"""DeepSeek API 客户端封装，含指数退避重试逻辑"""

import time
from typing import Callable

from openai import OpenAI
import openai

from exceptions import ApiError

# 文件扩展名 → MIME 类型映射
EXTENSION_MIME_MAP = {
    ".png": "image/png",
    ".jpg": "image/jpeg",
    ".jpeg": "image/jpeg",
    ".gif": "image/gif",
    ".bmp": "image/bmp",
    ".webp": "image/webp",
}


class ApiClient:
    """封装 DeepSeek API 调用，含重试和错误处理"""

    RETRY_DELAYS = [1, 2, 4]  # 指数退避延迟（秒）
    MAX_RETRIES = 3

    def __init__(
        self,
        api_key: str,
        base_url: str = "https://api.deepseek.com",
        _sleep: Callable[[float], None] = time.sleep,
        _client: "OpenAI | None" = None,
    ):
        self._client = _client or OpenAI(api_key=api_key, base_url=base_url)
        self._sleep = _sleep


    def chat(self, system_prompt: str, user_content: str, model: str = "deepseek-chat") -> str:
        """
        调用 Chat Completion API。
        速率限制和网络异常时自动指数退避重试，最多 3 次。

        Raises:
            ApiError: API 调用失败（非可重试错误或重试耗尽）
        """
        def _call():
            response = self._client.chat.completions.create(
                model=model,
                messages=[
                    {"role": "system", "content": system_prompt},
                    {"role": "user", "content": user_content},
                ],
            )
            return response.choices[0].message.content

        return self._retry(_call)

    def vision(
        self,
        system_prompt: str,
        image_base64: str,
        mime_type: str = "image/png",
        model: str = "deepseek-chat",
    ) -> str:
        """
        调用 Vision API 识别图片内容。
        速率限制和网络异常时自动指数退避重试，最多 3 次。

        Args:
            system_prompt: 系统提示词
            image_base64: 图片的 base64 编码
            mime_type: 图片 MIME 类型（如 image/jpeg、image/png）
            model: 模型名称

        Raises:
            ApiError: API 调用失败
        """
        def _call():
            response = self._client.chat.completions.create(
                model=model,
                messages=[
                    {"role": "system", "content": system_prompt},
                    {
                        "role": "user",
                        "content": [
                            {
                                "type": "image_url",
                                "image_url": {
                                    "url": f"data:{mime_type};base64,{image_base64}",
                                },
                            },
                        ],
                    },
                ],
            )
            return response.choices[0].message.content

        return self._retry(_call)

    def _retry(self, call: Callable[[], str]) -> str:
        """执行带指数退避重试的 API 调用，对速率限制和网络异常重试"""
        for attempt in range(self.MAX_RETRIES + 1):
            try:
                return call()
            except openai.RateLimitError:
                if attempt < self.MAX_RETRIES:
                    self._sleep(self.RETRY_DELAYS[attempt])
                else:
                    raise ApiError("速率限制重试耗尽", status_code=429)
            except openai.APIConnectionError:
                if attempt < self.MAX_RETRIES:
                    self._sleep(self.RETRY_DELAYS[attempt])
                else:
                    raise ApiError("网络连接失败，重试耗尽")
            except openai.APITimeoutError:
                if attempt < self.MAX_RETRIES:
                    self._sleep(self.RETRY_DELAYS[attempt])
                else:
                    raise ApiError("API 请求超时，重试耗尽")
            except openai.APIError as e:
                raise ApiError(str(e), status_code=getattr(e, "status_code", None))