#!/usr/bin/env python3.11
import argparse
import logging
import subprocess
from pathlib import Path


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(
        description="Encode middle 1-min slice of video with multiple CRF values.",
        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
    )
    parser.add_argument("video", type=Path, help="Input video file")
    parser.add_argument("--codec", choices=["x264", "x265"], default="x265", help="Codec to use")
    parser.add_argument("--crf", nargs="+", type=int, default=[15, 20, 25, 30, 35, 40], help="CRF values")
    return parser.parse_args()


def read_video_duration(video_path: Path) -> float:
    cmd = [
        "ffprobe",
        "-v",
        "error",
        "-show_entries",
        "format=duration",
        "-of",
        "default=noprint_wrappers=1:nokey=1",
        str(video_path),
    ]
    result = subprocess.run(cmd, capture_output=True, text=True, check=True)
    return float(result.stdout.strip())


def encode_clip(clip_path: Path, codec: str, crf: int, out_path: Path) -> Path:
    # clip_path is actually the input video, we encode the middle slice on the fly
    total_duration = read_video_duration(clip_path)
    slice_duration = 60
    start = max(0, int(total_duration // 2 - slice_duration // 2))
    if codec == "x264":
        lib = "h264_videotoolbox"
    else:
        lib = "hevc_videotoolbox"
    cmd = [
        "ffmpeg",
        "-y",
        "-ss",
        str(start),
        "-t",
        str(slice_duration),
        "-i",
        str(clip_path),
        "-c:v",
        lib,
        "-q:v",
        str(crf),
        "-preset",
        "medium",
        "-c:a",
        "copy",
        str(out_path),
    ]
    logging.info(f"Encoding {out_path.name} with {lib} q:v={crf} (hwaccel) from middle slice")
    subprocess.run(cmd, check=True)


def main():
    logging.basicConfig(level=logging.INFO, format="%(asctime)s %(levelname)s: %(message)s")
    args = parse_args()
    outdir = args.video.parent
    outdir.mkdir(parents=True, exist_ok=True)
    for crf in args.crf:
        out_path = outdir / f"{args.video.stem}.{args.codec}_crf{crf}.mp4"
        encode_clip(clip_path=args.video, codec=args.codec, crf=crf, out_path=out_path)


if __name__ == "__main__":
    main()