From b71d030433d8065c2b26b5768913f989f274f6ef Mon Sep 17 00:00:00 2001
From: indigo-san <lugongdao07@gmail.com>
Date: Tue, 12 Sep 2023 21:06:35 +0900
Subject: [PATCH] =?UTF-8?q?=E8=A6=81=E7=B4=A0=E3=82=92=E5=88=86=E5=89=B2?=
 =?UTF-8?q?=E3=81=97=E3=81=9F=E3=81=A8=E3=81=8D=E3=80=81=E5=8B=95=E7=94=BB?=
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---
 .../Source/SourceVideoOperator.cs             | 31 +++++++++++++++++++
 .../ChangeSetterValueCommand.cs               | 29 +++++++++++++++++
 .../Operation/SourceOperation.cs              |  8 +++++
 .../Operation/SourceOperator.cs               | 16 ++++++++++
 src/Beutl/ViewModels/ElementViewModel.cs      |  4 +++
 5 files changed, 88 insertions(+)
 create mode 100644 src/Beutl.ProjectSystem/ChangeSetterValueCommand.cs

diff --git a/src/Beutl.Operators/Source/SourceVideoOperator.cs b/src/Beutl.Operators/Source/SourceVideoOperator.cs
index fe6a0b972..ddd83af34 100644
--- a/src/Beutl.Operators/Source/SourceVideoOperator.cs
+++ b/src/Beutl.Operators/Source/SourceVideoOperator.cs
@@ -54,4 +54,35 @@ protected override void OnAttachedToHierarchy(in HierarchyAttachmentEventArgs ar
             setter.Value = videoSource;
         }
     }
+
+    public override bool HasOriginalLength()
+    {
+        return Source.Value?.IsDisposed == false;
+    }
+
+    public override bool TryGetOriginalLength(out TimeSpan timeSpan)
+    {
+        if (Source.Value?.IsDisposed == false)
+        {
+            timeSpan = Source.Value.Duration - OffsetPosition.Value;
+            return true;
+        }
+        else
+        {
+            timeSpan = TimeSpan.Zero;
+            return false;
+        }
+    }
+
+    public override IRecordableCommand? OnSplit(bool backward, TimeSpan startDelta, TimeSpan lengthDelta)
+    {
+        if (backward)
+        {
+            return new ChangeSetterValueCommand<TimeSpan>(OffsetPosition, OffsetPosition.Value, OffsetPosition.Value + startDelta);
+        }
+        else
+        {
+            return base.OnSplit(backward, startDelta, lengthDelta);
+        }
+    }
 }
diff --git a/src/Beutl.ProjectSystem/ChangeSetterValueCommand.cs b/src/Beutl.ProjectSystem/ChangeSetterValueCommand.cs
new file mode 100644
index 000000000..23ae3d0f8
--- /dev/null
+++ b/src/Beutl.ProjectSystem/ChangeSetterValueCommand.cs
@@ -0,0 +1,29 @@
+using Beutl.Styling;
+
+namespace Beutl;
+
+public sealed class ChangeSetterValueCommand<T> : IRecordableCommand
+{
+    private readonly Setter<T> _setter;
+    private readonly T _oldValue;
+    private readonly T _newValue;
+
+    public ChangeSetterValueCommand(Setter<T> setter, T oldValue, T newValue)
+    {
+        _setter = setter;
+        _oldValue = oldValue;
+        _newValue = newValue;
+    }
+
+    public void Do()
+    {
+        _setter.Value = _newValue;
+    }
+
+    public void Redo() => Do();
+
+    public void Undo()
+    {
+        _setter.Value = _oldValue;
+    }
+}
diff --git a/src/Beutl.ProjectSystem/Operation/SourceOperation.cs b/src/Beutl.ProjectSystem/Operation/SourceOperation.cs
index 384a7de10..b2789544b 100644
--- a/src/Beutl.ProjectSystem/Operation/SourceOperation.cs
+++ b/src/Beutl.ProjectSystem/Operation/SourceOperation.cs
@@ -40,6 +40,14 @@ public SourceOperation()
     [NotAutoSerialized]
     public ICoreList<SourceOperator> Children => _children;
 
+    public IRecordableCommand OnSplit(bool backward, TimeSpan startDelta,TimeSpan lengthDelta)
+    {
+        return _children.Select(v => v.OnSplit(backward, startDelta, lengthDelta))
+            .Where(v => v != null)
+            .ToArray()!
+            .ToCommand();
+    }
+
     public override void ReadFromJson(JsonObject json)
     {
         base.ReadFromJson(json);
diff --git a/src/Beutl.ProjectSystem/Operation/SourceOperator.cs b/src/Beutl.ProjectSystem/Operation/SourceOperator.cs
index 2a42a6ae5..b99029622 100644
--- a/src/Beutl.ProjectSystem/Operation/SourceOperator.cs
+++ b/src/Beutl.ProjectSystem/Operation/SourceOperator.cs
@@ -86,6 +86,22 @@ public virtual void Exit()
     {
     }
 
+    public virtual bool HasOriginalLength()
+    {
+        return false;
+    }
+    
+    public virtual bool TryGetOriginalLength(out TimeSpan timeSpan)
+    {
+        timeSpan = default;
+        return false;
+    }
+
+    public virtual IRecordableCommand? OnSplit(bool backward, TimeSpan startDelta, TimeSpan lengthDelta)
+    {
+        return null;
+    }
+
     protected void RaiseInvalidated(RenderInvalidatedEventArgs args)
     {
         Invalidated?.Invoke(this, args);
diff --git a/src/Beutl/ViewModels/ElementViewModel.cs b/src/Beutl/ViewModels/ElementViewModel.cs
index c6388534c..aac63ba27 100644
--- a/src/Beutl/ViewModels/ElementViewModel.cs
+++ b/src/Beutl/ViewModels/ElementViewModel.cs
@@ -359,8 +359,12 @@ private void OnSplit(TimeSpan timeSpan)
 
         backwardLayer.Save(RandomFileNameGenerator.Generate(Path.GetDirectoryName(Scene.FileName)!, Constants.ElementFileExtension));
         IRecordableCommand command2 = Scene.AddChild(backwardLayer);
+        IRecordableCommand command3 = backwardLayer.Operation.OnSplit(true, forwardLength, -forwardLength);
+        IRecordableCommand command4 = Model.Operation.OnSplit(false, TimeSpan.Zero, -backwardLength);
 
         command1.Append(command2)
+            .Append(command3)
+            .Append(command4)
             .DoAndRecord(CommandRecorder.Default);
     }