#!/usr/bin/env python
# -*- coding: utf-8 -*-

import os
import cv2
import argparse
from tqdm import tqdm
import concurrent.futures
import logging
import time

# 配置日志
logging.basicConfig(level=logging.INFO, 
                    format='%(asctime)s - %(levelname)s - %(message)s',
                    handlers=[logging.FileHandler("extract_frames.log"), 
                              logging.StreamHandler()])
logger = logging.getLogger(__name__)

def extract_first_frame(video_path, output_path):
    """
    提取视频的第一帧并保存为JPEG图像
    
    参数:
        video_path: 视频文件路径
        output_path: 输出图像路径
    
    返回:
        成功返回True，失败返回False
    """
    try:
        # 确保输出目录存在
        os.makedirs(os.path.dirname(output_path), exist_ok=True)
        
        # 打开视频文件
        video = cv2.VideoCapture(video_path)
        
        # 检查视频是否成功打开
        if not video.isOpened():
            logger.error(f"无法打开视频: {video_path}")
            return False
        
        # 读取第一帧
        success, frame = video.read()
        
        if not success:
            logger.error(f"无法读取视频帧: {video_path}")
            return False
        
        # 保存帧为JPEG
        cv2.imwrite(output_path, frame)
        
        # 释放视频对象
        video.release()
        
        return True
    
    except Exception as e:
        logger.error(f"处理视频 {video_path} 时出错: {str(e)}")
        return False

def process_video(args):
    """处理单个视频的包装函数，用于并行处理"""
    video_path, output_path, output_ext = args
    try:
        # 修改输出路径的扩展名
        base_output_path = os.path.splitext(output_path)[0] + output_ext
        return extract_first_frame(video_path, base_output_path)
    except Exception as e:
        logger.error(f"处理视频 {video_path} 时出错: {str(e)}")
        return False

def scan_videos(input_dir, output_dir, video_extensions, output_ext, num_workers):
    """
    扫描输入目录中的所有视频并提取第一帧
    
    参数:
        input_dir: 输入目录路径
        output_dir: 输出目录路径
        video_extensions: 视频文件扩展名列表
        output_ext: 输出图像文件扩展名
        num_workers: 并行工作线程数
    """
    start_time = time.time()
    video_files = []
    
    # 扫描所有视频文件
    logger.info(f"开始扫描目录: {input_dir}")
    for root, _, files in os.walk(input_dir):
        for file in files:
            if any(file.lower().endswith(ext) for ext in video_extensions):
                video_path = os.path.join(root, file)
                
                # 构建相对路径
                rel_path = os.path.relpath(video_path, input_dir)
                output_path = os.path.join(output_dir, rel_path)
                
                video_files.append((video_path, output_path, output_ext))
    
    total_videos = len(video_files)
    logger.info(f"找到 {total_videos} 个视频文件")
    
    # 创建输出目录
    os.makedirs(output_dir, exist_ok=True)
    
    # 并行提取帧
    success_count = 0
    error_count = 0
    
    with concurrent.futures.ThreadPoolExecutor(max_workers=num_workers) as executor:
        results = list(tqdm(executor.map(process_video, video_files), 
                           total=total_videos, 
                           desc="提取视频首帧"))
    
    success_count = sum(1 for r in results if r)
    error_count = total_videos - success_count
    
    elapsed_time = time.time() - start_time
    logger.info(f"处理完成! 总耗时: {elapsed_time:.2f} 秒")
    logger.info(f"成功: {success_count}, 失败: {error_count}")

def main():
    parser = argparse.ArgumentParser(description='批量提取视频首帧并保持原始目录结构')
    parser.add_argument('--input_dir', required=True, help='输入视频目录路径')
    parser.add_argument('--output_dir', required=True, help='输出图像目录路径')
    parser.add_argument('--video_ext', default='.mp4,.avi,.mov,.mkv,.wmv,.flv', 
                        help='视频文件扩展名，用逗号分隔 (默认: .mp4,.avi,.mov,.mkv,.wmv,.flv)')
    parser.add_argument('--output_ext', default='.jpg', 
                        help='输出图像扩展名 (默认: .jpg)')
    parser.add_argument('--workers', type=int, default=4, 
                        help='并行处理的工作线程数 (默认: 4)')
    
    args = parser.parse_args()
    
    video_extensions = [ext.strip() for ext in args.video_ext.split(',')]
    
    logger.info("开始提取视频首帧")
    logger.info(f"输入目录: {args.input_dir}")
    logger.info(f"输出目录: {args.output_dir}")
    logger.info(f"并行线程数: {args.workers}")
    
    scan_videos(args.input_dir, args.output_dir, video_extensions, args.output_ext, args.workers)
    
    logger.info("所有视频处理完成!")

if __name__ == "__main__":
    main()