expand proxy options, catch invalid commands from server

src/ChatCommands.cc

@@ -200,6 +200,11 @@ static void server_command_dbgid(shared_ptr<ServerState>, shared_ptr<Lobby>,
 
 static void server_command_proxygc(shared_ptr<ServerState>, shared_ptr<Lobby>,
     shared_ptr<Client> c, const std::u16string& args) {
+  if (args.empty()) {
+    client_options_cache.delete_key(
+        string_printf("proxy_remote_guild_card_number:%" PRIX32, c->license->serial_number));
+    send_text_message(c, u"Proxy remote Guild\nCard number cleared");
+  } else {
     uint32_t proxy_remote_guild_card_number = stoll(encode_sjis(args), nullptr, 0);
     client_options_cache.replace(
         string_printf("proxy_remote_guild_card_number:%" PRIX32, c->license->serial_number),
@@ -207,6 +212,7 @@ static void server_command_proxygc(shared_ptr<ServerState>, shared_ptr<Lobby>,
     send_text_message_printf(c, "Proxy remote Guild\nCard number set to\n$C6%" PRIu32,
         proxy_remote_guild_card_number);
   }
+}
 
 static void proxy_command_proxygc(shared_ptr<ServerState>,
     ProxyServer::LinkedSession& session, const std::u16string& args) {

src/ProxyServer.cc

@@ -663,6 +663,12 @@ void ProxyServer::LinkedSession::on_error(Channel& ch, short events) {
   }
 }
 
+void ProxyServer::LinkedSession::clear_lobby_players(size_t num_slots) {
+  this->lobby_players.clear();
+  this->lobby_players.resize(num_slots);
+  this->log.info("Cleared lobby players");
+}
+
 void ProxyServer::LinkedSession::send_to_game_server(const char* error_message) {
   // Delete all the other players
   for (size_t x = 0; x < this->lobby_players.size(); x++) {

src/ProxyServer.hh

@@ -147,6 +147,8 @@ public:
     static void on_error(Channel& ch, short events);
     void on_timeout();
 
+    void clear_lobby_players(size_t num_slots);
+
     void send_to_game_server(const char* error_message = nullptr);
     void disconnect();