"""
LLM 客户端封装 - 统一 Anthropic/OpenAI/AIHubMix 接口
"""
from typing import Generator
import os


class LLMClient:
    """LLM API 统一客户端"""
    
    def __init__(
        self, 
        provider: str = None, 
        api_key: str = None,
        base_url: str = None,
        model: str = None
    ):
        """
        初始化 LLM 客户端
        
        Args:
            provider: 'anthropic', 'openai', 'aihubmix', 或 'custom'
            api_key: API 密钥
            base_url: 自定义 API 地址（用于 aihubmix/custom）
            model: 指定模型名称
        """
        self.provider = provider or "aihubmix"
        self.model = model or "gpt-4o"
        
        if self.provider == "anthropic":
            from anthropic import Anthropic
            self.client = Anthropic(api_key=api_key)
            
        elif self.provider == "openai":
            from openai import OpenAI
            self.client = OpenAI(api_key=api_key)
            self.model = model or "gpt-4o"
            
        elif self.provider in ["aihubmix", "deepseek", "siliconflow", "custom"]:
            # OpenAI 兼容接口 Providers
            from openai import OpenAI
            
            default_urls = {
                "aihubmix": "https://aihubmix.com/v1",
                "deepseek": "https://api.deepseek.com",
                "siliconflow": "https://api.siliconflow.cn/v1",
                "custom": "http://localhost:8000/v1"
            }
            
            final_base_url = base_url or default_urls.get(self.provider)
            
            self.client = OpenAI(
                api_key=api_key,
                base_url=final_base_url
            )
            self.model = model or "gpt-4o"
            
        else:
            raise ValueError(f"不支持的 provider: {self.provider}")
    
    def chat_stream(
        self,
        system_prompt: str,
        user_prompt: str,
        max_tokens: int = 1024
    ) -> Generator[str, None, None]:
        """
        流式对话
        
        Args:
            system_prompt: 系统提示词
            user_prompt: 用户输入
            max_tokens: 最大输出 token 数
            
        Yields:
            str: 流式输出的文本片段
        """
        if self.provider == "anthropic":
            yield from self._anthropic_stream(system_prompt, user_prompt, max_tokens)
        else:
            yield from self._openai_stream(system_prompt, user_prompt, max_tokens)
    
    def _anthropic_stream(
        self,
        system_prompt: str,
        user_prompt: str,
        max_tokens: int
    ) -> Generator[str, None, None]:
        """Anthropic 流式调用"""
        with self.client.messages.stream(
            model=self.model,
            max_tokens=max_tokens,
            system=system_prompt,
            messages=[{"role": "user", "content": user_prompt}]
        ) as stream:
            for text in stream.text_stream:
                yield text
    
    def _openai_stream(
        self,
        system_prompt: str,
        user_prompt: str,
        max_tokens: int
    ) -> Generator[str, None, None]:
        """OpenAI 兼容接口流式调用（支持 AIHubMix、vLLM 等）"""
        try:
            stream = self.client.chat.completions.create(
                model=self.model,
                max_tokens=max_tokens,
                stream=True,
                messages=[
                    {"role": "system", "content": system_prompt},
                    {"role": "user", "content": user_prompt}
                ]
            )
            for chunk in stream:
                # 安全地获取 content，处理各种边界情况
                if chunk.choices and len(chunk.choices) > 0:
                    delta = chunk.choices[0].delta
                    if delta and hasattr(delta, 'content') and delta.content:
                        yield delta.content
        except Exception as e:
            yield f"\n\n[错误: {str(e)}]"
    
    def chat(
        self,
        system_prompt: str,
        user_prompt: str,
        max_tokens: int = 1024
    ) -> str:
        """
        非流式对话
        
        Args:
            system_prompt: 系统提示词
            user_prompt: 用户输入
            max_tokens: 最大输出 token 数
            
        Returns:
            str: 完整的响应文本
        """
        return "".join(self.chat_stream(system_prompt, user_prompt, max_tokens))