing service directory has unexpected ownership/permissions")
        marker = path / ".invemory-storage.json"
        if marker.is_symlink():
            raise RuntimeError("marker must not be a symlink")
        if marker.exists():
            marker_info = marker.stat()
            if (marker_info.st_uid, marker_info.st_gid, stat.S_IMODE(marker_info.st_mode)) != (0, 0, 0o644):
                raise RuntimeError("existing marker has unexpected ownership/permissions")
            if json.loads(marker.read_text(encoding="utf-8")) != {"uuid": UUID, "role": "shared-notification/" + name}:
                raise RuntimeError("existing marker mismatch; never overwritten")
        elif any(path.iterdir()):
            raise RuntimeError("unmarked service directory is not empty; never adopted")
    os.umask(0o077)
    if not BASE.exists():
        BASE.mkdir(mode=0o755)
        os.chown(BASE, 0, 0)
        os.chmod(BASE, 0o755)
    for name, uid, gid in DIRECTORIES:
        path = BASE / name
        if not path.exists():
            path.mkdir(mode=0o700)
            os.chown(path, uid, gid)
        marker = path / ".invemory-storage.json"
        if not marker.exists():
            fd = os.open(marker, os.O_WRONLY | os.O_CREAT | os.O_EXCL, 0o644)
            with os.fdopen(fd, "w", encoding="utf-8") as stream:
                json.dump({"uuid": UUID, "role": "shared-notification/" + name}, stream)
                stream.write("\n")
            os.chown(marker, 0, 0)
            os.chmod(marker, 0o644)
        info = path.stat()
        marker_info = marker.stat()
        if (info.st_uid, info.st_gid, stat.S_IMODE(info.st_mode)) != (uid, gid, 0o700):
            raise RuntimeError("directory ownership verification failed")
        if (marker_info.st_uid, marker_info.st_gid, stat.S_IMODE(marker_info.st_mode)) != (0, 0, 0o644):
            raise RuntimeError("marker ownership verification failed")
    print("Provisioned two Notification Service directories; XFS UUID and permissions verified.")


if __name__ == "__main__":
    try:
        main()
    except (RuntimeError, OSError, ValueError, subprocess.SubprocessError) as error:
        print("STOP: " + str(error), file=sys.stderr)
        sys.exit(1)