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, profile: str = "standard"):
        if stream_key in self._processes:
            return

        procs = []
        qualities = settings.transcode_profiles.get(profile, settings.qualities)
        segment_seconds = max(1, settings.hls_segment_seconds)
        keyframe_frames = segment_seconds * 30
        for quality in qualities:
            label = quality["label"]
            width = quality["width"]
            height = quality["height"]
            bitrate = quality["bitrate"]
            hls_dir = f"/tmp/hls/{stream_key}/{label}"
            os.makedirs(hls_dir, exist_ok=True)
            cmd = [
                "ffmpeg", "-y",
                "-i", input_url,
                "-c:v", "libx264", "-preset", "ultrafast",
                "-b:v", bitrate,
                "-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*{segment_seconds})",
                "-copyts", "-start_at_zero",
                "-c:a", "aac", "-b:a", "128k",
                "-f", "hls",
                "-hls_time", str(segment_seconds),
                "-hls_list_size", "6",
                "-hls_flags", "delete_segments+independent_segments+program_date_time",
                "-hls_segment_filename", f"{hls_dir}/segment_%03d.ts",
                f"{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()