import os

import cv2

from loguru import logger


def _get_first_frame(video_path, output_path):
    """
    提取视频的第一帧并保存为图片
    :param video_path: 视频文件路径
    :param output_path: 输出图片路径
    :return: 输出图片的绝对路径，如果失败则返回None
    """
    cap = None
    try:
        logger.info(f"开始提取视频首帧: {video_path}")
        # 打开视频文件
        cap = cv2.VideoCapture(video_path)
        if not cap.isOpened():
            logger.error(f"无法打开视频: {video_path}")
            return None

        # 读取首帧
        ret, frame = cap.read()
        if not ret:
            logger.error("无法读取视频帧")
            cap.release()
            return None

        # 保存首帧为图片
        try:
            cv2.imwrite(output_path, frame)
            logger.info(f"首帧已保存为: {output_path}")
        except Exception as e:
            logger.error(f"保存首帧图片失败: {e}")
            cap.release()
            return None

        # 释放资源
        cap.release()
        return os.path.abspath(output_path)

    except Exception as e:
        logger.error(f"提取视频首帧时出错: {e}")
        return None
    finally:
        cap.release()