catching errors

app/repos/productsRepo/productsRepo.go

@@ -10,6 +10,7 @@ import (
 	"git.ma-al.com/goc_daniel/b2b/app/model/dbmodel"
 	"git.ma-al.com/goc_daniel/b2b/app/utils/query/filters"
 	"git.ma-al.com/goc_daniel/b2b/app/utils/query/find"
+	"git.ma-al.com/goc_daniel/b2b/app/utils/responseErrors"
 	"git.ma-al.com/goc_marek/gormcol"
 	"github.com/WinterYukky/gorm-extra-clause-plugin/exclause"
 )
@@ -129,6 +130,29 @@ func (repo *ProductsRepo) Find(id_lang, userID uint, p find.Paging, filt *filter
 }
 
 func (repo *ProductsRepo) AddToFavorites(userID uint, productID uint) error {
+	var count int64
+	err := db.Get().
+		Table(dbmodel.TableNamePsProduct).
+		Where(dbmodel.PsProductCols.IDProduct.Col()+" = ?", productID).
+		Count(&count).Error
+	if err != nil {
+		return err
+	}
+	if count == 0 {
+		return responseErrors.ErrProductNotFound
+	}
+
+	err = db.Get().
+		Table("b2b_favorites").
+		Where("user_id = ? AND product_id = ?", userID, productID).
+		Count(&count).Error
+	if err != nil {
+		return err
+	}
+	if count > 0 {
+		return responseErrors.ErrAlreadyInFavorites
+	}
+
 	fav := model.B2bFavorite{
 		UserID:    userID,
 		ProductID: productID,