backend-service/internal/services/notification_service.go

package services

import (
	"fmt"
	"log"
	"time"

	"attune-heart-therapy/internal/config"
	"attune-heart-therapy/internal/models"
	"attune-heart-therapy/internal/repositories"
	"attune-heart-therapy/internal/templates"

	"gopkg.in/gomail.v2"
)

// notificationService implements the NotificationService interface
type notificationService struct {
	notificationRepo repositories.NotificationRepository
	templateService  *templates.EmailTemplateService
	config           *config.Config
	dialer           *gomail.Dialer
}

// NewNotificationService creates a new instance of NotificationService
func NewNotificationService(notificationRepo repositories.NotificationRepository, cfg *config.Config) NotificationService {
	dialer := gomail.NewDialer(
		cfg.SMTP.Host,
		cfg.SMTP.Port,
		cfg.SMTP.Username,
		cfg.SMTP.Password,
	)

	return &notificationService{
		notificationRepo: notificationRepo,
		templateService:  templates.NewEmailTemplateService(),
		config:           cfg,
		dialer:           dialer,
	}
}

// SendWelcomeEmail sends a welcome email to a newly registered user
func (s *notificationService) SendWelcomeEmail(user *models.User) error {
	templateData := templates.TemplateData{
		User: user,
	}

	emailTemplate, err := s.templateService.RenderTemplate(models.NotificationTypeWelcome, templateData)
	if err != nil {
		return fmt.Errorf("failed to render welcome email template: %w", err)
	}

	notification := &models.Notification{
		UserID:  user.ID,
		Type:    models.NotificationTypeWelcome,
		Subject: emailTemplate.Subject,
		Body:    emailTemplate.Body,
		Status:  models.NotificationStatusPending,
	}

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

	return s.sendEmail(user.Email, emailTemplate.Subject, emailTemplate.Body)
}

// SendPaymentNotification sends payment status notification to user
func (s *notificationService) SendPaymentNotification(user *models.User, booking *models.Booking, success bool) error {
	var notificationType models.NotificationType
	if success {
		notificationType = models.NotificationTypePaymentSuccess
	} else {
		notificationType = models.NotificationTypePaymentFailed
	}

	templateData := templates.TemplateData{
		User:    user,
		Booking: booking,
	}

	emailTemplate, err := s.templateService.RenderTemplate(notificationType, templateData)
	if err != nil {
		return fmt.Errorf("failed to render payment notification template: %w", err)
	}

	notification := &models.Notification{
		UserID:    user.ID,
		BookingID: &booking.ID,
		Type:      notificationType,
		Subject:   emailTemplate.Subject,
		Body:      emailTemplate.Body,
		Status:    models.NotificationStatusPending,
	}

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

	return s.sendEmail(user.Email, emailTemplate.Subject, emailTemplate.Body)
}

// SendMeetingInfo sends meeting information to user after successful booking
func (s *notificationService) SendMeetingInfo(user *models.User, booking *models.Booking) error {
	templateData := templates.TemplateData{
		User:    user,
		Booking: booking,
	}

	emailTemplate, err := s.templateService.RenderTemplate(models.NotificationTypeMeetingInfo, templateData)
	if err != nil {
		return fmt.Errorf("failed to render meeting info template: %w", err)
	}

	notification := &models.Notification{
		UserID:    user.ID,
		BookingID: &booking.ID,
		Type:      models.NotificationTypeMeetingInfo,
		Subject:   emailTemplate.Subject,
		Body:      emailTemplate.Body,
		Status:    models.NotificationStatusPending,
	}

	if err := s.notificationRepo.Create(notification); err != nil {
		return fmt.Errorf("failed to create meeting info notification: %w", err)
	}

	return s.sendEmail(user.Email, emailTemplate.Subject, emailTemplate.Body)
}

// SendReminder sends a reminder notification to user before their meeting
func (s *notificationService) SendReminder(user *models.User, booking *models.Booking) error {
	templateData := templates.TemplateData{
		User:         user,
		Booking:      booking,
		ReminderText: templates.GetReminderText(booking.ScheduledAt),
	}

	emailTemplate, err := s.templateService.RenderTemplate(models.NotificationTypeReminder, templateData)
	if err != nil {
		return fmt.Errorf("failed to render reminder template: %w", err)
	}

	notification := &models.Notification{
		UserID:    user.ID,
		BookingID: &booking.ID,
		Type:      models.NotificationTypeReminder,
		Subject:   emailTemplate.Subject,
		Body:      emailTemplate.Body,
		Status:    models.NotificationStatusPending,
	}

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

	return s.sendEmail(user.Email, emailTemplate.Subject, emailTemplate.Body)
}

// ScheduleReminder schedules a reminder notification for a specific time
func (s *notificationService) ScheduleReminder(bookingID uint, reminderTime time.Time) error {
	// Create a scheduled notification that will be processed later
	notification := &models.Notification{
		BookingID:   &bookingID,
		Type:        models.NotificationTypeReminder,
		Subject:     "Scheduled Reminder",
		Body:        "This is a scheduled reminder notification",
		Status:      models.NotificationStatusPending,
		ScheduledAt: &reminderTime,
	}

	if err := s.notificationRepo.Create(notification); err != nil {
		return fmt.Errorf("failed to schedule reminder: %w", err)
	}

	log.Printf("Reminder scheduled for booking %d at %s", bookingID, reminderTime.Format(time.RFC3339))
	return nil
}

// ProcessPendingNotifications processes all pending notifications that are ready to be sent
func (s *notificationService) ProcessPendingNotifications() error {
	notifications, err := s.notificationRepo.GetPendingNotifications()
	if err != nil {
		return fmt.Errorf("failed to get pending notifications: %w", err)
	}

	for _, notification := range notifications {
		if !notification.IsReadyToSend() {
			continue
		}

		// For reminder notifications, we need to fetch the booking and user data
		if notification.Type == models.NotificationTypeReminder && notification.BookingID != nil {
			// This would require additional repository methods to fetch booking with user
			// For now, we'll skip processing reminders in batch processing
			log.Printf("Skipping reminder notification %d - requires specific booking context", notification.ID)
			continue
		}

		// Send the notification
		if err := s.sendEmail(notification.User.Email, notification.Subject, notification.Body); err != nil {
			notification.MarkAsFailed(err.Error())
			log.Printf("Failed to send notification %d: %v", notification.ID, err)
		} else {
			notification.MarkAsSent()
			log.Printf("Successfully sent notification %d to %s", notification.ID, notification.User.Email)
		}

		// Update the notification status
		if err := s.notificationRepo.Update(&notification); err != nil {
			log.Printf("Failed to update notification %d status: %v", notification.ID, err)
		}
	}

	return nil
}

// sendEmail sends an email using the configured SMTP settings
func (s *notificationService) sendEmail(to, subject, body string) error {
	if s.config.SMTP.Host == "" || s.config.SMTP.From == "" {
		log.Printf("SMTP not configured, skipping email to %s", to)
		return nil // Don't fail if SMTP is not configured
	}

	message := gomail.NewMessage()
	message.SetHeader("From", s.config.SMTP.From)
	message.SetHeader("To", to)
	message.SetHeader("Subject", subject)
	message.SetBody("text/html", body)

	if err := s.dialer.DialAndSend(message); err != nil {
		return fmt.Errorf("failed to send email to %s: %w", to, err)
	}

	log.Printf("Email sent successfully to %s", to)
	return nil
}