Artemis/src/Avalonia/Artemis.UI/Screens/VisualScripting/NodeScriptView.axaml.cs

using System.Collections.Generic;
using System.Linq;
using Artemis.UI.Shared.Controls;
using Artemis.UI.Shared.Events;
using Avalonia;
using Avalonia.Controls;
using Avalonia.Controls.Generators;
using Avalonia.Controls.PanAndZoom;
using Avalonia.Input;
using Avalonia.Interactivity;
using Avalonia.Markup.Xaml;
using Avalonia.Media;
using Avalonia.ReactiveUI;

namespace Artemis.UI.Screens.VisualScripting;

public class NodeScriptView : ReactiveUserControl<NodeScriptViewModel>
{
    private readonly Grid _grid;
    private readonly ItemsControl _nodesContainer;
    private readonly SelectionRectangle _selectionRectangle;
    private readonly ZoomBorder _zoomBorder;

    public NodeScriptView()
    {
        InitializeComponent();

        _grid = this.Find<Grid>("ContainerGrid");
        _zoomBorder = this.Find<ZoomBorder>("ZoomBorder");
        _nodesContainer = this.Find<ItemsControl>("NodesContainer");
        _selectionRectangle = this.Find<SelectionRectangle>("SelectionRectangle");
        _zoomBorder.PropertyChanged += ZoomBorderOnPropertyChanged;
        UpdateZoomBorderBackground();

        _grid.AddHandler(PointerReleasedEvent, CanvasOnPointerReleased, RoutingStrategies.Direct | RoutingStrategies.Tunnel | RoutingStrategies.Bubble, true);
    }

    private void CanvasOnPointerReleased(object? sender, PointerReleasedEventArgs e)
    {
        // If the flyout handled the click, update the position of the node picker
        if (e.Handled && ViewModel != null)
            ViewModel.NodePickerViewModel.Position = e.GetPosition(_grid);
    }

    private void ZoomBorderOnPropertyChanged(object? sender, AvaloniaPropertyChangedEventArgs e)
    {
        if (e.Property.Name == nameof(_zoomBorder.Background))
            UpdateZoomBorderBackground();
    }

    private void UpdateZoomBorderBackground()
    {
        if (_zoomBorder.Background is VisualBrush visualBrush)
            visualBrush.DestinationRect = new RelativeRect(_zoomBorder.OffsetX * -1, _zoomBorder.OffsetY * -1, 20, 20, RelativeUnit.Absolute);
    }

    private void InitializeComponent()
    {
        AvaloniaXamlLoader.Load(this);
    }

    private void ZoomBorder_OnZoomChanged(object sender, ZoomChangedEventArgs e)
    {
        UpdateZoomBorderBackground();
    }

    private void SelectionRectangle_OnSelectionUpdated(object? sender, SelectionRectangleEventArgs e)
    {
        List<ItemContainerInfo> itemContainerInfos = _nodesContainer.ItemContainerGenerator.Containers.Where(c => c.ContainerControl.Bounds.Intersects(e.Rectangle)).ToList();
        List<NodeViewModel> nodes = itemContainerInfos.Where(c => c.Item is NodeViewModel).Select(c => (NodeViewModel) c.Item).ToList();
        ViewModel?.UpdateNodeSelection(nodes, e.KeyModifiers.HasFlag(KeyModifiers.Shift), e.KeyModifiers.HasFlag(KeyModifiers.Control));
    }

    private void SelectionRectangle_OnSelectionFinished(object? sender, SelectionRectangleEventArgs e)
    {
        ViewModel?.FinishNodeSelection();
    }

    private void ZoomBorder_OnPointerReleased(object? sender, PointerReleasedEventArgs e)
    {
        if (!_selectionRectangle.IsSelecting)
            ViewModel?.ClearNodeSelection();
    }
}