import os

import requests
import mimetypes


def download_file(url, local_filename):
    """
    下载文件并保存到本地，基于Content-Type设置文件扩展名。

    参数:
    - url (str): 文件的URL地址。
    - local_filename (str): 本地保存的文件名（不含扩展名）。

    返回:
    - tuple: (完整文件名, 文件类型代码)
             文件类型代码:
                 1 - .docx
                 2 - .pdf
                 3 - .doc
                 4 - 其他
    - None: 下载失败
    """
    try:
        with requests.get(url, stream=True) as response:
            response.raise_for_status()  # 确保请求成功，否则抛出异常

            # 获取Content-Type并猜测文件扩展名
            content_type = response.headers.get('Content-Type', '')
            extension = mimetypes.guess_extension(content_type, strict=False) or '.docx'

            # 分离文件名和现有扩展名
            base, ext = os.path.splitext(local_filename)
            if ext.lower() != extension:
                full_filename = base + extension
            else:
                full_filename = local_filename

            # 下载并保存文件
            with open(full_filename, 'wb') as file:
                for chunk in response.iter_content(chunk_size=8192):
                    if chunk:  # 避免写入空块
                        file.write(chunk)

            # 定义扩展名到代码的映射
            extension_mapping = {
                '.docx': 1,
                '.pdf': 2,
                '.doc': 3
            }
            file_code = extension_mapping.get(extension.lower(), 4)
            return full_filename, file_code

    except requests.HTTPError as e:
        print(f"download: HTTP 错误: {e}")
    except requests.RequestException as e:
        print(f"download: 下载文件时出错: {e}")
    except Exception as e:
        print(f"download: 发生错误: {e}")

    return None

if __name__ == '__main__':
    # 测试下载的URL
    test_url ="https://bid-assistance.oss-cn-wuhan-lr.aliyuncs.com/test/01%20%E6%8B%9B%E6%A0%87%E6%96%87%E4%BB%B6-%E5%A4%A7%E8%8D%94%E5%8E%BF%E5%85%AC%E5%AE%89%E5%B1%80%E6%83%85%E6%8C%87%E5%8B%A4%E8%88%86%E4%B8%80%E4%BD%93%E5%8C%96%E5%B9%B3%E5%8F%B0%E5%BB%BA%E8%AE%BE%E9%A1%B9%E7%9B%AE%28%E4%BA%8C%E6%AC%A1%29.pdf?Expires=1728751377&OSSAccessKeyId=TMP.3KeYhAGeJr2LGiNctSPvSmdSwxhrU8pbaDYRJcNCCgv8ijyWN613QahKb3nhXydfAvHaqpw4nTHXMzq7hmTHmNnPA77DgL&Signature=mwPHW8v7dVmHP1udTDL%2ByzllwCE%3D"
    local_file_name = 'C:\\Users\\Administrator\\Desktop\\招标文件\\output\\testdownload'
    file_path,file_type = download_file(test_url, local_file_name)
    if file_path:
        print(f"Downloaded file path: {file_path}")
        print(file_type)