Editor: Add 'Discard Changes' button

It got removed while merging the editor/viewer

lib/editors/common.dart

@@ -9,13 +9,14 @@ abstract class Editor {
   NoteCallback get exitEditorSelected;
   NoteCallback get renameNoteSelected;
   NoteCallback get moveNoteToFolderSelected;
+  NoteCallback get discardChangesSelected;
 }
 
 abstract class EditorState {
   Note getNote();
 }
 
-enum DropDownChoices { Rename, MoveToFolder }
+enum DropDownChoices { Rename, MoveToFolder, DiscardChanges }
 
 AppBar buildEditorAppBar(
   Editor editor,
@@ -58,6 +59,11 @@ AppBar buildEditorAppBar(
               var note = editorState.getNote();
               editor.moveNoteToFolderSelected(note);
               return;
+
+            case DropDownChoices.DiscardChanges:
+              var note = editorState.getNote();
+              editor.discardChangesSelected(note);
+              return;
           }
         },
         itemBuilder: (BuildContext context) =>
@@ -70,6 +76,10 @@ AppBar buildEditorAppBar(
             value: DropDownChoices.MoveToFolder,
             child: Text('Move to Folder'),
           ),
+          const PopupMenuItem<DropDownChoices>(
+            value: DropDownChoices.DiscardChanges,
+            child: Text('Discard Changes'),
+          ),
         ],
       ),
     ],

lib/editors/markdown_editor.dart

@@ -17,6 +17,8 @@ class MarkdownEditor extends StatefulWidget implements Editor {
   final NoteCallback renameNoteSelected;
   @override
   final NoteCallback moveNoteToFolderSelected;
+  @override
+  final NoteCallback discardChangesSelected;
 
   final bool autofocusOnEditor;
 
@@ -28,6 +30,7 @@ class MarkdownEditor extends StatefulWidget implements Editor {
     @required this.exitEditorSelected,
     @required this.renameNoteSelected,
     @required this.moveNoteToFolderSelected,
+    @required this.discardChangesSelected,
     this.autofocusOnEditor = false,
   }) : super(key: key);
 

lib/editors/raw_editor.dart

@@ -17,6 +17,8 @@ class RawEditor extends StatefulWidget implements Editor {
   final NoteCallback renameNoteSelected;
   @override
   final NoteCallback moveNoteToFolderSelected;
+  @override
+  final NoteCallback discardChangesSelected;
 
   RawEditor({
     Key key,
@@ -26,6 +28,7 @@ class RawEditor extends StatefulWidget implements Editor {
     @required this.exitEditorSelected,
     @required this.renameNoteSelected,
     @required this.moveNoteToFolderSelected,
+    @required this.discardChangesSelected,
   }) : super(key: key);
 
   @override

lib/editors/todo_editor.dart

@@ -16,6 +16,8 @@ class TodoEditor extends StatefulWidget implements Editor {
   final NoteCallback renameNoteSelected;
   @override
   final NoteCallback moveNoteToFolderSelected;
+  @override
+  final NoteCallback discardChangesSelected;
 
   TodoEditor({
     Key key,
@@ -25,6 +27,7 @@ class TodoEditor extends StatefulWidget implements Editor {
     @required this.exitEditorSelected,
     @required this.renameNoteSelected,
     @required this.moveNoteToFolderSelected,
+    @required this.discardChangesSelected,
   }) : super(key: key);
 
   @override

lib/screens/note_editor.dart

@@ -12,7 +12,7 @@ import 'package:gitjournal/utils.dart';
 import 'package:gitjournal/widgets/folder_selection_dialog.dart';
 import 'package:gitjournal/widgets/rename_dialog.dart';
 
-final todoEditorEnabled = false;
+final todoEditorEnabled = true;
 
 class NoteEditor extends StatefulWidget {
   final Note note;
@@ -77,6 +77,7 @@ class NoteEditorState extends State<NoteEditor> {
           exitEditorSelected: _exitEditorSelected,
           renameNoteSelected: _renameNoteSelected,
           moveNoteToFolderSelected: _moveNoteToFolderSelected,
+          discardChangesSelected: _discardChangesSelected,
           autofocusOnEditor: _isNewNote,
         );
       case EditorType.Raw:
@@ -88,6 +89,7 @@ class NoteEditorState extends State<NoteEditor> {
           exitEditorSelected: _exitEditorSelected,
           renameNoteSelected: _renameNoteSelected,
           moveNoteToFolderSelected: _moveNoteToFolderSelected,
+          discardChangesSelected: _discardChangesSelected,
         );
       case EditorType.Todo:
         return TodoEditor(
@@ -98,6 +100,7 @@ class NoteEditorState extends State<NoteEditor> {
           exitEditorSelected: _exitEditorSelected,
           renameNoteSelected: _renameNoteSelected,
           moveNoteToFolderSelected: _moveNoteToFolderSelected,
+          discardChangesSelected: _discardChangesSelected,
         );
     }
     return null;
@@ -262,4 +265,42 @@ class NoteEditorState extends State<NoteEditor> {
       stateContainer.moveNote(note, destFolder);
     }
   }
+
+  void _discardChangesSelected(Note note) {
+    if (_noteModified(note)) {
+      showDialog(context: context, builder: _buildDiscardChangesAlertDialog);
+    } else {
+      Navigator.pop(context);
+    }
+  }
+
+  Widget _buildDiscardChangesAlertDialog(BuildContext context) {
+    var title = _isNewNote
+        ? "Do you want to discard this?"
+        : "Do you want to ignore the changes?";
+
+    var editText = _isNewNote ? "Keep Writing" : "Keep Editing";
+    var discardText = _isNewNote ? "Discard" : "Discard Changes";
+
+    return AlertDialog(
+      title: Text(title),
+      actions: <Widget>[
+        FlatButton(
+          onPressed: () => Navigator.of(context).pop(false),
+          child: Text(editText),
+        ),
+        FlatButton(
+          onPressed: () {
+            // FIXME: This shouldn't be required. Why is the original note modified?
+            var serializer = MarkdownYAMLSerializer();
+            note.data = serializer.decode(noteSerialized);
+
+            Navigator.pop(context); // Alert box
+            Navigator.pop(context); // Note Editor
+          },
+          child: Text(discardText),
+        ),
+      ],
+    );
+  }
 }