From 3398f1d6526b78330b88d1d1e0661f3ba6eed689 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20D=C3=B6ll?= <sebastian@katallaxie.dev>
Date: Tue, 25 Jun 2024 09:59:53 +0000
Subject: [PATCH] wip: transform function

---
 transform.go      | 28 ++++++++++++++--------------
 transform_test.go | 22 +++++++++++-----------
 2 files changed, 25 insertions(+), 25 deletions(-)

diff --git a/transform.go b/transform.go
index f2c90ff..8ba9449 100644
--- a/transform.go
+++ b/transform.go
@@ -106,7 +106,7 @@ func Transform(name string, s interface{}) error {
 	return t.Transform(name, s)
 }
 
-// NewTransformer
+// NewTransformer ...
 func NewTransformer(opts ...TransformerOpt) *TransformerImpl {
 	t := new(TransformerImpl)
 	t.TagName = defaultTagName
@@ -126,6 +126,10 @@ func (t *TransformerImpl) Transform(name string, s interface{}) error {
 		return ErrNoPointer
 	}
 
+	if val.IsNil() {
+		return nil // bail out if nil
+	}
+
 	val = val.Elem()
 	if !val.CanAddr() {
 		return ErrNoAddressable
@@ -140,8 +144,6 @@ func (t *TransformerImpl) transform(val reflect.Value, field ...FieldLevel) erro
 
 	valKind := getKind(reflect.Indirect(val))
 
-	fmt.Println(field)
-
 	if len(field) > 0 {
 		valKind = getKind(field[0].Field())
 	}
@@ -151,8 +153,6 @@ func (t *TransformerImpl) transform(val reflect.Value, field ...FieldLevel) erro
 		err = t.transformType(field[0])
 	case reflect.Struct:
 		err = t.transformStruct(val)
-	case reflect.Interface:
-		return t.transform(reflect.ValueOf(val.Interface()))
 	default:
 		// we have to work on here for value to pointed to
 		return fmt.Errorf("transformer: unsupported type %s", valKind)
@@ -163,14 +163,18 @@ func (t *TransformerImpl) transform(val reflect.Value, field ...FieldLevel) erro
 
 // transcodeType
 func (t *TransformerImpl) transformType(field FieldLevel) error {
-	fmt.Println("transformType")
+	for _, f := range field.Funcs() {
+		fn, ok := internalTransformers[f]
+		if !ok {
+			return fmt.Errorf("transformer: function %s does not exist", f)
+		}
 
-	fn, ok := internalTransformers["trim"]
-	if !ok {
-		return nil
+		if err := fn(field); err != nil {
+			return err
+		}
 	}
 
-	return fn(field)
+	return nil
 }
 
 // transdecodeStruct
@@ -209,8 +213,6 @@ func (t *TransformerImpl) transformStruct(val reflect.Value) error {
 		tag := field.Tag.Get(t.TagName)
 		tag = strings.SplitN(tag, ",", 2)[0]
 
-		fmt.Println("here", val.CanAddr())
-
 		if !val.CanAddr() {
 			continue
 		}
@@ -230,8 +232,6 @@ func (t *TransformerImpl) transformStruct(val reflect.Value) error {
 			continue
 		}
 
-		fmt.Print("tag: ", tag, "\n")
-
 		if err := t.transform(val, f); err != nil {
 			return err
 		}
diff --git a/transform_test.go b/transform_test.go
index 88f3a40..a982a56 100644
--- a/transform_test.go
+++ b/transform_test.go
@@ -11,10 +11,14 @@ import (
 func TestStruct(t *testing.T) {
 	trans := transform.NewTransformer()
 
+	type testStruct struct {
+		Name string `transform:"trim"`
+	}
+
 	tests := []struct {
 		name string
-		in   interface{}
-		out  interface{}
+		in   *testStruct
+		out  *testStruct
 	}{
 		{
 			name: "nil",
@@ -23,19 +27,15 @@ func TestStruct(t *testing.T) {
 		},
 		{
 			name: "empty",
-			in:   struct{}{},
-			out:  struct{}{},
+			in:   &testStruct{},
+			out:  &testStruct{},
 		},
 		{
 			name: "string",
-			in: struct {
-				Name string `transform:"trim,lowercase"`
-			}{
+			in: &testStruct{
 				Name: "  test  ",
 			},
-			out: struct {
-				Name string `transform:"trim,lowercase"`
-			}{
+			out: &testStruct{
 				Name: "test",
 			},
 		},
@@ -43,7 +43,7 @@ func TestStruct(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			err := trans.Transform(tt.name, &tt.in)
+			err := trans.Transform(tt.name, tt.in)
 			require.NoError(t, err)
 			require.Equal(t, tt.out, tt.in)
 		})