import subprocess
import os
from config import settings


class TranscodeManager:
    _processes: dict[str, list[subprocess.Popen]] = {}

    def start_transcode(self, stream_key: str, input_url: str, qualities: list[dict]):
        if stream_key in self._processes:
            return

        procs = []
        segment_seconds = max(1, settings.hls_segment_seconds)
        for quality in qualities:
            label = quality["label"]
            width = quality["width"]
            height = quality["height"]
            fps = quality.get("fps", 30)
            codec = quality.get("codec", "libx264")
            bitrate = quality["bitrate"]
            crf = quality.get("crf", 23)
            preset = quality.get("preset", "ultrafast")
            audio_bitrate = quality.get("audio_bitrate", "128k")
            keyframe_seconds = quality.get("keyframe_seconds", segment_seconds)
            keyframe_frames = keyframe_seconds * fps
            hls_dir = os.path.join(settings.hls_runtime_dir, stream_key, label)
            os.makedirs(hls_dir, exist_ok=True)
            cmd = [
                "ffmpeg", "-y",
                "-i", input_url,
                "-c:v", codec, "-preset", preset,
                "-r", str(fps), "-b:v", bitrate, "-crf", str(crf),
                "-s", f"{width}x{height}",
                "-sc_threshold", "0",
                "-g", str(keyframe_frames),
                "-keyint_min", str(keyframe_frames),
                "-force_key_frames", f"expr:gte(t,n_forced*{keyframe_seconds})",
                "-copyts", "-start_at_zero",
                "-c:a", "aac", "-b:a", audio_bitrate,
                "-f", "hls",
                "-hls_time", str(segment_seconds),
                "-hls_list_size", "6",
                "-hls_flags", "delete_segments+independent_segments+program_date_time",
                "-hls_segment_filename", os.path.join(hls_dir, "segment_%03d.ts"),
                os.path.join(hls_dir, "index.m3u8"),
            ]
            try:
                proc = subprocess.Popen(
                    cmd, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL
                )
                procs.append(proc)
            except FileNotFoundError:
                pass

        self._processes[stream_key] = procs

    def stop_transcode(self, stream_key: str):
        procs = self._processes.pop(stream_key, [])
        for proc in procs:
            try:
                proc.terminate()
                proc.wait(timeout=5)
            except Exception:
                try:
                    proc.kill()
                except Exception:
                    pass

    def stop_all(self):
        for key in list(self._processes.keys()):
            self.stop_transcode(key)


transcode_mgr = TranscodeManager()