"""
Extract all frames from video/ as JPEG files into frames/.
Run once; idempotent (skips sessions already fully extracted).

Usage: python extract_frames.py
"""
import cv2
from pathlib import Path
from config import VIDEO_DIR, FRAMES_DIR

sessions = sorted(d for d in VIDEO_DIR.iterdir() if d.is_dir())
print(f"{len(sessions)} sessions found")

for si, sess_dir in enumerate(sessions):
    for eye in (0, 1):
        src = sess_dir / f"eye{eye}.mp4"
        if not src.exists():
            print(f"[SKIP] {sess_dir.name}/eye{eye} — no mp4")
            continue

        out_dir = FRAMES_DIR / sess_dir.name / f"eye{eye}"

        cap = cv2.VideoCapture(str(src))
        total = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))

        if out_dir.exists() and len(list(out_dir.glob("frame_*.jpg"))) == total:
            print(f"[DONE] ({si+1}/{len(sessions)}) {sess_dir.name}/eye{eye} — already extracted")
            cap.release()
            continue

        out_dir.mkdir(parents=True, exist_ok=True)
        fi = 0
        while True:
            ret, frame = cap.read()
            if not ret:
                break
            cv2.imwrite(str(out_dir / f"frame_{fi:05d}.jpg"), frame,
                        [cv2.IMWRITE_JPEG_QUALITY, 95])
            fi += 1
        cap.release()
        print(f"[OK] ({si+1}/{len(sessions)}) {sess_dir.name}/eye{eye} — {fi} frames")

print("Done")