app.py

from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
from utils.validators import ChatRequest, ChatResponse
from utils.logger import log
from modules.travel_assistant import TravelAssistant
import traceback

# --- FastAPI 应用设置 ---
app = FastAPI(
    title="Modular Travel Assistant API",
    description="一个采用模块化和分层架构的旅行助手API",
    version="2.0.0",
    docs_url="/docs",
    redoc_url="/redoc"
)

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# --- 全局服务实例 ---
try:
    log.info("🔄 开始初始化 Travel Assistant 服务...")
    assistant = TravelAssistant()
    SERVICE_READY = True
    log.info("🚀 FastAPI 应用启动成功，服务已就绪。")
except Exception as e:
    assistant = None
    SERVICE_READY = False
    log.critical(f"💥 FATAL: 服务初始化失败: {e}")
    log.critical(f"💥 错误详情: {traceback.format_exc()}")

# --- API 端点 ---
@app.get("/")
async def root():
    """根路径 - 提供基本信息"""
    ai_available = False
    if SERVICE_READY and assistant and hasattr(assistant, 'ai_model'):
        ai_available = assistant.ai_model.is_available()
    
    return {
        "message": "Travel Assistant API",
        "version": "2.0.0",
        "status": "ready" if SERVICE_READY else "degraded", 
        "ai_model_status": "available" if ai_available else "unavailable",
        "docs": "/docs",
        "health": "/health"
    }

@app.get("/health")
async def health_check():
    """健康检查端点"""
    if SERVICE_READY and assistant:
        ai_available = assistant.ai_model.is_available() if hasattr(assistant.ai_model, 'is_available') else False
        return {
            "status": "healthy" if ai_available else "degraded",
            "service_ready": True,
            "ai_model_available": ai_available,
            "components": {
                "config": True,
                "knowledge_base": len(assistant.kb.knowledge) > 0 if hasattr(assistant, 'kb') else False,
                "ai_model": ai_available,
                "session_manager": True
            }
        }
    else:
        return JSONResponse(
            status_code=503,
            content={
                "status": "unhealthy", 
                "service_ready": False,
                "ai_model_available": False
            }
        )

@app.post("/api/chat", response_model=ChatResponse)
async def chat_endpoint(request: ChatRequest):
    """主要的聊天API端点"""
    if not SERVICE_READY or not assistant:
        raise HTTPException(
            status_code=503,
            detail="Service Unavailable: Backend assistant failed to initialize."
        )
    
    try:
        log.info(f"收到聊天请求: {request.message[:50]}...")
        
        reply, session_id, status_info, history = assistant.chat(
            request.message, 
            request.session_id,
            request.history or []
        )
        
        log.info(f"聊天响应生成成功，会话ID: {session_id}")
        
        return ChatResponse(
            reply=reply,
            session_id=session_id,
            status_info=status_info,
            history=history
        )
        
    except Exception as e:
        log.error(f"❌ Chat endpoint error: {e}", exc_info=True)
        raise HTTPException(
            status_code=500,
            detail="Internal Server Error: Failed to process chat request."
        )

@app.post("/api/reset")
async def reset_session(session_id: str):
    """重置会话端点"""
    if not SERVICE_READY or not assistant:
        raise HTTPException(
            status_code=503,
            detail="Service Unavailable"
        )
    
    try:
        assistant.session_manager.reset(session_id)
        log.info(f"会话重置成功: {session_id}")
        return {
            "message": "Session reset successfully", 
            "session_id": session_id,
            "status": "success"
        }
    except Exception as e:
        log.error(f"❌ Reset session error: {e}")
        raise HTTPException(
            status_code=500,
            detail="Failed to reset session"
        )

# --- 全局异常处理 ---
@app.exception_handler(Exception)
async def global_exception_handler(request, exc):
    """全局异常处理器"""
    log.error(f"❌ 未处理的异常: {exc}", exc_info=True)
    return JSONResponse(
        status_code=500,
        content={"detail": "Internal server error", "message": "请稍后重试"}
    )

# HuggingFace Spaces 和本地运行配置
if __name__ == "__main__":
    import uvicorn
    log.info("🔧 本地开发模式启动...")
    uvicorn.run(
        app, 
        host="0.0.0.0", 
        port=7860,
        reload=True,
        log_level="info"
    )