Unity Project

reference
https://cardgames.io/yahtzee/

Library/PackageCache/com.unity.timeline@1.2.15/Editor/Manipulators/Utils/EditModeReplaceUtils.cs

@@ -0,0 +1,57 @@
+using System.Collections.Generic;
+using System.Linq;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    static class EditModeReplaceUtils
+    {
+        public static void Insert(IEnumerable<ItemsPerTrack> itemsGroups)
+        {
+            foreach (var itemsGroup in itemsGroups)
+            {
+                Insert(itemsGroup.targetTrack, itemsGroup.items);
+            }
+        }
+
+        static void Insert(TrackAsset track, IEnumerable<ITimelineItem> items)
+        {
+            if (track == null) return;
+            var orderedItems = ItemsUtils.GetItemsExcept(track, items)
+                .OfType<ITrimmable>()
+                .OrderBy(i => i.start).ToArray();
+
+            foreach (var item in items.OfType<ITrimmable>())
+            {
+                var from = item.start;
+                var to = item.end;
+
+                var overlappedItems = orderedItems.Where(i => EditModeUtils.Overlaps(i, from, to));
+
+                foreach (var overlappedItem in overlappedItems)
+                {
+                    if (EditModeUtils.IsItemWithinRange(overlappedItem, from, to))
+                    {
+                        overlappedItem.Delete();
+                    }
+                    else
+                    {
+                        if (overlappedItem.start >= from)
+                            overlappedItem.TrimStart(to);
+                        else
+                            overlappedItem.TrimEnd(from);
+                    }
+                }
+
+                var includingItems = orderedItems.Where(c => c.start<from && c.end> to);
+                foreach (var includingItem in includingItems)
+                {
+                    var newItem = includingItem.CloneTo(track, includingItem.start) as ITrimmable;
+                    includingItem.TrimStart(to);
+                    if (newItem != null)
+                        newItem.SetEnd(from, false);
+                }
+            }
+        }
+    }
+}