Enhance cut list report formatting and readability

Improves the exported text file format with better organization, visual
hierarchy, and comprehensive summary information.

- Add header with creation timestamp and overall statistics
- Redesign bar sections with clearer labels and formatting
- Replace verbose item format with tabular layout (QTY/Length/Tag)
- Add final summary section with totals and best/worst utilization
- Use Unicode box-drawing characters for visual separation
- Fix namespace references (SawCut.FormatHelper → FormatHelper)
- Add null safety with DefaultIfEmpty for empty bin collections
- Make _bins field readonly for immutability

The new format is more professional and easier to scan visually, making it
simpler for operators to execute the cut list.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

CutList/Forms/BinFileSaver.cs

@@ -9,7 +9,7 @@ namespace CutList.Forms
 {
     public class BinFileSaver
     {
-        private IEnumerable<Bin> _bins;
+        private readonly IEnumerable<Bin> _bins;
 
         private int PaddingWidthOfItemLength { get; set; }
 
@@ -25,13 +25,22 @@ namespace CutList.Forms
             using (var writer = new StreamWriter(file))
             {
                 writer.AutoFlush = true;
-                PaddingWidthOfItemLength = _bins.Max(b => b.Items.Max(i => SawCut.FormatHelper.ConvertToMixedFraction(i.Length).Length));
-                var id = 1;
 
+                PaddingWidthOfItemLength = _bins
+                    .SelectMany(b => b.Items)
+                    .Select(i => FormatHelper.ConvertToMixedFraction(i.Length).Length)
+                    .DefaultIfEmpty(0)
+                    .Max();
+
+                WriteHeader(writer);
+
+                var id = 1;
                 foreach (var bin in _bins)
                 {
                     WriteBinSummary(writer, bin, id++);
                 }
+
+                WriteFinalSummary(writer);
             }
 
             if (OpenFileAfterSave)
@@ -46,38 +55,128 @@ namespace CutList.Forms
             {
                 Process.Start("notepad.exe", file);
             }
-            catch (Exception)
+            catch
             {
-                // Notepad is not installed, so just open the file
                 Process.Start(file);
             }
         }
 
+        private void WriteHeader(StreamWriter writer)
+        {
+            var totalBars = _bins.Count();
+            var totalItems = _bins.Sum(b => b.Items.Count);
+            var avgUtil = _bins.Any()
+                ? Math.Round(_bins.Average(b => b.Utilization) * 100, 1)
+                : 0;
+
+            writer.WriteLine("CUT LIST");
+            writer.WriteLine($"Created: {DateTime.Now:g}");
+            writer.WriteLine();
+
+            writer.WriteLine($"Bars: {totalBars}   Items: {totalItems}   Avg utilization: {avgUtil:0.0}%");
+            writer.WriteLine(new string('─', 80));
+            writer.WriteLine();
+        }
+
         private void WriteBinSummary(StreamWriter writer, Bin bin, int id)
         {
-            var totalLength = SawCut.FormatHelper.ConvertToMixedFraction(bin.Length);
+            var stockLength = FormatHelper.ConvertToMixedFraction(bin.Length);
-            var remainingLength = SawCut.FormatHelper.ConvertToMixedFraction(bin.RemainingLength);
+            var dropLength = FormatHelper.ConvertToMixedFraction(bin.RemainingLength);
+            var usedLengthValue = bin.Length - bin.RemainingLength;
+            var usedLength = FormatHelper.ConvertToMixedFraction(usedLengthValue);
             var utilization = Math.Round(bin.Utilization * 100, 2);
 
-            writer.WriteLine($"{id}. Length: {totalLength}, {remainingLength} remaining, {bin.Items.Count} items, {utilization}% utilization");
+            var barLabel = $"BAR {id:000}";
+
+            writer.WriteLine(barLabel);
+            writer.WriteLine(
+                $"Stock: {stockLength}   Used: {usedLength}   Drop: {dropLength}   " +
+                $"Items: {bin.Items.Count}   Utilization: {utilization:0.##}%");
+            writer.WriteLine();
+
             WriteBinItems(writer, bin);
-            writer.WriteLine("---------------------------------------------------------------------");
+
+            writer.WriteLine();
+            writer.WriteLine(new string('─', 80));
+            writer.WriteLine();
         }
 
         private void WriteBinItems(StreamWriter writer, Bin bin)
         {
-            var groups = bin.Items.GroupBy(i => $"{i.Name} {i.Length}");
+            // Group by name + length to keep same behavior as before
+            var groups = bin.Items
+                .GroupBy(i => new { i.Name, i.Length })
+                .OrderBy(g => g.Key.Name)
+                .ThenBy(g => g.Key.Length);
+
+            // Header
+            var lengthHeader = "Length".PadLeft(PaddingWidthOfItemLength);
+            writer.WriteLine($"  QTY   {lengthHeader}   TAG");
+            writer.WriteLine($"  ---   {new string('-', PaddingWidthOfItemLength)}   ----------------");
 
             foreach (var group in groups)
             {
                 var first = group.First();
                 var count = group.Count();
-                var length = SawCut.FormatHelper.ConvertToMixedFraction(first.Length).PadLeft(PaddingWidthOfItemLength);
+                var length = FormatHelper
-                var name = first.Name;
+                    .ConvertToMixedFraction(first.Length)
-                var pcsSingularOrPlural = count == 1 ? "pc " : "pcs";
+                    .PadLeft(PaddingWidthOfItemLength);
 
-                writer.WriteLine($"   {count}{pcsSingularOrPlural}  @  {length} LG   Tag: {name}");
+                var tag = first.Name;
+
+                writer.WriteLine($"  {count,3}   {length}   {tag}");
             }
         }
+
+        private void WriteFinalSummary(StreamWriter writer)
+        {
+            var totalBars = _bins.Count();
+            var totalItems = _bins.Sum(b => b.Items.Count);
+
+            var totalStock = _bins.Sum(b => b.Length);
+            var totalUsed = _bins.Sum(b => b.Length - b.RemainingLength);
+            var totalDrop = _bins.Sum(b => b.RemainingLength);
+
+            var avgUtil = _bins.Any()
+                ? Math.Round(_bins.Average(b => b.Utilization) * 100, 2)
+                : 0;
+
+            var best = _bins.OrderByDescending(b => b.Utilization).FirstOrDefault();
+            var worst = _bins.OrderBy(b => b.Utilization).FirstOrDefault();
+
+            string fmt(double v) => FormatHelper.ConvertToMixedFraction(v);
+
+            writer.WriteLine();
+            writer.WriteLine("FINAL SUMMARY");
+            writer.WriteLine(new string('═', 80));
+            writer.WriteLine();
+
+            writer.WriteLine($"Total bars:       {totalBars}");
+            writer.WriteLine($"Total items:      {totalItems}");
+            writer.WriteLine();
+
+            writer.WriteLine($"Total stock:      {fmt(totalStock)}");
+            writer.WriteLine($"Total used:       {fmt(totalUsed)}");
+            writer.WriteLine($"Total drop:       {fmt(totalDrop)}");
+            writer.WriteLine($"Average util:     {avgUtil}%");
+            writer.WriteLine();
+
+            if (best != null)
+            {
+                writer.WriteLine($"Best bar:         Util {Math.Round(best.Utilization * 100, 2)}%   " +
+                                 $"Drop {fmt(best.RemainingLength)}");
+            }
+
+            if (worst != null)
+            {
+                writer.WriteLine($"Worst bar:        Util {Math.Round(worst.Utilization * 100, 2)}%   " +
+                                 $"Drop {fmt(worst.RemainingLength)}");
+            }
+
+            writer.WriteLine();
+            writer.WriteLine(new string('═', 80));
+            writer.WriteLine("End of Report");
+        }
+
     }
-}
+}