photowall/go/internal/service/region_service.go

package service

import (
	"photowall/internal/model"

	"gorm.io/gorm"
)

type RegionService struct {
	db *gorm.DB
}

func NewRegionService(db *gorm.DB) *RegionService {
	return &RegionService{db: db}
}

// ListByParent 根据父级ID查子地区；parentID=0 查国家
func (s *RegionService) ListByParent(parentID uint) ([]model.Region, error) {
	var list []model.Region
	err := s.db.Where("parent_id = ?", parentID).Order("sort_order, name").Find(&list).Error
	return list, err
}

// ListCountries 查所有国家
func (s *RegionService) ListCountries() ([]model.Region, error) {
	var list []model.Region
	err := s.db.Where("level = ?", model.LevelCountry).Order("sort_order, name").Find(&list).Error
	return list, err
}

// GetPath 获取某地区的完整路径（国家->省->县）
func (s *RegionService) GetPath(regionID uint) ([]model.Region, error) {
	var r model.Region
	if err := s.db.First(&r, regionID).Error; err != nil {
		return nil, err
	}
	path := []model.Region{r}
	cur := r
	for cur.ParentID != 0 {
		var parent model.Region
		if err := s.db.First(&parent, cur.ParentID).Error; err != nil {
			break
		}
		// 插到前面
		path = append([]model.Region{parent}, path...)
		cur = parent
	}
	return path, nil
}

// Search 按名称搜索地区（用于快速定位）
func (s *RegionService) Search(keyword string, limit int) ([]model.Region, error) {
	if limit <= 0 {
		limit = 20
	}
	var list []model.Region
	err := s.db.Where("name LIKE ? OR name_en LIKE ?", "%"+keyword+"%", "%"+keyword+"%").
		Order("level, sort_order, name").Limit(limit).Find(&list).Error
	return list, err
}

// BatchCreate 平台管理员批量录入地区（导入完整行政区划数据用）
func (s *RegionService) BatchCreate(regions []model.Region) error {
	if len(regions) == 0 {
		return nil
	}
	return s.db.CreateInBatches(regions, 100).Error
}