From d0351ab765102c7a406c289c900d959324234b0b Mon Sep 17 00:00:00 2001
From: AJ Isaacs <ajisaacs27@gmail.com>
Date: Mon, 16 Mar 2026 00:27:57 -0400
Subject: [PATCH] feat: add directional part sequencers (RightSide, LeftSide,
 BottomSide)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 .../Sequencing/BottomSideSequencer.cs         | 17 +++++
 .../Sequencing/LeftSideSequencer.cs           | 17 +++++
 .../Sequencing/RightSideSequencer.cs          | 17 +++++
 .../Sequencing/DirectionalSequencerTests.cs   | 75 +++++++++++++++++++
 4 files changed, 126 insertions(+)
 create mode 100644 OpenNest.Engine/Sequencing/BottomSideSequencer.cs
 create mode 100644 OpenNest.Engine/Sequencing/LeftSideSequencer.cs
 create mode 100644 OpenNest.Engine/Sequencing/RightSideSequencer.cs
 create mode 100644 OpenNest.Tests/Sequencing/DirectionalSequencerTests.cs

diff --git a/OpenNest.Engine/Sequencing/BottomSideSequencer.cs b/OpenNest.Engine/Sequencing/BottomSideSequencer.cs
new file mode 100644
index 0000000..de06053
--- /dev/null
+++ b/OpenNest.Engine/Sequencing/BottomSideSequencer.cs
@@ -0,0 +1,17 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace OpenNest.Engine.Sequencing
+{
+    public class BottomSideSequencer : IPartSequencer
+    {
+        public List<SequencedPart> Sequence(IReadOnlyList<Part> parts, Plate plate)
+        {
+            return parts
+                .OrderBy(p => p.Location.Y)
+                .ThenBy(p => p.Location.X)
+                .Select(p => new SequencedPart { Part = p })
+                .ToList();
+        }
+    }
+}
diff --git a/OpenNest.Engine/Sequencing/LeftSideSequencer.cs b/OpenNest.Engine/Sequencing/LeftSideSequencer.cs
new file mode 100644
index 0000000..ca0f20a
--- /dev/null
+++ b/OpenNest.Engine/Sequencing/LeftSideSequencer.cs
@@ -0,0 +1,17 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace OpenNest.Engine.Sequencing
+{
+    public class LeftSideSequencer : IPartSequencer
+    {
+        public List<SequencedPart> Sequence(IReadOnlyList<Part> parts, Plate plate)
+        {
+            return parts
+                .OrderBy(p => p.Location.X)
+                .ThenBy(p => p.Location.Y)
+                .Select(p => new SequencedPart { Part = p })
+                .ToList();
+        }
+    }
+}
diff --git a/OpenNest.Engine/Sequencing/RightSideSequencer.cs b/OpenNest.Engine/Sequencing/RightSideSequencer.cs
new file mode 100644
index 0000000..f804a38
--- /dev/null
+++ b/OpenNest.Engine/Sequencing/RightSideSequencer.cs
@@ -0,0 +1,17 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace OpenNest.Engine.Sequencing
+{
+    public class RightSideSequencer : IPartSequencer
+    {
+        public List<SequencedPart> Sequence(IReadOnlyList<Part> parts, Plate plate)
+        {
+            return parts
+                .OrderByDescending(p => p.Location.X)
+                .ThenBy(p => p.Location.Y)
+                .Select(p => new SequencedPart { Part = p })
+                .ToList();
+        }
+    }
+}
diff --git a/OpenNest.Tests/Sequencing/DirectionalSequencerTests.cs b/OpenNest.Tests/Sequencing/DirectionalSequencerTests.cs
new file mode 100644
index 0000000..0a64a98
--- /dev/null
+++ b/OpenNest.Tests/Sequencing/DirectionalSequencerTests.cs
@@ -0,0 +1,75 @@
+using System.Collections.Generic;
+using OpenNest.CNC;
+using OpenNest.Engine.Sequencing;
+using OpenNest.Geometry;
+using Xunit;
+
+namespace OpenNest.Tests.Sequencing;
+
+public class DirectionalSequencerTests
+{
+    private static Part MakePartAt(double x, double y) => TestHelpers.MakePartAt(x, y);
+    private static Plate MakePlate(params Part[] parts) => TestHelpers.MakePlate(60, 120, parts);
+
+    [Fact]
+    public void RightSide_SortsXDescending()
+    {
+        var a = MakePartAt(10, 5);
+        var b = MakePartAt(30, 5);
+        var c = MakePartAt(20, 5);
+        var plate = MakePlate(a, b, c);
+
+        var sequencer = new RightSideSequencer();
+        var result = sequencer.Sequence(plate.Parts.ToList(), plate);
+
+        Assert.Same(b, result[0].Part);
+        Assert.Same(c, result[1].Part);
+        Assert.Same(a, result[2].Part);
+    }
+
+    [Fact]
+    public void LeftSide_SortsXAscending()
+    {
+        var a = MakePartAt(10, 5);
+        var b = MakePartAt(30, 5);
+        var c = MakePartAt(20, 5);
+        var plate = MakePlate(a, b, c);
+
+        var sequencer = new LeftSideSequencer();
+        var result = sequencer.Sequence(plate.Parts.ToList(), plate);
+
+        Assert.Same(a, result[0].Part);
+        Assert.Same(c, result[1].Part);
+        Assert.Same(b, result[2].Part);
+    }
+
+    [Fact]
+    public void BottomSide_SortsYAscending()
+    {
+        var a = MakePartAt(5, 20);
+        var b = MakePartAt(5, 5);
+        var c = MakePartAt(5, 10);
+        var plate = MakePlate(a, b, c);
+
+        var sequencer = new BottomSideSequencer();
+        var result = sequencer.Sequence(plate.Parts.ToList(), plate);
+
+        Assert.Same(b, result[0].Part);
+        Assert.Same(c, result[1].Part);
+        Assert.Same(a, result[2].Part);
+    }
+
+    [Fact]
+    public void RightSide_TiesBrokenByPerpendicularAxis()
+    {
+        var a = MakePartAt(10, 20);
+        var b = MakePartAt(10, 5);
+        var plate = MakePlate(a, b);
+
+        var sequencer = new RightSideSequencer();
+        var result = sequencer.Sequence(plate.Parts.ToList(), plate);
+
+        Assert.Same(b, result[0].Part);
+        Assert.Same(a, result[1].Part);
+    }
+}