import os
import asyncio
import uuid
import shutil
from pathlib import Path
from typing import Optional
from ..config import get_settings


HLS_SEGMENT_DURATION = 10  # Sekunden pro Segment


async def create_hls_session(
    session_id: str,
    audio_files: list[str],
    start_time: float = 0.0,
) -> str:
    """
    Erstellt HLS-Segmente via FFmpeg für die gegebenen Audio-Dateien.
    Gibt den Pfad zum HLS-Verzeichnis zurück.
    """
    settings = get_settings()
    session_dir = os.path.join(settings.hls_cache_dir, session_id)
    os.makedirs(session_dir, exist_ok=True)

    playlist_path = os.path.join(session_dir, "output.m3u8")

    if len(audio_files) == 1:
        input_path = audio_files[0]
    else:
        # Mehrere Dateien: Concat-Liste erstellen
        concat_file = os.path.join(session_dir, "concat.txt")
        with open(concat_file, "w", encoding="utf-8") as f:
            for af in audio_files:
                safe_path = af.replace("\\", "/")
                f.write(f"file '{safe_path}'\n")
        input_path = concat_file

    if len(audio_files) == 1:
        cmd = [
            "ffmpeg", "-y",
            "-ss", str(start_time),
            "-i", input_path,
            "-c:a", "aac",
            "-b:a", "192k",
            "-ac", "2",
            "-hls_time", str(HLS_SEGMENT_DURATION),
            "-hls_list_size", "0",
            "-hls_segment_filename", os.path.join(session_dir, "seg%05d.ts"),
            "-hls_flags", "independent_segments",
            playlist_path,
        ]
    else:
        cmd = [
            "ffmpeg", "-y",
            "-f", "concat", "-safe", "0",
            "-i", input_path,
            "-ss", str(start_time),
            "-c:a", "aac",
            "-b:a", "192k",
            "-ac", "2",
            "-hls_time", str(HLS_SEGMENT_DURATION),
            "-hls_list_size", "0",
            "-hls_segment_filename", os.path.join(session_dir, "seg%05d.ts"),
            "-hls_flags", "independent_segments",
            playlist_path,
        ]

    proc = await asyncio.create_subprocess_exec(
        *cmd,
        stdout=asyncio.subprocess.DEVNULL,
        stderr=asyncio.subprocess.PIPE,
    )
    _, stderr = await proc.communicate()

    if proc.returncode != 0:
        error_msg = stderr.decode(errors="replace") if stderr else "unknown error"
        raise RuntimeError(f"FFmpeg fehler: {error_msg}")

    return session_dir


def cleanup_hls_session(session_id: str):
    settings = get_settings()
    session_dir = os.path.join(settings.hls_cache_dir, session_id)
    if os.path.exists(session_dir):
        shutil.rmtree(session_dir, ignore_errors=True)


def get_hls_session_path(session_id: str) -> Optional[str]:
    settings = get_settings()
    session_dir = os.path.join(settings.hls_cache_dir, session_id)
    playlist = os.path.join(session_dir, "output.m3u8")
    return session_dir if os.path.exists(playlist) else None


def parse_m3u8_duration(playlist_path: str) -> float:
    """Berechnet Gesamtdauer aus M3U8-Playlist."""
    total = 0.0
    try:
        with open(playlist_path, "r") as f:
            for line in f:
                if line.startswith("#EXTINF:"):
                    duration_str = line.split(":")[1].split(",")[0]
                    total += float(duration_str)
    except Exception:
        pass
    return total