add $battle command for dcv1

src/ChatCommands.cc

@@ -2293,6 +2293,21 @@ static void proxy_command_item(shared_ptr<ProxyServer::LinkedSession> ses, const
   }
 }
 
+static void server_command_enable_battle_mode_v1(shared_ptr<Client> c, const std::string&) {
+  check_is_game(c->require_lobby(), false);
+  if (!is_v1(c->version())) {
+    send_text_message(c, "$C6This command can\nonly be used on\nDC v1 and earlier");
+    return;
+  }
+
+  c->config.toggle_flag(Client::Flag::FORCE_BATTLE_MODE_GAME);
+  if (c->config.check_flag(Client::Flag::FORCE_BATTLE_MODE_GAME)) {
+    send_text_message(c, "$C6Battle mode enabled\nfor next game");
+  } else {
+    send_text_message(c, "$C6Battle mode disabled\nfor next game");
+  }
+}
+
 static void server_command_enable_ep3_battle_debug_menu(shared_ptr<Client> c, const std::string& args) {
   check_debug_enabled(c);
 
@@ -2625,6 +2640,7 @@ static const unordered_map<string, ChatCommandDefinition> chat_commands({
     {"$ax", {server_command_ax, nullptr}},
     {"$ban", {server_command_ban, nullptr}},
     {"$bank", {server_command_change_bank, nullptr}},
+    {"$battle", {server_command_enable_battle_mode_v1, nullptr}},
     {"$bbchar", {server_command_bbchar, nullptr}},
     {"$cheat", {server_command_cheat, nullptr}},
     {"$debug", {server_command_debug, nullptr}},

src/Client.hh

@@ -35,7 +35,7 @@ public:
     // TODO: It'd be nice to use a pattern here (e.g. all server-side flags are
     // in the high bits) but that would require re-recording or manually
     // rewriting all the tests
-    CLIENT_SIDE_MASK                           = 0xFF3CFFFF7C0BFFFB,
+    CLIENT_SIDE_MASK                           = 0xF73CFFFF7C0BFFFB,
 
     // Version-related flags
     CHECKED_FOR_DC_V1_PROTOTYPE                = 0x0000000000000002,
@@ -80,6 +80,7 @@ public:
     DEBUG_ENABLED                              = 0x0000000800000000,
     ITEM_DROP_NOTIFICATIONS_1                  = 0x0010000000000000,
     ITEM_DROP_NOTIFICATIONS_2                  = 0x0020000000000000,
+    FORCE_BATTLE_MODE_GAME                     = 0x0800000000000000,
 
     // Proxy option flags
     PROXY_SAVE_FILES                           = 0x0000001000000000,

src/ReceiveCommands.cc

@@ -4570,8 +4570,9 @@ static void on_0C_C1_E7_EC(shared_ptr<Client> c, uint16_t command, uint32_t, str
 
     GameMode mode = GameMode::NORMAL;
     bool spectators_forbidden = false;
-    if (cmd.battle_mode) {
+    if (cmd.battle_mode || c->config.check_flag(Client::Flag::FORCE_BATTLE_MODE_GAME)) {
       mode = GameMode::BATTLE;
+      c->config.clear_flag(Client::Flag::FORCE_BATTLE_MODE_GAME);
     }
     if (cmd.challenge_mode) {
       if (client_is_ep3) {