"""
K2Think API 代理服务 - 重构版本
提供OpenAI兼容的API接口，代理到K2Think服务
"""
import time
import logging
from contextlib import asynccontextmanager
from fastapi import FastAPI, Request
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse, Response

from src.config import Config
from src.constants import APIConstants
from src.exceptions import K2ThinkProxyError
from src.models import ChatCompletionRequest
from src.api_handler import APIHandler

# 初始化配置
try:
    Config.validate()
    Config.setup_logging()
except Exception as e:
    print(f"配置错误: {e}")
    exit(1)

logger = logging.getLogger(__name__)

# 全局HTTP客户端管理
@asynccontextmanager
async def lifespan(app: FastAPI):
    logger.info("K2Think API Proxy 启动中...")
    yield
    logger.info("K2Think API Proxy 关闭中...")

# 创建FastAPI应用
app = FastAPI(
    title="K2Think API Proxy", 
    description="OpenAI兼容的K2Think API代理服务",
    version="2.0.0",
    lifespan=lifespan
)

# CORS配置
app.add_middleware(
    CORSMiddleware,
    allow_origins=Config.CORS_ORIGINS,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# 初始化API处理器
api_handler = APIHandler(Config)

@app.get("/")
async def homepage():
    """首页 - 返回服务状态"""
    return JSONResponse(content={
        "status": "success",
        "message": "K2Think API Proxy is running",
        "service": "K2Think API Gateway", 
        "model": APIConstants.MODEL_ID,
        "version": "2.0.0",
        "endpoints": {
            "chat": "/v1/chat/completions",
            "models": "/v1/models"
        }
    })

@app.get("/health")
async def health_check():
    """健康检查"""
    return JSONResponse(content={
        "status": "healthy",
        "timestamp": int(time.time()),
        "config": {
            "tool_support": Config.TOOL_SUPPORT,
            "debug_logging": Config.DEBUG_LOGGING,
            "note": "思考内容输出现在通过模型名控制"
        }
    })

@app.get("/favicon.ico")
async def favicon():
    """返回favicon"""
    return Response(content="", media_type="image/x-icon")

@app.get("/v1/models")
async def get_models():
    """获取模型列表"""
    return await api_handler.get_models()

@app.post("/v1/chat/completions")
async def chat_completions(request: ChatCompletionRequest, auth_request: Request):
    """处理聊天补全请求"""
    return await api_handler.chat_completions(request, auth_request)

@app.exception_handler(K2ThinkProxyError)
async def proxy_exception_handler(request: Request, exc: K2ThinkProxyError):
    """处理自定义代理异常"""
    return JSONResponse(
        status_code=exc.status_code,
        content={
            "error": {
                "message": exc.message,
                "type": exc.error_type
            }
        }
    )

@app.exception_handler(404)
async def not_found_handler(request: Request, exc):
    """处理404错误"""
    return JSONResponse(
        status_code=404,
        content={"error": "Not Found"}
    )

if __name__ == "__main__":
    import uvicorn
    
    # 配置日志级别
    log_level = "debug" if Config.DEBUG_LOGGING else "info"
    
    logger.info(f"启动服务器: {Config.HOST}:{Config.PORT}")
    logger.info(f"工具支持: {Config.TOOL_SUPPORT}")
    logger.info("思考内容输出: 通过模型名控制 (MBZUAI-IFM/K2-Think vs MBZUAI-IFM/K2-Think-nothink)")
    
    uvicorn.run(
        app, 
        host=Config.HOST, 
        port=Config.PORT, 
        access_log=Config.ENABLE_ACCESS_LOG,
        log_level=log_level
    )