From c38395490d1ebd0ea2a51ef85b34f029f72e17b0 Mon Sep 17 00:00:00 2001
From: Alex Yatskov <alex@foosoft.net>
Date: Thu, 28 Dec 2017 13:10:50 -0800
Subject: [PATCH] allow setting nested metadata

---
 file.go      |  7 +++---
 goldsmith.go |  2 +-
 util.go      | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+), 5 deletions(-)

diff --git a/file.go b/file.go
index 6e12532..3145986 100644
--- a/file.go
+++ b/file.go
@@ -127,12 +127,11 @@ func (f *file) ModTime() time.Time {
 }
 
 func (f *file) Value(key string) (interface{}, bool) {
-	value, ok := f.Meta[key]
-	return value, ok
+	return getDelimValue(f.Meta, key)
 }
 
-func (f *file) SetValue(key string, value interface{}) {
-	f.Meta[key] = value
+func (f *file) SetValue(key string, value interface{}) bool {
+	return setDelimValue(f.Meta, key, value)
 }
 
 func (f *file) CopyValues(src File) {
diff --git a/goldsmith.go b/goldsmith.go
index 407cc7a..ce49920 100644
--- a/goldsmith.go
+++ b/goldsmith.go
@@ -51,7 +51,7 @@ type File interface {
 	ModTime() time.Time
 
 	Value(key string) (interface{}, bool)
-	SetValue(key string, value interface{})
+	SetValue(key string, value interface{}) bool
 	CopyValues(src File)
 
 	Read(p []byte) (int, error)
diff --git a/util.go b/util.go
index f5d0164..5c0d91c 100644
--- a/util.go
+++ b/util.go
@@ -25,6 +25,8 @@ package goldsmith
 import (
 	"os"
 	"path/filepath"
+	"reflect"
+	"strings"
 )
 
 type fileInfo struct {
@@ -55,3 +57,67 @@ func scanDir(root string, infos chan fileInfo) {
 		return nil
 	})
 }
+
+func setDelimValue(container interface{}, path string, data interface{}) bool {
+	containerVal := reflect.Indirect(reflect.ValueOf(container))
+
+	segments := strings.Split(path, ".")
+	segmentHead := segments[0]
+
+	if len(segments) > 1 {
+		var fieldVal reflect.Value
+		switch containerVal.Kind() {
+		case reflect.Map:
+			fieldVal = containerVal.MapIndex(reflect.ValueOf(segmentHead))
+		case reflect.Struct:
+			fieldVal = containerVal.FieldByName(segmentHead)
+			if fieldVal.CanAddr() {
+				fieldVal = fieldVal.Addr()
+			}
+		}
+
+		if fieldVal.IsValid() && fieldVal.CanInterface() {
+			pathRest := strings.Join(segments[1:], ".")
+			return setDelimValue(fieldVal.Interface(), pathRest, data)
+		}
+	} else {
+		switch containerVal.Kind() {
+		case reflect.Map:
+			containerVal.SetMapIndex(reflect.ValueOf(segmentHead), reflect.ValueOf(data))
+			return true
+		case reflect.Struct:
+			fieldVal := containerVal.FieldByName(segmentHead)
+			if fieldVal.CanSet() {
+				fieldVal.Set(reflect.ValueOf(data))
+				return true
+			}
+		}
+	}
+
+	return false
+}
+
+func getDelimValue(container interface{}, path string) (interface{}, bool) {
+	containerVal := reflect.Indirect(reflect.ValueOf(container))
+
+	segments := strings.Split(path, ".")
+	segmentHead := segments[0]
+
+	var fieldVal reflect.Value
+	switch containerVal.Kind() {
+	case reflect.Map:
+		fieldVal = containerVal.MapIndex(reflect.ValueOf(segmentHead))
+	case reflect.Struct:
+		fieldVal = containerVal.FieldByName(segmentHead)
+	}
+
+	if fieldVal.IsValid() && fieldVal.CanInterface() {
+		if len(segments) > 1 {
+			return getDelimValue(fieldVal.Interface(), strings.Join(segments[1:], "."))
+		}
+
+		return fieldVal.Interface(), true
+	}
+
+	return nil, false
+}