feat(desktop): add Nest > Clear Nest

Clear Nest removes every plate after the first and empties the remaining
plate (parts, cut-offs, repeat quantity), keeping nest metadata and the
first plate's configuration. It asks first, defaulting to No, and refuses
while nesting, a fill, a busy plate action or a database save is running.
The menu item is enabled only when there is something to clear.

OpenNest.Core/PlateManager.cs

@@ -195,6 +195,54 @@ namespace OpenNest
             nest.Plates.RemoveAt(CurrentIndex);
         }
 
+        /// <summary>
+        /// Whether <see cref="ClearAll"/> would change anything: more than one plate, or the
+        /// remaining plate still holds parts or cut-off definitions.
+        /// </summary>
+        public bool CanClearAll
+        {
+            get
+            {
+                if (Count == 0)
+                    return false;
+
+                var remaining = nest.Plates[0];
+                return Count > 1
+                    || remaining.Parts.Count > 0
+                    || remaining.CutOffs.Count > 0
+                    || remaining.Quantity > 1;
+            }
+        }
+
+        /// <summary>
+        /// Clears the nest: removes every plate after the first and empties the remaining
+        /// plate (parts and cut-off definitions), resetting its repeat quantity. Nest metadata
+        /// and plate defaults are preserved; the first plate's configuration stays as the
+        /// workspace sentinel — the same result as removing every other plate one at a time.
+        /// The plate count never reaches zero, so observers never see a null current plate.
+        /// </summary>
+        public void ClearAll()
+        {
+            if (Count == 0)
+                return;
+
+            BeginBatch();
+            try
+            {
+                while (nest.Plates.Count > 1)
+                    nest.Plates.RemoveAt(nest.Plates.Count - 1);
+
+                var remaining = nest.Plates[0];
+                remaining.CutOffs.Clear();
+                remaining.Parts.Clear();
+                remaining.Quantity = 1;
+            }
+            finally
+            {
+                EndBatch();
+            }
+        }
+
         private void SubscribeToTailPlates()
         {
             UnsubscribeFromTailPlates();

OpenNest.Tests/PlateManagerTests.cs

@@ -399,6 +399,166 @@ public class PlateManagerTests
         Assert.True(mgr.CanRemoveCurrent);
     }
 
+    [Fact]
+    public void ClearAll_RemovesAllButFirstAndEmptiesRemaining()
+    {
+        var nest = CreateNest();
+        var plate1 = nest.CreatePlate();
+        plate1.Parts.Add(MakePart());
+        var plate2 = nest.CreatePlate();
+        plate2.Parts.Add(MakePart());
+        var plate3 = nest.CreatePlate();
+        plate3.Parts.Add(MakePart());
+        plate3.CutOffs.Add(new CutOff(new Vector(1, 1), CutOffAxis.Vertical));
+        plate3.Quantity = 5;
+        using var mgr = new PlateManager(nest);
+        mgr.EnsureSentinel();
+        Assert.Equal(4, nest.Plates.Count);
+        mgr.LoadAt(2);
+
+        mgr.ClearAll();
+
+        // The first plate survives, empty, with its repeat quantity reset
+        Assert.Single(nest.Plates);
+        Assert.Same(plate1, nest.Plates[0]);
+        Assert.Empty(nest.Plates[0].Parts);
+        Assert.Empty(nest.Plates[0].CutOffs);
+        Assert.Equal(1, nest.Plates[0].Quantity);
+        Assert.Equal(0, mgr.CurrentIndex);
+        Assert.Same(plate1, mgr.CurrentPlate);
+    }
+
+    [Fact]
+    public void ClearAll_NeverExposesNullCurrentPlate()
+    {
+        var nest = CreateNest();
+        for (var i = 0; i < 3; i++)
+        {
+            var plate = nest.CreatePlate();
+            plate.Parts.Add(MakePart());
+        }
+        using var mgr = new PlateManager(nest);
+        mgr.EnsureSentinel();
+
+        var currentPlates = new List<Plate>();
+        mgr.CurrentPlateChanged += (s, e) => currentPlates.Add(e.Plate);
+
+        mgr.ClearAll();
+
+        // Every event during the clear reported a live plate (the one that stays)
+        Assert.NotEmpty(currentPlates);
+        Assert.All(currentPlates, p => Assert.NotNull(p));
+        Assert.All(currentPlates, p => Assert.Same(nest.Plates[0], p));
+    }
+
+    [Fact]
+    public void ClearAll_FiresPlateListAndCurrentPlateChanged()
+    {
+        var nest = CreateNest();
+        var plate1 = nest.CreatePlate();
+        plate1.Parts.Add(MakePart());
+        nest.CreatePlate();
+        using var mgr = new PlateManager(nest);
+        mgr.EnsureSentinel();
+
+        var listChanged = 0;
+        var currentChanged = 0;
+        mgr.PlateListChanged += (s, e) => listChanged++;
+        mgr.CurrentPlateChanged += (s, e) => currentChanged++;
+
+        mgr.ClearAll();
+
+        Assert.True(listChanged > 0);
+        Assert.True(currentChanged > 0);
+    }
+
+    [Fact]
+    public void ClearAll_SinglePlateWithParts_EmptiesIt()
+    {
+        var nest = CreateNest();
+        var plate1 = nest.CreatePlate();
+        plate1.Parts.Add(MakePart());
+        plate1.CutOffs.Add(new CutOff(new Vector(2, 2), CutOffAxis.Horizontal));
+        plate1.Quantity = 3;
+        using var mgr = new PlateManager(nest);
+
+        mgr.ClearAll();
+
+        Assert.Single(nest.Plates);
+        Assert.Same(plate1, nest.Plates[0]);
+        Assert.Empty(plate1.Parts);
+        Assert.Empty(plate1.CutOffs);
+        Assert.Equal(1, plate1.Quantity);
+    }
+
+    [Fact]
+    public void ClearAll_PreservesNestMetadataAndFirstPlateConfiguration()
+    {
+        var nest = CreateNest();
+        nest.Name = "my nest";
+        nest.Thickness = 0.25;
+        var defaults = nest.PlateDefaults.Size;
+        var plate1 = nest.CreatePlate();
+        plate1.Parts.Add(MakePart());
+        // Edit the survivor away from the defaults so replacement would be visible
+        plate1.Size = new Size(99, 88);
+        plate1.PartSpacing = 0.4;
+        nest.CreatePlate();
+        using var mgr = new PlateManager(nest);
+
+        mgr.ClearAll();
+
+        Assert.Equal("my nest", nest.Name);
+        Assert.Equal(0.25, nest.Thickness);
+        // The survivor keeps its own configuration; it was not replaced by a default plate
+        Assert.Same(plate1, nest.Plates[0]);
+        Assert.Equal(new Size(99, 88), nest.Plates[0].Size);
+        Assert.Equal(0.4, nest.Plates[0].PartSpacing);
+        Assert.Equal(defaults, nest.PlateDefaults.Size);
+    }
+
+    [Fact]
+    public void ClearAll_EmptyNest_DoesNothing()
+    {
+        var nest = CreateNest();
+        using var mgr = new PlateManager(nest);
+
+        mgr.ClearAll();
+
+        Assert.Empty(nest.Plates);
+    }
+
+    [Fact]
+    public void CanClearAll_ReflectsClearableState()
+    {
+        var nest = CreateNest();
+        using var mgr = new PlateManager(nest);
+
+        Assert.False(mgr.CanClearAll);
+
+        var plate1 = nest.CreatePlate();
+        Assert.False(mgr.CanClearAll); // a single untouched empty plate has nothing to clear
+
+        plate1.Quantity = 2;
+        Assert.True(mgr.CanClearAll);
+        plate1.Quantity = 1;
+        Assert.False(mgr.CanClearAll);
+
+        plate1.CutOffs.Add(new CutOff(new Vector(0, 0), CutOffAxis.Vertical));
+        Assert.True(mgr.CanClearAll);
+        plate1.CutOffs.Clear();
+        Assert.False(mgr.CanClearAll);
+
+        plate1.Parts.Add(MakePart());
+        Assert.Equal(2, nest.Plates.Count); // trailing sentinel created reactively
+        Assert.True(mgr.CanClearAll); // multiple plates are clearable
+
+        plate1.Parts.Clear();
+        // The reactive sentinel collapses the now-trailing empty pair back to one plate
+        Assert.Single(nest.Plates);
+        Assert.False(mgr.CanClearAll);
+    }
+
     [Fact]
     public void RemoveEmptyPlates_SentinelIsRestored()
     {

OpenNest/Forms/EditNestForm.cs

@@ -894,6 +894,11 @@ namespace OpenNest.Forms
             PlateManager.RemoveCurrent();
         }
 
+        public void ClearNest()
+        {
+            PlateManager.ClearAll();
+        }
+
         public void AutoSequenceCurrentPlate()
         {
             SequencePlate(PlateView.Plate);

OpenNest/Forms/MainForm.Designer.cs

@@ -102,6 +102,7 @@ namespace OpenNest.Forms
             runAutoNestToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
             autoSequenceAllPlatesToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
             mnuNestRemoveEmptyPlates = new System.Windows.Forms.ToolStripMenuItem();
+            mnuNestClear = new System.Windows.Forms.ToolStripMenuItem();
             mnuNestValidate = new System.Windows.Forms.ToolStripMenuItem();
             mnuNestPost = new System.Windows.Forms.ToolStripMenuItem();
             toolStripMenuItem19 = new System.Windows.Forms.ToolStripSeparator();
@@ -573,7 +574,7 @@ namespace OpenNest.Forms
             // 
             // mnuNest
             // 
-            mnuNest.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] { mnuNestEdit, mnuNestClamps, mnuNestImportDrawing, mnuNestShapeLibrary, mnuNestDrawingLibrary, toolStripMenuItem7, mnuNestFirstPlate, mnuNestLastPlate, toolStripMenuItem6, mnuNestNextPlate, mnuNestPreviousPlate, toolStripMenuItem12, runAutoNestToolStripMenuItem, autoSequenceAllPlatesToolStripMenuItem, mnuNestRemoveEmptyPlates, mnuNestValidate, mnuNestPost, toolStripMenuItem19, calculateCutTimeToolStripMenuItem, toolStripMenuItem22, mnuNestAutomaticCutOff, mnuNestPlanCutting, mnuNestAssignLeadIns, mnuNestRemoveLeadIns });
+            mnuNest.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] { mnuNestEdit, mnuNestClamps, mnuNestImportDrawing, mnuNestShapeLibrary, mnuNestDrawingLibrary, toolStripMenuItem7, mnuNestFirstPlate, mnuNestLastPlate, toolStripMenuItem6, mnuNestNextPlate, mnuNestPreviousPlate, toolStripMenuItem12, runAutoNestToolStripMenuItem, autoSequenceAllPlatesToolStripMenuItem, mnuNestRemoveEmptyPlates, mnuNestClear, mnuNestValidate, mnuNestPost, toolStripMenuItem19, calculateCutTimeToolStripMenuItem, toolStripMenuItem22, mnuNestAutomaticCutOff, mnuNestPlanCutting, mnuNestAssignLeadIns, mnuNestRemoveLeadIns });
             mnuNest.Name = "mnuNest";
             mnuNest.Size = new System.Drawing.Size(43, 20);
             mnuNest.Text = "&Nest";
@@ -685,6 +686,13 @@ namespace OpenNest.Forms
             mnuNestRemoveEmptyPlates.Text = "Remove Empty Plates";
             mnuNestRemoveEmptyPlates.Click += RemoveEmptyPlates_Click;
             // 
+            // mnuNestClear
+            // 
+            mnuNestClear.Name = "mnuNestClear";
+            mnuNestClear.Size = new System.Drawing.Size(205, 22);
+            mnuNestClear.Text = "Clear Nest...";
+            mnuNestClear.Click += ClearNest_Click;
+            // 
             // mnuNestValidate
             //
             mnuNestValidate.Name = "mnuNestValidate";
@@ -1401,6 +1409,7 @@ namespace OpenNest.Forms
         private System.Windows.Forms.ToolStripButton btnNew;
         private System.Windows.Forms.ToolStripMenuItem mnuPlateAdd;
         private System.Windows.Forms.ToolStripMenuItem mnuNestRemoveEmptyPlates;
+        private System.Windows.Forms.ToolStripMenuItem mnuNestClear;
         private System.Windows.Forms.ToolStripMenuItem mnuViewZoomIn;
         private System.Windows.Forms.ToolStripMenuItem mnuViewZoomOut;
         private System.Windows.Forms.ToolStripSeparator toolStripMenuItem14;

OpenNest/Forms/MainForm.File.cs

@@ -26,6 +26,7 @@ namespace OpenNest.Forms
                 NavigationEnableCheck();
                 statusBar.UpdatePlate();
                 mnuPlateRemove.Enabled = activeForm?.PlateManager.CanRemoveCurrent ?? false;
+                mnuNestClear.Enabled = activeForm?.PlateManager.CanClearAll ?? false;
             };
             editForm.WindowState = windowState;
             editForm.Show();

OpenNest/Forms/MainForm.Nest.cs

@@ -43,6 +43,8 @@ namespace OpenNest.Forms
             mnuNest.DropDown.ShowItemToolTips = true;
             mnuNestDrawingLibrary.Enabled = activeForm != null && databaseMode;
             mnuNestDrawingLibrary.ToolTipText = databaseMode ? "" : NestStorage.DatabaseModeOnly;
+            // Parts can be added without a plate change, so refresh the clear state on open.
+            mnuNestClear.Enabled = activeForm?.PlateManager.CanClearAll ?? false;
         }
 
         private async void EditNest_Click(object sender, EventArgs e)
@@ -85,6 +87,37 @@ namespace OpenNest.Forms
 
         private void RemoveEmptyPlates_Click(object sender, EventArgs e) => WithActive(f => f.Nest.Plates.RemoveEmptyPlates());
 
+        private void ClearNest_Click(object sender, EventArgs e)
+        {
+            var editForm = activeForm;
+            if (editForm == null)
+                return;
+
+            const string busy = "Finish or cancel the current nesting, save or plate action first.";
+            if (storage.IsSaving)
+            {
+                MessageBox.Show(this, busy, "Clear Nest", MessageBoxButtons.OK, MessageBoxIcon.Information);
+                return;
+            }
+
+            if (!TryBeginPlateCommand(editForm.Nest, busy, "Clear Nest"))
+                return;
+
+            var result = MessageBox.Show(
+                this,
+                "Remove all plates and parts from this nest?\nOne empty plate will remain. This cannot be undone.",
+                "Clear Nest",
+                MessageBoxButtons.YesNo,
+                MessageBoxIcon.Warning,
+                MessageBoxDefaultButton.Button2
+            );
+
+            if (result != DialogResult.Yes)
+                return;
+
+            editForm.ClearNest();
+        }
+
         private void LoadFirstPlate_Click(object sender, EventArgs e) => WithActive(f => f.PlateManager.LoadFirst());
 
         private void LoadLastPlate_Click(object sender, EventArgs e) => WithActive(f => f.PlateManager.LoadLast());

OpenNest/Forms/MainForm.Status.cs

@@ -15,6 +15,7 @@ namespace OpenNest.Forms
             btnSave.Enabled = hasValue && !storage.IsSaving;
             btnSaveAs.Enabled = hasValue && !storage.IsSaving;
             mnuFileSaveAs.Enabled = hasValue && !storage.IsSaving;
+            mnuNestClear.Enabled = activeForm?.PlateManager.CanClearAll ?? false;
             exportNestMenu.Enabled = hasValue;
             mnuFileExport.Enabled = hasValue;
             mnuFileExportAll.Enabled = hasValue;