OpenNest/OpenNest/Controls/PlateView.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;
using OpenNest.Actions;
using OpenNest.Collections;
using OpenNest.Diagnostics;
using OpenNest.Engine;
using OpenNest.Engine.Fill;
using OpenNest.Engine.Jobs.Placement;
using OpenNest.Forms;
using OpenNest.Geometry;
using OpenNest.Math;
using Timer = System.Timers.Timer;

namespace OpenNest.Controls
{
    public class PlateView : DrawControl
    {
        private readonly Timer redrawTimer;
        private readonly OverlapOverlayController overlapOverlay;
        private readonly ValidationOverlay validationOverlay;

        private string status;
        private Plate plate;
        private ActionManager actionManager;
        private CutOffSettings cutOffSettings = new CutOffSettings();
        private SelectionManager selection;
        private CutOffHandler cutOffHandler;
        private readonly ClampMenuHandler clampMenu;
        private PreviewManager previewManager;
        protected List<LayoutPart> parts;
        private Point middleMouseDownPoint;
        private Box activeWorkArea;
        private List<Box> debugRemnants;
        private PlateRenderer renderer;
        private LayoutPart hoveredPart;
        private Point hoverPoint;
        private bool showTooltip;
        private bool hoverPending;
        private Timer hoverTimer;

        public Box ActiveWorkArea
        {
            get => activeWorkArea;
            set
            {
                activeWorkArea = value;
                Invalidate();
            }
        }

        public List<Box> DebugRemnants
        {
            get => debugRemnants;
            set
            {
                debugRemnants = value;
                Invalidate();
            }
        }

        public List<int> DebugRemnantPriorities { get; set; }

        public List<LayoutPart> SelectedParts => selection.SelectedParts;
        public ReadOnlyCollection<LayoutPart> Parts => new ReadOnlyCollection<LayoutPart>(parts);

        internal SelectionManager Selection => selection;
        internal CutOffHandler CutOffs => cutOffHandler;
        internal ClampMenuHandler ClampMenu => clampMenu;
        internal ActionManager Actions => actionManager;
        internal PreviewManager Previews => previewManager;

        public event EventHandler<ItemAddedEventArgs<Part>> PartAdded;
        public event EventHandler<ItemRemovedEventArgs<Part>> PartRemoved;

        /// <summary>
        /// Raised after the plate's parts were reordered in place, for example by an applied cutting
        /// plan that also installed new programs. The view has already redrawn its parts in the new order.
        /// </summary>
        public event EventHandler PartsReordered;
        public event EventHandler StatusChanged;

        /// <summary>
        /// Raised when files are dropped on the plate and something is listening (see
        /// <see cref="OnDragEnter"/>); callers decide which paths to act on.
        /// </summary>
        public event EventHandler<string[]> FilesDropped;

        public event EventHandler SelectionChanged
        {
            add => selection.SelectionChanged += value;
            remove => selection.SelectionChanged -= value;
        }

        public PlateView()
            : this(ColorScheme.Default) { }

        public PlateView(ColorScheme colorScheme)
        {
            overlapOverlay = new OverlapOverlayController(this);
            validationOverlay = new ValidationOverlay(this);
            Plate = new Plate(60, 120);
            origin = new PointF();
            parts = new List<LayoutPart>();
            selection = new SelectionManager(this);
            cutOffHandler = new CutOffHandler(this);
            clampMenu = new ClampMenuHandler(this);
            previewManager = new PreviewManager(this);

            redrawTimer = new Timer()
            {
                AutoReset = false,
                Enabled = true,
                Interval = 50,
            };
            redrawTimer.Elapsed += redrawTimer_Elapsed;

            hoverTimer = new Timer() { AutoReset = false, Interval = 1000 };
            hoverTimer.Elapsed += hoverTimer_Elapsed;

            SetStyle(
                ControlStyles.AllPaintingInWmPaint
                    | ControlStyles.OptimizedDoubleBuffer
                    | ControlStyles.UserPaint,
                true
            );

            ViewScale = 1.0f;
            RotateIncrementAngle = 10;
            OffsetIncrementDistance = 10;
            ColorScheme = colorScheme;
            BackColor = colorScheme.BackgroundColor;
            Cursor = Cursors.Cross;
            AllowPan = true;
            AllowSelect = true;
            AllowZoom = true;
            AllowDrop = true;
            DrawOrigin = true;
            DrawRapid = false;
            DrawBounds = true;
            DrawOffset = false;
            FillParts = true;
            renderer = new PlateRenderer(this);
            actionManager = new ActionManager(this);
            actionManager.SetAction(typeof(ActionSelect));

            UpdateMatrix();
        }

        public ColorScheme ColorScheme { get; set; }

        internal bool InspectionOnly { get; set; }
        internal System.Action InspectionCloseRequested { get; set; }

        /// <summary>
        /// Asked before a right-click changes which clamps are on the sheet; false refuses
        /// (e.g. a nest run is using the clamps). Null allows.
        /// </summary>
        internal Func<bool> CanEditClamps { get; set; }

        public bool AllowZoom { get; set; }

        public bool AllowSelect { get; set; }

        public bool AllowPan { get; set; }

        public bool DrawOrigin { get; set; }

        public bool DrawRapid { get; set; }

        public bool DrawPiercePoints { get; set; }

        public bool DrawBounds { get; set; }

        public bool DrawOffset { get; set; }

        public bool DrawCutDirection { get; set; }

        public bool ShowBendLines { get; set; }

        public double OffsetTolerance { get; set; } = 0.001;

        public bool FillParts { get; set; }

        internal List<LayoutPart> LayoutParts => parts;

        private Plate displayPlate;
        private List<LayoutPart> displayParts;
        private Func<bool> displayIsCurrent;
        internal Plate DisplayPlate => displayPlate ?? plate;
        internal List<LayoutPart> DisplayLayoutParts => displayParts ?? parts;
        internal bool HasProposalDisplay => displayPlate != null;

        internal void ShowProposalDisplay(Plate proposal, Func<bool> isCurrent)
        {
            if (!InspectionOnly)
                throw new InvalidOperationException("Proposal display requires an inspection lock.");
            ClearProposalDisplay();
            if (proposal == null || isCurrent?.Invoke() != true)
                return;
            var layouts = new List<LayoutPart>();
            try
            {
                foreach (var part in proposal.Parts)
                    layouts.Add(LayoutPart.Create(part, this));
                displayPlate = proposal;
                displayIsCurrent = isCurrent;
                displayParts = layouts;
            }
            catch
            {
                foreach (var layout in layouts)
                    layout.ReleaseDisplayResources();
                throw;
            }
            ClearHover();
            validationOverlay.Clear();
            Invalidate();
        }

        internal void ClearProposalDisplay()
        {
            var old = displayParts;
            displayPlate = null;
            displayParts = null;
            displayIsCurrent = null;
            if (old != null)
                foreach (var layout in old)
                    layout.ReleaseDisplayResources();
            validationOverlay?.Clear();
            if (!IsDisposed && !Disposing)
                Invalidate();
        }

        internal IReadOnlyList<LayoutPart> PreviewParts => HasProposalDisplay ? Array.Empty<LayoutPart>() : previewManager.PreviewParts;
        internal Brush PreviewBrush => previewManager.PreviewBrush;
        internal Pen PreviewPen => previewManager.PreviewPen;

        internal RectangleF GetViewBounds() => new RectangleF(-origin.X, -origin.Y, Width, Height);

        internal PlateRenderer Renderer => renderer;

        public CutOffSettings CutOffSettings
        {
            get => cutOffSettings;
            set
            {
                cutOffSettings = value;
                Plate?.RegenerateCutOffs(value);
                Invalidate();
            }
        }

        public double RotateIncrementAngle { get; set; }

        public double OffsetIncrementDistance { get; set; }

        public Plate Plate
        {
            get { return plate; }
            set { SetPlate(value); }
        }

        private void SetPlate(Plate p)
        {
            ClearProposalDisplay();
            if (plate != null)
            {
                plate.PartAdded -= plate_PartAdded;
                plate.PartRemoved -= plate_PartRemoved;
                plate.PartsReordered -= plate_PartsReordered;
                plate.ClampZonesChanged -= plate_ClampZonesChanged;
                parts.Clear();
                previewManager.Clear();
                selection.Clear();
            }

            validationOverlay.Clear();
            plate = p;
            plate.PartAdded += plate_PartAdded;
            plate.PartRemoved += plate_PartRemoved;
            plate.PartsReordered += plate_PartsReordered;
            plate.ClampZonesChanged += plate_ClampZonesChanged;

            foreach (var part in plate.Parts)
                parts.Add(LayoutPart.Create(part, this));

            overlapOverlay.SetPlate(plate);
            actionManager?.OnPlateChanged();
        }

        internal OverlapOverlayController OverlapOverlay => overlapOverlay;
        internal ValidationOverlay ValidationOverlay => validationOverlay;
        internal (float Scale, PointF Origin) CaptureViewport() => (ViewScale, origin);
        internal void RestoreViewport((float Scale, PointF Origin) viewport)
        {
            ViewScale = viewport.Scale;
            origin = viewport.Origin;
            UpdateMatrix();
            Invalidate();
        }
        internal void ShowValidationFinding(PostVerificationFinding finding) => validationOverlay.Show(finding);
        internal void ClearValidationFinding() => validationOverlay.Clear();
        internal void CenterValidationPoint(Vector location, Point target)
        {
            var current = PointWorldToControl(location);
            origin.X += target.X - current.X;
            origin.Y += target.Y - current.Y;
            UpdateMatrix();
            Invalidate();
        }
        public OverlapCheckStatus OverlapStatus => overlapOverlay.Status;
        public PlateOverlapReport OverlapReport => overlapOverlay.Report;
        public bool IsOverlapCheckRunning => overlapOverlay.IsRunning;
        public OverlapDisplayMode OverlapDisplay
        {
            get => overlapOverlay.DisplayMode;
            set => overlapOverlay.DisplayMode = value;
        }
        public event EventHandler OverlapStateChanged
        {
            add => overlapOverlay.StateChanged += value;
            remove => overlapOverlay.StateChanged -= value;
        }
        public Task CheckOverlapsAsync(Units units) => overlapOverlay.CheckAsync(units);
        public void CancelOverlapCheck() => overlapOverlay.Cancel();
        /// <summary>
        /// Call before any editor that may mutate clean drawing programs in place: marks the
        /// report out of date and drops cached drawing material.
        /// </summary>
        public void InvalidateOverlapCheck() => overlapOverlay.InvalidateGeometry();

        /// <summary>
        /// Recheck overlaps automatically once layout edits have been quiet for
        /// <see cref="OverlapAutoCheckDelay"/> ms. Null restores manual-only checks.
        /// </summary>
        public void SetOverlapAutoCheck(Func<Units> units) => overlapOverlay.SetAutoCheck(units);

        public int OverlapAutoCheckDelay
        {
            get => overlapOverlay.AutoCheckDelay;
            set => overlapOverlay.AutoCheckDelay = value;
        }

        public string Status
        {
            get { return status; }
            set
            {
                status = value;

                if (StatusChanged != null)
                    StatusChanged.Invoke(this, new EventArgs());
            }
        }

        protected override void OnMouseEnter(EventArgs e)
        {
            base.OnMouseEnter(e);
        }

        protected override void OnMouseLeave(EventArgs e)
        {
            ClearHover();
            base.OnMouseLeave(e);
        }

        private void ClearHover()
        {
            overlapOverlay?.ClearHover();
            hoverTimer?.Stop();
            hoverPending = false;
            hoveredPart = null;
            showTooltip = false;
            Invalidate();
        }

        protected override void OnResize(EventArgs e)
        {
            ClearHover();
            base.OnResize(e);
        }

        protected override void OnDpiChangedAfterParent(EventArgs e)
        {
            ClearHover();
            base.OnDpiChangedAfterParent(e);
        }

        protected override void OnFontChanged(EventArgs e)
        {
            ClearHover();
            base.OnFontChanged(e);
        }

        protected override void OnDragEnter(DragEventArgs drgevent)
        {
            if (InspectionOnly)
                return;
            if (drgevent.Data.GetData(typeof(Drawing)) != null)
                drgevent.Effect = DragDropEffects.Copy;
            else if (FilesDropped != null && drgevent.Data.GetDataPresent(DataFormats.FileDrop))
                drgevent.Effect = DragDropEffects.Copy;
        }

        protected override void OnDragDrop(DragEventArgs drgevent)
        {
            if (InspectionOnly)
                return;
            if (drgevent.Data.GetDataPresent(DataFormats.FileDrop))
            {
                FilesDropped?.Invoke(this, (string[])drgevent.Data.GetData(DataFormats.FileDrop));
                return;
            }

            var dwg = drgevent.Data.GetData(typeof(Drawing)) as Drawing;

            if (dwg == null)
                return;

            var pt1 = PointToClient(new Point(drgevent.X, drgevent.Y));
            var pt2 = PointControlToWorld(pt1);

            AddPartFromDrawing(dwg, pt2);
        }

        protected override void OnMouseDown(MouseEventArgs e)
        {
            ClearHover();
            if (!Focused)
                Focus();

            if (e.Button == MouseButtons.Middle)
                middleMouseDownPoint = e.Location;

            if (InspectionOnly)
                return;

            if (e.Button == MouseButtons.Left && actionManager.CurrentAction is ActionSelect)
            {
                var hitCutOff = cutOffHandler.TryStartDrag(CurrentPoint, 5.0 / ViewScale);
                if (hitCutOff != null)
                {
                    selection.DeselectParts();
                    selection.SelectedCutOffs.Clear();
                    selection.SelectedCutOffs.Add(hitCutOff);
                    Invalidate();
                    return;
                }
                else
                {
                    selection.DeselectCutOffs();
                }
            }

            base.OnMouseDown(e);
        }

        protected override void OnMouseUp(MouseEventArgs e)
        {
            if (InspectionOnly)
                return;
            if (e.Button == MouseButtons.Middle && SelectedParts.Count > 0)
            {
                var dx = e.X - middleMouseDownPoint.X;
                var dy = e.Y - middleMouseDownPoint.Y;

                if (dx * dx + dy * dy < 25)
                {
                    selection.RotateSelectedParts(Angle.ToRadians(90));
                    Invalidate();
                }
            }

            if (e.Button == MouseButtons.Left && cutOffHandler.IsDragging)
            {
                cutOffHandler.EndDrag();
                return;
            }

            if (e.Button == MouseButtons.Right)
                clampMenu.TryShow(e.Location, 3.0 / ViewScale);

            base.OnMouseUp(e);
        }

        protected override void OnMouseWheel(MouseEventArgs e)
        {
            if (!InspectionOnly)
                base.OnMouseWheel(e);

            var multiplier = System.Math.Abs(e.Delta / 120);

            if (!InspectionOnly && SelectedParts.Count > 0 && ((ModifierKeys & Keys.Shift) == Keys.Shift))
            {
                var increment =
                    (ModifierKeys & Keys.Control) == Keys.Control
                        ? RotateIncrementAngle * 0.1
                        : RotateIncrementAngle;

                var angle = Angle.ToRadians((e.Delta > 0 ? -increment : increment) * multiplier);

                selection.RotateSelectedParts(angle);
            }
            else
            {
                if (AllowZoom)
                {
                    if (e.Delta > 0)
                        ZoomToControlPoint(
                            e.Location,
                            (float)System.Math.Pow(ZoomInFactor, multiplier)
                        );
                    else
                        ZoomToControlPoint(
                            e.Location,
                            (float)System.Math.Pow(ZoomOutFactor, multiplier)
                        );
                }
            }

            Invalidate();
        }

        protected override void OnMouseMove(MouseEventArgs e)
        {
            if (e.Button != MouseButtons.None)
                ClearHover();
            if (e.Button == MouseButtons.Middle)
            {
                if (AllowPan)
                {
                    var diffx = e.X - lastPoint.X;
                    var diffy = e.Y - lastPoint.Y;

                    origin.X += diffx;
                    origin.Y += diffy;

                    Invalidate();
                }
            }
            else
            {
                LastPoint = CurrentPoint;
                CurrentPoint = PointControlToWorld(e.Location);
            }

            lastPoint = e.Location;

            if (InspectionOnly)
                return;

            if (cutOffHandler.IsDragging && e.Button == MouseButtons.Left
                && selection.SelectedCutOffs.Count > 0)
            {
                cutOffHandler.UpdateDrag(CurrentPoint, selection.SelectedCutOffs[0]);
                return;
            }

            if (e.Button == MouseButtons.None && actionManager.CurrentAction is ActionSelect)
            {
                hoverPoint = e.Location;
                hoverPending = true;
                showTooltip = false;
                hoverTimer.Stop();
                hoverTimer.Start();

                if (hoveredPart != null)
                    Invalidate();
                overlapOverlay.UpdateHover(e.Location);
            }
            else
            {
                ClearHover();
            }

            base.OnMouseMove(e);
        }

        protected override void OnMouseDoubleClick(MouseEventArgs e)
        {
            if (!InspectionOnly)
                base.OnMouseDoubleClick(e);

            if (e.Button == MouseButtons.Middle && (InspectionOnly || SelectedParts.Count == 0))
                ZoomToFit();
        }

        protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
        {
            if (InspectionOnly)
            {
                if (keyData == Keys.Escape && InspectionCloseRequested != null)
                    InspectionCloseRequested();
                else if (keyData == Keys.F)
                    ZoomToFit();
                else if (keyData is (Keys.Control | Keys.Oemplus) or (Keys.Control | Keys.OemMinus))
                    return base.ProcessCmdKey(ref msg, keyData); // The host's zoom shortcuts stay live.
                return true;
            }
            // Audited: DrawControl/PlateView, Action key handlers, EditNestForm,
            // MainForm.ProcessCmdKey and menu shortcuts have no plain PgUp/PgDn
            // binding. BestFitViewerForm owns these only in its separate dialog.
            // No modifier keys, clicks, or wheel events are consumed by hover paging.
            if ((keyData == Keys.PageUp || keyData == Keys.PageDown)
                && overlapOverlay.TryPageHover(keyData == Keys.PageUp ? -1 : 1))
                return true;
            return base.ProcessCmdKey(ref msg, keyData);
        }

        protected override void OnKeyDown(KeyEventArgs e)
        {
            if (InspectionOnly)
            {
                if (e.KeyData == Keys.F)
                    ZoomToFit();
                return;
            }
            switch (e.KeyCode)
            {
                case Keys.Delete:
                    selection.DeleteSelected();
                    break;

                case Keys.F:
                    if ((ModifierKeys & Keys.Control) == 0)
                        ZoomToFit();
                    else
                        base.OnKeyDown(e);
                    break;

                default:
                    base.OnKeyDown(e);
                    break;
            }
        }

        public void ProcessEscapeKey() => actionManager.ProcessEscapeKey();

        public void EndAction() => actionManager.EndAction();

        protected override bool ProcessDialogKey(Keys keyData)
        {
            if (InspectionOnly)
            {
                if (keyData == Keys.Escape)
                    InspectionCloseRequested?.Invoke();
                return true;
            }
            // Only handle TAB, RETURN, ESC, and ARROW KEYS here.
            // All other keys can be handled in OnKeyDown method.

            switch (keyData)
            {
                case Keys.Escape:
                    ProcessEscapeKey();
                    break;

                case Keys.Left:
                    SelectedParts.ForEach(part => part.Offset(-OffsetIncrementDistance, 0));
                    Invalidate();
                    break;

                case Keys.X:
                case Keys.Shift | Keys.Left:
                    selection.PushSelected(PushDirection.Left);
                    break;

                case Keys.Shift | Keys.X:
                case Keys.Shift | Keys.Right:
                    selection.PushSelected(PushDirection.Right);
                    break;

                case Keys.Shift | Keys.Y:
                case Keys.Shift | Keys.Up:
                    selection.PushSelected(PushDirection.Up);
                    break;

                case Keys.Y:
                case Keys.Shift | Keys.Down:
                    selection.PushSelected(PushDirection.Down);
                    break;

                case Keys.Right:
                    SelectedParts.ForEach(part => part.Offset(OffsetIncrementDistance, 0));
                    Invalidate();
                    break;

                case Keys.Up:
                    SelectedParts.ForEach(part => part.Offset(0, OffsetIncrementDistance));
                    Invalidate();
                    break;

                case Keys.Down:
                    SelectedParts.ForEach(part => part.Offset(0, -OffsetIncrementDistance));
                    Invalidate();
                    break;
            }

            return base.ProcessDialogKey(keyData);
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            if (displayPlate != null && displayIsCurrent?.Invoke() != true)
                ClearProposalDisplay();
            if (BackColor != ColorScheme.BackgroundColor)
                BackColor = ColorScheme.BackgroundColor;

            e.Graphics.SmoothingMode = SmoothingMode.HighSpeed;

            if (DrawOrigin)
            {
                e.Graphics.DrawLine(ColorScheme.OriginPen, origin.X, 0, origin.X, Height);
                e.Graphics.DrawLine(ColorScheme.OriginPen, 0, origin.Y, Width, origin.Y);
            }

            e.Graphics.TranslateTransform(origin.X, origin.Y);

            renderer.DrawPlate(e.Graphics);
            renderer.DrawParts(e.Graphics);
            renderer.DrawClampZones(e.Graphics);
            renderer.DrawRemovedClamps(e.Graphics);
            renderer.DrawCutOffs(e.Graphics);
            if (!HasProposalDisplay)
            {
                renderer.DrawActiveWorkArea(e.Graphics);
                renderer.DrawDebugRemnants(e.Graphics);
                DrawOverlapOverlay(e.Graphics);
            }
            // Plan Cutting marks findings on its proposal as well as on the live plate.
            validationOverlay.Draw(e.Graphics);

            base.OnPaint(e);

            if (!InspectionOnly && !overlapOverlay.DrawHover(e.Graphics) && hoveredPart != null && showTooltip)
            {
                e.Graphics.ResetTransform();
                var text = hoveredPart.BasePart.BaseDrawing.Name;
                var size = e.Graphics.MeasureString(text, Font);
                var x = hoverPoint.X + 16f;
                var y = hoverPoint.Y - size.Height - 6f;

                if (x + size.Width + 8 > ClientSize.Width)
                    x = hoverPoint.X - size.Width - 8;
                if (y < 0)
                    y = hoverPoint.Y + 20;

                var rect = new RectangleF(x, y, size.Width + 6, size.Height + 4);
                using (var bgBrush = new SolidBrush(Color.FromArgb(230, Color.White)))
                    e.Graphics.FillRectangle(bgBrush, rect);
                e.Graphics.DrawRectangle(Pens.DimGray, rect.X, rect.Y, rect.Width, rect.Height);
                e.Graphics.DrawString(text, Font, Brushes.Black, x + 3, y + 2);
            }
        }

        private void DrawOverlapOverlay(Graphics graphics) => overlapOverlay.Draw(graphics);

        protected override void OnHandleDestroyed(EventArgs e)
        {
            ClearHover();
            overlapOverlay.ReleaseHandle();
            validationOverlay.Clear();
            base.OnHandleDestroyed(e);
            actionManager.Cleanup();
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                ClearProposalDisplay();
                InspectionCloseRequested = null;
                // A plate can outlive its view; stop it calling back into a disposed one.
                if (plate != null)
                {
                    plate.PartAdded -= plate_PartAdded;
                    plate.PartRemoved -= plate_PartRemoved;
                    plate.PartsReordered -= plate_PartsReordered;
                    plate.ClampZonesChanged -= plate_ClampZonesChanged;
                }
                clampMenu?.Dispose();
                CanEditClamps = null;
                overlapOverlay?.Dispose();
                validationOverlay?.Dispose();
                hoverTimer?.Dispose();
                hoverTimer = null;
                redrawTimer?.Dispose();
            }
            base.Dispose(disposing);
        }

        public override void Refresh()
        {
            parts.ForEach(p => p.Update(this));
            previewManager.Update();
            Invalidate();
        }

        public CutOff GetCutOffAtPoint(Vector point, double tolerance) =>
            cutOffHandler.GetCutOffAtPoint(point, tolerance);

        public LayoutPart GetPartAtControlPoint(Point pt) => selection.GetPartAtControlPoint(pt);

        public LayoutPart GetPartAtGraphPoint(PointF pt) => selection.GetPartAtGraphPoint(pt);

        public LayoutPart GetPartAtPoint(Vector pt) => selection.GetPartAtPoint(pt);

        public IList<LayoutPart> GetPartsFromWindow(RectangleF rect, SelectionType selectionType) =>
            selection.GetPartsFromWindow(rect, selectionType);

        public void SetAction(Type type) => actionManager.SetAction(type);

        public void SetAction(Type type, params object[] args) =>
            actionManager.SetAction(type, args);

        public void AlignSelected(AlignType alignType) => selection.AlignSelected(alignType);

        public void AlignSelected(AlignType alignType, LayoutPart fixedPart) =>
            selection.AlignSelected(alignType, fixedPart);

        public void AddPartFromDrawing(Drawing dwg, Vector location)
        {
            var part = new Part(dwg, location);

            part.Offset(
                part.Location.X - part.BoundingBox.Center.X,
                part.Location.Y - part.BoundingBox.Center.Y
            );

            Plate.Parts.Add(part);
        }

        public void SetActiveParts(List<Part> parts) => previewManager.SetActiveParts(parts);

        public void ClearPreviewParts() => previewManager.ClearPreviewParts();

        public void AcceptPreviewParts(List<Part> parts) =>
            previewManager.AcceptPreviewParts(parts);

        // UI-thread state: closing the progress window only requests cancellation.
        public bool IsFillInProgress { get; private set; }

        public async void FillWithProgress(List<Part> groupParts, Box workArea)
        {
            if (IsFillInProgress)
                return;

            IsFillInProgress = true;
            var operationActive = true;
            try
            {
                var sw = Stopwatch.StartNew();
                using var cts = new CancellationTokenSource();
                using var progressForm = new NestProgressForm(cts, showPlateRow: false);
                try
                {
                    var progress = new Progress<NestProgress>(p =>
                    {
                        // This callback can outlive its operation, even into the next fill.
                        if (!operationActive || IsDisposed || progressForm.IsDisposed)
                            return;

                        progressForm.UpdateProgress(p);

                        if (p.IsOverallBest)
                            SetActiveParts(p.BestParts);

                        ActiveWorkArea = p.ActiveWorkArea;
                    });

                    progressForm.Show(FindForm());
                    var strategy = EngineSelection.FillStrategy;
                    var spacing = Plate.PartSpacing;
                    var parts = await Task.Run(() =>
                    {
                        var result = PlateFillService.FillGroup(
                            strategy,
                            Plate,
                            groupParts,
                            workArea,
                            progress,
                            cts.Token
                        );
                        if (Plate.ClampZones.Count == 0)
                            Compactor.Settle(result, workArea, spacing);
                        else
                            Compactor.Settle(result, Plate, workArea);
                        return result;
                    });
                    operationActive = false;

                    if (parts.Count > 0 && (!cts.IsCancellationRequested || progressForm.Accepted))
                    {
                        SetActiveParts(parts);
                        AcceptPreviewParts(parts);

                        if (Plate.CutOffs.Count > 0)
                            Plate.RegenerateCutOffs(cutOffSettings);

                        sw.Stop();
                        Status = $"Fill: {parts.Count} parts in {sw.ElapsedMilliseconds} ms";
                    }
                    else
                    {
                        ClearPreviewParts();
                    }

                    progressForm.ShowCompleted();
                }
                finally
                {
                    operationActive = false;
                    ActiveWorkArea = null;
                    progressForm.Close();
                    Focus();
                }
            }
            catch (Exception)
            {
                ClearPreviewParts();
            }
            finally
            {
                operationActive = false;
                IsFillInProgress = false;
            }
        }

        public void RemoveSelectedParts() => selection.RemoveSelectedParts();

        private void redrawTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            if (IsDisposed || !IsHandleCreated)
                return;
            BeginInvoke(new System.Action(Invalidate));
        }

        private void hoverTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            if (IsDisposed || !IsHandleCreated)
                return;
            BeginInvoke(new System.Action(HoverCheck));
        }

        private void HoverCheck()
        {
            if (!hoverPending || IsDisposed || Disposing)
                return;
            hoverPending = false;
            var graphPt = PointControlToGraph(hoverPoint);
            LayoutPart hitPart = null;

            for (var i = parts.Count - 1; i >= 0; --i)
            {
                var path = parts[i].SelectionPath;
                if (path?.GetBounds().Contains(graphPt) == true && path.IsVisible(graphPt))
                {
                    hitPart = parts[i];
                    break;
                }
            }

            hoveredPart = hitPart;
            showTooltip = hitPart != null;

            if (showTooltip)
                Invalidate();
        }

        private void plate_PartAdded(object sender, ItemAddedEventArgs<Part> e)
        {
            if (PartAdded != null)
                PartAdded.Invoke(this, e);

            parts.Insert(e.Index, LayoutPart.Create(e.Item, this));
            redrawTimer.Start();
        }

        private void plate_PartRemoved(object sender, ItemRemovedEventArgs<Part> e)
        {
            if (PartRemoved != null)
                PartRemoved.Invoke(this, e);

            parts.RemoveAll(p => p.BasePart == e.Item);
        }

        // Clamp zones are display-only here: repaint, nothing to select or rebuild.
        private void plate_ClampZonesChanged(object sender, EventArgs e) => Invalidate();

        private void plate_PartsReordered(object sender, EventArgs e)
        {
            // Part numbers are drawn from the layout order, and an applied cutting plan can also
            // replace programs, so follow the plate's order and rebuild every part's graphics.
            // A reorder keeps repeated references, so reuse each existing layout once.
            var layouts = new Dictionary<Part, Queue<LayoutPart>>(ReferenceEqualityComparer.Instance);
            foreach (var layout in parts)
            {
                if (!layouts.TryGetValue(layout.BasePart, out var queue))
                    layouts.Add(layout.BasePart, queue = new Queue<LayoutPart>());
                queue.Enqueue(layout);
            }
            var reordered = plate.Parts
                .Select(part => layouts.TryGetValue(part, out var queue) && queue.Count > 0
                    ? queue.Dequeue()
                    : LayoutPart.Create(part, this))
                .ToList();
            parts.Clear();
            parts.AddRange(reordered);
            foreach (var layout in parts)
                layout.IsDirty = true;

            PartsReordered?.Invoke(this, EventArgs.Empty);
            Invalidate();
        }

        public void DeselectAll() => selection.DeselectAll();

        public void SelectAll() => selection.SelectAll();

        public void NotifySelectionChanged() => selection.NotifySelectionChanged();

        public override void ZoomToPoint(Vector pt, float zoomFactor, bool redraw = true)
        {
            base.ZoomToPoint(pt, zoomFactor, false);

            if (redraw)
                Invalidate();
        }

        public override void ZoomToArea(
            double x,
            double y,
            double width,
            double height,
            bool redraw = true
        )
        {
            base.ZoomToArea(x, y, width, height, false);

            if (redraw)
                Invalidate();
        }

        public virtual void ZoomToFit(bool redraw = true)
        {
            ZoomToArea(DisplayPlate.BoundingBox(true), redraw);
        }

        public virtual void ZoomToSelected(bool redraw = true)
        {
            ZoomToArea(SelectedParts.Select(p => p.BasePart).ToList().GetBoundingBox(), redraw);
        }

        public virtual void ZoomToPlate(bool redraw = true)
        {
            ZoomToArea(plate.BoundingBox(false), redraw);
        }

        public void PushSelected(PushDirection direction) => selection.PushSelected(direction);

        public bool ExpandSelected(
            Func<Func<CancellationToken, Expander.Result>, Expander.Result> run = null
        ) => selection.ExpandSelected(run);

        public void RotateSelectedParts(double angle) => selection.RotateSelectedParts(angle);

        protected override void UpdateMatrix()
        {
            ClearHover();
            base.UpdateMatrix();
            parts.ForEach(p => p.Update(this));
            displayParts?.ForEach(p => p.Update(this));
            previewManager.Update();
        }
    }
}