import subprocess
from pathlib import Path

VIDEOS_DIR = "/videos"
CHUNK_SIZE = 64 * 1024


def _get_stream_urls(youtube_url: str):
    result = subprocess.run(
        [
            "yt-dlp",
            "-f", "bestvideo[ext=mp4][vcodec^=avc]+bestaudio[ext=m4a]/best[ext=mp4]",
            "--print", "urls",
            youtube_url,
        ],
        capture_output=True, text=True, timeout=30,
    )
    if result.returncode != 0:
        return None, None

    lines = result.stdout.strip().splitlines()
    if len(lines) >= 2:
        return lines[0], lines[1]
    elif len(lines) == 1:
        return lines[0], None
    return None, None


def stream_video_live(video_id: int, youtube_url: str):
    output_path = f"{VIDEOS_DIR}/{video_id}.mp4"

    video_url, audio_url = _get_stream_urls(youtube_url)
    if not video_url:
        return

    if audio_url:
        cmd = [
            "ffmpeg",
            "-reconnect", "1",
            "-reconnect_streamed", "1",
            "-reconnect_delay_max", "5",
            "-i", video_url,
            "-reconnect", "1",
            "-reconnect_streamed", "1",
            "-reconnect_delay_max", "5",
            "-i", audio_url,
            "-c:v", "copy",
            "-c:a", "aac",
            "-movflags", "frag_keyframe+empty_moov+default_base_moof",
            "-f", "mp4",
            "pipe:1",
        ]
    else:
        cmd = [
            "ffmpeg",
            "-reconnect", "1",
            "-reconnect_streamed", "1",
            "-reconnect_delay_max", "5",
            "-i", video_url,
            "-c", "copy",
            "-movflags", "frag_keyframe+empty_moov+default_base_moof",
            "-f", "mp4",
            "pipe:1",
        ]

    process = subprocess.Popen(
        cmd,
        stdout=subprocess.PIPE,
        stderr=subprocess.DEVNULL,
    )

    try:
        with open(output_path, "wb") as f:
            while True:
                chunk = process.stdout.read(CHUNK_SIZE)
                if not chunk:
                    break
                f.write(chunk)
                yield chunk
    except GeneratorExit:
        pass
    finally:
        if process.poll() is None:
            process.kill()
        process.wait()
        if process.stdout:
            process.stdout.close()

        path = Path(output_path)
        if process.returncode != 0 and path.exists():
            path.unlink()