"""
API Gateway - Central entry point for all microservices
Handles routing, authentication, rate limiting, and cross-cutting concerns
"""

import asyncio
import structlog
from fastapi import FastAPI, Request, HTTPException, Depends
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
import httpx
import time
from typing import Dict, Any

from app.core.config import settings
from app.core.service_discovery import ServiceDiscovery
from app.middleware.auth import AuthMiddleware
from app.middleware.logging import LoggingMiddleware
from app.middleware.rate_limit import RateLimitMiddleware
from app.routes import auth, tenant, notification, nominatim, user
from shared.monitoring.logging import setup_logging
from shared.monitoring.metrics import MetricsCollector

# Setup logging
setup_logging("gateway", settings.LOG_LEVEL)
logger = structlog.get_logger()

# Create FastAPI app
app = FastAPI(
    title="Bakery Forecasting API Gateway",
    description="Central API Gateway for bakery forecasting microservices",
    version="1.0.0",
    docs_url="/docs",
    redoc_url="/redoc"
)

# Initialize metrics collector
metrics_collector = MetricsCollector("gateway")

# Service discovery
service_discovery = ServiceDiscovery()

# CORS middleware - Add first
app.add_middleware(
    CORSMiddleware,
    allow_origins=settings.CORS_ORIGINS_LIST,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Custom middleware - Add in correct order (outer to inner)
app.add_middleware(LoggingMiddleware)
app.add_middleware(RateLimitMiddleware, calls_per_minute=60)
app.add_middleware(AuthMiddleware)

# Include routers
app.include_router(auth.router, prefix="/api/v1/auth", tags=["authentication"])
app.include_router(user.router, prefix="/api/v1/users", tags=["users"])
app.include_router(tenant.router, prefix="/api/v1/tenants", tags=["tenants"])
app.include_router(notification.router, prefix="/api/v1/notifications", tags=["notifications"])
app.include_router(nominatim.router, prefix="/api/v1/nominatim", tags=["location"])

@app.on_event("startup")
async def startup_event():
    """Application startup"""
    logger.info("Starting API Gateway")
    
    # Start metrics server
    metrics_collector.register_counter(
        "gateway_auth_requests_total",
        "Total authentication requests through gateway"
    )
    metrics_collector.register_counter(
        "gateway_auth_responses_total", 
        "Total authentication responses through gateway"
    )
    metrics_collector.register_histogram(
        "gateway_request_duration_seconds",
        "Gateway request duration"
    )
    
    
    metrics_collector.start_metrics_server(8080)
    
    logger.info("API Gateway started successfully")

@app.on_event("shutdown")
async def shutdown_event():
    """Application shutdown"""
    logger.info("Shutting down API Gateway")
    
    # Clean up service discovery
    # await service_discovery.cleanup()
    
    logger.info("API Gateway shutdown complete")

@app.get("/health")
async def health_check():
    """Health check endpoint"""
    return {
        "status": "healthy",
        "service": "api-gateway",
        "version": "1.0.0",
        "timestamp": time.time()
    }

@app.get("/metrics")
async def metrics():
    """Metrics endpoint for monitoring"""
    return {"metrics": "enabled"}

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)