new endpoint to return product list

app/utils/query/query_params/key_mapping.go

@@ -0,0 +1,43 @@
+package query_params
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+
+	mreflect "git.ma-al.com/goc_daniel/b2b/app/utils/reflect"
+)
+
+// MapParamsKeyToDbColumn will attempt to map provided key into unique (prefixed
+// with table) column name. It will do so using following priority of sources of
+// mapping:
+// 1. `formColumnMapping` argument. If the mapped values contain a dot, the part
+// before the dot will be used for the table name. Otherwise the table name will
+// be derived from the generic parameter `T`.
+// 2. json tags of provided as generic `T` struct. The table name will be also
+// derived from the generic if not provided as dot prefix.
+func MapParamsKeyToDbColumn[DEFAULT_TABLE_MODEL any](key string, mapping ...map[string]string) (string, error) {
+	ERR := "Failed to find appropiate mapping from form field to database column for key: '%s', and default table name: '%s'"
+
+	if len(mapping) > 0 {
+		if field, ok := (mapping[0])[key]; ok {
+			return field, nil
+		}
+	} else {
+		var t DEFAULT_TABLE_MODEL
+		if table, field, ok := strings.Cut(key, "."); ok {
+			if column, err := mreflect.GetGormColumnFromJsonField(field, reflect.TypeOf(t)); err == nil {
+				return table + "." + column, nil
+			}
+			return "", fmt.Errorf(ERR, key, table)
+		} else {
+			table := mreflect.GetTableName[DEFAULT_TABLE_MODEL]()
+			if column, err := mreflect.GetGormColumnFromJsonField(key, reflect.TypeOf(t)); err == nil {
+				return table + "." + column, nil
+			} else {
+				return "", fmt.Errorf(ERR, key, table)
+			}
+		}
+	}
+	return "", fmt.Errorf(ERR, key, mreflect.GetTableName[DEFAULT_TABLE_MODEL]())
+}