package main

import (
	"context"
	"embed"
	"fmt"
	"io/fs"
	"log"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"simplefinancedash/backend/internal/api"
	"simplefinancedash/backend/internal/db"
)

// These directories are populated at build time:
// - frontend_dist/ is copied from frontend/dist by the Dockerfile
// - migrations/ is symlinked or copied from backend/migrations/

//go:embed frontend_dist
var frontendFiles embed.FS

//go:embed migrations
var migrationsFiles embed.FS

func main() {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	databaseURL := getEnv("DATABASE_URL", "postgres://simplefin:simplefin@localhost:5432/simplefindb?sslmode=disable")
	sessionSecret := getEnv("SESSION_SECRET", "change-me-in-production")
	port := getEnv("PORT", "8080")

	// Connect to database
	pool, err := db.Connect(ctx, databaseURL)
	if err != nil {
		log.Fatalf("Failed to connect to database: %v", err)
	}
	defer pool.Close()

	// Run migrations
	migrationsFS, err := fs.Sub(migrationsFiles, "migrations")
	if err != nil {
		log.Fatalf("Failed to setup migrations filesystem: %v", err)
	}
	if err := db.RunMigrations(ctx, pool, migrationsFS); err != nil {
		log.Fatalf("Failed to run migrations: %v", err)
	}
	log.Println("Migrations completed")

	// Setup frontend filesystem
	frontendFS, err := fs.Sub(frontendFiles, "frontend_dist")
	if err != nil {
		log.Fatalf("Failed to setup frontend filesystem: %v", err)
	}

	// Create router
	queries := db.NewQueries(pool)
	router := api.NewRouter(queries, sessionSecret, frontendFS)

	// Start server
	server := &http.Server{
		Addr:         ":" + port,
		Handler:      router,
		ReadTimeout:  15 * time.Second,
		WriteTimeout: 15 * time.Second,
		IdleTimeout:  60 * time.Second,
	}

	go func() {
		log.Printf("Server starting on :%s", port)
		if err := server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			log.Fatalf("Server failed: %v", err)
		}
	}()

	// Graceful shutdown
	quit := make(chan os.Signal, 1)
	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
	<-quit
	log.Println("Shutting down server...")

	shutdownCtx, shutdownCancel := context.WithTimeout(ctx, 10*time.Second)
	defer shutdownCancel()

	if err := server.Shutdown(shutdownCtx); err != nil {
		log.Fatalf("Server forced to shutdown: %v", err)
	}

	fmt.Println("Server stopped")
}

func getEnv(key, fallback string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return fallback
}