package services

import (
	"errors"
	"gobeyhan/database"
	"gobeyhan/database/models"

	"gorm.io/gorm"
)

type CategoryService struct{}

func NewCategoryService() *CategoryService {
	return &CategoryService{}
}

// GetAllCategories retrieves all categories, optionally filtering by active status
func (s *CategoryService) GetAllCategories(activeOnly bool) ([]models.Category, error) {
	var categories []models.Category
	query := database.DB.Preload("Parent").Preload("Children")

	if activeOnly {
		query = query.Where("is_active = ?", true)
	}

	err := query.Order("`order` ASC, created_at DESC").Find(&categories).Error
	return categories, err
}

// GetCategoryByID retrieves a category by ID with parent and children relationships
func (s *CategoryService) GetCategoryByID(id uint64) (*models.Category, error) {
	var category models.Category
	err := database.DB.
		Preload("Parent").
		Preload("Children").
		First(&category, id).Error

	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, nil
		}
		return nil, err
	}

	return &category, nil
}

// GetCategoryBySlug retrieves a category by slug
func (s *CategoryService) GetCategoryBySlug(slug string) (*models.Category, error) {
	var category models.Category
	err := database.DB.
		Preload("Parent").
		Preload("Children").
		Where("slug = ?", slug).
		First(&category).Error

	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, nil
		}
		return nil, err
	}

	return &category, nil
}

// CreateCategory creates a new category
func (s *CategoryService) CreateCategory(category *models.Category) error {
	return database.DB.Create(category).Error
}

// UpdateCategory updates an existing category
func (s *CategoryService) UpdateCategory(id uint64, updates map[string]interface{}) error {
	result := database.DB.Model(&models.Category{}).Where("id = ?", id).Updates(updates)
	if result.Error != nil {
		return result.Error
	}
	if result.RowsAffected == 0 {
		return gorm.ErrRecordNotFound
	}
	return nil
}

// DeleteCategory deletes a category by ID
func (s *CategoryService) DeleteCategory(id uint64) error {
	result := database.DB.Delete(&models.Category{}, id)
	if result.Error != nil {
		return result.Error
	}
	if result.RowsAffected == 0 {
		return gorm.ErrRecordNotFound
	}
	return nil
}

// GetCategoriesByParent retrieves child categories of a parent
func (s *CategoryService) GetCategoriesByParent(parentID uint64, activeOnly bool) ([]models.Category, error) {
	var categories []models.Category
	query := database.DB.Where("parent_id = ?", parentID)

	if activeOnly {
		query = query.Where("is_active = ?", true)
	}

	err := query.Order("`order` ASC, created_at DESC").Find(&categories).Error
	return categories, err
}