add $song on proxy server

src/ChatCommands.cc

@@ -1012,7 +1012,17 @@ static void server_command_song(shared_ptr<ServerState>, shared_ptr<Lobby>,
   check_is_ep3(c, true);
 
   uint32_t song = stoul(encode_sjis(args), nullptr, 0);
-  send_ep3_change_music(c, song);
+  send_ep3_change_music(c->channel, song);
+}
+
+static void proxy_command_song(shared_ptr<ServerState>,
+    ProxyServer::LinkedSession& session, const std::u16string& args) {
+  int32_t song = stol(encode_sjis(args), nullptr, 0);
+  if (song < 0) {
+    song = -song;
+    send_ep3_change_music(session.server_channel, song);
+  }
+  send_ep3_change_music(session.client_channel, song);
 }
 
 static void server_command_infinite_hp(shared_ptr<ServerState>, shared_ptr<Lobby> l,
@@ -1200,7 +1210,7 @@ static const unordered_map<u16string, ChatCommandDefinition> chat_commands({
     {u"$secid",    {server_command_secid,              proxy_command_secid,           u"Usage:\nsecid [section ID]\nomit section ID to\nrevert to normal"}},
     {u"$silence",  {server_command_silence,            nullptr,                       u"Usage:\nsilence <name-or-number>"}},
     // TODO: implement this on proxy server
-    {u"$song",     {server_command_song,               nullptr,                       u"Usage:\nsong <song-number>"}},
+    {u"$song",     {server_command_song,               proxy_command_song,            u"Usage:\nsong <song-number>"}},
     {u"$spec",     {server_command_spec,               nullptr,                       u"Usage:\nspec"}},
     {u"$ss",       {nullptr,                           proxy_command_send_server,     u"Usage:\nss <data>"}},
     {u"$swa",      {server_command_switch_assist,      proxy_command_switch_assist,   u"Usage:\nswa"}},

src/ReceiveCommands.cc

@@ -226,7 +226,7 @@ void on_login_complete(shared_ptr<ServerState> s, shared_ptr<Client> c) {
     // menu or welcome message
     if (c->flags & Client::Flag::IS_EPISODE_3) {
       if (s->ep3_menu_song >= 0) {
-        send_ep3_change_music(c, s->ep3_menu_song);
+        send_ep3_change_music(c->channel, s->ep3_menu_song);
       } else if (s->pre_lobby_event) {
         send_change_event(c, s->pre_lobby_event);
       }

src/SendCommands.cc

@@ -1743,9 +1743,9 @@ void send_warp(shared_ptr<Client> c, uint32_t area) {
   c->area = area;
 }
 
-void send_ep3_change_music(shared_ptr<Client> c, uint32_t song) {
+void send_ep3_change_music(Channel& ch, uint32_t song) {
   G_ChangeLobbyMusic_GC_Ep3_6xBF cmd = {{0xBF, 0x02, 0}, song};
-  send_command_t(c, 0x60, 0x00, cmd);
+  ch.send(0x60, 0x00, cmd);
 }
 
 void send_set_player_visibility(shared_ptr<Lobby> l, shared_ptr<Client> c,

src/SendCommands.hh

@@ -292,7 +292,7 @@ void send_player_stats_change(
 void send_warp(Channel& ch, uint8_t client_id, uint32_t area);
 void send_warp(std::shared_ptr<Client> c, uint32_t area);
 
-void send_ep3_change_music(std::shared_ptr<Client> c, uint32_t song);
+void send_ep3_change_music(Channel& ch, uint32_t song);
 void send_set_player_visibility(std::shared_ptr<Lobby> l,
     std::shared_ptr<Client> c, bool visible);
 void send_revive_player(std::shared_ptr<Lobby> l, std::shared_ptr<Client> c);