using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Input;
using Microsoft.Xaml.Behaviors;
using SheetMe.Designer.ViewModels;

namespace SheetMe.Designer.Behaviors;

/// <summary>
/// 캔버스 키보드 단축키 — 텍스트 입력 요소에 포커스가 있으면 통과(입력 보호).
/// 화살표 넛지(Shift=그리드), Del, Ctrl+A/C/V/D/Z/Y, Esc.
/// </summary>
public sealed class CanvasKeyboardBehavior : Behavior<UIElement>
{
    #region Methods
    protected override void OnAttached()
    {
        base.OnAttached();
        AssociatedObject.PreviewKeyDown += OnPreviewKeyDown;
    }

    protected override void OnDetaching()
    {
        AssociatedObject.PreviewKeyDown -= OnPreviewKeyDown;
        base.OnDetaching();
    }

    private void OnPreviewKeyDown(object sender, KeyEventArgs e)
    {
        if ((AssociatedObject as FrameworkElement)?.DataContext is not DesignerViewModel designer)
        {
            return;
        }
        // 텍스트 입력 보호 — 포커스가 편집 컨트롤이면 단축키 라우팅 안 함
        if (Keyboard.FocusedElement is TextBoxBase or ComboBox or PasswordBox)
        {
            return;
        }

        var ctrl = Keyboard.Modifiers.HasFlag(ModifierKeys.Control);
        var shift = Keyboard.Modifiers.HasFlag(ModifierKeys.Shift);
        var step = shift ? designer.Snap.GridSize * 2 : 1;
        var handled = true;

        switch (e.Key)
        {
            case Key.Left: designer.NudgeSelection(-step, 0); break;
            case Key.Right: designer.NudgeSelection(step, 0); break;
            case Key.Up: designer.NudgeSelection(0, -step); break;
            case Key.Down: designer.NudgeSelection(0, step); break;
            case Key.Delete: designer.DeleteSelection(); break;
            case Key.Escape: designer.Interaction.Cancel(); break;
            case Key.A when ctrl: designer.SelectAllOnActivePage(); break;
            case Key.C when ctrl: designer.CopySelection(); break;
            case Key.X when ctrl: designer.CutSelection(); break;
            case Key.V when ctrl: designer.Paste(); break;
            case Key.D when ctrl: designer.CopySelection(); designer.Paste(); break;
            case Key.Z when ctrl: designer.Undo.Undo(); break;
            case Key.Y when ctrl: designer.Undo.Redo(); break;
            case Key.G when ctrl && shift: designer.UngroupSelection(); break;
            case Key.G when ctrl: designer.GroupSelection(); break;
            default: handled = false; break;
        }

        e.Handled = handled;
    }
    #endregion
}