initial commit

pkg/helper/struct.go

@@ -0,0 +1,79 @@
+package helper
+
+import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"strings"
+)
+
+func MapToStruct(source map[string]interface{}, target interface{}) error {
+	jsonBytes, err := json.Marshal(source)
+	if err != nil {
+		return err
+	}
+
+	err = json.Unmarshal(jsonBytes, target)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// StructToMap converts a struct to a map[string]interface{}
+// Uses json tag name as key when available, so keys match validation schema (e.g. "provider" not "Provider")
+// does not support nested structs
+func StructToMap(v any) map[string]interface{} {
+	result := make(map[string]interface{})
+	val := reflect.ValueOf(v)
+	typ := reflect.TypeOf(v)
+
+	if val.Kind() == reflect.Ptr {
+		val = val.Elem()
+		typ = typ.Elem()
+	}
+
+	for i := 0; i < val.NumField(); i++ {
+		field := typ.Field(i)
+		value := val.Field(i)
+
+		// Skip unexported fields
+		if !value.CanInterface() {
+			continue
+		}
+
+		key := field.Name
+		if tag := field.Tag.Get("json"); tag != "" {
+			// Use first part before comma (e.g. "provider,omitempty" -> "provider")
+			if name := strings.TrimSpace(strings.Split(tag, ",")[0]); name != "" && name != "-" {
+				key = name
+			}
+		}
+		fieldVal := value.Interface()
+		// If type implements String(), use it so validation gets string (e.g. oauth.Provider -> "mock")
+		// Use reflect to detect nil pointer - s != nil passes for interface holding (*T)(nil)
+		if s, ok := fieldVal.(fmt.Stringer); ok {
+			if isNilValue(value) {
+				result[key] = fieldVal // keep nil/zero for optional fields
+			} else {
+				result[key] = s.String()
+			}
+		} else {
+			result[key] = fieldVal
+		}
+	}
+
+	return result
+}
+
+// isNilValue returns true if v is nil (ptr, slice, map, chan, func, interface).
+// Used to avoid calling String() on nil receivers (e.g. *uuid.UUID).
+func isNilValue(v reflect.Value) bool {
+	switch v.Kind() {
+	case reflect.Ptr, reflect.Slice, reflect.Map, reflect.Chan, reflect.Func, reflect.Interface:
+		return v.IsNil()
+	default:
+		return false
+	}
+}