feat: initial building endpoints

internal/storage/datastore.go

@@ -177,3 +177,29 @@ func (s *DataStore) DeleteCategoryByID(id uint64) (bool, error) {
 	}
 	return true, nil
 }
+
+func (s *DataStore) GetBuildings(offset, limit uint64) ([]*types.Building, error) {
+	var buildings []*types.Building
+	s.db.Order("id asc").Offset(int(offset)).Limit(int(limit)).Find(&buildings)
+	if len(buildings) == 0 {
+		return nil, fmt.Errorf("no buildings found")
+	}
+	return buildings, nil
+}
+
+func (s *DataStore) TotalBuildings() (int64, error) {
+	var count int64
+	if tx := s.db.Find(&types.Building{}).Count(&count); tx.Error != nil {
+		return 0, tx.Error
+	}
+	return count, nil
+}
+
+func (s *DataStore) GetBuildingByID(id uint64) (*types.Building, error) {
+	var result types.Building
+	tx := s.db.Model(&types.Building{}).Where("id = ?", id).First(&result)
+	if tx.Error != nil {
+		return nil, fmt.Errorf("building %d not found", id)
+	}
+	return &result, nil
+}