package application

import (
	"context"
	"errors"

	"mengstack/internal/modules/notification/domain"

	"gorm.io/gorm"
)

type Service struct {
	repo domain.NotificationRepository
}

func NewService(repo domain.NotificationRepository) *Service {
	return &Service{repo: repo}
}

func (s *Service) Create(ctx context.Context, tenantID string, req *domain.CreateNotificationRequest) (*domain.NotificationDTO, error) {
	n := &domain.Notification{
		TenantID: tenantID,
		UserID:   req.UserID,
		Title:    req.Title,
		Content:  req.Content,
		Type:     req.Type,
	}
	if n.Type == "" {
		n.Type = "info"
	}
	if err := s.repo.Create(ctx, n); err != nil {
		return nil, err
	}
	dto := domain.ToNotificationDTO(n)
	return &dto, nil
}

func (s *Service) Get(ctx context.Context, tenantID string, id uint) (*domain.NotificationDTO, error) {
	n, err := s.repo.FindByID(ctx, tenantID, id)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, nil
		}
		return nil, err
	}
	dto := domain.ToNotificationDTO(n)
	return &dto, nil
}

func (s *Service) ListByUser(ctx context.Context, tenantID string, userID uint, page, pageSize int) ([]domain.NotificationDTO, int64, error) {
	if page < 1 {
		page = 1
	}
	if pageSize < 1 || pageSize > 100 {
		pageSize = 20
	}
	notifications, total, err := s.repo.FindByUser(ctx, tenantID, userID, page, pageSize)
	if err != nil {
		return nil, 0, err
	}
	result := make([]domain.NotificationDTO, len(notifications))
	for i, n := range notifications {
		result[i] = domain.ToNotificationDTO(&n)
	}
	return result, total, nil
}

func (s *Service) MarkAsRead(ctx context.Context, tenantID string, id uint) error {
	return s.repo.MarkAsRead(ctx, tenantID, id)
}

func (s *Service) MarkAllAsRead(ctx context.Context, tenantID string, userID uint) error {
	return s.repo.MarkAllAsRead(ctx, tenantID, userID)
}

func (s *Service) CountUnread(ctx context.Context, tenantID string, userID uint) (int64, error) {
	return s.repo.CountUnread(ctx, tenantID, userID)
}

func (s *Service) Delete(ctx context.Context, tenantID string, id uint) error {
	return s.repo.Delete(ctx, tenantID, id)
}