using System;
using System.Collections.Generic;
using Avalonia.Collections;
using Avalonia.Controls.Presenters;
using Avalonia.Controls.Templates;
using Avalonia.Data;
using Avalonia.Input;
using Avalonia.Platform;
using Avalonia.Styling;
using Avalonia.UnitTests;
using Moq;
using Xunit;
using System;
using Avalonia.Input.Raw;
using Factory = System.Func<int, System.Action<object>, Avalonia.Controls.Window, Avalonia.AvaloniaObject>;

namespace Avalonia.Controls.UnitTests.Utils
{
    public class HotKeyManagerTests
    {
        [Fact]
        public void HotKeyManager_Should_Register_And_Unregister_Key_Binding()
        {
            using (AvaloniaLocator.EnterScope())
            {
                var styler = new Mock<Styler>();

                AvaloniaLocator.CurrentMutable
                    .Bind<IWindowingPlatform>().ToConstant(new WindowingPlatformMock())
                    .Bind<IStyler>().ToConstant(styler.Object);

                var gesture1 = new KeyGesture(Key.A, KeyModifiers.Control);
                var gesture2 = new KeyGesture(Key.B, KeyModifiers.Control);

                var tl = new Window();
                var button = new Button();
                tl.Content = button;
                tl.Template = CreateWindowTemplate();
                tl.ApplyTemplate();
                tl.Presenter.ApplyTemplate();

                HotKeyManager.SetHotKey(button, gesture1);

                Assert.Equal(gesture1, tl.KeyBindings[0].Gesture);

                HotKeyManager.SetHotKey(button, gesture2);
                Assert.Equal(gesture2, tl.KeyBindings[0].Gesture);

                tl.Content = null;
                tl.Presenter.ApplyTemplate();

                Assert.Empty(tl.KeyBindings);

                tl.Content = button;
                tl.Presenter.ApplyTemplate();

                Assert.Equal(gesture2, tl.KeyBindings[0].Gesture);

                HotKeyManager.SetHotKey(button, null);
                Assert.Empty(tl.KeyBindings);
            }
        }

        [Fact]
        public void HotKeyManager_Should_Release_Reference_When_Control_Detached()
        {
            using (AvaloniaLocator.EnterScope())
            {
                var styler = new Mock<Styler>();

                AvaloniaLocator.CurrentMutable
                    .Bind<IWindowingPlatform>().ToConstant(new WindowingPlatformMock())
                    .Bind<IStyler>().ToConstant(styler.Object);

                var gesture1 = new KeyGesture(Key.A, KeyModifiers.Control);

                WeakReference reference = null;

                var tl = new Window();

                new Action(() =>
                {
                    var button = new Button();
                    reference = new WeakReference(button, true);
                    tl.Content = button;
                    tl.Template = CreateWindowTemplate();
                    tl.ApplyTemplate();
                    tl.Presenter.ApplyTemplate();
                    HotKeyManager.SetHotKey(button, gesture1);

                    // Detach the button from the logical tree, so there is no reference to it
                    tl.Content = null;
                    tl.ApplyTemplate();
                })();


                // The button should be collected since it's detached from the listbox
                GC.Collect();
                GC.WaitForPendingFinalizers();
                GC.Collect();
                GC.WaitForPendingFinalizers();

                Assert.Null(reference?.Target);
            }
        }

        [Fact]
        public void HotKeyManager_Should_Release_Reference_When_Control_In_Item_Template_Detached()
        {
            using (UnitTestApplication.Start(TestServices.StyledWindow))
            {
                var styler = new Mock<Styler>();

                AvaloniaLocator.CurrentMutable
                    .Bind<IWindowingPlatform>().ToConstant(new WindowingPlatformMock())
                    .Bind<IStyler>().ToConstant(styler.Object);

                var gesture1 = new KeyGesture(Key.A, KeyModifiers.Control);

                var weakReferences = new List<WeakReference>();
                var tl = new Window { SizeToContent = SizeToContent.WidthAndHeight, IsVisible = true };
                var lm = tl.LayoutManager;

                var keyGestures = new AvaloniaList<KeyGesture> { gesture1 };
                var listBox = new ListBox
                {
                    Width = 100,
                    Height = 100,
                    VirtualizationMode = ItemVirtualizationMode.None,
                    // Create a button with binding to the KeyGesture in the template and add it to references list
                    ItemTemplate = new FuncDataTemplate(typeof(KeyGesture), (o, scope) =>
                    {
                        var keyGesture = o as KeyGesture;
                        var button = new Button
                        {
                            DataContext = keyGesture, [!Button.HotKeyProperty] = new Binding("")
                        };
                        weakReferences.Add(new WeakReference(button, true));
                        return button;
                    })
                };
                // Add the listbox and render it
                tl.Content = listBox;
                lm.ExecuteInitialLayoutPass();
                listBox.Items = keyGestures;
                lm.ExecuteLayoutPass();

                // Let the button detach when clearing the source items
                keyGestures.Clear();
                lm.ExecuteLayoutPass();
                
                // Add it again to double check,and render
                keyGestures.Add(gesture1);
                lm.ExecuteLayoutPass();
                
                keyGestures.Clear();
                lm.ExecuteLayoutPass();
                
                // The button should be collected since it's detached from the listbox
                GC.Collect();
                GC.WaitForPendingFinalizers();
                GC.Collect();
                GC.WaitForPendingFinalizers();
                
                Assert.True(weakReferences.Count > 0);
                foreach (var weakReference in weakReferences)
                {
                    Assert.Null(weakReference.Target);
                }
            }
        }

        [Theory]
        [MemberData(nameof(ElementsFactory))]
        public void HotKeyManager_Should_Use_CommandParameter(string factoryName, Factory factory)
        {
            using (AvaloniaLocator.EnterScope())
            {
                var styler = new Mock<Styler>();
                var target = new KeyboardDevice();
                var commandResult = 0;
                var expectedParameter = 1;
                AvaloniaLocator.CurrentMutable
                    .Bind<IWindowingPlatform>().ToConstant(new WindowingPlatformMock())
                    .Bind<IStyler>().ToConstant(styler.Object);

                var gesture = new KeyGesture(Key.A, KeyModifiers.Control);

                var action = new Action<object>(parameter =>
                {
                    if (parameter is int value)
                    {
                        commandResult = value;
                    }
                });

                var root = new Window();
                var element = factory(expectedParameter, action, root);

                root.Template = CreateWindowTemplate();
                root.ApplyTemplate();
                root.Presenter.ApplyTemplate();

                HotKeyManager.SetHotKey(element, gesture);

                target.ProcessRawEvent(new RawKeyEventArgs(target,
                    0,
                    root,
                    RawKeyEventType.KeyDown,
                    Key.A,
                    RawInputModifiers.Control));

                Assert.True(expectedParameter == commandResult, $"{factoryName} HotKey did not carry the CommandParameter.");
            }
        }


        [Theory]
        [MemberData(nameof(ElementsFactory))]
        public void HotKeyManager_Should_Do_Not_Executed_When_IsEnabled_False(string factoryName, Factory factory)
        {
            using (AvaloniaLocator.EnterScope())
            {
                var styler = new Mock<Styler>();
                var target = new KeyboardDevice();
                var isExecuted = false;
                AvaloniaLocator.CurrentMutable
                    .Bind<IWindowingPlatform>().ToConstant(new WindowingPlatformMock())
                    .Bind<IStyler>().ToConstant(styler.Object);

                var gesture = new KeyGesture(Key.A, KeyModifiers.Control);

                var action = new Action<object>(parameter =>
                {
                    isExecuted = true;
                });

                var root = new Window();
                var element = factory(0, action, root) as InputElement;

                element.IsEnabled = false;

                root.Template = CreateWindowTemplate();
                root.ApplyTemplate();
                root.Presenter.ApplyTemplate();

                HotKeyManager.SetHotKey(element, gesture);

                target.ProcessRawEvent(new RawKeyEventArgs(target,
                    0,
                    root,
                    RawKeyEventType.KeyDown,
                    Key.A,
                    RawInputModifiers.Control));

                Assert.True(isExecuted == false, $"{factoryName} Execution raised when IsEnabled is false.");
            }
        }

        public static TheoryData<string, Factory> ElementsFactory =>
            new TheoryData<string, Factory>()
            {
                {nameof(Button), MakeButton},
                {nameof(MenuItem),MakeMenu},
            };

        private static AvaloniaObject MakeMenu(int expectedParameter, Action<object> action, Window root)
        {
            var menuitem = new MenuItem()
            {
                Command = new Command(action),
                CommandParameter = expectedParameter,
            };
            var rootMenu = new Menu();

            rootMenu.Items = new[] { menuitem };

            root.Content = rootMenu;
            return menuitem;
        }

        private static AvaloniaObject MakeButton(int expectedParameter, Action<object> action, Window root)
        {
            var button = new Button()
            {
                Command = new Command(action),
                CommandParameter = expectedParameter,
            };

            root.Content = button;
            return button;
        }

        private FuncControlTemplate CreateWindowTemplate()
        {
            return new FuncControlTemplate<Window>((parent, scope) =>
            {
                return new ContentPresenter
                {
                    Name = "PART_ContentPresenter",
                    [~ContentPresenter.ContentProperty] = parent[~ContentControl.ContentProperty],
                }.RegisterInNameScope(scope);
            });
        }

        class Command : System.Windows.Input.ICommand
        {
            private readonly Action<object> _execeute;

#pragma warning disable 67 // Event not used
            public event EventHandler CanExecuteChanged;
#pragma warning restore 67 // Event not used

            public Command(Action<object> execeute)
            {
                _execeute = execeute;
            }
            public bool CanExecute(object parameter) => true;

            public void Execute(object parameter) => _execeute?.Invoke(parameter);
        }
    }
}