package server

import (
	"context"
	"fmt"
	"net/http"
	"time"

	"attune-heart-therapy/internal/config"
	"attune-heart-therapy/internal/container"
	"attune-heart-therapy/internal/health"
	"attune-heart-therapy/internal/logger"
	"attune-heart-therapy/internal/middleware"
	"attune-heart-therapy/internal/services"

	"github.com/gin-gonic/gin"
)

// MiddlewareContainer holds all middleware functions
type MiddlewareContainer struct {
	jwtService services.JWTService
}

// Auth returns the authentication middleware
func (m *MiddlewareContainer) Auth() gin.HandlerFunc {
	return middleware.AuthMiddleware(m.jwtService)
}

// RequireAdmin returns the admin authentication middleware
func (m *MiddlewareContainer) RequireAdmin() gin.HandlerFunc {
	return middleware.RequireAdmin(m.jwtService)
}

// StrictRateLimit returns the strict rate limiting middleware
func (m *MiddlewareContainer) StrictRateLimit() gin.HandlerFunc {
	return middleware.StrictRateLimitMiddleware()
}

type Server struct {
	config        *config.Config
	container     *container.Container
	router        *gin.Engine
	middleware    *MiddlewareContainer
	httpServer    *http.Server
	healthChecker *health.Checker
	log           *logger.Logger
}

func New(cfg *config.Config) *Server {
	// Set Gin mode based on environment
	gin.SetMode(gin.ReleaseMode)

	router := gin.New()

	// Configure middleware stack
	setupMiddlewareStack(router)

	// Initialize health checker
	healthChecker := health.NewChecker()

	// Initialize logger
	log := logger.New("server")

	return &Server{
		config:        cfg,
		router:        router,
		healthChecker: healthChecker,
		log:           log,
	}
}

// setupMiddlewareStack configures the Gin middleware stack
func setupMiddlewareStack(router *gin.Engine) {
	// Tracing middleware - should be first to ensure trace ID is available
	router.Use(middleware.TracingMiddleware())

	// Security middleware
	router.Use(middleware.SecurityMiddleware())

	// CORS middleware for frontend integration
	router.Use(middleware.CORSMiddleware())

	// Request logging middleware
	router.Use(middleware.StructuredLoggingMiddleware())

	// Monitoring middleware for error tracking and metrics
	router.Use(middleware.HealthCheckMiddleware())

	// Error handling and recovery middleware
	router.Use(middleware.ErrorHandlerMiddleware())

	// Rate limiting middleware for API protection
	router.Use(middleware.RateLimitMiddleware())

	// Handle 404 and 405 errors
	router.NoRoute(middleware.NotFoundHandler())
	router.NoMethod(middleware.MethodNotAllowedHandler())
}

// SetContainer sets the dependency injection container
func (s *Server) SetContainer(container *container.Container) {
	s.container = container
}

// Initialize sets up all application dependencies
func (s *Server) Initialize() error {
	s.log.Info("Initializing server...")

	if s.container == nil {
		return fmt.Errorf("container not set - call SetContainer first")
	}

	// Initialize middleware container with JWT service
	s.middleware = &MiddlewareContainer{
		jwtService: s.container.GetJWTService(),
	}

	// Register health checks
	s.registerHealthChecks()

	s.log.Info("Server initialization completed successfully")
	return nil
}

func (s *Server) Start() error {
	// Initialize server components
	if err := s.Initialize(); err != nil {
		return err
	}

	// Setup routes
	s.setupRoutes()

	// Create HTTP server with proper configuration
	addr := fmt.Sprintf("%s:%s", s.config.Server.Host, s.config.Server.Port)
	s.httpServer = &http.Server{
		Addr:         addr,
		Handler:      s.router,
		ReadTimeout:  30 * time.Second,
		WriteTimeout: 30 * time.Second,
		IdleTimeout:  120 * time.Second,
	}

	s.log.Info("Starting server", map[string]interface{}{
		"address": addr,
	})
	return s.httpServer.ListenAndServe()
}

// Shutdown gracefully shuts down the server
func (s *Server) Shutdown(ctx context.Context) error {
	s.log.Info("Shutting down server...")

	var shutdownErrors []error

	// Shutdown HTTP server gracefully
	if s.httpServer != nil {
		s.log.Info("Shutting down HTTP server...")
		if err := s.httpServer.Shutdown(ctx); err != nil {
			s.log.Error("Error shutting down HTTP server", err)
			shutdownErrors = append(shutdownErrors, fmt.Errorf("HTTP server shutdown error: %w", err))
		} else {
			s.log.Info("HTTP server shutdown completed")
		}
	}

	// Shutdown application dependencies
	if s.container != nil {
		if err := s.container.Shutdown(); err != nil {
			s.log.Error("Error shutting down dependencies", err)
			shutdownErrors = append(shutdownErrors, err)
		}
	}

	if len(shutdownErrors) > 0 {
		return fmt.Errorf("server shutdown completed with errors: %v", shutdownErrors)
	}

	s.log.Info("Server shutdown completed successfully")
	return nil
}

func (s *Server) setupRoutes() {
	// Health check endpoints - no middleware needed
	s.router.GET("/health", s.healthCheck)
	s.router.GET("/health/detailed", s.detailedHealthCheck)
	s.router.GET("/metrics", s.metricsEndpoint)

	// API v1 routes group with base middleware
	v1 := s.router.Group("/api")
	{
		// Public routes group - no authentication required
		public := v1.Group("/")
		{
			// Auth routes - public endpoints for registration and login
			auth := public.Group("/auth")
			{
				// Apply strict rate limiting to auth endpoints
				auth.Use(s.middleware.StrictRateLimit())
				auth.POST("/register", s.container.AuthHandler.Register)
				auth.POST("/login", s.container.AuthHandler.Login)
			}

			// Schedule routes - public endpoint for getting available slots
			public.GET("/schedules", s.container.BookingHandler.GetAvailableSlots)

			// Payment webhook - public endpoint for Stripe webhooks (no auth needed)
			public.POST("/payments/webhook", s.container.PaymentHandler.HandleWebhook)
		}

		// Authenticated routes group - require JWT authentication
		authenticated := v1.Group("/")
		authenticated.Use(s.middleware.Auth())
		{
			// Auth profile routes - require authentication
			authProfile := authenticated.Group("/auth")
			{
				authProfile.GET("/profile", s.container.AuthHandler.GetProfile)
				authProfile.PUT("/profile", s.container.AuthHandler.UpdateProfile)
				authProfile.POST("/logout", s.container.AuthHandler.Logout)
			}

			// Booking routes - require authentication
			bookings := authenticated.Group("/bookings")
			{
				bookings.GET("/", s.container.BookingHandler.GetUserBookings)
				bookings.POST("/", s.container.BookingHandler.CreateBooking)
				bookings.PUT("/:id/cancel", s.container.BookingHandler.CancelBooking)
				bookings.PUT("/:id/reschedule", s.container.BookingHandler.RescheduleBooking)
			}

			// Meeting routes - require authentication
			meetings := authenticated.Group("/meetings")
			{
				meetings.GET("/:id/link", s.container.MeetingHandler.GetMeetingLink)
			}

			// Payment routes - require authentication (except webhook)
			payments := authenticated.Group("/payments")
			{
				payments.POST("/intent", s.container.PaymentHandler.CreatePaymentIntent)
				payments.POST("/confirm", s.container.PaymentHandler.ConfirmPayment)
			}
		}

		// Admin routes - require admin authentication
		admin := v1.Group("/admin")
		admin.Use(s.middleware.RequireAdmin())
		{
			admin.GET("/dashboard", s.container.AdminHandler.GetDashboard)
			admin.POST("/schedules", s.container.AdminHandler.CreateSchedule)
			admin.PUT("/schedules/:id", s.container.AdminHandler.UpdateSchedule)
			admin.GET("/users", s.container.AdminHandler.GetUsers)
			admin.GET("/bookings", s.container.AdminHandler.GetBookings)
			admin.GET("/reports/financial", s.container.AdminHandler.GetFinancialReports)
		}
	}
}

// healthCheck handles the basic health check endpoint
func (s *Server) healthCheck(c *gin.Context) {
	// Simple health check - just return OK if server is running
	c.JSON(200, gin.H{
		"status":    "ok",
		"message":   "Video Conference Booking System API",
		"timestamp": time.Now().UTC().Format(time.RFC3339),
	})
}

// detailedHealthCheck handles the detailed health check endpoint
func (s *Server) detailedHealthCheck(c *gin.Context) {
	ctx := c.Request.Context()

	// Perform comprehensive health checks
	response := s.healthChecker.BuildResponse(ctx)

	// Determine HTTP status code based on health status
	statusCode := 200
	switch response.Status {
	case health.StatusUnhealthy:
		statusCode = 503
	case health.StatusDegraded:
		statusCode = 503
	}

	c.JSON(statusCode, response)
}

// metricsEndpoint handles the metrics endpoint
func (s *Server) metricsEndpoint(c *gin.Context) {
	// Import monitoring package to get metrics
	// Note: In a real implementation, you might want to use a proper metrics format like Prometheus
	response := map[string]interface{}{
		"status":    "ok",
		"timestamp": time.Now().UTC().Format(time.RFC3339),
		"service":   "Video Conference Booking System",
		"message":   "Metrics endpoint - monitoring data would be available here",
	}

	c.JSON(200, response)
}

// registerHealthChecks registers all health checks
func (s *Server) registerHealthChecks() {
	s.log.Info("Registering health checks...")

	// Database health check
	s.healthChecker.RegisterCheck("database", health.DatabaseHealthCheck(s.container.Database))

	// Job manager health check
	s.healthChecker.RegisterCheck("job_manager", health.JobManagerHealthCheck(s.container.JobManagerService))

	// Monitoring system health check
	s.healthChecker.RegisterCheck("monitoring", health.MonitoringHealthCheck())

	// Memory health check (example with 512MB limit)
	s.healthChecker.RegisterCheck("memory", health.MemoryHealthCheck(512))

	// Disk space health check (example with 1GB minimum)
	s.healthChecker.RegisterCheck("disk_space", health.DiskSpaceHealthCheck("/", 1))

	s.log.Info("Health checks registered successfully")
}