import logging
from contextlib import asynccontextmanager
from fastapi import FastAPI, HTTPException
from fastapi.exceptions import RequestValidationError
from starlette.exceptions import HTTPException as StarletteHTTPException

# Import routers
from api.routers import medical, hbv_assessment
from api.middleware import (
    ProcessTimeMiddleware, 
    LoggingMiddleware, 
    RateLimitMiddleware,
    get_cors_middleware_config
)
from fastapi.middleware.cors import CORSMiddleware
from api.exceptions import (
    http_exception_handler,
    validation_exception_handler,
    general_exception_handler,
    starlette_exception_handler
)

# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)


@asynccontextmanager
async def lifespan(app: FastAPI):
    """Application lifespan management with background initialization"""
    # Startup
    logger.info("Starting HBV AI Assistant API...")
    
    # Start background initialization of heavy components (optional for AI chat)
    try:
        from core.background_init import start_background_initialization
        logger.info("🚀 Starting background initialization of components...")
        start_background_initialization()
        logger.info("API started successfully (components loading in background)")
    except Exception as e:
        logger.error(f"Failed to start background initialization: {e}")
        logger.info("API started with lazy loading fallback")
    
    yield
    
    # Shutdown
    logger.info("Shutting down HBV AI Assistant API...")


# Create FastAPI application
app = FastAPI(
    title="HBV AI Assistant API",
    description="HBV Patient Selection System - Evaluates patient eligibility for HBV treatment according to SASLT 2021 guidelines",
    version="1.0.0",
    docs_url="/docs",
    redoc_url="/redoc",
    lifespan=lifespan
)

# Add middleware
app.add_middleware(CORSMiddleware, **get_cors_middleware_config())
app.add_middleware(ProcessTimeMiddleware)
app.add_middleware(LoggingMiddleware)
app.add_middleware(RateLimitMiddleware, calls_per_minute=100)  # Adjust as needed

# Add exception handlers
app.add_exception_handler(HTTPException, http_exception_handler)
app.add_exception_handler(RequestValidationError, validation_exception_handler)
app.add_exception_handler(StarletteHTTPException, starlette_exception_handler)
app.add_exception_handler(Exception, general_exception_handler)

# Include routers
app.include_router(hbv_assessment.router)  # Primary HBV assessment endpoint
app.include_router(medical.router)  # Optional AI chat for guideline exploration

# Root endpoint
@app.get("/")
async def root():
    """Root endpoint with API information"""
    return {
        "name": "HBV AI Assistant API",
        "version": "1.0.0",
        "description": "HBV Patient Selection System - Evaluates patient eligibility for HBV treatment according to SASLT 2021 guidelines",
        "docs": "/docs",
        "endpoints": {
            "assess": "/assess (POST) - Primary endpoint for HBV patient eligibility assessment",
            "assess_text": "/assess/text (POST) - Text-based HBV patient eligibility assessment",
            "ask": "/ask (POST) - Optional AI chat for guideline exploration",
            "ask_stream": "/ask/stream (POST) - Streaming AI chat responses",
            "health": "/health (GET) - Simple health check",
        }
    }


# Simple health check endpoint
@app.get("/health")
async def health_check():
    """Simple health check endpoint"""
    from datetime import datetime
    return {
        "status": "healthy",
        "version": "1.0.0",
        "timestamp": datetime.now().isoformat()
    }




if __name__ == "__main__":
    import uvicorn
    uvicorn.run(
        "api.app:app",
        host="127.0.0.1",
        port=8000,
        reload=True,
        log_level="info"
    )