backend-service/internal/repositories/notification_repository.go

package repositories

import (
	"errors"
	"fmt"

	"attune-heart-therapy/internal/models"

	"gorm.io/gorm"
)

// notificationRepository implements the NotificationRepository interface
type notificationRepository struct {
	db *gorm.DB
}

// NewNotificationRepository creates a new instance of NotificationRepository
func NewNotificationRepository(db *gorm.DB) NotificationRepository {
	return &notificationRepository{
		db: db,
	}
}

// Create creates a new notification in the database
func (r *notificationRepository) Create(notification *models.Notification) error {
	if notification == nil {
		return errors.New("notification cannot be nil")
	}

	if err := r.db.Create(notification).Error; err != nil {
		return fmt.Errorf("failed to create notification: %w", err)
	}

	return nil
}

// GetByID retrieves a notification by its ID with user and booking preloaded
func (r *notificationRepository) GetByID(id uint) (*models.Notification, error) {
	if id == 0 {
		return nil, errors.New("invalid notification ID")
	}

	var notification models.Notification
	if err := r.db.Preload("User").Preload("Booking").First(&notification, id).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, fmt.Errorf("notification with ID %d not found", id)
		}
		return nil, fmt.Errorf("failed to get notification by ID: %w", err)
	}

	return &notification, nil
}

// Update updates an existing notification in the database
func (r *notificationRepository) Update(notification *models.Notification) error {
	if notification == nil {
		return errors.New("notification cannot be nil")
	}

	if notification.ID == 0 {
		return errors.New("notification ID is required for update")
	}

	// Check if notification exists
	var existingNotification models.Notification
	if err := r.db.First(&existingNotification, notification.ID).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return fmt.Errorf("notification with ID %d not found", notification.ID)
		}
		return fmt.Errorf("failed to check notification existence: %w", err)
	}

	// Update the notification
	if err := r.db.Save(notification).Error; err != nil {
		return fmt.Errorf("failed to update notification: %w", err)
	}

	return nil
}

// GetPendingNotifications retrieves all notifications that are ready to be sent
func (r *notificationRepository) GetPendingNotifications() ([]models.Notification, error) {
	var notifications []models.Notification

	if err := r.db.Preload("User").Preload("Booking").
		Where("status = ? AND (scheduled_at IS NULL OR scheduled_at <= NOW())", models.NotificationStatusPending).
		Order("created_at ASC").
		Find(&notifications).Error; err != nil {
		return nil, fmt.Errorf("failed to get pending notifications: %w", err)
	}

	return notifications, nil
}