"""Clips zusammenführen via ffmpeg concat."""

from __future__ import annotations

import subprocess
import tempfile
from pathlib import Path

from .config import VIDEO_EXTENSIONS, IMAGE_EXTENSIONS


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


def image_to_clip(
    image_path: Path,
    output_path: Path,
    duration: float = 3.0,
    width: int = 1920,
    height: int = 1080,
) -> Path:
    """Standbild in Video-Clip konvertieren."""
    output_path.parent.mkdir(parents=True, exist_ok=True)
    cmd = [
        "ffmpeg", "-y",
        "-loop", "1",
        "-i", str(image_path),
        "-t", str(duration),
        "-vf", f"scale={width}:{height}:force_original_aspect_ratio=decrease,"
               f"pad={width}:{height}:(ow-iw)/2:(oh-ih)/2",
        "-c:v", "libx264",
        "-pix_fmt", "yuv420p",
        "-r", "25",
        str(output_path),
    ]
    result = _run(cmd)
    if result.returncode != 0:
        raise RuntimeError(f"ffmpeg image-to-clip Fehler: {result.stderr}")
    return output_path


def normalize_clip(input_path: Path, output_path: Path) -> Path:
    """Clip auf einheitliches Format re-encoden (für concat-Kompatibilität)."""
    output_path.parent.mkdir(parents=True, exist_ok=True)
    cmd = [
        "ffmpeg", "-y",
        "-i", str(input_path),
        "-c:v", "libx264",
        "-c:a", "aac",
        "-pix_fmt", "yuv420p",
        "-r", "25",
        str(output_path),
    ]
    result = _run(cmd)
    if result.returncode != 0:
        raise RuntimeError(f"ffmpeg normalize Fehler: {result.stderr}")
    return output_path


def merge_clips(
    clips: list[Path],
    output_path: Path,
    intro: Path | None = None,
    outro: Path | None = None,
    normalize: bool = True,
) -> Path:
    """Clips zusammenführen, optional mit Intro und Outro."""
    output_path.parent.mkdir(parents=True, exist_ok=True)

    all_clips: list[Path] = []
    if intro:
        all_clips.append(intro)
    all_clips.extend(clips)
    if outro:
        all_clips.append(outro)

    if not all_clips:
        raise ValueError("Keine Clips zum Zusammenführen.")

    if len(all_clips) == 1:
        if normalize:
            return normalize_clip(all_clips[0], output_path)
        cmd = ["ffmpeg", "-y", "-i", str(all_clips[0]), "-c", "copy", str(output_path)]
        result = _run(cmd)
        if result.returncode != 0:
            raise RuntimeError(f"ffmpeg copy Fehler: {result.stderr}")
        return output_path

    with tempfile.TemporaryDirectory() as tmp_dir:
        tmp = Path(tmp_dir)

        if normalize:
            ready_clips = [
                normalize_clip(clip, tmp / f"norm_{i:04d}.mp4")
                for i, clip in enumerate(all_clips)
            ]
        else:
            ready_clips = all_clips

        list_file = tmp / "clips.txt"
        with open(list_file, "w", encoding="utf-8") as fh:
            for clip in ready_clips:
                fh.write(f"file '{clip.resolve()}'\n")

        cmd = [
            "ffmpeg", "-y",
            "-f", "concat", "-safe", "0",
            "-i", str(list_file),
            "-c", "copy",
            str(output_path),
        ]
        result = _run(cmd)
        if result.returncode != 0:
            raise RuntimeError(f"ffmpeg concat Fehler: {result.stderr}")

    return output_path