services/video_service.py

import cv2
import os
import logging

# Setup logging
logging.basicConfig(
    filename="app.log",
    level=logging.INFO,
    format="%(asctime)s - %(levelname)s - %(message)s"
)

# Global state
VIDEO_DIR = "data"
video_files = []
video_index = 0
cap = None
FRAME_SKIP = 3
PRELOADED_FRAMES = []

def update_video_files(video_path: str = None):
    global video_files
    if video_path and os.path.exists(video_path) and video_path.endswith((".mp4", ".avi")):
        video_files = [video_path]
    else:
        if os.path.exists(VIDEO_DIR):
            video_files = [
                os.path.join(VIDEO_DIR, file)
                for file in sorted(os.listdir(VIDEO_DIR))
                if file.endswith((".mp4", ".avi"))
            ]
        else:
            video_files = []
    if not video_files:
        logging.warning("No video files found.")
    else:
        logging.info(f"Found video files: {video_files}")

def preload_video(video_path: str = None):
    global cap, video_index, PRELOADED_FRAMES, video_files
    update_video_files(video_path)
    if not video_files:
        logging.error("No video files available to preload.")
        raise RuntimeError("No video files found in the 'data' directory or provided path.")

    try:
        video_index = 0
        cap = cv2.VideoCapture(video_files[video_index])
        if not cap.isOpened():
            raise RuntimeError(f"Failed to open video {video_files[video_index]}")
        PRELOADED_FRAMES = []
        for _ in range(5):
            ret, frame = cap.read()
            if ret:
                frame = cv2.resize(frame, (320, 240))
                PRELOADED_FRAMES.append(frame)
            else:
                break
        cap.release()
        cap = None
        logging.info(f"Preloaded {len(PRELOADED_FRAMES)} frames from {video_files[video_index]}")
    except Exception as e:
        logging.error(f"Error preloading video: {str(e)}")
        raise RuntimeError(f"Failed to preload video: {str(e)}")

def get_next_video_frame():
    global cap, video_index, PRELOADED_FRAMES
    if not video_files:
        raise RuntimeError("No video files found.")
    
    if PRELOADED_FRAMES:
        frame = PRELOADED_FRAMES.pop(0)
        logging.debug(f"Retrieved preloaded frame {len(PRELOADED_FRAMES) + 1}")
        return frame

    if cap is None or not cap.isOpened():
        cap = cv2.VideoCapture(video_files[video_index])

    try:
        for _ in range(FRAME_SKIP):
            ret, frame = cap.read()
            if not ret:
                cap.release()
                video_index = (video_index + 1) % len(video_files)
                cap = cv2.VideoCapture(video_files[video_index])
                ret, frame = cap.read()
                if not ret:
                    raise RuntimeError(f"Cannot read video {video_files[video_index]}")
                break
        frame = cv2.resize(frame, (320, 240))
        logging.debug(f"Retrieved frame from {video_files[video_index]}")
        return frame
    except Exception as e:
        logging.error(f"Error retrieving frame: {str(e)}")
        raise RuntimeError(f"Failed to retrieve frame: {str(e)}")

def reset_video_index():
    global video_index
    video_index = 0
    logging.info("Reset video index to 0.")

def release_video():
    global cap
    if cap is not None:
        cap.release()
        cap = None
        logging.info("Released video capture object.")