implement Ep3 card trade window

src/CommandFormats.hh

@@ -2711,35 +2711,39 @@ union C_UpdateAccountData_BB_ED {
   parray<uint8_t, 0x140> challenge_battle_config; // 08ED
 };
 
-// EE (S->C): Unknown (Episode 3)
-// This command has different forms depending on the header.flag value. Since
-// the relevant flag values match the Episodes 1 & 2 trade window commands, this
-// is likely used for trading cards.
+// EE (S->C): Trade cards sequence (Episode 3)
+// This command has different forms depending on the header.flag value; the flag
+// values match the command numbers from the Episodes 1&2 trade window sequence.
+// The general sequence of events with the EE command also matches that of the
+// Episodes 1&2 trade - see the description of the D0 command for details.
 
-struct C_Unknown_GC_Ep3_EE_FlagD0 {
-  parray<le_uint32_t, 9> unknown_a1;
-};
-
-struct S_Unknown_GC_Ep3_EE_FlagD1 {
-  le_uint32_t unknown_a1;
-};
-
-// EE D2 04 00 (C->S) - no arguments
-
-struct S_Unknown_GC_Ep3_EE_FlagD3 {
-  le_uint16_t unknown_a1;
-  le_uint16_t unknown_a2;
+// EE D0 (C->S): Begin trade
+struct SC_TradeCards_GC_Ep3_EE_FlagD0_FlagD3 {
+  le_uint16_t target_client_id;
+  le_uint16_t entry_count;
   struct Entry {
-    le_uint32_t unknown_a1;
-    le_uint32_t unknown_a2;
+    le_uint32_t card_type;
+    le_uint32_t count;
   };
   Entry entries[4];
 };
 
-// EE D4 04 00 (C->S) - no arguments
+// EE D1 (S->C): Advance trade state
+struct S_AdvanceCardTradeState_GC_Ep3_EE_FlagD1 {
+  le_uint32_t unused;
+};
 
-struct S_Unknown_GC_Ep3_EE_FlagD4 {
-  le_uint32_t unknown_a1;
+// EE D2 (C->S): Trade can proceed
+// No arguments
+
+// EE D3 (S->C): Execute trade
+// Same format as EE D0
+
+// EE D4 (C->S): Trade failed
+// EE D4 (S->C): Trade complete
+
+struct S_CardTradeComplete_GC_Ep3_EE_FlagD4 {
+  le_uint32_t success; // 0 = failed, 1 = success, anything else = invalid
 };
 
 // EE (S->C): Scrolling message (BB)

src/Player.hh

@@ -5,6 +5,7 @@
 
 #include <string>
 #include <vector>
+#include <utility>
 #include <phosg/Encoding.hh>
 
 #include "LevelTable.hh"
@@ -91,6 +92,12 @@ struct PendingItemTrade {
   std::vector<ItemData> items;
 };
 
+struct PendingCardTrade {
+  uint8_t other_client_id;
+  bool confirmed; // true if client has sent an EE D2 command
+  std::vector<std::pair<uint32_t, uint32_t>> card_to_count;
+};
+
 
 
 struct PlayerDispDataBB;
@@ -494,8 +501,9 @@ public:
 
   // The following fields are not saved, and are only used in certain situations
 
-  // Null unless the client is within the trade sequence (D0-D4 commands)
+  // Null unless the client is within the trade sequence (D0-D4 or EE commands)
   std::unique_ptr<PendingItemTrade> pending_item_trade;
+  std::unique_ptr<PendingCardTrade> pending_card_trade;
 
   // Null unless the client is Episode 3 and has sent its config already
   std::shared_ptr<Ep3Config> ep3_config;

src/ReceiveCommands.cc

@@ -2682,6 +2682,114 @@ static void on_trade_error(shared_ptr<ServerState> s, shared_ptr<Client> c,
 
 
 
+static void on_card_trade(shared_ptr<ServerState> s, shared_ptr<Client> c,
+    uint16_t, uint32_t flag, const string& data) { // EE
+  if (!(c->flags & Client::Flag::IS_EPISODE_3)) {
+    throw runtime_error("non-Ep3 client sent card trade command");
+  }
+  auto l = s->find_lobby(c->lobby_id);
+  if (!(l->flags & Lobby::Flag::EPISODE_3_ONLY)) {
+    throw runtime_error("client sent card trade command outside of Ep3 lobby");
+  }
+  if (!l->is_game()) {
+    throw runtime_error("client sent card trade command in non-game lobby");
+  }
+
+  if (flag == 0xD0) {
+    auto& cmd = check_size_t<SC_TradeCards_GC_Ep3_EE_FlagD0_FlagD3>(data);
+
+    if (c->game_data.pending_card_trade) {
+      throw runtime_error("player started a card trade when one is already pending");
+    }
+    if (cmd.entry_count > 4) {
+      throw runtime_error("invalid entry count in card trade command");
+    }
+
+    auto target_c = l->clients.at(cmd.target_client_id);
+    if (!target_c) {
+      throw runtime_error("card trade command sent to missing player");
+    }
+    if (!(target_c->flags & Client::Flag::IS_EPISODE_3)) {
+      throw runtime_error("card trade target is not Episode 3");
+    }
+
+    c->game_data.pending_card_trade.reset(new PendingCardTrade());
+    c->game_data.pending_card_trade->other_client_id = cmd.target_client_id;
+    for (size_t x = 0; x < cmd.entry_count; x++) {
+      c->game_data.pending_card_trade->card_to_count.emplace_back(
+          make_pair(cmd.entries[x].card_type, cmd.entries[x].count));
+    }
+
+    // If the other player has a pending trade as well, assume this is the
+    // second half of the trade sequence, and send an EE D1 to both clients. If
+    // the other player does not have a pending trade, assume this is the first
+    // half of the trade sequence, and send an EE D1 only to the target player
+    // (to request its EE D0 command).
+    // See the description of the D0 command in CommandFormats.hh for more
+    // information on how this sequence is supposed to work. (The EE D0 command
+    // is analogous to Episodes 1&2's D0 command.)
+    S_AdvanceCardTradeState_GC_Ep3_EE_FlagD1 resp = {0};
+    send_command_t(target_c, 0xEE, 0xD1, resp);
+    if (target_c->game_data.pending_card_trade) {
+      send_command_t(c, 0xEE, 0xD1, resp);
+    }
+
+  } else if (flag == 0xD2) {
+    check_size_v(data.size(), 0);
+
+    if (!c->game_data.pending_card_trade) {
+      throw runtime_error("player executed a card trade with none pending");
+    }
+
+    auto target_c = l->clients.at(c->game_data.pending_card_trade->other_client_id);
+    if (!target_c) {
+      throw runtime_error("card trade target player is missing");
+    }
+    if (!target_c->game_data.pending_card_trade) {
+      throw runtime_error("player executed a card trade with no other side pending");
+    }
+
+    c->game_data.pending_card_trade->confirmed = true;
+    if (target_c->game_data.pending_card_trade->confirmed) {
+      send_execute_card_trade(c, target_c->game_data.pending_card_trade->card_to_count);
+      send_execute_card_trade(target_c, c->game_data.pending_card_trade->card_to_count);
+      S_CardTradeComplete_GC_Ep3_EE_FlagD4 resp = {1};
+      send_command_t(c, 0xEE, 0xD4, resp);
+      send_command_t(target_c, 0xEE, 0xD4, resp);
+      c->game_data.pending_card_trade.reset();
+      target_c->game_data.pending_card_trade.reset();
+    }
+
+  } else if (flag == 0xD4) {
+    check_size_v(data.size(), 0);
+
+    // See the D4 handler for why this check exists (and why it doesn't throw)
+    if (!c->game_data.pending_card_trade) {
+      return;
+    }
+    uint8_t other_client_id = c->game_data.pending_card_trade->other_client_id;
+    c->game_data.pending_card_trade.reset();
+    S_CardTradeComplete_GC_Ep3_EE_FlagD4 resp = {0};
+    send_command_t(c, 0xEE, 0xD4, resp);
+
+    // Cancel the other side of the trade too, if it's open
+    auto target_c = l->clients.at(other_client_id);
+    if (!target_c) {
+      return;
+    }
+    if (!target_c->game_data.pending_card_trade) {
+      return;
+    }
+    target_c->game_data.pending_card_trade.reset();
+    send_command_t(target_c, 0xEE, 0xD4, resp);
+
+  } else {
+    throw runtime_error("invalid card trade operation");
+  }
+}
+
+
+
 static void on_team_command_bb(shared_ptr<ServerState>, shared_ptr<Client> c,
     uint16_t command, uint32_t, const string&) { // EA
 
@@ -3111,7 +3219,7 @@ static on_command_t handlers[0x100][6] = {
   /* EB */ {nullptr,                 nullptr,                    nullptr,                         nullptr,                     nullptr,                     on_stream_file_request_bb,      }, /* EB */
   /* EC */ {nullptr,                 nullptr,                    nullptr,                         on_create_game_dc_v3,        nullptr,                     on_leave_char_select_bb,        }, /* EC */
   /* ED */ {nullptr,                 nullptr,                    nullptr,                         nullptr,                     nullptr,                     on_change_account_data_bb,      }, /* ED */
-  /* EE */ {nullptr,                 nullptr,                    nullptr,                         nullptr,                     nullptr,                     nullptr,                        }, /* EE */
+  /* EE */ {nullptr,                 nullptr,                    nullptr,                         on_card_trade,               nullptr,                     nullptr,                        }, /* EE */
   /* EF */ {nullptr,                 nullptr,                    nullptr,                         nullptr,                     nullptr,                     nullptr,                        }, /* EF */
   /* F0 */ {nullptr,                 nullptr,                    nullptr,                         nullptr,                     nullptr,                     nullptr,                        }, /* F0 */
   /* F1 */ {nullptr,                 nullptr,                    nullptr,                         nullptr,                     nullptr,                     nullptr,                        }, /* F1 */

src/ReceiveSubcommands.cc

@@ -39,25 +39,27 @@ const CmdT* check_size_sc(
     max_size = min_size;
   }
   const auto* cmd = &check_size_t<CmdT>(data, min_size, max_size);
-  if (check_size_field && (cmd->size != data.size() / 4)) {
-    throw runtime_error("invalid subcommand size field");
+  if (check_size_field) {
+    const PSOSubcommand* sub = reinterpret_cast<const PSOSubcommand*>(data.data());
+    if (sub[0].byte[1] == 0) {
+      if (data.size() < 8) {
+        throw runtime_error("subcommand has extended size but is shorter than 8 bytes");
+      }
+      if (sub[1].dword != data.size()) {
+        throw runtime_error("invalid subcommand extended size field");
+      }
+    } else {
+      if (data.size() < 4) {
+        throw runtime_error("subcommand is shorter than 4 bytes");
+      }
+      if ((sub[0].byte[1] * 4) != data.size()) {
+        throw runtime_error("invalid subcommand size field");
+      }
+    }
   }
   return cmd;
 }
 
-template <>
-const PSOSubcommand* check_size_sc<PSOSubcommand>(
-    const string& data, size_t min_size, size_t max_size, bool check_size_field) {
-  if (max_size < min_size) {
-    max_size = min_size;
-  }
-  const auto* ret = &check_size_t<PSOSubcommand>(data, min_size, max_size);
-  if (check_size_field && (ret[0].byte[1] != data.size() / 4)) {
-    throw runtime_error("invalid subcommand size field");
-  }
-  return ret;
-}
-
 
 
 static void forward_subcommand(shared_ptr<Lobby> l, shared_ptr<Client> c,
@@ -596,10 +598,12 @@ static void on_subcommand_open_shop_bb_or_unknown_ep3(shared_ptr<ServerState>,
   }
 }
 
-static void on_subcommand_open_bank_bb(shared_ptr<ServerState>,
-    shared_ptr<Lobby> l, shared_ptr<Client> c, uint8_t, uint8_t, const string&) {
+static void on_subcommand_open_bank_bb_or_card_trade_counter_ep3(shared_ptr<ServerState>,
+    shared_ptr<Lobby> l, shared_ptr<Client> c, uint8_t command, uint8_t flag, const string& data) {
   if ((l->version == GameVersion::BB) && l->is_game()) {
     send_bank(c);
+  } else if (l->version == GameVersion::GC && l->flags & Lobby::Flag::EPISODE_3_ONLY) {
+    forward_subcommand(l, c, command, flag, data);
   }
 }
 
@@ -1355,8 +1359,8 @@ subcommand_handler_t subcommand_handlers[0x100] = {
   /* B8 */ on_subcommand_identify_item_bb,
   /* B9 */ nullptr,
   /* BA */ on_subcommand_accept_identify_item_bb,
-  /* BB */ on_subcommand_open_bank_bb,
-  /* BC */ nullptr, // BB bank contents (server->client only)
+  /* BB */ on_subcommand_open_bank_bb_or_card_trade_counter_ep3,
+  /* BC */ on_subcommand_forward_check_size_ep3_game, // BB bank contents (server->client only), Ep3 card trade sequence
   /* BD */ on_subcommand_bank_action_bb,
   /* BE */ nullptr, // BB create inventory item (server->client only)
   /* BF */ on_subcommand_forward_check_size_ep3_lobby, // Ep3 change music, also BB give EXP (BB usage is server->client only)

src/SendCommands.cc

@@ -1315,6 +1315,32 @@ void send_execute_item_trade(std::shared_ptr<Client> c,
   send_command_t(c, 0xD3, 0x00, cmd);
 }
 
+void send_execute_card_trade(std::shared_ptr<Client> c,
+    const std::vector<std::pair<uint32_t, uint32_t>>& card_to_count) {
+  if (!(c->flags & Client::Flag::IS_EPISODE_3)) {
+    throw logic_error("cannot send trade cards command to non-Ep3 client");
+  }
+
+  SC_TradeCards_GC_Ep3_EE_FlagD0_FlagD3 cmd;
+  constexpr size_t max_entries = sizeof(cmd.entries) / sizeof(cmd.entries[0]);
+  if (card_to_count.size() > max_entries) {
+    throw logic_error("too many items in execute card trade command");
+  }
+
+  cmd.target_client_id = c->lobby_client_id;
+  cmd.entry_count = card_to_count.size();
+  size_t x;
+  for (x = 0; x < card_to_count.size(); x++) {
+    cmd.entries[x].card_type = card_to_count[x].first;
+    cmd.entries[x].count = card_to_count[x].second;
+  }
+  for (; x < max_entries; x++) {
+    cmd.entries[x].card_type = 0;
+    cmd.entries[x].count = 0;
+  }
+  send_command_t(c, 0xEE, 0xD3, cmd);
+}
+
 
 
 ////////////////////////////////////////////////////////////////////////////////

src/SendCommands.hh

@@ -210,6 +210,8 @@ void send_get_player_info(std::shared_ptr<Client> c);
 
 void send_execute_item_trade(std::shared_ptr<Client> c,
     const std::vector<ItemData>& items);
+void send_execute_card_trade(std::shared_ptr<Client> c,
+    const std::vector<std::pair<uint32_t, uint32_t>>& card_to_count);
 
 void send_arrow_update(std::shared_ptr<Lobby> l);
 void send_resume_game(std::shared_ptr<Lobby> l,