document the CARD lobby battle table commands

src/Client.cc

@@ -53,6 +53,8 @@ Client::Client(
           bufferevent_get_base(bev), -1, EV_TIMEOUT | EV_PERSIST,
           &Client::dispatch_save_game_data, this),
         event_free),
+    card_battle_table_number(-1),
+    card_battle_table_seat_number(0),
     next_exp_value(0),
     override_section_id(-1),
     override_random_seed(-1),

src/Client.hh

@@ -105,6 +105,8 @@ struct Client {
   int64_t preferred_lobby_id; // <0 = no preference
   ClientGameData game_data;
   std::unique_ptr<struct event, void(*)(struct event*)> save_game_data_event;
+  int16_t card_battle_table_number;
+  uint8_t card_battle_table_seat_number;
 
   // Miscellaneous (used by chat commands)
   uint32_t next_exp_value; // next EXP value to give

src/CommandFormats.hh

@@ -2430,10 +2430,12 @@ struct S_PlayerPreview_NoPlayer_BB_00E4 {
   le_uint32_t error; // 2 = no player present
 };
 
-// E5 (C->S): Unknown (CARD lobby battle table) (Episode 3)
+// E5 (C->S): Confirm CARD lobby battle table choice (Episode 3)
+// header.flag specifies whether the client answered "Yes" (1) or "No" (0).
 
-struct S_CardBattleTable_Unknown_GC_Ep3_E5 {
+struct S_CardBattleTableConfirmation_GC_Ep3_E5 {
-  le_uint32_t unknown_a1;
+  le_uint16_t table_number;
+  le_uint16_t seat_number;
 };
 
 // E5 (S->C): Player preview (BB)

src/ReceiveCommands.cc

@@ -770,6 +770,41 @@ static void on_ep3_meseta_transaction(shared_ptr<ServerState>,
   send_command(c, command, 0x03, &out_cmd, sizeof(out_cmd));
 }
 
+static void on_ep3_battle_table_state(shared_ptr<ServerState> s,
+    shared_ptr<Client> c, uint16_t, uint32_t flag, const string& data) { // E4
+  const auto& cmd = check_size_t<C_CardBattleTableState_GC_Ep3_E4>(data);
+  auto l = s->find_lobby(c->lobby_id);
+  if (l->is_game() || !(l->flags & Lobby::Flag::EPISODE_3_ONLY)) {
+    throw runtime_error("battle table command sent in non-CARD lobby");
+  }
+
+  if (flag) {
+    c->card_battle_table_number = cmd.table_number;
+    c->card_battle_table_seat_number = cmd.seat_number;
+  } else {
+    c->card_battle_table_number = -1;
+    c->card_battle_table_seat_number = 0;
+  }
+  send_ep3_card_battle_table_state(l, c->card_battle_table_number);
+  // TODO: If a client disconnects while at the battle table, we need to send
+  // a table update to all the other clients at the table (if any). Use a
+  // disconnect hook for this.
+}
+
+static void on_ep3_battle_table_confirm(shared_ptr<ServerState> s,
+    shared_ptr<Client> c, uint16_t, uint32_t flag, const string& data) { // E4
+  check_size_t<S_CardBattleTableConfirmation_GC_Ep3_E5>(data);
+  auto l = s->find_lobby(c->lobby_id);
+  if (l->is_game() || !(l->flags & Lobby::Flag::EPISODE_3_ONLY)) {
+    throw runtime_error("battle table command sent in non-CARD lobby");
+  }
+
+  if (flag) {
+    // TODO
+    send_lobby_message_box(c, u"CARD battles are\nnot yet supported.");
+  }
+}
+
 static void on_ep3_counter_state(shared_ptr<ServerState>, shared_ptr<Client> c,
     uint16_t, uint32_t flag, const string& data) { // DC
   check_size_v(data.size(), 0);
@@ -3226,8 +3261,8 @@ static on_command_t handlers[0x100][6] = {
   /* E1 */ {nullptr,                 nullptr,                    nullptr,                         nullptr,                     nullptr,                     nullptr,                        }, /* E1 */
   /* E2 */ {nullptr,                 nullptr,                    nullptr,                         on_ep3_tournament_control,   nullptr,                     on_update_key_config_bb,        }, /* E2 */
   /* E3 */ {nullptr,                 nullptr,                    nullptr,                         nullptr,                     nullptr,                     on_player_preview_request_bb,   }, /* E3 */
-  /* E4 */ {nullptr,                 nullptr,                    nullptr,                         on_ignored_command,          nullptr,                     nullptr,                        }, /* E4 */
+  /* E4 */ {nullptr,                 nullptr,                    nullptr,                         on_ep3_battle_table_state,   nullptr,                     nullptr,                        }, /* E4 */
-  /* E5 */ {nullptr,                 nullptr,                    nullptr,                         nullptr,                     nullptr,                     on_create_character_bb,         }, /* E5 */
+  /* E5 */ {nullptr,                 nullptr,                    nullptr,                         on_ep3_battle_table_confirm, nullptr,                     on_create_character_bb,         }, /* E5 */
   /* E6 */ {nullptr,                 nullptr,                    nullptr,                         nullptr,                     nullptr,                     nullptr,                        }, /* E6 */
   /* E7 */ {nullptr,                 nullptr,                    nullptr,                         nullptr,                     nullptr,                     on_return_player_data_bb,       }, /* E7 */
   /* E8 */ {nullptr,                 nullptr,                    nullptr,                         nullptr,                     nullptr,                     on_client_checksum_bb,          }, /* E8 */

src/SendCommands.cc

@@ -1649,6 +1649,38 @@ void send_ep3_map_data(shared_ptr<ServerState> s, shared_ptr<Lobby> l, uint32_t
   send_command(l, 0x6C, 0x00, w.str());
 }
 
+void send_ep3_card_battle_table_state(shared_ptr<Lobby> l, uint16_t table_number) {
+  S_CardBattleTableState_GC_Ep3_E4 cmd;
+  for (size_t z = 0; z < 4; z++) {
+    cmd.entries[z].present = 0;
+    cmd.entries[z].unknown_a1 = 0;
+    cmd.entries[z].guild_card_number = 0;
+  }
+
+  set<shared_ptr<Client>> clients;
+  for (const auto& c : l->clients) {
+    if (!c) {
+      continue;
+    }
+    if (c->card_battle_table_number == table_number) {
+      if (c->card_battle_table_seat_number > 3) {
+        throw runtime_error("invalid battle table seat number");
+      }
+      auto& e = cmd.entries[c->card_battle_table_seat_number];
+      if (e.present) {
+        throw runtime_error("multiple clients in the same battle table seat");
+      }
+      e.present = 1;
+      e.guild_card_number = c->license->serial_number;
+      clients.emplace(c);
+    }
+  }
+
+  for (const auto& c : clients) {
+    send_command_t(c, 0xE4, table_number, cmd);
+  }
+}
+
 void set_mask_for_ep3_game_command(void* vdata, size_t size, uint8_t mask_key) {
   if (size < 8) {
     throw logic_error("Episode 3 game command is too short for masking");

src/SendCommands.hh

@@ -264,6 +264,7 @@ void send_ep3_map_list(
     std::shared_ptr<ServerState> s, std::shared_ptr<Lobby> l);
 void send_ep3_map_data(
     std::shared_ptr<ServerState> s, std::shared_ptr<Lobby> l, uint32_t map_id);
+void send_ep3_card_battle_table_state(std::shared_ptr<Lobby> l, uint16_t table_number);
 
 // Pass mask_key = 0 to unmask the command
 void set_mask_for_ep3_game_command(void* vdata, size_t size, uint8_t mask_key);