import requests
from requests.exceptions import RequestException
import time
from typing import Optional, Dict, Any, Tuple, Union


def send_request(
        method: str,
        url: str,
        headers: Optional[Dict[str, str]] = None,
        data: Optional[Union[Dict[str, Any], str]] = None,
        files: Optional[Dict[str, Any]] = None,
        timeout: int = 30,
        retries: int = 3,
        backoff_factor: float = 0.5,
        retry_on_status: Optional[Tuple[int, ...]] = None
) -> requests.Response:
    """
    发送HTTP请求，支持重试机制

    参数:
        method: 请求方法，支持"GET"或"POST"
        url: 请求URL
        headers: 请求头字典
        data: 请求数据，可以是字典或字符串
        files: 上传文件字典，格式为{'file': open('path', 'rb')}
        timeout: 请求超时时间（秒）
        retries: 失败重试次数
        backoff_factor: 重试间隔退避因子（秒）
        retry_on_status: 需要重试的HTTP状态码元组，如(500, 502, 503)

    返回:
        requests.Response: 响应对象

    抛出:
        RequestException: 所有重试后仍然失败时抛出
    """
    # 规范化方法名称
    method = method.upper()

    # 验证方法是否支持
    if method not in ["GET", "POST"]:
        raise ValueError(f"Unsupported HTTP method: {method}")

    # 初始化重试计数器
    retry_attempts = 0

    # 主循环：处理重试逻辑
    while True:
        try:
            # 根据请求方法调用对应的requests函数
            if method == "GET":
                response = requests.get(
                    url=url,
                    headers=headers,
                    timeout=timeout
                )
            else:  # POST
                response = requests.post(
                    url=url,
                    headers=headers,
                    data=data,
                    files=files,
                    timeout=timeout
                )

            # 检查状态码是否需要重试
            if retry_on_status and response.status_code in retry_on_status:
                raise RequestException(f"Server returned retryable status code: {response.status_code}")

            # 状态码正常，返回响应
            return response

        except RequestException as e:
            # 重试次数耗尽，抛出异常
            if retry_attempts >= retries:
                raise RequestException(f"All {retries} retry attempts failed: {str(e)}") from e

            # 计算退避时间：backoff_factor * (2 ** (retry_attempts))
            wait_time = backoff_factor * (2 ** retry_attempts)
            print(f"Request failed (attempt {retry_attempts + 1}/{retries}): {str(e)}")
            print(f"Retrying in {wait_time:.2f} seconds...")

            # 等待后重试
            time.sleep(wait_time)
            retry_attempts += 1