refactor: use dtos in controllers

backend/internal/dto/dto_mapper.go

@@ -0,0 +1,79 @@
+package dto
+
+import (
+	"errors"
+	"reflect"
+)
+
+// MapStructList maps a list of source structs to a list of destination structs
+func MapStructList[S any, D any](source []S, destination *[]D) error {
+	for _, item := range source {
+		var destItem D
+		if err := MapStruct(item, &destItem); err != nil {
+			return err
+		}
+		*destination = append(*destination, destItem)
+	}
+	return nil
+}
+
+// MapStruct maps a source struct to a destination struct
+func MapStruct[S any, D any](source S, destination *D) error {
+	// Ensure destination is a non-nil pointer
+	destValue := reflect.ValueOf(destination)
+	if destValue.Kind() != reflect.Ptr || destValue.IsNil() {
+		return errors.New("destination must be a non-nil pointer to a struct")
+	}
+
+	// Ensure source is a struct
+	sourceValue := reflect.ValueOf(source)
+	if sourceValue.Kind() != reflect.Struct {
+		return errors.New("source must be a struct")
+	}
+
+	return mapStructInternal(sourceValue, destValue.Elem())
+}
+
+func mapStructInternal(sourceVal reflect.Value, destVal reflect.Value) error {
+	// Loop through the fields of the destination struct
+	for i := 0; i < destVal.NumField(); i++ {
+		destField := destVal.Field(i)
+		destFieldType := destVal.Type().Field(i)
+
+		if destFieldType.Anonymous {
+			// Recursively handle embedded structs
+			if err := mapStructInternal(sourceVal, destField); err != nil {
+				return err
+			}
+			continue
+		}
+
+		sourceField := sourceVal.FieldByName(destFieldType.Name)
+
+		// If the source field is valid and can be assigned to the destination field
+		if sourceField.IsValid() && destField.CanSet() {
+			// Handle direct assignment for simple types
+			if sourceField.Type() == destField.Type() {
+				destField.Set(sourceField)
+			} else if sourceField.Kind() == reflect.Slice && destField.Kind() == reflect.Slice {
+				// Handle slices
+				if sourceField.Type().Elem() == destField.Type().Elem() {
+					newSlice := reflect.MakeSlice(destField.Type(), sourceField.Len(), sourceField.Cap())
+
+					for j := 0; j < sourceField.Len(); j++ {
+						newSlice.Index(j).Set(sourceField.Index(j))
+					}
+
+					destField.Set(newSlice)
+				}
+			} else if sourceField.Kind() == reflect.Struct && destField.Kind() == reflect.Struct {
+				// Recursively map nested structs
+				if err := mapStructInternal(sourceField, destField); err != nil {
+					return err
+				}
+			}
+		}
+	}
+
+	return nil
+}