package app

import (
	"context"
	"fmt"
	"net/http"
	"os"
	"os/signal"
	"strconv"
	"strings"
	"syscall"
	"time"

	"git.linuxforward.com/byom/byom-core/config"
	"git.linuxforward.com/byom/byom-core/handlers"
	"git.linuxforward.com/byom/byom-core/hook"
	"git.linuxforward.com/byom/byom-core/jwtutils"
	"git.linuxforward.com/byom/byom-core/logger"
	"git.linuxforward.com/byom/byom-core/middleware"
	"git.linuxforward.com/byom/byom-core/smtp"
	"git.linuxforward.com/byom/byom-core/store"
	"github.com/gin-gonic/gin"
	"github.com/sirupsen/logrus"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
)

type App struct {
	entry            *logrus.Entry
	cnf              *config.Config
	ctx              context.Context
	cancel           context.CancelFunc
	dataStore        *store.DataStore
	emailSvc         *smtp.Service
	jwtSvc           *jwtutils.Service
	hookSvc          *hook.HookClient
	userHandler      *handlers.UserHandler
	workspaceHandler *handlers.WorkspaceHandler
	profileHandler   *handlers.ProfileHandler
	router           *gin.Engine
}

type ServiceHandler interface {
	SetupRoutes(r *gin.Engine)
	Close() error
}

// NewApp creates a new application instance with the given options
func NewApp(cnf *config.Config) (*App, error) {
	ctx, cancel := context.WithCancel(context.Background())

	// Create logger
	entry := logger.NewLogger("app")

	// Create app instance
	app := &App{
		entry:  entry,
		cnf:    cnf,
		ctx:    ctx,
		cancel: cancel,
	}

	// Initialize router and middleware
	if err := app.initRouter(); err != nil {
		cancel()
		return nil, fmt.Errorf("init router: %w", err)
	}

	// Initialize services
	if err := app.initServices(); err != nil {
		cancel()
		return nil, fmt.Errorf("failed to initialize services: %w", err)
	}

	return app, nil
}

// initRouter initializes the router and middleware
func (a *App) initRouter() error {
	rtr := gin.New()

	// Add core middleware
	rtr.Use(middleware.Recovery(a.entry.Logger))
	rtr.Use(middleware.RequestID())
	rtr.Use(middleware.RequestLogger(a.entry.Logger))
	rtr.Use(middleware.ErrorHandler())

	// Add security middleware
	rtr.Use(middleware.SecurityHeaders())
	rtr.Use(middleware.RequestSanitizer())

	// Configure request timeout
	timeout := 30 * time.Second
	if a.cnf.Server.RequestTimeout > 0 {
		timeout = time.Duration(a.cnf.Server.RequestTimeout) * time.Second
	}
	rtr.Use(middleware.TimeoutMiddleware(timeout))

	// Configure CORS
	corsConfig := middleware.DefaultCORSConfig()
	if len(a.cnf.Server.CorsOrigins) > 0 {
		a.entry.WithField("origins", a.cnf.Server.CorsOrigins).Info("Configuring CORS with specific origins")
		corsConfig.AllowOrigins = a.cnf.Server.CorsOrigins
	} else {
		a.entry.Warn("No CORS origins specified, using development defaults (localhost only)")
	}
	rtr.Use(middleware.CORS(corsConfig))

	// Add health check endpoint
	addRoutes(rtr, a.jwtSvc, a.userHandler, a.workspaceHandler, a.profileHandler)

	a.router = rtr
	return nil
}

// initServices initializes all required services
func (a *App) initServices() error {
	// Initialize database
	dbConn, err := initDBConn(a.cnf.Database)
	if err != nil {
		return fmt.Errorf("init database: %w", err)
	}

	// Initialize services if not already set through options
	if a.emailSvc == nil {
		a.emailSvc = smtp.NewService(a.cnf.Smtp)
	}

	a.jwtSvc = jwtutils.NewService(a.cnf.Jwt.JwtSecret)
	a.hookSvc = hook.NewHookClient(a.cnf.Hook.BaseURL, a.cnf.Hook.Domain, a.cnf.Hook.SecretKey)
	a.dataStore = store.NewDataStore(dbConn)

	// Initialize handlers
	a.userHandler = handlers.NewUserHandler(a.dataStore, a.emailSvc, a.jwtSvc, a.hookSvc)
	a.workspaceHandler = handlers.NewWorkspaceHandler(a.dataStore)
	a.profileHandler = handlers.NewProfileHandler(a.dataStore)

	return nil
}

func (a *App) Run() error {
	a.entry.Info("Starting server...")

	if len(a.cnf.Server.Opts) > 0 {
		a.router.Use(func(c *gin.Context) {
			for _, opt := range a.cnf.Server.Opts {
				parts := strings.Split(opt, ": ")
				if len(parts) == 2 {
					c.Header(parts[0], parts[1])
				}
			}
			c.Next()
		})
	}

	// Configure server with timeouts
	srv := &http.Server{
		Addr:         fmt.Sprintf(":%s", strconv.Itoa(a.cnf.Server.ListeningPort)),
		Handler:      a.router,
		ReadTimeout:  15 * time.Second,
		WriteTimeout: 15 * time.Second,
		IdleTimeout:  60 * time.Second,
	}

	// Start server
	go func() {
		var err error
		if a.cnf.Server.TlsConfig.Enabled {
			a.entry.Infof("Starting server on port %d with TLS", a.cnf.Server.ListeningPort)
			err = srv.ListenAndServeTLS(
				a.cnf.Server.TlsConfig.CertFile,
				a.cnf.Server.TlsConfig.KeyFile,
			)
		} else {
			a.entry.Infof("Starting server on port %d without TLS", a.cnf.Server.ListeningPort)
			err = srv.ListenAndServe()
		}

		if err != nil && err != http.ErrServerClosed {
			a.entry.WithError(err).Error("Server error")
			// Signal shutdown on critical error
			a.cancel()
		}
	}()

	// Graceful shutdown
	quit := make(chan os.Signal, 1)
	signal.Notify(quit, os.Interrupt, syscall.SIGTERM)

	select {
	case <-quit:
		a.entry.Info("Shutdown signal received...")
	case <-a.ctx.Done():
		a.entry.Info("Server error occurred, initiating shutdown...")
	}

	// Create shutdown context with timeout
	ctxShutdown, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	// Shutdown server
	if err := srv.Shutdown(ctxShutdown); err != nil {
		a.entry.WithError(err).Error("Server forced to shutdown")
		return fmt.Errorf("server forced to shutdown: %w", err)
	}

	// Close all services
	if err := a.Close(); err != nil {
		a.entry.WithError(err).Error("Error during service cleanup")
		return fmt.Errorf("service cleanup error: %w", err)
	}

	a.entry.Info("Server stopped gracefully")
	return nil
}

func initDBConn(cnf *config.Database) (*gorm.DB, error) {

	db, err := gorm.Open(sqlite.Open(cnf.Path), &gorm.Config{})
	if err != nil {
		return nil, fmt.Errorf("database: %w", err)
	}

	//Tune the DB
	sqlDB, err := db.DB()
	if err != nil {
		return nil, fmt.Errorf("database: %w", err)
	}

	sqlDB.SetMaxOpenConns(cnf.MaxOpenConns)
	sqlDB.SetMaxIdleConns(cnf.MaxIdleConns)
	sqlDB.SetConnMaxLifetime(time.Duration(cnf.ConnMaxLifetime) * time.Second)

	for _, pragma := range cnf.Pragma {
		tx := db.Exec("PRAGMA " + pragma)
		if tx.Error != nil {
			return nil, fmt.Errorf("database: %w", tx.Error)
		}
	}

	return db, nil
}

func (a *App) Close() error {
	a.entry.Info("Closing application resources...")

	if err := a.dataStore.Close(); err != nil {
		a.entry.WithError(err).Error("Failed to close database connections")
		return err
	}

	if err := a.emailSvc.Close(); err != nil {
		a.entry.WithError(err).Error("Failed to close email service")
	}

	if err := a.hookSvc.Close(); err != nil {
		a.entry.WithError(err).Error("Failed to close hook service")
	}

	return nil
}