fix: keep favorite collection cursor valid

Author: anqtal

Assets/Scripts/Misc/Collections/MyFavoriteSongCollection.cs

@@ -27,6 +27,8 @@ public MyFavoriteSongCollection(List<ISongDetail> dataSet, HashSet<string> hashS
 
         public void Add(ISongDetail item)
         {
+            NormalizeIndex();
+            var currentHash = IsEmpty ? null : Current.Hash;
             if (!_hashSet.Add(item.Hash))
             {
                 return;
@@ -43,11 +45,19 @@ public void Add(ISongDetail item)
                 sorted.Add(item);
                 Sorted = sorted.ToArray();
             }
+            NormalizeIndex();
+            if (currentHash is not null)
+            {
+                SetCursor(currentHash);
+            }
         }
         public void Clear()
         {
             _dataSet.Clear();
             _hashSet.Clear();
+            Origin = Array.Empty<ISongDetail>();
+            Sorted = Origin;
+            NormalizeIndex();
         }
         public bool Contains(ISongDetail item)
         {
@@ -63,26 +73,12 @@ public void CopyTo(ISongDetail[] array, int arrayIndex)
         }
         public bool Remove(ISongDetail item)
         {
-            if(!_hashSet.Remove(item.Hash))
-            {
-                return false;
-            }
-            _dataSet.Remove(item);
-            Origin = _dataSet.ToArray();
-            if (!IsSorted)
-            {
-                Sorted = Origin;
-            }
-            else if (Sorted.Any(x => x.Hash == item.Hash))
-            {
-                var sorted = new List<ISongDetail>(Sorted);
-                sorted.Remove(item);
-                Sorted = sorted.ToArray();
-            }
-            return true;
+            return Remove(item.Hash);
         }
         public bool Remove(string hashBase64Str)
         {
+            NormalizeIndex();
+            var currentHash = IsEmpty ? null : Current.Hash;
             if (!_hashSet.Remove(hashBase64Str))
             {
                 return false;
@@ -98,6 +94,15 @@ public bool Remove(string hashBase64Str)
             {
                 Sorted = Origin;
             }
+            else
+            {
+                Sorted = Sorted.Where(x => x.Hash != hashBase64Str).ToArray();
+            }
+            NormalizeIndex();
+            if (currentHash is not null && currentHash != hashBase64Str)
+            {
+                SetCursor(currentHash);
+            }
             return true;
         }
         public HashSet<string> ExportHashSet()

Assets/Scripts/Misc/Collections/SongCollection.cs

@@ -32,7 +32,7 @@ public int Index
                 {
                     throw new ArgumentOutOfRangeException("this collection is empty");
                 }
-                _index = value.Clamp(0, Origin.Length - 1);
+                _index = value.Clamp(0, Sorted.Length - 1);
             }
         }
         public ISongDetail this[int index]
@@ -167,6 +167,7 @@ public void Move(int diff)
         }
         public void SortAndFilter(SongOrder orderBy)
         {
+            NormalizeIndex();
             if(Type == ChartStorageType.Dan || IsEmpty)
             {
                 return;
@@ -184,6 +185,7 @@ public async Task SortAndFilterAsync(SongOrder orderBy)
         }
         public void Reset()
         {
+            NormalizeIndex();
             if (!IsSorted)
             {
                 return;
@@ -201,6 +203,15 @@ public void Reset()
             }
             Sorted = Origin;
         }
+        protected void NormalizeIndex()
+        {
+            if (IsEmpty)
+            {
+                _index = 0;
+                return;
+            }
+            _index = _index.Clamp(0, Sorted.Length - 1);
+        }
         public void SetCursor(ISongDetail target)
         {
             if (IsEmpty)