CVRManager/Views/MainWindow.axaml.cs

using Avalonia;
using Avalonia.Controls;
using Avalonia.Input;
using Avalonia.Input.Platform;
using Avalonia.Interactivity;
using Avalonia.Layout;
using Avalonia.Platform.Storage;
using Avalonia.VisualTree;
using CVRManager.ViewModels;

namespace CVRManager.Views;

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        var vm = new MainViewModel
        {
            PickFolder = async () =>
            {
                var r = await StorageProvider.OpenFolderPickerAsync(new FolderPickerOpenOptions { AllowMultiple = false });
                return r.Count > 0 ? r[0].TryGetLocalPath() : null;
            },
            PickFiles = async () =>
            {
                var r = await StorageProvider.OpenFilePickerAsync(new FilePickerOpenOptions
                {
                    AllowMultiple = true,
                    FileTypeFilter = new[] { new FilePickerFileType("Mod files") { Patterns = new[] { "*.dll", "*.zip" } } },
                });
                return (IReadOnlyList<string>)r.Select(f => f.TryGetLocalPath()).Where(p => p != null).Select(p => p!).ToList();
            },
            Confirm = ConfirmAsync,
            CopyImage = async path =>
            {
                if (Clipboard == null) return;
                using var bmp = new Avalonia.Media.Imaging.Bitmap(path);
                await Clipboard.SetBitmapAsync(bmp);
            },
        };
        DataContext = vm;
        Opened += (_, _) => WindowIcons.Apply(this);
        HookInstallDrag(vm);
    }

    InstallVM? dragItem;
    Point dragStart;
    bool dragging;

    void HookInstallDrag(MainViewModel vm)
    {
        var list = InstallList;
        list.AddHandler(PointerPressedEvent, (_, e) =>
        {
            if (!e.GetCurrentPoint(list).Properties.IsLeftButtonPressed) return;
            if ((e.Source as Visual)?.FindAncestorOfType<Button>(true) != null) return;
            if ((e.Source as StyledElement)?.DataContext is not InstallVM item) return;
            dragItem = item;
            dragStart = e.GetPosition(list);
            dragging = false;
        }, RoutingStrategies.Bubble, true);

        list.AddHandler(PointerMovedEvent, (_, e) =>
        {
            if (dragItem == null) return;
            var p = e.GetPosition(list);
            if (!dragging)
            {
                if (Math.Abs(p.Y - dragStart.Y) < 6) return;
                dragging = true;
                e.Pointer.Capture(list);
                list.Cursor = new Cursor(StandardCursorType.SizeNorthSouth);
            }
            var from = vm.Installs.IndexOf(dragItem);
            for (var i = 0; i < list.ItemCount; i++)
            {
                if (i == from || list.ContainerFromIndex(i) is not Control c || c.TranslatePoint(default, list) is not { } top) continue;
                var mid = top.Y + c.Bounds.Height / 2;
                if ((i > from && p.Y > mid && p.Y < top.Y + c.Bounds.Height) || (i < from && p.Y < mid && p.Y > top.Y))
                {
                    vm.MoveInstall(dragItem, i);
                    break;
                }
            }
            MarkDragged(list);
        }, RoutingStrategies.Bubble, true);

        void End()
        {
            if (dragItem == null) return;
            var moved = dragging;
            dragItem = null;
            dragging = false;
            list.Cursor = null;
            MarkDragged(list);
            if (moved) vm.Save();
        }
        list.AddHandler(PointerReleasedEvent, (_, e) => { if (dragging) e.Pointer.Capture(null); End(); }, RoutingStrategies.Bubble, true);
        list.AddHandler(PointerCaptureLostEvent, (_, _) => End(), RoutingStrategies.Bubble, true);
    }

    void MarkDragged(ListBox list)
    {
        for (var i = 0; i < list.ItemCount; i++)
            if (list.ContainerFromIndex(i) is Control c)
                c.Opacity = dragging && c.DataContext == dragItem ? 0.6 : 1;
    }

    void OnTableSelection(object? sender, SelectionChangedEventArgs e)
    {
        if (e.AddedItems.Count > 0 && e.AddedItems[0] is GroupHeader header)
            header.ToggleCommand.Execute(null);
    }

    async Task<bool> ConfirmAsync(string message)
    {
        var dlg = new Window
        {
            Title = "Confirm",
            Width = 460,
            SizeToContent = SizeToContent.Height,
            WindowStartupLocation = WindowStartupLocation.CenterOwner,
            CanResize = false,
        };
        var ok = new Button { Content = "OK", Padding = new Thickness(18, 6) };
        var cancel = new Button { Content = "Cancel", Padding = new Thickness(18, 6) };
        ok.Click += (_, _) => dlg.Close(true);
        cancel.Click += (_, _) => dlg.Close(false);
        dlg.Content = new StackPanel
        {
            Margin = new Thickness(20),
            Spacing = 16,
            Children =
            {
                new TextBlock { Text = message, TextWrapping = Avalonia.Media.TextWrapping.Wrap },
                new StackPanel
                {
                    Orientation = Orientation.Horizontal,
                    Spacing = 8,
                    HorizontalAlignment = HorizontalAlignment.Right,
                    Children = { ok, cancel },
                },
            },
        };
        return await dlg.ShowDialog<bool>(this);
    }
}