package main

import (
	"context"
	"flag"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/user/go-proxy/internal/config"
	"github.com/user/go-proxy/internal/proxy"
	"github.com/user/go-proxy/internal/router"
	"github.com/user/go-proxy/pkg/middleware"
)

func main() {
	// Parse command line flags
	configPath := flag.String("config", "config.yaml", "Path to configuration file")
	flag.Parse()

	// 1. Load configuration dynamically
	cfg, err := config.LoadConfig(*configPath)
	if err != nil {
		log.Fatalf("Error loading config: %v", err)
		os.Exit(1)
	}

	fmt.Printf("Loaded configuration from %s\n", *configPath)

	// 2. Setup Router
	r := router.NewRouter(cfg.HTTP)

	// 3. Setup Middleware Chain
	handler := middleware.Chain(
		r,
		middleware.Recovery(),
		middleware.Logger(),
		middleware.RateLimit(10, 20),
	)

	// 4. Setup Config Watcher (Hot-Reload)
	err = config.WatchConfig(*configPath, func(newCfg *config.Config) {
		log.Println("Applying new configuration...")
		r.UpdateConfig(newCfg.HTTP)
	})
	if err != nil {
		log.Printf("Warning: Failed to start config watcher: %v", err)
	}

	// 5. Start TCP Proxy in a separate goroutine (if configured)
	if cfg.TCP.Port > 0 && cfg.TCP.Backend != "" {
		go func() {
			if err := proxy.RunTCPProxy(cfg.TCP.Port, cfg.TCP.Backend); err != nil {
				log.Printf("TCP proxy failed: %v", err)
			}
		}()
	}

	// 6. Start UDP Proxy in a separate goroutine (if configured)
	if cfg.UDP.Port > 0 && cfg.UDP.Backend != "" {
		go func() {
			if err := proxy.RunUDPProxy(cfg.UDP.Port, cfg.UDP.Backend); err != nil {
				log.Printf("UDP proxy failed: %v", err)
			}
		}()
	}

	// Prepare HTTP Servers
	httpServer := &http.Server{
		Addr:    fmt.Sprintf(":%d", cfg.HTTP.Port),
		Handler: handler,
	}

	var httpsServer *http.Server
	if cfg.HTTP.TLS.Enabled {
		httpsServer = &http.Server{
			Addr:    fmt.Sprintf(":%d", cfg.HTTP.TLS.Port),
			Handler: handler,
		}
	}

	// 6. Start HTTPS Server (if enabled)
	if httpsServer != nil {
		go func() {
			log.Printf("Starting HTTPS proxy server on port %s\n", httpsServer.Addr)
			if err := httpsServer.ListenAndServeTLS(cfg.HTTP.TLS.CertFile, cfg.HTTP.TLS.KeyFile); err != nil && err != http.ErrServerClosed {
				log.Fatalf("HTTPS Server error: %v", err)
			}
		}()
	}

	// 7. Start HTTP Server
	go func() {
		log.Printf("Starting HTTP proxy server on port %s\n", httpServer.Addr)
		if err := httpServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			log.Fatalf("HTTP Server error: %v", err)
		}
	}()

	// 8. Graceful Shutdown Waiter
	quit := make(chan os.Signal, 1)
	// kill (no param) default send syscall.SIGTERM
	// kill -2 is syscall.SIGINT
	// kill -9 is syscall.SIGKILL but can't be caught, so don't need to add it
	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
	<-quit
	log.Println("Shutdown signal received, draining traffic...")

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	if httpsServer != nil {
		if err := httpsServer.Shutdown(ctx); err != nil {
			log.Printf("HTTPS Server forced to shutdown: %v", err)
		}
	}

	if err := httpServer.Shutdown(ctx); err != nil {
		log.Printf("HTTP Server forced to shutdown: %v", err)
	}

	log.Println("Proxy server exiting gracefully")
}