Add drag-and-drop ordering for command buttons

src/main/java/work/msdnicrosoft/commandbuttons/data/CommandDestination.java

@@ -1,12 +1,12 @@
 package work.msdnicrosoft.commandbuttons.data;
 
-import io.github.cottonmc.cotton.gui.widget.WButton;
 import io.github.cottonmc.cotton.gui.widget.WPlainPanel;
 import lombok.Getter;
+import work.msdnicrosoft.commandbuttons.gui.DraggableButton;
 
 public class CommandDestination extends WPlainPanel {
     @Getter
-    WButton button = new WButton();
+    DraggableButton button = new DraggableButton();
 
     public CommandDestination() {
         //#if MC > 11605

src/main/java/work/msdnicrosoft/commandbuttons/gui/CommandGUI.java

@@ -65,6 +65,15 @@ private void createCommandPanel() {
 
     private void defBtnBehavior(@NotNull CommandItem item, @NotNull CommandDestination destination) {
         destination.getButton().setLabel(ComponentUtil.literal(item.getDisplayName()));
+        destination.getButton().setOnDrag((x, y) -> this.commandPanel.move(
+                item,
+                destination.getX() + destination.getButton().getX() + x,
+                destination.getY() + destination.getButton().getY() + y
+        ));
+        destination.getButton().setOnDragEnd(() -> {
+            ConfigManager.save();
+            this.commandPanel.layout();
+        });
         destination.getButton().setOnClick(() -> {
             if (this.editBtn.getToggle()) {
                 CommandEditGUI gui = new CommandEditGUI(item, true);

src/main/java/work/msdnicrosoft/commandbuttons/gui/CommandListPanel.java

@@ -21,6 +21,44 @@ public CommandListPanel(List<D> data, Supplier<W> supplier, BiConsumer<D, W> con
         this.search = search;
     }
 
+    private List<D> getVisibleData() {
+        List<D> visibleData = Lists.newArrayList(this.data);
+        if (!this.search.getText().isEmpty()) {
+            visibleData = visibleData.stream()
+                    .filter(d -> ((CommandItem) d).getDisplayName().contains(this.search.getText().trim()))
+                    .collect(Collectors.toList());
+        }
+        return visibleData;
+    }
+
+    /**
+     * Moves an item to the grid cell currently underneath the mouse pointer.
+     * The backing list is the same list ConfigManager serializes, so its order is persistent.
+     */
+    public void move(D dragged, int mouseX, int mouseY) {
+        List<D> visibleData = this.getVisibleData();
+        if (visibleData.size() < 2 || !visibleData.contains(dragged)) {
+            return;
+        }
+
+        int column = Math.max(0, Math.min(mouseX / 83, 3));
+        int row = Math.max(mouseY / 22, 0);
+        int visibleIndex = this.scrollBar.getValue() + row * 4 + column;
+        visibleIndex = Math.min(visibleIndex, visibleData.size() - 1);
+
+        D target = visibleData.get(visibleIndex);
+        if (dragged == target) {
+            return;
+        }
+
+        int targetIndex = this.data.indexOf(target);
+        if (targetIndex < 0 || !this.data.remove(dragged)) {
+            return;
+        }
+        this.data.add(Math.min(targetIndex, this.data.size()), dragged);
+        this.layout();
+    }
+
     /**
      * Modified from LibGui
      */
@@ -52,12 +90,7 @@ public void layout() {
         int layoutHeight = this.getHeight() - 4;
         int cellsHigh = Math.max((layoutHeight + 2) / (cellHeight + 2), 1);
 
-        List<D> data = Lists.newArrayList(this.data);
-        if (!this.search.getText().isEmpty()) {
-            data = data.stream()
-                    .filter(d -> ((CommandItem) d).getDisplayName().contains(this.search.getText().trim()))
-                    .collect(Collectors.toList());
-        }
+        List<D> data = this.getVisibleData();
 
         scrollBar.setWindow(cellsHigh);
         scrollBar.setMaxValue(data.size() > 32 ? data.size() - 8 : 8);

src/main/java/work/msdnicrosoft/commandbuttons/gui/DraggableButton.java

@@ -0,0 +1,147 @@
+package work.msdnicrosoft.commandbuttons.gui;
+
+import io.github.cottonmc.cotton.gui.widget.WButton;
+//#if MC >= 12109
+import net.minecraft.client.input.MouseButtonEvent;
+//#endif
+//#if MC > 11605
+import io.github.cottonmc.cotton.gui.widget.data.InputResult;
+//#else
+//$$ import io.github.cottonmc.cotton.gui.widget.WWidget;
+//#endif
+
+import java.util.function.BiConsumer;
+
+/**
+ * A regular LibGui button that also reports intentional drag gestures.
+ * Small mouse movements are kept as normal button clicks.
+ */
+public class DraggableButton extends WButton {
+    private static final double DRAG_THRESHOLD = 3.0D;
+
+    private BiConsumer<Integer, Integer> onDrag;
+    private Runnable onDragEnd;
+    private double draggedX;
+    private double draggedY;
+    private boolean dragging;
+    private boolean suppressNextClick;
+
+    public DraggableButton setOnDrag(BiConsumer<Integer, Integer> onDrag) {
+        this.onDrag = onDrag;
+        return this;
+    }
+
+    public DraggableButton setOnDragEnd(Runnable onDragEnd) {
+        this.onDragEnd = onDragEnd;
+        return this;
+    }
+
+    private void beginPointerInteraction() {
+        this.draggedX = 0.0D;
+        this.draggedY = 0.0D;
+        this.dragging = false;
+        this.suppressNextClick = false;
+    }
+
+    private void drag(int x, int y, double deltaX, double deltaY) {
+        this.draggedX += deltaX;
+        this.draggedY += deltaY;
+        if (!this.dragging && this.draggedX * this.draggedX + this.draggedY * this.draggedY
+                >= DRAG_THRESHOLD * DRAG_THRESHOLD) {
+            this.dragging = true;
+        }
+        if (this.dragging && this.onDrag != null) {
+            this.onDrag.accept(x, y);
+        }
+    }
+
+    private void endPointerInteraction() {
+        this.suppressNextClick = this.dragging;
+        if (this.dragging && this.onDragEnd != null) {
+            this.onDragEnd.run();
+        }
+        this.dragging = false;
+    }
+
+    //#if MC >= 12109
+    @Override
+    public InputResult onMouseDown(MouseButtonEvent click, boolean doubled) {
+        this.beginPointerInteraction();
+        return super.onMouseDown(click, doubled);
+    }
+
+    @Override
+    public InputResult onMouseDrag(MouseButtonEvent click, double offsetX, double offsetY) {
+        this.drag((int) click.x(), (int) click.y(), offsetX, offsetY);
+        return this.dragging ? InputResult.PROCESSED : super.onMouseDrag(click, offsetX, offsetY);
+    }
+
+    @Override
+    public InputResult onMouseUp(MouseButtonEvent click) {
+        this.endPointerInteraction();
+        return super.onMouseUp(click);
+    }
+
+    @Override
+    public InputResult onClick(MouseButtonEvent click, boolean doubled) {
+        if (this.suppressNextClick) {
+            this.suppressNextClick = false;
+            return InputResult.PROCESSED;
+        }
+        return super.onClick(click, doubled);
+    }
+    //#elseif MC > 11605
+    //$$ @Override
+    //$$ public InputResult onMouseDown(int x, int y, int button) {
+    //$$     this.beginPointerInteraction();
+    //$$     return super.onMouseDown(x, y, button);
+    //$$ }
+    //$$
+    //$$ @Override
+    //$$ public InputResult onMouseDrag(int x, int y, int button, double deltaX, double deltaY) {
+    //$$     this.drag(x, y, deltaX, deltaY);
+    //$$     return this.dragging ? InputResult.PROCESSED : super.onMouseDrag(x, y, button, deltaX, deltaY);
+    //$$ }
+    //$$
+    //$$ @Override
+    //$$ public InputResult onMouseUp(int x, int y, int button) {
+    //$$     this.endPointerInteraction();
+    //$$     return super.onMouseUp(x, y, button);
+    //$$ }
+    //$$
+    //$$ @Override
+    //$$ public InputResult onClick(int x, int y, int button) {
+    //$$     if (this.suppressNextClick) {
+    //$$         this.suppressNextClick = false;
+    //$$         return InputResult.PROCESSED;
+    //$$     }
+    //$$     return super.onClick(x, y, button);
+    //$$ }
+    //#else
+    //$$ @Override
+    //$$ public WWidget onMouseDown(int x, int y, int button) {
+    //$$     this.beginPointerInteraction();
+    //$$     return super.onMouseDown(x, y, button);
+    //$$ }
+    //$$
+    //$$ @Override
+    //$$ public void onMouseDrag(int x, int y, int button, double deltaX, double deltaY) {
+    //$$     this.drag(x, y, deltaX, deltaY);
+    //$$ }
+    //$$
+    //$$ @Override
+    //$$ public WWidget onMouseUp(int x, int y, int button) {
+    //$$     this.endPointerInteraction();
+    //$$     return super.onMouseUp(x, y, button);
+    //$$ }
+    //$$
+    //$$ @Override
+    //$$ public void onClick(int x, int y, int button) {
+    //$$     if (this.suppressNextClick) {
+    //$$         this.suppressNextClick = false;
+    //$$         return;
+    //$$     }
+    //$$     super.onClick(x, y, button);
+    //$$ }
+    //#endif
+}