package main

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

	"github.com/atlasos/calypso/internal/common/config"
	"github.com/atlasos/calypso/internal/common/database"
	"github.com/atlasos/calypso/internal/common/logger"
	"github.com/atlasos/calypso/internal/common/router"
	"golang.org/x/sync/errgroup"
)

var (
	version   = "dev"
	buildTime = "unknown"
	gitCommit = "unknown"
)

func main() {
	var (
		configPath = flag.String("config", "/etc/calypso/config.yaml", "Path to configuration file")
		showVersion = flag.Bool("version", false, "Show version information")
	)
	flag.Parse()

	if *showVersion {
		fmt.Printf("AtlasOS - Calypso API\n")
		fmt.Printf("Version: %s\n", version)
		fmt.Printf("Build Time: %s\n", buildTime)
		fmt.Printf("Git Commit: %s\n", gitCommit)
		os.Exit(0)
	}

	// Initialize logger
	logger := logger.NewLogger("calypso-api")

	// Load configuration
	cfg, err := config.Load(*configPath)
	if err != nil {
		logger.Fatal("Failed to load configuration", "error", err)
	}

	// Initialize database
	db, err := database.NewConnection(cfg.Database)
	if err != nil {
		logger.Fatal("Failed to connect to database", "error", err)
	}
	defer db.Close()

	// Run migrations
	if err := database.RunMigrations(context.Background(), db); err != nil {
		logger.Fatal("Failed to run database migrations", "error", err)
	}
	logger.Info("Database migrations completed successfully")

	// Initialize router
	r := router.NewRouter(cfg, db, logger)

	// Create HTTP server
	srv := &http.Server{
		Addr:         fmt.Sprintf(":%d", cfg.Server.Port),
		Handler:      r,
		ReadTimeout:  15 * time.Second,
		WriteTimeout: 15 * time.Second,
		IdleTimeout:  60 * time.Second,
	}

	// Setup graceful shutdown
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	g, gCtx := errgroup.WithContext(ctx)

	// Start HTTP server
	g.Go(func() error {
		logger.Info("Starting HTTP server", "port", cfg.Server.Port, "address", srv.Addr)
		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			return fmt.Errorf("server failed: %w", err)
		}
		return nil
	})

	// Graceful shutdown handler
	g.Go(func() error {
		sigChan := make(chan os.Signal, 1)
		signal.Notify(sigChan, os.Interrupt, syscall.SIGTERM)
		select {
		case <-sigChan:
			logger.Info("Received shutdown signal, initiating graceful shutdown...")
			cancel()
		case <-gCtx.Done():
			return gCtx.Err()
		}

		shutdownCtx, shutdownCancel := context.WithTimeout(context.Background(), 30*time.Second)
		defer shutdownCancel()

		if err := srv.Shutdown(shutdownCtx); err != nil {
			return fmt.Errorf("server shutdown failed: %w", err)
		}
		logger.Info("HTTP server stopped gracefully")
		return nil
	})

	// Wait for all goroutines
	if err := g.Wait(); err != nil {
		log.Fatalf("Server error: %v", err)
	}
}