#!/usr/bin/env python3
"""
模型服务客户端
提供与 model_server.py 交互的客户端接口
"""

import os
import asyncio
import logging
from typing import List, Union, Dict, Any
import numpy as np
import aiohttp
import json
from sentence_transformers import util

logger = logging.getLogger(__name__)

class ModelClient:
    """模型服务客户端"""
    
    def __init__(self, base_url: str = "http://127.0.0.1:8000"):
        self.base_url = base_url.rstrip('/')
        self.session = None
        
    async def __aenter__(self):
        self.session = aiohttp.ClientSession(
            timeout=aiohttp.ClientTimeout(total=300)  # 5分钟超时
        )
        return self
    
    async def __aexit__(self, exc_type, exc_val, exc_tb):
        if self.session:
            await self.session.close()
    
    async def health_check(self) -> Dict[str, Any]:
        """检查服务健康状态"""
        try:
            async with self.session.get(f"{self.base_url}/health") as response:
                return await response.json()
        except Exception as e:
            logger.error(f"健康检查失败: {e}")
            return {"status": "unavailable", "error": str(e)}
    
    async def load_model(self) -> bool:
        """预加载模型"""
        try:
            async with self.session.post(f"{self.base_url}/load_model") as response:
                result = await response.json()
                return response.status == 200
        except Exception as e:
            logger.error(f"模型加载失败: {e}")
            return False
    
    async def encode_texts(self, texts: List[str], batch_size: int = 32) -> np.ndarray:
        """编码文本为向量"""
        if not texts:
            return np.array([])
        
        try:
            data = {
                "texts": texts,
                "batch_size": batch_size
            }
            
            async with self.session.post(
                f"{self.base_url}/encode", 
                json=data
            ) as response:
                if response.status != 200:
                    error_text = await response.text()
                    raise Exception(f"编码失败: {error_text}")
                
                result = await response.json()
                return np.array(result["embeddings"])
                
        except Exception as e:
            logger.error(f"文本编码失败: {e}")
            raise
    
    async def compute_similarity(self, text1: str, text2: str) -> float:
        """计算两个文本的相似度"""
        try:
            data = {
                "text1": text1,
                "text2": text2
            }
            
            async with self.session.post(
                f"{self.base_url}/similarity", 
                json=data
            ) as response:
                if response.status != 200:
                    error_text = await response.text()
                    raise Exception(f"相似度计算失败: {error_text}")
                
                result = await response.json()
                return result["similarity_score"]
                
        except Exception as e:
            logger.error(f"相似度计算失败: {e}")
            raise

# 同步版本的客户端包装器
class SyncModelClient:
    """同步模型客户端"""
    
    def __init__(self, base_url: str = "http://127.0.0.1:8000"):
        self.base_url = base_url
        self._async_client = ModelClient(base_url)
    
    def _run_async(self, coro):
        """运行异步协程"""
        try:
            loop = asyncio.get_event_loop()
        except RuntimeError:
            loop = asyncio.new_event_loop()
            asyncio.set_event_loop(loop)
        
        return loop.run_until_complete(coro)
    
    def encode_texts(self, texts: List[str], batch_size: int = 32) -> np.ndarray:
        """同步版本的文本编码"""
        async def _encode():
            async with self._async_client as client:
                return await client.encode_texts(texts, batch_size)
        
        return self._run_async(_encode())
    
    def compute_similarity(self, text1: str, text2: str) -> float:
        """同步版本的相似度计算"""
        async def _similarity():
            async with self._async_client as client:
                return await client.compute_similarity(text1, text2)
        
        return self._run_async(_similarity())
    
    def health_check(self) -> Dict[str, Any]:
        """同步版本的健康检查"""
        async def _health():
            async with self._async_client as client:
                return await client.health_check()
        
        return self._run_async(_health())
    
    def load_model(self) -> bool:
        """同步版本的模型加载"""
        async def _load():
            async with self._async_client as client:
                return await client.load_model()
        
        return self._run_async(_load())

# 全局客户端实例（单例模式）
_client_instance = None

def get_model_client(base_url: str = None) -> SyncModelClient:
    """获取模型客户端实例（单例）"""
    global _client_instance
    
    if _client_instance is None:
        url = base_url or os.environ.get('MODEL_SERVER_URL', 'http://127.0.0.1:8000')
        _client_instance = SyncModelClient(url)
    
    return _client_instance

# 便捷函数
def encode_texts(texts: List[str], batch_size: int = 32) -> np.ndarray:
    """便捷的文本编码函数"""
    client = get_model_client()
    return client.encode_texts(texts, batch_size)

def compute_similarity(text1: str, text2: str) -> float:
    """便捷的相似度计算函数"""
    client = get_model_client()
    return client.compute_similarity(text1, text2)

def is_service_available() -> bool:
    """检查模型服务是否可用"""
    client = get_model_client()
    health = client.health_check()
    return health.get("status") == "running" or health.get("status") == "ready"