Multi-bin nesting

SawCut/Nesting/BestFitEngine.cs

@@ -11,6 +11,8 @@ namespace SawCut.Nesting
 
         public double Spacing { get; set; }
 
+        public int MaxBinCount { get; set; } = int.MaxValue;
+
         private List<BinItem> Items { get; set; }
 
         public Result Pack(List<BinItem> items)
@@ -30,6 +32,16 @@ namespace SawCut.Nesting
 
             result.Bins = GetBins();
 
+            foreach (var bin in result.Bins)
+            {
+                foreach (var item in bin.Items)
+                {
+                    Items.Remove(item);
+                }
+            }
+
+            result.ItemsNotUsed.AddRange(Items);
+
             return result;
         }
 
@@ -46,8 +58,11 @@ namespace SawCut.Nesting
                     if (item.Length > StockLength)
                         continue;
 
-                    best_bin = CreateBin();
-                    bins.Add(best_bin);
+                    if (bins.Count < MaxBinCount)
+                    {
+                        best_bin = CreateBin();
+                        bins.Add(best_bin);
+                    }
                 }
 
                 best_bin.Items.Add(item);

SawCut/Nesting/Engine2.cs

@@ -11,6 +11,8 @@ namespace SawCut.Nesting
 
         public double Spacing { get; set; }
 
+        public int MaxBinCount { get; set; } = int.MaxValue;
+
         private List<BinItem> Items { get; set; }
 
         public Result Pack(List<BinItem> items)
@@ -30,6 +32,16 @@ namespace SawCut.Nesting
 
             result.Bins = GetBins();
 
+            foreach (var bin in result.Bins)
+            {
+                foreach (var item in bin.Items)
+                {
+                    Items.Remove(item);
+                }
+            }
+
+            result.ItemsNotUsed.AddRange(Items);
+
             return result;
         }
 
@@ -37,7 +49,7 @@ namespace SawCut.Nesting
         {
             var bins = new List<Bin>();
 
-            while (Items.Count > 0)
+            while (Items.Count > 0 && bins.Count < MaxBinCount)
             {
                 var bin = new Bin(StockLength);
                 bin.Spacing = Spacing;

SawCut/Nesting/MultiBinEngine.cs

@@ -0,0 +1,70 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace SawCut.Nesting
+{
+    public class MultiBinEngine : IEngine
+    {
+        public List<MultiBin> Bins { get; set; }
+
+        public double Spacing { get; set; }
+
+        public Result Pack(List<BinItem> items)
+        {
+            var bins = Bins
+                .Where(b => b.Length > 0)
+                .OrderByDescending(b => b.Priority)
+                .ThenBy(b => b.Length)
+                .ToList();
+
+            var result = new Result();
+            var remainingItems = new List<BinItem>(items);
+
+            foreach (var bin in bins)
+            {
+                var e = new Engine2();
+                e.MaxBinCount = bin.Quantity;
+                e.StockLength = bin.Length;
+                e.Spacing = Spacing;
+                var r = e.Pack(remainingItems);
+
+                result.Bins.AddRange(r.Bins);
+                remainingItems = r.ItemsNotUsed;
+            }
+
+            result.ItemsNotUsed = remainingItems;
+
+            // sanity check
+
+            //var itemsNested = result.Bins.SelectMany(b => b.Items).ToList();
+            //var lengths = items.Select(i => i.Length).Distinct();
+
+            //foreach (var length in lengths)
+            //{
+            //    var nameLengthGroups1 = items.Where(i => i.Length == length).GroupBy(i => i.Name).ToList();
+            //    var nameLengthGroups2 = itemsNested.Where(i => i.Length == length).GroupBy(i => i.Name).ToList();
+
+            //    foreach (var group in nameLengthGroups1)
+            //    {
+            //        var name = group.Key;
+
+            //        var nestedWithSameName = nameLengthGroups2.FirstOrDefault(g => g.Key == group.Key);
+
+            //        if (group.Count() != nestedWithSameName.Count())
+            //        {
+            //            throw new Exception("Failed sanity check.");
+
+            //        }
+            //    }
+
+            //    if (nameLengthGroups1.Count() != nameLengthGroups2.Count())
+            //    {
+            //        throw new Exception("Failed sanity check.");
+            //    }
+            //}
+
+            return result;
+        }
+    }
+}

SawCut/Nesting/Result.cs

@@ -7,6 +7,7 @@ namespace SawCut.Nesting
         public Result()
         {
             ItemsNotUsed = new List<BinItem>();
+            Bins = new List<Bin>();
         }
 
         public List<BinItem> ItemsNotUsed { get; set; }