feat(console): add testable ConsoleInputPump rendezvous with EOF handling

Projects/Server/Console/ConsoleInputPump.cs

@@ -0,0 +1,138 @@
+using System;
+using System.IO;
+using System.Threading;
+
+namespace Server;
+
+/// <summary>
+/// Owns a console input stream. Each line read is atomically either delivered to a
+/// waiting <see cref="ReadLine"/> caller (a prompt) or dispatched as a command via the
+/// supplied lookup. EOF ends the loop instead of spinning. Correct-by-construction:
+/// the prompt-vs-command decision is made under a single lock at the moment a line is read.
+/// </summary>
+internal sealed class ConsoleInputPump
+{
+    private readonly TextReader _input;
+    private readonly Func<string, Action<string>> _lookup;
+    private readonly object _gate = new();
+    private readonly AutoResetEvent _promptDelivered = new(false);
+
+    private bool _promptPending;
+    private string _promptResult;
+    private volatile bool _running = true;
+
+    public ConsoleInputPump(TextReader input, Func<string, Action<string>> lookup)
+    {
+        _input = input ?? throw new ArgumentNullException(nameof(input));
+        _lookup = lookup ?? throw new ArgumentNullException(nameof(lookup));
+    }
+
+    public bool Running => _running;
+
+    public void Stop()
+    {
+        _running = false;
+        ReleasePendingPrompt(null);
+    }
+
+    public void Run()
+    {
+        while (_running && !Core.Closing)
+        {
+            string line;
+            try
+            {
+                line = _input.ReadLine();
+            }
+            catch
+            {
+                break;
+            }
+
+            if (line == null)
+            {
+                break; // EOF — never spin
+            }
+
+            bool isCommand;
+            lock (_gate)
+            {
+                if (_promptPending)
+                {
+                    _promptResult = line;
+                    _promptPending = false;
+                    _promptDelivered.Set();
+                    isCommand = false;
+                }
+                else
+                {
+                    isCommand = true;
+                }
+            }
+
+            if (!isCommand)
+            {
+                continue;
+            }
+
+            var trimmed = line.Trim();
+            if (trimmed.Length == 0)
+            {
+                continue;
+            }
+
+            var split = trimmed.Split(' ', 2);
+            var action = _lookup(split[0].ToLower());
+            if (action == null)
+            {
+                continue;
+            }
+
+            try
+            {
+                action(split.Length > 1 ? split[1] : string.Empty);
+            }
+            catch
+            {
+                // Command handlers log their own failures; never let one kill the loop.
+            }
+        }
+
+        _running = false;
+        ReleasePendingPrompt(null);
+    }
+
+    public string ReadLine()
+    {
+        lock (_gate)
+        {
+            if (!_running)
+            {
+                return null;
+            }
+
+            _promptResult = null;
+            _promptPending = true;
+        }
+
+        _promptDelivered.WaitOne();
+
+        lock (_gate)
+        {
+            return _promptResult;
+        }
+    }
+
+    private void ReleasePendingPrompt(string result)
+    {
+        lock (_gate)
+        {
+            if (_promptPending)
+            {
+                _promptResult = result;
+                _promptPending = false;
+                _promptDelivered.Set();
+            }
+        }
+    }
+}