import httpx
import json
import logging
from typing import List, Dict, Any, Optional

logger = logging.getLogger(__name__)

class LLMService:
    @staticmethod
    async def chat_completion(
        api_key: str,
        base_url: str,
        model_name: str,
        messages: List[Dict[str, str]],
        api_path: str = "/chat/completions",
        temperature: float = 0.7,
        top_p: float = 0.9,
        max_tokens: int = 4000
    ) -> str:
        """
        Generic OpenAI-compatible chat completion caller.
        """
        # Ensure base_url doesn't end with trailing slash if path starts with one
        url = f"{base_url.rstrip('/')}{api_path}"
        
        headers = {
            "Authorization": f"Bearer {api_key}",
            "Content-Type": "application/json"
        }
        
        payload = {
            "model": model_name,
            "messages": messages,
            "temperature": temperature,
            "top_p": top_p,
            "max_tokens": max_tokens
        }
        
        async with httpx.AsyncClient(timeout=120.0) as client:
            try:
                logger.info(f"Sending request to LLM: {url} (Model: {model_name})")
                response = await client.post(url, headers=headers, json=payload)
                response.raise_for_status()
                
                result = response.json()
                content = result["choices"][0]["message"]["content"]
                return content
            except httpx.HTTPStatusError as e:
                error_body = e.response.text
                logger.error(f"LLM API Error ({e.response.status_code}): {error_body}")
                # Try to parse error message from body
                try:
                    err_json = json.loads(error_body)
                    detail = err_json.get("error", {}).get("message", error_body)
                except:
                    detail = error_body
                raise Exception(f"AI 服务调用失败: {detail}")
            except Exception as e:
                logger.error(f"Error calling LLM: {str(e)}")
                raise Exception(f"连接 AI 服务发生错误: {str(e)}")