import cv2
import os
import logging

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

# Global video capture object
video_cap = None
current_frame_index = 0

def preload_video(video_path):
    """
    Preload the video file.
    Args:
        video_path: Path to the video file
    Returns:
        str: Status message
    """
    global video_cap, current_frame_index
    try:
        if not os.path.exists(video_path):
            raise FileNotFoundError(f"Video file not found at {video_path}")

        video_cap = cv2.VideoCapture(video_path)
        if not video_cap.isOpened():
            raise RuntimeError("Failed to open video file.")

        current_frame_index = 0
        total_frames = int(video_cap.get(cv2.CAP_PROP_FRAME_COUNT))
        logging.info(f"Preloaded video: {video_path} with {total_frames} frames.")
        return f"Successfully loaded video: {video_path} ({total_frames} frames)"
    except Exception as e:
        logging.error(f"Error preloading video: {str(e)}")
        return f"Error loading video: {str(e)}"

def get_next_video_frame():
    """
    Get the next frame from the video.
    Returns:
        numpy array: Frame if successful, None otherwise
    """
    global video_cap, current_frame_index
    if video_cap is None or not video_cap.isOpened():
        logging.error("Video capture not initialized.")
        return None

    try:
        # Set frame position
        video_cap.set(cv2.CAP_PROP_POS_FRAMES, current_frame_index)
        ret, frame = video_cap.read()
        if not ret:
            # Loop back to the start
            current_frame_index = 0
            video_cap.set(cv2.CAP_PROP_POS_FRAMES, current_frame_index)
            ret, frame = video_cap.read()
            if not ret:
                raise RuntimeError("Failed to read frame from video.")

        current_frame_index += 1
        logging.debug(f"Retrieved frame {current_frame_index} from video.")
        return frame
    except Exception as e:
        logging.error(f"Error retrieving frame: {str(e)}")
        return None

def reset_video_index():
    """
    Reset the frame index to the beginning.
    """
    global current_frame_index
    current_frame_index = 0
    logging.info("Reset video frame index to 0.")

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