import subprocess
from pathlib import Path
import cv2

from config import FRAMES_SUBDIR

def ensure_dir(p: Path):
    p.mkdir(parents=True, exist_ok=True)

def extract_audio_ffmpeg(video_path: Path, wav_path: Path, sr: int = 16000):
    ensure_dir(wav_path.parent)
    cmd = [
        "ffmpeg", "-y",
        "-i", str(video_path),
        "-vn",  # no video
        "-ac", "1",
        "-ar", str(sr),
        str(wav_path),
    ]
    subprocess.run(cmd, check=True)
    return wav_path

def extract_frames(video_path: Path, out_dir: Path, interval_sec: float, max_frames: int):
    ensure_dir(out_dir)
    cap = cv2.VideoCapture(str(video_path))
    if not cap.isOpened():
        raise RuntimeError("Cannot open video")
    fps = cap.get(cv2.CAP_PROP_FPS) or 25.0
    step = max(int(fps * interval_sec), 1)

    idx, saved = 0, 0
    while True:
        ok, frame = cap.read()
        if not ok:
            break
        if idx % step == 0:
            (out_dir / f"frame_{saved:05d}.jpg").write_bytes(
                cv2.imencode(".jpg", frame, [int(cv2.IMWRITE_JPEG_QUALITY), 92])[1].tobytes()
            )
            saved += 1
            if saved >= max_frames:
                break
        idx += 1
    cap.release()
    return saved

def prepare_dirs(out_root: Path, video_file: Path):
    base = video_file.stem
    run_dir = out_root / base
    frames_dir = run_dir / FRAMES_SUBDIR
    ensure_dir(run_dir)
    ensure_dir(frames_dir)
    return run_dir, frames_dir