# core/llm_client.py - LLM API 调用封装
import time
import json
from typing import Optional

from openai import OpenAI, APIError, APITimeoutError, RateLimitError

import config


class LLMClient:
    """封装 OpenAI 兼容接口，提供统一的调用入口与重试机制"""

    def __init__(
        self,
        api_key:  str = None,
        api_base: str = None,
        model:    str = None,
    ):
        self.model  = model    or config.LLM_MODEL
        self.client = OpenAI(
            api_key  = api_key  or config.LLM_API_KEY,
            base_url = api_base or config.LLM_API_BASE,
            timeout  = config.LLM_TIMEOUT,
        )

    def chat(
        self,
        prompt:      str,
        system:      str  = "You are a helpful assistant.",
        temperature: float = 0.2,
        max_tokens:  int   = 4096,
    ) -> str:
        """
        发送单轮对话请求，返回模型回复文本。

        Args:
            prompt:      用户消息
            system:      系统提示词
            temperature: 采样温度
            max_tokens:  最大输出 token 数

        Returns:
            模型回复的纯文本字符串

        Raises:
            RuntimeError: 超过最大重试次数后仍失败
        """
        last_error = None
        for attempt in range(1, config.LLM_MAX_RETRY + 1):
            try:
                resp = self.client.chat.completions.create(
                    model    = self.model,
                    messages = [
                        {"role": "system",  "content": system},
                        {"role": "user",    "content": prompt},
                    ],
                    temperature = temperature,
                    max_tokens  = max_tokens,
                )
                return resp.choices[0].message.content.strip()
            except RateLimitError as e:
                wait = 2 ** attempt
                last_error = e
                time.sleep(wait)
            except APITimeoutError as e:
                last_error = e
                time.sleep(2)
            except APIError as e:
                last_error = e
                if attempt >= config.LLM_MAX_RETRY:
                    break
                time.sleep(1)
        raise RuntimeError(
            f"LLM 调用失败（已重试 {config.LLM_MAX_RETRY} 次）: {last_error}"
        )

    def chat_json(
        self,
        prompt:      str,
        system:      str   = "You are a helpful assistant. Always respond with valid JSON.",
        temperature: float = 0.1,
        max_tokens:  int   = 4096,
    ) -> any:
        """
        发送请求并将回复解析为 JSON 对象。

        Returns:
            解析后的 Python 对象（dict 或 list）

        Raises:
            ValueError:   JSON 解析失败
            RuntimeError: LLM 调用失败
        """
        raw = self.chat(prompt, system=system, temperature=temperature, max_tokens=max_tokens)
        # 去除可能的 markdown 代码块包裹
        cleaned = self._strip_markdown_code_block(raw)
        try:
            return json.loads(cleaned)
        except json.JSONDecodeError as e:
            raise ValueError(f"LLM 返回内容无法解析为 JSON: {e}\n原始内容:\n{raw}")

    @staticmethod
    def _strip_markdown_code_block(text: str) -> str:
        """去除 ```json ... ``` 或 ``` ... ``` 包裹"""
        text = text.strip()
        if text.startswith("```"):
            lines = text.splitlines()
            # 去掉首行（```json 或 ```）和末行（```）
            inner = lines[1:] if lines[-1].strip() == "```" else lines[1:]
            if inner and inner[-1].strip() == "```":
                inner = inner[:-1]
            text = "\n".join(inner).strip()
        return text