add cheat command to remove an FC in an Ep3 battle

src/ChatCommands.cc

@@ -1279,6 +1279,28 @@ static void server_command_ep3_infinite_time(
   send_text_message(l, infinite_time_enabled ? u"$C6Infinite time enabled" : u"$C6Infinite time disabled");
 }
 
+static void server_command_ep3_unset_field_character(
+    shared_ptr<ServerState> s, shared_ptr<Lobby> l, shared_ptr<Client> c, const std::u16string& args) {
+  check_is_game(l, true);
+  check_is_ep3(c, true);
+  check_cheats_enabled(s, l);
+
+  if (l->episode != Episode::EP3) {
+    throw logic_error("non-Ep3 client in Ep3 game");
+  }
+  if (!l->ep3_server) {
+    send_text_message(c, u"$C6Episode 3 server\nis not initialized");
+    return;
+  }
+  if (l->ep3_server->setup_phase != Episode3::SetupPhase::MAIN_BATTLE) {
+    send_text_message(c, u"$C6Battle has not\nyet begun");
+    return;
+  }
+
+  size_t index = stoull(encode_sjis(args)) - 1;
+  l->ep3_server->force_destroy_field_character(c->lobby_client_id, index);
+}
+
 static void server_command_surrender(
     shared_ptr<ServerState>, shared_ptr<Lobby> l, shared_ptr<Client> c, const std::u16string&) {
   check_is_game(l, true);
@@ -1351,6 +1373,7 @@ static const unordered_map<u16string, ChatCommandDefinition> chat_commands({
     {u"$ss", {nullptr, proxy_command_send_server}},
     {u"$surrender", {server_command_surrender, nullptr}},
     {u"$swa", {server_command_switch_assist, proxy_command_switch_assist}},
+    {u"$unset", {server_command_ep3_unset_field_character, nullptr}},
     {u"$warp", {server_command_warpme, proxy_command_warpme}},
     {u"$warpme", {server_command_warpme, proxy_command_warpme}},
     {u"$warpall", {server_command_warpall, proxy_command_warpall}},

src/Episode3/Server.cc

@@ -536,6 +536,31 @@ bool Server::check_for_battle_end() {
   return ret;
 }
 
+void Server::force_destroy_field_character(uint8_t client_id, size_t visible_index) {
+  auto ps = this->player_states[client_id];
+
+  // TODO: Is it possible for there to be gaps in the set cards array? If not,
+  // we could just do a direct array lookup here instead of this loop
+  shared_ptr<Card> set_card = nullptr;
+  for (size_t set_index = 0; set_index < 8; set_index++) {
+    if (!ps->set_cards[set_index]) {
+      continue;
+    }
+    if (visible_index == 0) {
+      set_card = ps->set_cards[set_index];
+      break;
+    } else {
+      visible_index--;
+    }
+  }
+
+  if (set_card) {
+    set_card->card_flags |= 2;
+    this->check_for_destroyed_cards_and_send_6xB4x05_6xB4x02();
+    this->check_for_battle_end();
+  }
+}
+
 void Server::force_battle_result(uint8_t specified_client_id, bool set_winner) {
   auto specified_ps = this->player_states[specified_client_id];
   for (size_t z = 0; z < 4; z++) {

src/Episode3/Server.hh

@@ -100,9 +100,11 @@ public:
     this->send(&cmd, cmd.header.size * 4);
   }
   void send(const void* data, size_t size) const;
-
   void send_commands_for_joining_spectator(Channel& ch, bool is_trial) const;
 
+  void force_battle_result(uint8_t surrendered_client_id, bool set_winner);
+  void force_destroy_field_character(uint8_t client_id, size_t set_index);
+
   __attribute__((format(printf, 2, 3))) void send_debug_message_printf(const char* fmt, ...) const;
   __attribute__((format(printf, 2, 3))) void send_info_message_printf(const char* fmt, ...) const;
   void send_debug_command_received_message(
@@ -124,7 +126,6 @@ public:
   uint16_t card_id_for_card_ref(uint16_t card_ref) const;
   bool card_ref_is_empty_or_has_valid_card_id(uint16_t card_ref) const;
   bool check_for_battle_end();
-  void force_battle_result(uint8_t surrendered_client_id, bool set_winner);
   void check_for_destroyed_cards_and_send_6xB4x05_6xB4x02();
   bool check_presence_entry(uint8_t client_id) const;
   void clear_player_flags_after_dice_phase();