Add command auto-unregister mechanism (#1492)

* Add command auto-unregister mechanism

* Improve logic

MinecraftClient/ChatBot.cs

@@ -40,6 +40,7 @@ namespace MinecraftClient
         private McClient _handler = null;
         private ChatBot master = null;
         private List<string> registeredPluginChannels = new List<String>();
+        private List<string> registeredCommands = new List<string>();
         private McClient Handler
         {
             get
@@ -781,6 +782,10 @@ namespace MinecraftClient
         /// </summary>
         protected void UnloadBot()
         {
+            foreach (string cmdName in registeredCommands)
+            {
+                Handler.UnregisterCommand(cmdName);
+            }
             Handler.BotUnLoad(this);
         }
 
@@ -1261,7 +1266,7 @@ namespace MinecraftClient
         }
 
         /// <summary>
-        /// Register a command in command prompt
+        /// Register a command in command prompt. Command will be automatically unregistered when unloading ChatBot
         /// </summary>
         /// <param name="cmdName">Name of the command</param>
         /// <param name="cmdDesc">Description/usage of the command</param>
@@ -1269,7 +1274,10 @@ namespace MinecraftClient
         /// <returns>True if successfully registered</returns>
         protected bool RegisterChatBotCommand(string cmdName, string cmdDesc, string cmdUsage, CommandRunner callback)
         {
-            return Handler.RegisterCommand(cmdName, cmdDesc, cmdUsage, callback);
+            bool result = Handler.RegisterCommand(cmdName, cmdDesc, cmdUsage, callback);
+            if (result)
+                registeredCommands.Add(cmdName.ToLower());
+            return result;
         }
 
         /// <summary>

MinecraftClient/McClient.cs

@@ -629,6 +629,26 @@ namespace MinecraftClient
             }
         }
 
+        /// <summary>
+        /// Unregister a console command
+        /// </summary>
+        /// <remarks>
+        /// There is no check for the command is registered by above method or is embedded command.
+        /// Which mean this can unload any command
+        /// </remarks>
+        /// <param name="cmdName">The name of command to be unregistered</param>
+        /// <returns></returns>
+        public bool UnregisterCommand(string cmdName)
+        {
+            if (cmds.ContainsKey(cmdName.ToLower()))
+            {
+                cmds.Remove(cmdName.ToLower());
+                cmd_names.Remove(cmdName.ToLower());
+                return true;
+            }
+            else return false;
+        }
+
         #region Management: Load/Unload ChatBots and Enable/Disable settings
 
         /// <summary>