feat: profit sharing

internal/repository/product_repository.go

@@ -101,6 +101,8 @@ func (r *ProductRepositoryImpl) List(ctx context.Context, filters map[string]int
 			query = query.Where("price >= ?", value)
 		case "price_max":
 			query = query.Where("price <= ?", value)
+		case "category_id":
+			query = query.Where("category_id IN (?)", r.categoryAndChildrenIDs(value))
 		default:
 			query = query.Where(key+" = ?", value)
 		}
@@ -114,6 +116,15 @@ func (r *ProductRepositoryImpl) List(ctx context.Context, filters map[string]int
 	return products, total, err
 }
 
+// categoryAndChildrenIDs builds a subquery resolving to the category itself plus its
+// direct children, so filtering by a parent category also returns the children's
+// products. For a category without children it resolves to just that category.
+func (r *ProductRepositoryImpl) categoryAndChildrenIDs(categoryID interface{}) *gorm.DB {
+	return r.db.Model(&entities.Category{}).
+		Select("id").
+		Where("id = ? OR parent_id = ?", categoryID, categoryID)
+}
+
 func (r *ProductRepositoryImpl) Count(ctx context.Context, filters map[string]interface{}) (int64, error) {
 	var count int64
 	query := r.db.WithContext(ctx).Model(&entities.Product{})
@@ -127,6 +138,8 @@ func (r *ProductRepositoryImpl) Count(ctx context.Context, filters map[string]in
 			query = query.Where("price >= ?", value)
 		case "price_max":
 			query = query.Where("price <= ?", value)
+		case "category_id":
+			query = query.Where("category_id IN (?)", r.categoryAndChildrenIDs(value))
 		default:
 			query = query.Where(key+" = ?", value)
 		}
@@ -232,6 +245,8 @@ func (r *ProductRepositoryImpl) ListWithOutletPrice(ctx context.Context, filters
 			query = query.Where("products.price >= ?", value)
 		case "price_max":
 			query = query.Where("products.price <= ?", value)
+		case "category_id":
+			query = query.Where("products.category_id IN (?)", r.categoryAndChildrenIDs(value))
 		default:
 			query = query.Where("products."+key+" = ?", value)
 		}