refactor(engine): share jobs placement identity and progress mechanics

OpenNest.Engine/Jobs/Placement/StripPlateNester.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using System.Threading;
 
 using OpenNest.Engine.Jobs.Adapters;
@@ -11,17 +10,15 @@ namespace OpenNest.Engine.Jobs.Placement;
 /// remaining demand is read from the request and placement counts are derived from returned placements.
 /// </summary>
 /// <remarks>
-/// A private <see cref="Drawing"/> per requirement is created once per solve and reused across trials
+/// The identity/progress boundary mechanics live in <see cref="CandidatePlacementContext"/>: a private
+/// <see cref="Drawing"/> per requirement is created once per solve and reused across trials
 /// (safe: the engine mutates per-trial <see cref="NestItem.Quantity"/> and canonical copies, never the
 /// shared Drawing). Identity is by Drawing reference. Each trial gets a fresh private <see cref="Plate"/>.
 /// </remarks>
 public sealed class StripPlateNester : IPlateNester
 {
     private readonly Func<Plate, StripNestEngine> engineFactory;
-    private readonly Dictionary<string, Drawing> drawingsById = new(StringComparer.Ordinal);
-    private readonly Dictionary<Drawing, string> idByDrawing = new(
-        ReferenceEqualityComparer.Instance
-    );
+    private readonly CandidatePlacementContext context = new();
 
     public StripPlateNester()
         : this(static plate => new StripNestEngine(plate)) { }
@@ -43,28 +40,7 @@ public sealed class StripPlateNester : IPlateNester
         token.ThrowIfCancellationRequested();
 
         var plate = DrawingJobMapper.CreatePlate(request.Stock);
-        var items = new List<NestItem>(request.Parts.Count);
-        foreach (var requirement in request.Parts)
-        {
-            if (!drawingsById.TryGetValue(requirement.Id, out var drawing))
-            {
-                drawing = DrawingJobMapper.CreateDrawing(requirement);
-                drawingsById.Add(requirement.Id, drawing);
-                idByDrawing.Add(drawing, requirement.Id);
-            }
-
-            items.Add(
-                new NestItem
-                {
-                    Drawing = drawing,
-                    Quantity = requirement.Quantity,
-                    Priority = requirement.Priority,
-                    StepAngle = DrawingJobMapper.LegacyStep(requirement.Rotation),
-                    RotationStart = requirement.Rotation.Start,
-                    RotationEnd = requirement.Rotation.End,
-                }
-            );
-        }
+        var items = context.CreateItems(request.Parts);
 
         var engine =
             engineFactory(plate)
@@ -75,18 +51,6 @@ public sealed class StripPlateNester : IPlateNester
         if (parts == null)
             throw new InvalidOperationException("Engine returned null placements.");
 
-        var placements = new List<NestJobPlacement>(parts.Count);
-        foreach (var part in parts)
-        {
-            if (part?.BaseDrawing == null || !idByDrawing.TryGetValue(part.BaseDrawing, out var id))
-                throw new InvalidOperationException(
-                    "Placement does not reference a known requirement drawing."
-                );
-            placements.Add(
-                new NestJobPlacement(id, 0, part.Location.X, part.Location.Y, part.Rotation)
-            );
-        }
-
-        return new PlateCandidate(placements);
+        return new PlateCandidate(context.MapPlacements(parts));
     }
 }