From 6c31d2be4432b07c925296c9269c53411addae2b Mon Sep 17 00:00:00 2001
From: Mira <56395159+TheXorog@users.noreply.github.com>
Date: Mon, 3 Oct 2022 12:43:42 +0200
Subject: [PATCH] Add ObservableList

---
 Entities/ObservableList.cs       | 106 +++++++++++++++++++++++++++++++
 Entities/ObservableListUpdate.cs |   9 +++
 2 files changed, 115 insertions(+)
 create mode 100644 Entities/ObservableList.cs
 create mode 100644 Entities/ObservableListUpdate.cs

diff --git a/Entities/ObservableList.cs b/Entities/ObservableList.cs
new file mode 100644
index 0000000..45d5b90
--- /dev/null
+++ b/Entities/ObservableList.cs
@@ -0,0 +1,106 @@
+using System.Collections;
+
+namespace Xorog.UniversalExtensions.Entities;
+
+public class ObservableList<T> : IList<T>
+{
+    private List<T> _items = new();
+
+    public event EventHandler<ObservableListUpdate<T>>? ItemsChanged;
+
+    public T this[int index] { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
+
+    public int Count => _items.Count;
+
+    public bool IsReadOnly => false;
+
+    public void Add(T item)
+    {
+        _ = Task.Run(() =>
+        {
+            this.ItemsChanged?.Invoke(null, new ObservableListUpdate<T>
+            {
+               List = this,
+               NewItems = new List<T>() { item },
+               RemovedItems = null
+            });
+        });
+
+        _items.Add(item);
+    }
+
+    public void Insert(int index, T item)
+    {
+        _ = Task.Run(() =>
+        {
+            this.ItemsChanged?.Invoke(null, new ObservableListUpdate<T>
+            {
+                List = this,
+                NewItems = new List<T>() { item },
+                RemovedItems = null
+            });
+        });
+
+        _items.Insert(index, item);
+    }
+
+    public void Clear()
+    {
+        _ = Task.Run(() =>
+        {
+            this.ItemsChanged?.Invoke(null, new ObservableListUpdate<T>
+            {
+                List = this,
+                NewItems = null,
+                RemovedItems = _items.ToList()
+            });
+        });
+
+        _items.Clear();
+    }
+
+    public void RemoveAt(int index)
+    {
+        _ = Task.Run(() =>
+        {
+            this.ItemsChanged?.Invoke(null, new ObservableListUpdate<T>
+            {
+                List = this,
+                NewItems = null,
+                RemovedItems = new List<T>() { _items.ElementAt(index) }
+            });
+        });
+
+        _items.RemoveAt(index);
+    }
+
+    public bool Remove(T item)
+    {
+        _ = Task.Run(() =>
+        {
+            this.ItemsChanged?.Invoke(null, new ObservableListUpdate<T>
+            {
+                List = this,
+                NewItems = null,
+                RemovedItems = new List<T>() { item }
+            });
+        });
+
+        return _items.Remove(item);
+    }
+
+    public bool Contains(T item)
+        => _items.Contains(item);
+
+    public void CopyTo(T[] array, int arrayIndex)
+        => _items.CopyTo(array, arrayIndex);
+
+    public IEnumerator<T> GetEnumerator()
+        => _items.GetEnumerator();
+
+    public int IndexOf(T item)
+        => _items.IndexOf(item);
+
+    IEnumerator IEnumerable.GetEnumerator() 
+        => _items.GetEnumerator();
+}
diff --git a/Entities/ObservableListUpdate.cs b/Entities/ObservableListUpdate.cs
new file mode 100644
index 0000000..27e1f49
--- /dev/null
+++ b/Entities/ObservableListUpdate.cs
@@ -0,0 +1,9 @@
+namespace Xorog.UniversalExtensions.Entities;
+
+public class ObservableListUpdate<T>
+{
+    public ObservableList<T>? List { get; internal set; }
+
+    public IReadOnlyList<T>? NewItems { get; internal set; }
+    public IReadOnlyList<T>? RemovedItems { get; internal set; }
+}