Add frontend production project

engine/Age.Engine.Frontend/StepLimitDiagnosticFormatter.cs

@@ -0,0 +1,46 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Text;
+using Age.Engine.Model;
+
+/// <summary>Formats the bounded trace retained by the Godot frontend when the VM safety cap fires.</summary>
+public static class StepLimitDiagnosticFormatter
+{
+    public static string Format(GodotTraceSnapshot snapshot, OpcodeTable table,
+                                int topSites = 8, int tailSteps = 16)
+    {
+        string Location(GodotTraceStepSnapshot step)
+        {
+            string script = Path.GetFileNameWithoutExtension(step.Script).ToUpperInvariant();
+            string mnemonic = table.Label(step.Opcode);
+            if (string.IsNullOrEmpty(mnemonic)) mnemonic = "unknown";
+            return $"{script}@0x{step.Offset:x} op=0x{step.Opcode:x3} {mnemonic}";
+        }
+
+        var output = new StringBuilder();
+        var current = new GodotTraceStepSnapshot(
+            snapshot.CurrentScript, snapshot.CurrentOffset, snapshot.CurrentOpcode, snapshot.CurrentDepth);
+        output.AppendLine($"[step-limit] last: {Location(current)} depth={snapshot.CurrentDepth}");
+        output.AppendLine($"[step-limit] frames: {string.Join(" > ",
+            snapshot.CallStack.Select(name => Path.GetFileNameWithoutExtension(name).ToUpperInvariant()))}");
+        output.AppendLine($"[step-limit] hot sites in final {snapshot.RecentSteps.Count} steps:");
+        foreach (var site in snapshot.RecentSteps
+                     .GroupBy(step => (step.Script, step.Offset, step.Opcode))
+                     .OrderByDescending(group => group.Count())
+                     .ThenBy(group => group.Key.Script, StringComparer.Ordinal)
+                     .ThenBy(group => group.Key.Offset)
+                     .Take(Math.Max(0, topSites)))
+        {
+            var sample = new GodotTraceStepSnapshot(
+                site.Key.Script, site.Key.Offset, site.Key.Opcode, 0);
+            output.AppendLine($"[step-limit]   {site.Count(),4}x {Location(sample)}");
+        }
+
+        int tailStart = Math.Max(0, snapshot.RecentSteps.Count - Math.Max(0, tailSteps));
+        output.AppendLine($"[step-limit] final {snapshot.RecentSteps.Count - tailStart} steps:");
+        for (int index = tailStart; index < snapshot.RecentSteps.Count; index++)
+            output.AppendLine($"[step-limit]   {Location(snapshot.RecentSteps[index])}");
+        return output.ToString().TrimEnd();
+    }
+}