feat(io): persist part cutting programs and plate parameters

OpenNest.Core/DrawingProgramSnapshot.cs

@@ -0,0 +1,79 @@
+using System;
+using System.Collections.Generic;
+using OpenNest.CNC;
+
+namespace OpenNest;
+
+/// <summary>
+/// Captures drawing program text before an edit and rebuilds only the parts whose
+/// drawing program changed. Drawing keys use reference identity because names are editable.
+/// </summary>
+public sealed class DrawingProgramSnapshot
+{
+    private readonly Dictionary<Drawing, string> programs;
+    private readonly Func<Program, string> fingerprint;
+
+    private DrawingProgramSnapshot(
+        Dictionary<Drawing, string> programs,
+        Func<Program, string> fingerprint)
+    {
+        this.programs = programs;
+        this.fingerprint = fingerprint;
+    }
+
+    /// <summary>
+    /// Capture before handing drawings to an editor, including its load operation:
+    /// programs can be edited in place. The callback must include both the main
+    /// program text and its hole sub-programs, and must not mutate the program.
+    /// </summary>
+    public static DrawingProgramSnapshot Capture(
+        IEnumerable<Drawing> drawings,
+        Func<Program, string> fingerprint)
+    {
+        ArgumentNullException.ThrowIfNull(drawings);
+        ArgumentNullException.ThrowIfNull(fingerprint);
+        var programs = new Dictionary<Drawing, string>(ReferenceEqualityComparer.Instance);
+
+        foreach (var drawing in drawings)
+        {
+            if (!drawing.IsCutOff && !programs.ContainsKey(drawing))
+                programs.Add(drawing, fingerprint(drawing.Program));
+        }
+
+        return new DrawingProgramSnapshot(programs, fingerprint);
+    }
+
+    /// <summary>
+    /// Complete the captured edit by rebuilding changed drawings' parts across all plates.
+    /// Part.Update preserves the placement and clears obsolete lead-ins, tabs and locks.
+    /// Unchanged and uncaptured drawings' parts retain their program instances and state.
+    /// Returns the rebuilt parts so a UI can invalidate just their graphics.
+    /// </summary>
+    public IReadOnlyList<Part> UpdateChangedParts(IEnumerable<Plate> plates)
+    {
+        ArgumentNullException.ThrowIfNull(plates);
+        var changed = new HashSet<Drawing>(ReferenceEqualityComparer.Instance);
+
+        foreach (var entry in programs)
+        {
+            if (!entry.Key.IsCutOff
+                && !string.Equals(entry.Value, fingerprint(entry.Key.Program), StringComparison.Ordinal))
+                changed.Add(entry.Key);
+        }
+
+        var updated = new List<Part>();
+        foreach (var plate in plates)
+        {
+            foreach (var part in plate.Parts)
+            {
+                if (!changed.Contains(part.BaseDrawing))
+                    continue;
+
+                part.Update();
+                updated.Add(part);
+            }
+        }
+
+        return updated;
+    }
+}

OpenNest.Core/Part.cs

@@ -111,6 +111,30 @@ namespace OpenNest
             UpdateBounds();
         }
 
+        /// <summary>
+        /// Installs an owned, already-rotated saved cutting program without rotating it again.
+        /// The current pose remains the clean-drawing pose used by RemoveLeadIns.
+        /// </summary>
+        public bool RestoreLeadInProgram(Program program, bool locked)
+        {
+            if (program == null || !program.Codes.Any(code => code is Motion
+                || code is SubProgramCall call && call.Program != null
+                    && call.Program.Codes.Any(subCode => subCode is Motion)))
+                return false;
+
+            // Compute before changing state, so a malformed program cannot half-install.
+            var bounds = program.BoundingBox();
+            bounds.Offset(Location);
+            preLeadInRotation = Rotation;
+            Program = program;
+            ownsProgram = true;
+            HasManualLeadIns = true;
+            LeadInsLocked = locked;
+            CuttingParameters = null;
+            BoundingBox = bounds;
+            return true;
+        }
+
         public void RemoveLeadIns()
         {
             var rotation = preLeadInRotation;