import os
import uuid
import subprocess
import requests
import tempfile
import shutil
import logging
import threading
import time
from contextlib import contextmanager

UPLOAD_FOLDER = 'temp_files'

@contextmanager
def temp_directory(dir=None):
    temp_dir = tempfile.mkdtemp(dir=dir)
    try:
        yield temp_dir
    finally:
        # 不再在这里自动删除临时目录
        pass

def download_file(url, temp_dir):
    try:
        headers = {
            'User-Agent': 'Mozilla/5.0',
            'Accept': '*/*'
        }
        
        logging.info(f"开始从URL下载文件: {url}")
        response = requests.get(url, headers=headers, stream=True, timeout=30)
        response.raise_for_status()
        
        file_path = os.path.join(temp_dir, 'input_audio')
        
        with open(file_path, 'wb') as f:
            for chunk in response.iter_content(chunk_size=8192):
                if chunk:
                    f.write(chunk)
        
        file_size = os.path.getsize(file_path)
        if file_size < 1024:
            error_msg = f"下载的文件太小(仅{file_size}字节)，可能无效"
            logging.error(error_msg)
            raise Exception(error_msg)
            
        logging.info(f"文件下载成功，保存到: {file_path} (大小: {file_size}字节)")
        return file_path
    except Exception as e:
        logging.error(f"从 {url} 下载文件时出错: {e}")
        raise

def execute_ffmpeg(input_path, output_path, ffmpeg_args):
    try:
        filtered_args = [arg for arg in ffmpeg_args if not (arg.lower() in ['-i', '-input'] or 
                                                            (ffmpeg_args.index(arg) > 0 and ffmpeg_args[ffmpeg_args.index(arg) - 1].lower() == '-i'))]
        
        cmd = ['lib/ffmpeg/bin/ffmpeg', '-i', input_path] + filtered_args + [output_path]
        logging.info(f"执行FFmpeg命令: {' '.join(cmd)}")
        
        result = subprocess.run(
            cmd,
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
            universal_newlines=True,
            encoding='utf-8',
            errors='replace'
        )
        
        if result.returncode != 0:
            error_msg = f"FFmpeg处理失败，返回码: {result.returncode}, 错误: {result.stderr}"
            logging.error(error_msg)
            raise Exception(error_msg)
            
        logging.info("FFmpeg处理成功完成")
        return True
    except Exception as e:
        logging.error(f"执行FFmpeg时出错: {e}")
        raise


def process_ffmpeg(data, file_registry, file_lock):
    try:
        temp_dir = tempfile.mkdtemp(dir=UPLOAD_FOLDER)
        logging.info(f"创建临时目录: {temp_dir}")
        
        input_url = data.get('input_url')
        ffmpeg_args = data.get('args', [])
        input_path = download_file(input_url, temp_dir)
        
        output_id = str(uuid.uuid4())[:8]
        output_format = data.get('output_format', 'mp4')
        output_filename = f"{output_id}.{output_format}"
        output_path = os.path.join(temp_dir, output_filename)
        
        execute_ffmpeg(input_path, output_path, ffmpeg_args)
        
        with file_lock:
            file_registry[output_id] = {
                'path': os.path.abspath(output_path),
                'filename': output_filename,
                'last_access': time.time(),
                'download_count': 0
            }
            logging.info(f"已注册新文件ID: {output_id}, 路径: {output_path}")
        
        # 返回临时目录路径以便在主函数中删除
        return {
            'status': 'success',
            'download_url': f"http://ffmpeg.liulikeji.cn/download/{output_id}/{output_filename}",
            'file_id': output_id,
            'temp_dir': temp_dir  # 返回临时目录路径
        }
        
    except Exception as e:
        logging.error(f"处理过程中出错: {e}")
        return {'error': str(e)}