From 466017c10224c4229fbb8b7691c757835f65485a Mon Sep 17 00:00:00 2001
From: bd_ <bd_@nadena.dev>
Date: Mon, 2 Sep 2024 19:30:40 -0700
Subject: [PATCH] feat: add support for drag-and-drop on the MA Object Toggle
 inspector (#1087)

---
 .../ObjectToggle/ObjectSwitcherEditor.cs      | 100 ++++++++++++++++++
 .../ObjectToggle/ObjectSwitcherStyles.uss     |   4 +
 2 files changed, 104 insertions(+)

diff --git a/Editor/Inspector/ObjectToggle/ObjectSwitcherEditor.cs b/Editor/Inspector/ObjectToggle/ObjectSwitcherEditor.cs
index e954dda7..8807e221 100644
--- a/Editor/Inspector/ObjectToggle/ObjectSwitcherEditor.cs
+++ b/Editor/Inspector/ObjectToggle/ObjectSwitcherEditor.cs
@@ -1,6 +1,7 @@
 #region
 
 using System;
+using System.Linq;
 using UnityEditor;
 using UnityEditor.UIElements;
 using UnityEngine;
@@ -16,6 +17,7 @@ namespace nadena.dev.modular_avatar.core.editor.ShapeChanger
         [SerializeField] private StyleSheet uss;
         [SerializeField] private VisualTreeAsset uxml;
 
+        private DragAndDropManipulator _dragAndDropManipulator;
 
         protected override void OnInnerInspectorGUI()
         {
@@ -33,11 +35,109 @@ namespace nadena.dev.modular_avatar.core.editor.ShapeChanger
             ROSimulatorButton.BindRefObject(root, target);
 
             var listView = root.Q<ListView>("Shapes");
+            _dragAndDropManipulator = new DragAndDropManipulator(listView)
+            {
+                TargetComponent = target as ModularAvatarObjectToggle
+            };
 
             listView.showBoundCollectionSize = false;
             listView.virtualizationMethod = CollectionVirtualizationMethod.DynamicHeight;
 
             return root;
         }
+
+        private void OnEnable()
+        {
+            if (_dragAndDropManipulator != null)
+                _dragAndDropManipulator.TargetComponent = target as ModularAvatarObjectToggle;
+        }
+
+        private class DragAndDropManipulator : PointerManipulator
+        {
+            public ModularAvatarObjectToggle TargetComponent;
+            private GameObject[] _nowDragging = Array.Empty<GameObject>();
+            private Transform _avatarRoot;
+
+            private readonly VisualElement _parentElem;
+
+            public DragAndDropManipulator(VisualElement target)
+            {
+                this.target = target;
+                _parentElem = target.parent;
+            }
+
+            protected override void RegisterCallbacksOnTarget()
+            {
+                target.RegisterCallback<DragEnterEvent>(OnDragEnter);
+                target.RegisterCallback<DragLeaveEvent>(OnDragLeave);
+                target.RegisterCallback<DragPerformEvent>(OnDragPerform);
+                target.RegisterCallback<DragUpdatedEvent>(OnDragUpdate);
+            }
+
+            protected override void UnregisterCallbacksFromTarget()
+            {
+                target.UnregisterCallback<DragEnterEvent>(OnDragEnter);
+                target.UnregisterCallback<DragLeaveEvent>(OnDragLeave);
+                target.UnregisterCallback<DragPerformEvent>(OnDragPerform);
+                target.RegisterCallback<DragUpdatedEvent>(OnDragUpdate);
+            }
+
+
+            private void OnDragEnter(DragEnterEvent evt)
+            {
+                if (TargetComponent == null) return;
+
+                _avatarRoot = RuntimeUtil.FindAvatarTransformInParents(TargetComponent.transform);
+                if (_avatarRoot == null) return;
+
+                _nowDragging = DragAndDrop.objectReferences.OfType<GameObject>()
+                    .Where(o => RuntimeUtil.FindAvatarTransformInParents(o.transform) == _avatarRoot)
+                    .ToArray();
+
+                if (_nowDragging.Length > 0)
+                {
+                    DragAndDrop.visualMode = DragAndDropVisualMode.Link;
+
+                    _parentElem.AddToClassList("drop-area--drag-active");
+                }
+            }
+
+            private void OnDragUpdate(DragUpdatedEvent _)
+            {
+                if (_nowDragging.Length > 0) DragAndDrop.visualMode = DragAndDropVisualMode.Link;
+            }
+
+            private void OnDragLeave(DragLeaveEvent evt)
+            {
+                _nowDragging = Array.Empty<GameObject>();
+                _parentElem.RemoveFromClassList("drop-area--drag-active");
+            }
+
+            private void OnDragPerform(DragPerformEvent evt)
+            {
+                if (_nowDragging.Length > 0 && TargetComponent != null && _avatarRoot != null)
+                {
+                    var knownObjs = TargetComponent.Objects.Select(o => o.Object.Get(TargetComponent)).ToHashSet();
+
+                    Undo.RecordObject(TargetComponent, "Add Toggled Objects");
+                    foreach (var obj in _nowDragging)
+                    {
+                        if (knownObjs.Contains(obj)) continue;
+
+                        var aor = new AvatarObjectReference();
+                        aor.Set(obj);
+
+                        var toggledObject = new ToggledObject { Object = aor, Active = !obj.activeSelf };
+                        TargetComponent.Objects.Add(toggledObject);
+                    }
+
+                    EditorUtility.SetDirty(TargetComponent);
+                    PrefabUtility.RecordPrefabInstancePropertyModifications(TargetComponent);
+                }
+
+                _nowDragging = Array.Empty<GameObject>();
+                _parentElem.RemoveFromClassList("drop-area--drag-active");
+            }
+        }
     }
 }
\ No newline at end of file
diff --git a/Editor/Inspector/ObjectToggle/ObjectSwitcherStyles.uss b/Editor/Inspector/ObjectToggle/ObjectSwitcherStyles.uss
index db197753..133b6154 100644
--- a/Editor/Inspector/ObjectToggle/ObjectSwitcherStyles.uss
+++ b/Editor/Inspector/ObjectToggle/ObjectSwitcherStyles.uss
@@ -112,3 +112,7 @@
     flex-grow: 1;
     -unity-text-align: middle-left;
 }
+
+.drop-area--drag-active > ListView ScrollView {
+    background-color: rgba(0, 255, 255, 0.1);
+}
\ No newline at end of file