Move production code into place

src/console/CommandTree/CommandTreeExtensions.cs

@@ -0,0 +1,82 @@
+using System;
+using System.Collections.Immutable;
+using System.Linq;
+using System.Text;
+
+namespace Shamir.Console
+{
+    public static class CommandTreeExtensions
+    {
+        public static ICommand FindCommand(this ICommandTree tree, ReadOnlySpan<string> args)
+        {
+            if (tree is null)
+            {
+                throw new ArgumentNullException(nameof(tree));
+            }
+
+            return tree.FindCommand(ImmutableStack<ICommandTree>.Empty, args);
+        }
+
+        public static string BuildHelpText(IImmutableStack<ICommandTree> path)
+        {
+            var sb = new StringBuilder();
+            sb.AppendLine("Group");
+            sb.Append("    ");
+
+            var pathNodes = path.ToArray();
+            for (var i = pathNodes.Length - 1; i > 0; i--)
+            {
+                sb.Append(pathNodes[i].Name);
+                sb.Append(' ');
+            }
+
+            var tree = pathNodes[0];
+            sb.Append(tree.Name);
+            sb.Append(" : ");
+            sb.AppendLine(tree.Description);
+            sb.AppendLine();
+
+            if (!tree.SubTrees.IsEmpty)
+            {
+                sb.AppendLine("Subgroups:");
+
+                var maxSpacing = tree.SubTrees.Max(c => c.Name.Length) + 1;
+                
+                foreach (var child in tree.SubTrees)
+                {
+                    sb.Append("    ");
+                    sb.Append(child.Name);
+                    for (var i = 0; i < maxSpacing - child.Name.Length; i++)
+                    {
+                        sb.Append(' ');
+                    }
+                    sb.Append(": ");
+                    sb.AppendLine(child.Description);
+                }
+
+                sb.AppendLine();
+            }
+
+            if (!tree.Commands.IsEmpty)
+            {
+                sb.AppendLine("Commands:");
+
+                var maxSpacing = tree.Commands.Max(c => c.Name.Length) + 1;
+                
+                foreach (var command in tree.Commands)
+                {
+                    sb.Append("    ");
+                    sb.Append(command.Name);
+                    for (var i = 0; i < maxSpacing - command.Name.Length; i++)
+                    {
+                        sb.Append(' ');
+                    }
+                    sb.Append(": ");
+                    sb.AppendLine(command.Description);
+                }
+            }
+            
+            return sb.ToString();
+        }
+    }
+}