#!/usr/bin/env python3
"""Publish local video file(s) as looping RTSP stream(s) (fake camera) for local dev.

The Operation Room server only opens RTSP URLs (OpenCV); there is no video-upload API.
This script does NOT change the application backend: it runs ffmpeg + a small
RTSP server (MediaMTX) so you can point VIDEO_RTSP_URLS_JSON to rtsp://.../yourpath.

Requires:
  - ffmpeg in PATH
  - Docker, with the image pulled: bluenviron/mediamtx (recommended), OR a local
    `mediamtx` binary in PATH (advanced).

Single stream (legacy)::
  python3 scripts/demo_client/fake_rtsp_from_file.py /path/to/video.mp4
  python3 scripts/demo_client/fake_rtsp_from_file.py video.mp4 --port 18554 --path demo

Multiple streams (one MediaMTX, one ffmpeg per camera; different RTSP path per stream)::

  python3 scripts/demo_client/fake_rtsp_from_file.py --port 18554 \\
    --stream 'or-cam-01|./a.mp4|demo1' \\
    --stream 'or-cam-02|./b.mp4|demo2'

--stream format: ``CAMERA_ID|FILE|RTSP_PATH`` (use quotes in shell; RTSP path is
the last segment, e.g. ``demo1`` -> ``rtsp://127.0.0.1:<port>/demo1``).
"""

from __future__ import annotations

import argparse
import atexit
import json
import os
import signal
import shutil
import subprocess
import sys
import time
from pathlib import Path

MEDIAMTX_IMAGE = os.environ.get("MEDIAMTX_DOCKER_IMAGE", "bluenviron/mediamtx:latest")
CONTAINER_NAME = "orm-fake-rtsp-mediamtx"


def _has_docker() -> bool:
    return shutil.which("docker") is not None


def _has_ffmpeg() -> bool:
    return shutil.which("ffmpeg") is not None


def _stop_mediamtx_container() -> None:
    if not _has_docker():
        return
    try:
        subprocess.run(
            ["docker", "rm", "-f", CONTAINER_NAME],
            capture_output=True,
            check=False,
            timeout=30,
        )
    except (OSError, subprocess.SubprocessError):
        pass


def _start_mediamtx_docker(host_port: int) -> bool:
    _stop_mediamtx_container()
    cmd = [
        "docker", "run", "-d",
        "--name", CONTAINER_NAME,
        "-p", f"127.0.0.1:{host_port}:8554",
        MEDIAMTX_IMAGE,
    ]
    print("[fake-rtsp] Starting MediaMTX:", " ".join(cmd), file=sys.stderr)
    try:
        proc = subprocess.run(cmd, capture_output=True, text=True, timeout=120)
    except (OSError, subprocess.SubprocessError) as exc:
        print(f"[fake-rtsp] docker run failed: {exc}", file=sys.stderr)
        return False
    if proc.returncode != 0:
        err = (proc.stderr or proc.stdout or "").strip()
        print(f"[fake-rtsp] docker run exit {proc.returncode}: {err}", file=sys.stderr)
        return False
    atexit.register(_stop_mediamtx_container)
    return True


def _parse_stream_arg(spec: str) -> tuple[str, Path, str]:
    parts = spec.split("|", 2)
    if len(parts) != 3:
        raise ValueError(
            f"Invalid --stream {spec!r}; expected CAM|FILE|RTSP_PATH (three fields separated by |)"
        )
    cam = parts[0].strip()
    fpath = Path(parts[1].strip()).expanduser()
    rpath = parts[2].strip().strip("/")
    if not cam:
        raise ValueError("empty camera id in --stream")
    if not rpath:
        rpath = "demo"
    return cam, fpath, rpath


def main() -> int:
    parser = argparse.ArgumentParser(
        description="Loop video file(s) to RTSP URL(s) (dev fake camera; no backend code change).",
    )
    parser.add_argument(
        "video",
        nargs="?",
        type=Path,
        default=None,
        help="(single-stream mode) Path to a video file",
    )
    parser.add_argument(
        "--path",
        default="demo",
        help="(single-stream mode) RTSP path segment (rtsp://host:port/<path>)",
    )
    parser.add_argument(
        "--port",
        type=int,
        default=18554,
        help="Host port mapped to MediaMTX RTSP (container internal 8554). Default: 18554",
    )
    parser.add_argument(
        "--stream",
        action="append",
        default=None,
        help=(
            "Multi-stream mode. Repeat for each camera. "
            "Format: CAM|FILE|RTSP_PATH e.g. or-cam-01|./a.mp4|demo1"
        ),
    )
    parser.add_argument(
        "--no-docker",
        action="store_true",
        help="Do not start Docker; run MediaMTX yourself on the host port mapping.",
    )
    args = parser.parse_args()

    if not _has_ffmpeg():
        print("ffmpeg not found in PATH. Install ffmpeg and retry.", file=sys.stderr)
        return 1

    streams: list[tuple[str, Path, str]] = []
    if args.stream:
        for s in args.stream:
            try:
                streams.append(_parse_stream_arg(s))
            except ValueError as exc:
                print(f"[fake-rtsp] {exc}", file=sys.stderr)
                return 1
    elif args.video is not None:
        fpath = args.video.resolve()
        sp = (args.path or "demo").strip().strip("/") or "demo"
        streams = [("or-cam-01", fpath, sp)]
    else:
        parser.error("Provide a video file (single mode) or one or more --stream CAM|FILE|RTSP_PATH")

    for cam, fpath, rpath in streams:
        rp_file = fpath.resolve()
        if not rp_file.is_file():
            print(f"File not found: {rp_file} (camera {cam!r})", file=sys.stderr)
            return 1
        for ch in rpath:
            if ch not in "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_.-":
                print(
                    f"[fake-rtsp] RTSP path segment {rpath!r} for {cam!r} should be "
                    r"[a-zA-Z0-9_.-] only; adjust --path/--stream",
                    file=sys.stderr,
                )
                return 1

    host_port: int = args.port
    if not args.no_docker:
        if not _has_docker():
            print("Docker not found. Use --no-docker and start MediaMTX manually.", file=sys.stderr)
            return 1
        if not _start_mediamtx_docker(host_port):
            return 1
        print("[fake-rtsp] MediaMTX container started. Waiting for RTSP…", file=sys.stderr)
        time.sleep(1.0)
    else:
        print(
            f"[fake-rtsp] --no-docker: ensure an RTSP server is listening for publish on port {host_port}.",
            file=sys.stderr,
        )

    procs: list[subprocess.Popen] = []
    url_map: dict[str, str] = {}

    for cam, fpath, stream_path in streams:
        fp = fpath.resolve()
        dest_url = f"rtsp://127.0.0.1:{host_port}/{stream_path}"
        url_map[cam] = dest_url
        publish_cmd: list[str] = [
            "ffmpeg",
            "-hide_banner", "-loglevel", "info",
            "-re",
            "-stream_loop", "-1",
            "-i", str(fp),
            "-c", "copy",
            "-f", "rtsp",
            "-rtsp_transport", "tcp",
            dest_url,
        ]
        print("---", file=sys.stderr)
        print(f"Publish {cam} -> {dest_url}", file=sys.stderr)
        print("  " + " ".join(publish_cmd), file=sys.stderr)
        p = subprocess.Popen(publish_cmd)  # noqa: S603
        procs.append(p)

    j_compact = json.dumps(url_map, ensure_ascii=False, separators=(",", ":"))
    print("---", file=sys.stderr)
    print("RTSP mapping (set on monitoring server):", file=sys.stderr)
    for k, u in url_map.items():
        print(f"  {k}: {u}", file=sys.stderr)
    print("", file=sys.stderr)
    print("export (same machine as monitoring server, env snippet):", file=sys.stderr)
    print(f"  export VIDEO_RTSP_URLS_JSON='{j_compact}'", file=sys.stderr)
    print("", file=sys.stderr)
    print("If the server runs in Docker on Mac/Win, use host.docker.internal, e.g.:", file=sys.stderr)
    for cam, u in url_map.items():
        h = u.replace("127.0.0.1", "host.docker.internal", 1)
        print(f"  {cam}: {h}", file=sys.stderr)
    print("---", file=sys.stderr)
    print("Fake RTSP running (Ctrl+C to stop; MediaMTX container removed on exit).", file=sys.stderr)

    def on_sigint(_sig: int, _frame) -> None:
        for p in procs:
            if p.poll() is None:
                p.terminate()
        _stop_mediamtx_container()
        raise SystemExit(130)

    signal.signal(signal.SIGINT, on_sigint)
    signal.signal(signal.SIGTERM, on_sigint)

    try:
        while True:
            time.sleep(0.5)
        for p in procs:
            if p.poll() is not None:
                    print(
                        f"[fake-rtsp] ffmpeg ended (code {p.returncode}), stopping all.",
                        file=sys.stderr,
                    )
                    raise KeyboardInterrupt
    except KeyboardInterrupt:
        pass
    finally:
        for p in procs:
            if p.poll() is None:
                p.terminate()
                try:
                    p.wait(timeout=5)
                except subprocess.TimeoutExpired:
                    p.kill()
        _stop_mediamtx_container()

    return 0


if __name__ == "__main__":
    raise SystemExit(main())