using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Windows;

using System.Windows.Controls;

using System.Windows.Ink;

using System.Windows.Input;

using SoftwarePatterns.Core.Momento;

namespace SoftwarePatterns.WPF

{

/// <summary>

/// Interaction logic for MainWindow.xaml

/// </summary>

public partial class MainWindow : Window

{

private readonly Stack<IMemento> priorStates = new Stack<IMemento>();

public MainWindow()

{

InitializeComponent();

CommandBindings.Add(new CommandBinding(ApplicationCommands.Undo,

OnExectedCommands));

Canvas1.MouseUp += Canvas1OnMouseUp;

StoreState();

}

private void Canvas1OnMouseUp(object sender, MouseButtonEventArgs mouseButtonEventArgs)

{

StoreState();

}

private void OnExectedCommands(object sender, ExecutedRoutedEventArgs e)

{

var window = (MainWindow) sender;

if (e.Command == ApplicationCommands.Undo)

{

window.Undo(sender, e);

}

}

private void Undo(object sender, ExecutedRoutedEventArgs executedRoutedEventArgs)

{

if (priorStates.Count > 1)

{

priorStates.Pop();

var lastState = priorStates.Peek();

Canvas1.SetMemento(lastState);

}

Label1.Content = priorStates.Count;

}

private void StoreState()

{

var memento = Canvas1.CreateMemento();

priorStates.Push(memento);

Label1.Content = priorStates.Count;

}

}

public class InkCanvasWithUndo : InkCanvas

{

public IMemento CreateMemento()

{

var copy = Strokes.ToArray();

return new InkCanvasMemeto { State = copy };

}

public void SetMemento(IMemento memento)

{

Strokes = new StrokeCollection((Stroke[])memento.State);

}

}

}