#!/usr/bin/env python3
"""Transcode video archive files to browser-compatible H.264 MP4 format."""

import os
import sys
import subprocess
import shutil
from pathlib import Path

VIDEO_EXTS = {".mp4", ".mkv", ".mov", ".avi", ".webm", ".m4v"}

def probe_codec(file_path: Path) -> str:
    cmd = [
        "ffprobe", "-v", "error", "-select_streams", "v:0",
        "-show_entries", "stream=codec_name",
        "-of", "default=noprint_wrappers=1:nokey=1", str(file_path)
    ]
    res = subprocess.run(cmd, capture_output=True, text=True)
    return res.stdout.strip().lower()

def transcode_video(file_path: Path):
    tmp_path = file_path.with_name(f"_transcoded_{file_path.stem}.mp4")
    cmd = [
        "ffmpeg", "-hide_banner", "-loglevel", "error", "-y",
        "-i", str(file_path),
        "-c:v", "libx264", "-preset", "fast", "-crf", "22",
        "-c:a", "aac", "-b:a", "128k",
        "-movflags", "+faststart",
        str(tmp_path)
    ]
    res = subprocess.run(cmd)
    if res.returncode == 0 and tmp_path.exists() and tmp_path.stat().st_size > 0:
        # Save as .mp4
        target_path = file_path.with_suffix(".mp4")
        if target_path != file_path and file_path.exists():
            file_path.unlink()
        shutil.move(str(tmp_path), str(target_path))
        print(f"  ✅ Transcoded -> {target_path}")
    else:
        if tmp_path.exists():
            tmp_path.unlink()
        print(f"  ❌ Failed to transcode {file_path}")

def process_archive(archive_dir: Path):
    if not archive_dir.exists():
        print(f"Archive directory {archive_dir} does not exist.")
        return

    print(f"Scanning {archive_dir} for non-H.264 videos...")
    for root, _, files in os.walk(archive_dir):
        for file in sorted(files):
            file_path = Path(root) / file
            if file_path.suffix.lower() in VIDEO_EXTS and not file.startswith("_transcoded_"):
                codec = probe_codec(file_path)
                if not codec:
                    print(f"⚠️ Could not probe codec or unreadable: {file_path}")
                    continue
                if codec != "h264":
                    print(f"🔄 Converting {file_path} (current codec: {codec})...")
                    transcode_video(file_path)
                else:
                    print(f"  ✓ Already H.264: {file_path}")

if __name__ == "__main__":
    target = Path(sys.argv[1]) if len(sys.argv) > 1 else Path("data/archive")
    process_archive(target)