Refactor Notification Sending Logic to Include Channel Checks

- Updated the Send method in the notification service to check for specified delivery channels (Push and Email) before sending notifications, enhancing the flexibility of the notification system.
- Utilized the slices package to streamline the channel checking process, improving code readability and maintainability.
- Ensured that notifications are only sent to recipients based on the selected channels, promoting more efficient notification delivery.

internal/notification/service.go

@@ -3,6 +3,7 @@ package notification
 import (
 	"context"
 	"errors"
+	"slices"
 	"strings"
 	"time"
 
@@ -60,6 +61,7 @@ func (s *notificationService) Send(ctx context.Context, req *NotificationRequest
 			return err
 		}
 		for _, recipient := range recipients {
+			if slices.Contains(req.Channels, DeliveryChannelPush) {
 				for _, v := range recipient.DeviceTokens {
 					s.sdk.SendNotification(ctx, &notification.NotificationRequest{
 						UserID:    recipient.UserID,
@@ -78,7 +80,9 @@ func (s *notificationService) Send(ctx context.Context, req *NotificationRequest
 						ScheduledAt: req.ScheduleAt,
 					})
 				}
+			}
 
+			if slices.Contains(req.Channels, DeliveryChannelEmail) {
 				if recipient.Email != "" {
 					s.sdk.SendNotification(ctx, &notification.NotificationRequest{
 						UserID:    recipient.UserID,
@@ -97,12 +101,14 @@ func (s *notificationService) Send(ctx context.Context, req *NotificationRequest
 					})
 				}
 			}
+		}
 	} else {
 		recipients, err := s.getCustomers(ctx, req.Recipient, string(req.Target))
 		if err != nil {
 			return err
 		}
 		for _, recipient := range recipients {
+			if slices.Contains(req.Channels, DeliveryChannelPush) {
 				for _, v := range recipient.DeviceTokens {
 					s.sdk.SendNotification(ctx, &notification.NotificationRequest{
 						UserID:    recipient.UserID,
@@ -120,7 +126,9 @@ func (s *notificationService) Send(ctx context.Context, req *NotificationRequest
 						},
 					})
 				}
+			}
 
+			if slices.Contains(req.Channels, DeliveryChannelEmail) {
 				if recipient.Email != "" {
 					s.sdk.SendNotification(ctx, &notification.NotificationRequest{
 						UserID:    recipient.UserID,
@@ -139,6 +147,7 @@ func (s *notificationService) Send(ctx context.Context, req *NotificationRequest
 					})
 				}
 			}
+		}
 		s.logger.Info("Notification sent", map[string]interface{}{
 			"recipient": req.Recipient,
 			"channels":  req.Channels,