"""Hintergrundmusik-Mixing und Audio-Logik."""

from __future__ import annotations

import random
import subprocess
from pathlib import Path

from .config import MUSIC_EXTENSIONS, get_music_files


def _run(cmd: list[str]) -> subprocess.CompletedProcess:
    return subprocess.run(cmd, capture_output=True, text=True, check=False)


def pick_music_file(
    music_files: list[Path],
    mode: str = "random",
) -> Path:
    """Musikdatei nach Modus auswählen."""
    if not music_files:
        raise FileNotFoundError("Keine Musikdateien gefunden.")

    if mode == "random":
        return random.choice(music_files)
    elif mode in ("alphabetical", "loop"):
        return sorted(music_files)[0]
    else:
        raise ValueError(f"Unbekannter Musik-Modus: {mode}")


def mix_music(
    video_path: Path,
    output_path: Path,
    music_file: Path,
    volume_original: float = 1.0,
    volume_music: float = 0.3,
) -> Path:
    """Hintergrundmusik in Video mixen."""
    output_path.parent.mkdir(parents=True, exist_ok=True)

    # Prüfen ob Video Audio-Stream hat
    probe_cmd = [
        "ffprobe", "-v", "error",
        "-select_streams", "a",
        "-show_entries", "stream=codec_type",
        "-of", "default=noprint_wrappers=1:nokey=1",
        str(video_path),
    ]
    probe = _run(probe_cmd)
    has_audio = bool(probe.stdout.strip())

    if has_audio:
        filter_complex = (
            f"[0:a]volume={volume_original}[v1];"
            f"[1:a]volume={volume_music}[v2];"
            f"[v1][v2]amix=inputs=2:duration=first[a]"
        )
        cmd = [
            "ffmpeg", "-y",
            "-i", str(video_path),
            "-stream_loop", "-1",
            "-i", str(music_file),
            "-filter_complex", filter_complex,
            "-c:v", "copy",
            "-c:a", "aac",
            "-map", "0:v:0",
            "-map", "[a]",
            "-shortest",
            str(output_path),
        ]
    else:
        # Kein Original-Audio → Musik direkt als Track
        cmd = [
            "ffmpeg", "-y",
            "-i", str(video_path),
            "-stream_loop", "-1",
            "-i", str(music_file),
            "-filter_complex", f"[1:a]volume={volume_music}[a]",
            "-c:v", "copy",
            "-c:a", "aac",
            "-map", "0:v:0",
            "-map", "[a]",
            "-shortest",
            str(output_path),
        ]

    result = _run(cmd)
    if result.returncode != 0:
        raise RuntimeError(f"ffmpeg Fehler beim Musik-Mixing: {result.stderr}")

    return output_path


def add_music_from_config(
    video_path: Path,
    output_path: Path,
    config: dict,
) -> Path:
    """Musik aus Konfiguration auswählen und mixen."""
    music_files = get_music_files(config)
    if not music_files:
        raise FileNotFoundError(
            f"Keine Musikdateien in: {config['resources']['folder']}/music/"
        )

    mode = config["music"]["mode"]
    music_file = pick_music_file(music_files, mode)

    return mix_music(
        video_path=video_path,
        output_path=output_path,
        music_file=music_file,
        volume_original=config["music"]["volume_original"],
        volume_music=config["music"]["volume_music"],
    )