Variation fallback & add chartdata only difficulties to difficulty toolbox

Author: Lasercar

source/funkin/ui/debug/charting/handlers/ChartEditorImportExportHandler.hx

@@ -118,10 +118,16 @@ class ChartEditorImportExportHandler
     state.songMetadata = newSongMetadata;
     state.songChartData = newSongChartData;
 
-    if (!state.songMetadata.exists(state.selectedVariation))
+    var variationMetadata:Null<SongMetadata> = state.songMetadata.get(state.selectedVariation);
+    if (variationMetadata == null)
     {
-      state.selectedVariation = Constants.DEFAULT_VARIATION;
+      // Use the default variation, or the first available variation if that doesn't exist for some reason.
+      if (state.availableDifficulties.indexOf(Constants.DEFAULT_VARIATION) < 0) state.selectedVariation = state.availableVariations[0];
+      else state.selectedVariation = Constants.DEFAULT_VARIATION;
+
+      variationMetadata = state.songMetadata.get(state.selectedVariation);
     }
+
     // Use the first available difficulty as a fallback if the currently selected one cannot be found.
     if (state.availableDifficulties.indexOf(state.selectedDifficulty) < 0) state.selectedDifficulty = state.availableDifficulties[0];
 

source/funkin/ui/debug/charting/toolboxes/ChartEditorDifficultyToolbox.hx

@@ -4,6 +4,7 @@ import haxe.ui.components.Button;
 import haxe.ui.containers.dialogs.Dialogs;
 import haxe.ui.containers.dialogs.Dialog.DialogButton;
 import funkin.data.song.SongData.SongMetadata;
+import funkin.data.song.SongData.SongChartData;
 import funkin.util.FileUtil;
 import haxe.ui.containers.dialogs.MessageBox.MessageBoxType;
 import funkin.play.song.SongSerializer;
@@ -133,6 +134,16 @@ class ChartEditorDifficultyToolbox extends ChartEditorBaseToolbox
 
       var difficultyList:Array<String> = variationMetadata.playData.difficulties;
 
+      var variationChartdata:Null<SongChartData> = chartEditorState.songChartData.get(curVariation);
+      if(variationChartdata != null)
+      {
+        var keys:Array<String> = [for (x in variationChartdata.notes.keys()) x];
+        for (key in keys)
+          {
+            difficultyList.pushUnique(key);
+          }
+      }
+
       for (difficulty in difficultyList)
       {
         var _treeDifficulty:TreeViewNode = treeVariation.addNode(