package notificationservice

import (
	"context"
	"errors"
	"log/slog"
	"sync"
	"time"

	"github.com/SamuelTariku/FortuneBet-Backend/internal/config"
	"github.com/SamuelTariku/FortuneBet-Backend/internal/domain"
	"github.com/SamuelTariku/FortuneBet-Backend/internal/pkgs/helpers"
	"github.com/SamuelTariku/FortuneBet-Backend/internal/repository"
	afro "github.com/amanuelabay/afrosms-go"
	"github.com/gofiber/websocket/v2"
)

type Service struct {
	repo           repository.NotificationRepository
	logger         *slog.Logger
	connections    sync.Map
	notificationCh chan *domain.Notification
	stopCh         chan struct{}
	config         *config.Config
}

func New(repo repository.NotificationRepository, logger *slog.Logger, cfg *config.Config) NotificationStore {
	svc := &Service{
		repo:           repo,
		logger:         logger,
		connections:    sync.Map{},
		notificationCh: make(chan *domain.Notification, 1000),
		stopCh:         make(chan struct{}),
		config:         cfg,
	}

	go svc.startWorker()
	go svc.startRetryWorker()

	return svc
}

func (s *Service) addConnection(ctx context.Context, recipientID int64, c *websocket.Conn) {
	if c == nil {
		s.logger.Warn("[NotificationSvc.AddConnection] Attempted to add nil WebSocket connection", "recipientID", recipientID)
		return
	}

	s.connections.Store(recipientID, c)
	s.logger.Info("[NotificationSvc.AddConnection] Added WebSocket connection", "recipientID", recipientID)
}

func (s *Service) SendNotification(ctx context.Context, notification *domain.Notification) error {
	notification.ID = helpers.GenerateID()
	notification.Timestamp = time.Now()
	notification.DeliveryStatus = domain.DeliveryStatusPending

	created, err := s.repo.CreateNotification(ctx, notification)
	if err != nil {
		s.logger.Error("[NotificationSvc.SendNotification] Failed to create notification", "id", notification.ID, "error", err)
		return err
	}

	notification = created

	select {
	case s.notificationCh <- notification:
	default:
		s.logger.Error("[NotificationSvc.SendNotification] Notification channel full, dropping notification", "id", notification.ID)
	}

	return nil
}

func (s *Service) MarkAsRead(ctx context.Context, notificationID string, recipientID int64) error {
	_, err := s.repo.UpdateNotificationStatus(ctx, notificationID, string(domain.DeliveryStatusSent), true, nil)
	if err != nil {
		s.logger.Error("[NotificationSvc.MarkAsRead] Failed to mark notification as read", "notificationID", notificationID, "recipientID", recipientID, "error", err)
		return err
	}
	s.logger.Info("[NotificationSvc.MarkAsRead] Notification marked as read", "notificationID", notificationID, "recipientID", recipientID)
	return nil
}

func (s *Service) ListNotifications(ctx context.Context, recipientID int64, limit, offset int) ([]domain.Notification, error) {
	notifications, err := s.repo.ListNotifications(ctx, recipientID, limit, offset)
	if err != nil {
		s.logger.Error("[NotificationSvc.ListNotifications] Failed to list notifications", "recipientID", recipientID, "limit", limit, "offset", offset, "error", err)
		return nil, err
	}
	s.logger.Info("[NotificationSvc.ListNotifications] Successfully listed notifications", "recipientID", recipientID, "count", len(notifications))
	return notifications, nil
}

func (s *Service) ConnectWebSocket(ctx context.Context, recipientID int64, c *websocket.Conn) error {
	s.addConnection(ctx, recipientID, c)
	s.logger.Info("[NotificationSvc.ConnectWebSocket] WebSocket connection established", "recipientID", recipientID)
	return nil
}

func (s *Service) DisconnectWebSocket(recipientID int64) {
	s.connections.Delete(recipientID)
	if conn, loaded := s.connections.LoadAndDelete(recipientID); loaded {
		conn.(*websocket.Conn).Close()
		s.logger.Info("[NotificationSvc.DisconnectWebSocket] Disconnected WebSocket", "recipientID", recipientID)
	}
}

func (s *Service) SendSMS(ctx context.Context, recipientID int64, message string) error {
	s.logger.Info("[NotificationSvc.SendSMS] SMS notification requested", "recipientID", recipientID, "message", message)

	apiKey := s.config.AFRO_SMS_API_KEY
	senderName := s.config.AFRO_SMS_SENDER_NAME
	receiverPhone := s.config.AFRO_SMS_RECEIVER_PHONE_NUMBER
	hostURL := s.config.ADRO_SMS_HOST_URL
	endpoint := "/api/send"

	request := afro.GetRequest(apiKey, endpoint, hostURL)
	request.Method = "GET"
	request.Sender(senderName)
	request.To(receiverPhone, message)

	response, err := afro.MakeRequestWithContext(ctx, request)
	if err != nil {
		s.logger.Error("[NotificationSvc.SendSMS] Failed to send SMS", "recipientID", recipientID, "error", err)
		return err
	}

	if response["acknowledge"] == "success" {
		s.logger.Info("[NotificationSvc.SendSMS] SMS sent successfully", "recipientID", recipientID)
	} else {
		s.logger.Error("[NotificationSvc.SendSMS] Failed to send SMS", "recipientID", recipientID, "response", response["response"])
		return errors.New("SMS delivery failed: " + response["response"].(string))
	}

	return nil
}

func (s *Service) SendEmail(ctx context.Context, recipientID int64, subject, message string) error {
	s.logger.Info("[NotificationSvc.SendEmail] Email notification requested", "recipientID", recipientID, "subject", subject)
	return nil
}

func (s *Service) startWorker() {
	for {
		select {
		case notification := <-s.notificationCh:
			s.handleNotification(notification)
		case <-s.stopCh:
			s.logger.Info("[NotificationSvc.StartWorker] Worker stopped")
			return
		}
	}
}

func (s *Service) ListRecipientIDs(ctx context.Context, receiver domain.NotificationRecieverSide) ([]int64, error) {
	return s.repo.ListRecipientIDs(ctx, receiver)
}

func (s *Service) handleNotification(notification *domain.Notification) {
	ctx := context.Background()

	if conn, ok := s.connections.Load(notification.RecipientID); ok {
		data, err := notification.ToJSON()
		if err != nil {
			s.logger.Error("[NotificationSvc.HandleNotification] Failed to serialize notification", "id", notification.ID, "error", err)
			return
		}
		if err := conn.(*websocket.Conn).WriteMessage(websocket.TextMessage, data); err != nil {
			s.logger.Error("[NotificationSvc.HandleNotification] Failed to send WebSocket message", "id", notification.ID, "error", err)
			notification.DeliveryStatus = domain.DeliveryStatusFailed
		} else {
			notification.DeliveryStatus = domain.DeliveryStatusSent
		}
	} else {
		s.logger.Warn("[NotificationSvc.HandleNotification] No WebSocket connection for recipient", "recipientID", notification.RecipientID)
		notification.DeliveryStatus = domain.DeliveryStatusFailed
	}

	if _, err := s.repo.UpdateNotificationStatus(ctx, notification.ID, string(notification.DeliveryStatus), notification.IsRead, notification.Metadata); err != nil {
		s.logger.Error("[NotificationSvc.HandleNotification] Failed to update notification status", "id", notification.ID, "error", err)
	}
}

func (s *Service) startRetryWorker() {
	ticker := time.NewTicker(1 * time.Minute)
	defer ticker.Stop()

	for {
		select {
		case <-ticker.C:
			s.retryFailedNotifications()
		case <-s.stopCh:
			s.logger.Info("[NotificationSvc.StartRetryWorker] Retry worker stopped")
			return
		}
	}
}

func (s *Service) retryFailedNotifications() {
	ctx := context.Background()
	failedNotifications, err := s.repo.ListFailedNotifications(ctx, 100)
	if err != nil {
		s.logger.Error("[NotificationSvc.RetryFailedNotifications] Failed to list failed notifications", "error", err)
		return
	}

	for _, n := range failedNotifications {
		notification := &n
		go func(notification *domain.Notification) {
			for attempt := 0; attempt < 3; attempt++ {
				time.Sleep(time.Duration(attempt) * time.Second)
				if conn, ok := s.connections.Load(notification.RecipientID); ok {
					data, err := notification.ToJSON()
					if err != nil {
						s.logger.Error("[NotificationSvc.RetryFailedNotifications] Failed to serialize notification for retry", "id", notification.ID, "error", err)
						continue
					}
					if err := conn.(*websocket.Conn).WriteMessage(websocket.TextMessage, data); err == nil {
						notification.DeliveryStatus = domain.DeliveryStatusSent
						if _, err := s.repo.UpdateNotificationStatus(ctx, notification.ID, string(notification.DeliveryStatus), notification.IsRead, notification.Metadata); err != nil {
							s.logger.Error("[NotificationSvc.RetryFailedNotifications] Failed to update after retry", "id", notification.ID, "error", err)
						}
						s.logger.Info("[NotificationSvc.RetryFailedNotifications] Successfully retried notification", "id", notification.ID)
						return
					}
				}
			}
			s.logger.Error("[NotificationSvc.RetryFailedNotifications] Max retries reached for notification", "id", notification.ID)
		}(notification)
	}
}