fix existing function add reflect, slow but safe

dbHandler.go

@@ -245,13 +245,16 @@ func (dH *DBHandler) DeleteById(model any, ids ...uint) error {
 	}
 
 	dH.logger.Debug("deleteById", "delete ids "+fmt.Sprint(ids))
+	if !dH.Exists(model, "id", ids, false) {
+		return errors.New("no matching id(s) found")
+	}
 
 	// Always use Model() to avoid GORM’s “limit 1” safeguard
 	if err := dH.db.Model(model).Where("id IN ?", ids).Delete(nil).Error; err != nil {
 		return fmt.Errorf("delete failed: %w", err)
 	}
 
-	return nil
+	return err
 }
 
 // deleteByKey
@@ -282,53 +285,45 @@ func (dH *DBHandler) DeleteByKey(model any, key string, value any, LikeSearch bo
 	return dH.db.Where(key+" = ?", value).Delete(model).Error
 }
 
-// exists
-//
-// Description:
-//
-//	Checks whether a record exists matching the specified key/value filter.
-//
-// Behavior:
-//   - Performs a `First` query on the database.
-//   - If `LikeSearch` is true, performs a LIKE query.
-//   - Returns an error if the record does not exist or query fails.
-//
-// Parameters:
-//   - model:      Model struct type to search.
-//   - key:        Column name to filter by.
-//   - value:      Value to match.
-//   - LikeSearch: Whether to use wildcard search.
-//
-// Returns:
-//   - error: “no record found” or DB error.
-func (dH *DBHandler) Exists(model any, key string, value any, likeSearch bool) (err error) {
+func (dH *DBHandler) Exists(model any, key string, value any, likeSearch bool) (found bool) {
 	var query string
+	var args any
 
-	switch v := value.(type) {
-	case []string, []int, []uint, []int64, []uint64, []float64:
-		// Handle slice case — use IN clause
-		query = fmt.Sprintf("%s IN ?", key)
-	case string:
-		if likeSearch {
-			v = strings.ReplaceAll(v, "*", "%")
-			query = fmt.Sprintf("%s LIKE ?", key)
-			value = v
-		} else {
-			query = fmt.Sprintf("%s = ?", key)
+	// Detect LIKE and IN behavior
+	val := reflect.ValueOf(value)
+	isSlice := val.Kind() == reflect.Slice
+
+	switch {
+	case isSlice:
+		if val.Len() == 0 {
+			dH.logger.Error("Exists", fmt.Sprintf("empty slice for %s", key))
+			return false
 		}
+		query = fmt.Sprintf("%s IN ?", key)
+		args = value
+
+	case likeSearch:
+		str := strings.ReplaceAll(fmt.Sprint(value), "*", "%")
+		query = fmt.Sprintf("%s LIKE ?", key)
+		args = str
+
 	default:
-		// Handle any other single value (numbers, bools, etc.)
 		query = fmt.Sprintf("%s = ?", key)
+		args = value
 	}
 
-	dH.logger.Debug("exists", "check if exists key "+query+" value "+fmt.Sprint(value))
+	dH.logger.Debug("exists", "checking existence for key "+query+" value "+fmt.Sprint(args))
 
-	err = dH.db.Where(query, value).First(model).Error
-	if errors.Is(err, gorm.ErrRecordNotFound) {
-		return fmt.Errorf("no record found for %s %v", key, value)
-	} else if err != nil {
-		return fmt.Errorf("query failed: %w", err)
+	t := reflect.TypeOf(model)
+	if t.Kind() == reflect.Ptr {
+		t = t.Elem()
 	}
 
-	return nil
+	tx := dH.db.Where(query, args).Find(model)
+
+	if tx.Error != nil {
+		dH.logger.Error("Exists", fmt.Sprintf("query failed: %w", tx.Error))
+		return false
+	}
+	return tx.RowsAffected > 0
 }