psopeeps-newserv/src/CommandFormats.hh

#pragma once

#include <string>
#include <stdexcept>
#include <phosg/Strings.hh>
#include <phosg/Encoding.hh>

#include "PSOProtocol.hh"
#include "Text.hh"
#include "Player.hh"



#pragma pack(push)
#pragma pack(1)



// This file is newserv's canonical reference of the PSO client/server protocol.

// For the unfamiliar, the le_uint and be_uint types (from phosg/Encoding.hh)
// are the same as normal uint types, but are explicitly little-endian or
// big-endian. The parray and ptext types (from Text.hh) are the same as
// standard arrays, but have various safety and convenience features so we don't
// have to use easy-to-mess-up functions like memset/memcpy and strncpy.

// Struct names are like [S|C|SC]_CommandName_[Versions]_Numbers
// S/C denotes who sends the command (S = server, C = client, SC = both)
// If versions are not specified, the format is the same for all versions.

// For variable-length commands, generally a zero-length array is included on
// the end of the struct if the command is received by newserv, and is omitted
// if it's sent by newserv. In the latter case, we often use StringWriter to
// construct the command data instead.

// Structures are sorted by command number. Long BB commands are placed in order
// according to their low byte; for example, command 01EB is in position as EB.



// This is the format of newserv's security data, which we call the client
// config. This data is opaque to the client, so this structure is not
// technically part of the PSO protocol. Because it is opaque to the client, we
// can use the server's native-endian types instead of being explicit as we do
// for all the other structs in this file.
enum ClientStateBB : uint8_t {
  // Initial connection; server will redirect client to another port
  INITIAL_LOGIN = 0x00,
  // Second connection; server will send client game data and account data
  DOWNLOAD_DATA = 0x01,
  // Third connection; client will show the choose character menu
  CHOOSE_PLAYER = 0x02,
  // Fourth connection; used for saving characters only. If you do not create a
  // character, the server sets this state during the third connection so this
  // connection is effectively skipped.
  SAVE_PLAYER = 0x03,
  // Fifth connection; redirects client to login server
  SHIP_SELECT = 0x04,
  // All other connections
  IN_GAME = 0x05,
};

struct ClientConfig {
  uint64_t magic;
  uint16_t flags;
  uint32_t proxy_destination_address;
  uint16_t proxy_destination_port;
  parray<uint8_t, 0x10> unused;
};

struct ClientConfigBB {
  ClientConfig cfg;
  uint8_t bb_game_state;
  uint8_t bb_player_index;
  parray<uint8_t, 0x06> unused;
};



// Patch server commands

// A patch server session generally goes like this:
// Server: 02 (unencrypted)
// (all the following commands encrypted with PSOPC encryption, even on BB)
// Client: 02
// Server: 04
// Client: 04
// Server: 13 (if desired)
// Server: 0B
// Server: 09 (with directory name ".")
// For each directory to be checked:
//   Server: 09
//   Server: (commands to check subdirectories - more 09/0A/0C)
//   For each file in the directory:
//     Server: 0C
//   Server: 0A
// Server: 0D
// For each 0C sent by the server earlier:
//   Client: 0F
// Client: 10
// If there are any files to be updated:
//   Server: 11
//   For each directory containing files to be updated:
//     Server: 09
//     Server: (commands to update subdirectories)
//     For each file to be updated in this directory:
//       Server: 06
//       Server: 07 (possibly multiple 07s if the file is large)
//       Server: 08
//     Server: 0A
// Server: 12

// 00: Invalid command
// 01: Invalid command

// 02 (S->C): Start encryption
// Client will respond with an 02 command.
// If this command is sent during an encrypted session, the client will not
// reject it; it will simply re-initialize its encryption state and respond with
// an 02 as normal.
// The copyright field in the below structure must contain the following text:
// "Patch Server. Copyright SonicTeam, LTD. 2001"

struct S_ServerInit_Patch_02 {
  ptext<char, 0x40> copyright;
  le_uint32_t server_key;
  le_uint32_t client_key;
  // BB rejects the command if it's larger than this size, so we can't add the
  // after_message like we do in the other server init commands
};

// 02 (C->S): Encryption started
// No arguments

// 03: Invalid command

// 04 (S->C): Request login information
// No arguments
// Client will respond with an 04 command.

// 04 (C->S): Log in (patch)

struct C_Login_Patch_04 {
  parray<le_uint32_t, 3> unused;
  ptext<char, 0x10> username;
  ptext<char, 0x10> password;
  ptext<char, 0x40> email; // Note: this field is blank on BB
};

// 05 (S->C): Unknown
// This is probably the disconnect command, like on the game server. It seems
// the client never sends it though.
// No arguments

// 06 (S->C): Open file for writing

struct S_OpenFile_Patch_06 {
  le_uint32_t unknown; // Seems to always be zero
  le_uint32_t size;
  ptext<char, 0x30> filename;
};

// 07 (S->C): Write file
// The client's handler table says this command's maximum size is 0x6010
// including the header, but the only servers I've seen use this command limit
// chunks to 0x4010 (including the header).

struct S_WriteFileHeader_Patch_07 {
  le_uint32_t chunk_index;
  le_uint32_t chunk_checksum; // CRC32 of the following chunk data
  le_uint32_t chunk_size;
  // The chunk data immediately follows here
};

// 08 (S->C): Close current file
// Maximum size 8 (including header)

struct S_CloseCurrentFile_Patch_08 {
  le_uint32_t unknown; // Seems to always be zero
};

// 09 (S->C): Enter directory

struct S_EnterDirectory_Patch_09 {
  ptext<char, 0x40> name;
};

// 0A (S->C): Exit directory
// No arguments

// 0B (S->C): Unknown; maybe start patch session, or go to game's root directory
// No arguments

// 0C (S->C): File checksum request

struct S_FileChecksumRequest_Patch_0C {
  le_uint32_t request_id;
  ptext<char, 0x20> filename;
};

// 0D (S->C): End of file check requests
// No arguments

// 0E: Invalid command

// 0F (C->S): File information

struct C_FileInformation_Patch_0F {
  le_uint32_t request_id;
  le_uint32_t checksum; // CRC32 of the file's data
  le_uint32_t size;
};

// 10 (C->S): End of file information command list
// No arguments

// 11 (S->C): Start file downloads

struct S_StartFileDownloads_Patch_11 {
  le_uint32_t total_bytes;
  le_uint32_t num_files;
};

// 12 (S->C): End patch session successfully
// No arguments

// 13 (S->C): Message box
// Same format and usage as commands 1A/D5 on the game server (described below).
// On PSOBB, the message box appears in the upper half of the screen and
// functions like a normal PSO message box - that is, you can use color escapes
// (\tCG, for example) and lines are terminated with \n. On PSOPC, the message
// appears in a Windows edit control, so the text functions differently: line
// breaks must be \r\n and standard PSO color escapes don't work. The maximum
// size of this command is 0x2004 bytes, including the header.

// 14 (S->C): Reconnect
// Same format and usage as command 19 on the game server (described below).

// 15 (S->C): Unknown
// No arguments

// No commands beyond 15 are valid on the patch server.



// Game server commands

// 00: Invalid command

// 01 (S->C): Lobby message box
// A small message box appears in lower-right corner, and the player must press
// a key to continue.

struct SC_TextHeader_01_06_11_B0_EE {
  le_uint32_t unused;
  le_uint32_t guild_card_number;
  // Text immediately follows this header (char[] on DC/GC, char16_t[] on PC/BB)
};

// 02 (S->C): Start encryption (except on BB)
// This command should be used for non-initial sessions (after the client has
// already selected a ship, for example). Command 17 should be used instead for
// the first connection.
// The client will respond with an (encrypted) 9A or 9E command on PSO GC; on
// PSO PC, the client will respond with an (encrypted) 9A or 9D command.
// The copyright field in the below structure must contain the following text:
// "DreamCast Port Map. Copyright SEGA Enterprises. 1999"

struct S_ServerInit_DC_PC_GC_02_17 {
  ptext<char, 0x40> copyright;
  le_uint32_t server_key; // Key for data sent by server
  le_uint32_t client_key; // Key for data sent by client
  // This field is not part of SEGA's implementation. The client ignores it.
  ptext<char, 0xC0> after_message;
};

// 03 (S->C): Start encryption (BB)
// Client will respond with an (encrypted) 93 command.
// The copyright field in the below structure must contain the following text:
// "Phantasy Star Online Blue Burst Game Server. Copyright 1999-2004 SONICTEAM."

struct S_ServerInit_BB_03 {
  ptext<char, 0x60> copyright;
  parray<uint8_t, 0x30> server_key;
  parray<uint8_t, 0x30> client_key;
  // This field is not part of SEGA's implementation. The client ignores it.
  ptext<char, 0xC0> after_message;
};

// 04 (S->C): Set guild card number and update client config ("security data")
// The client config field in this command is only used by V3 clients (PSO GC).
// We send it anyway to clients on earlier versions (e.g. PSO PC), but they
// simply ignore it.
// Client will respond with a 96 command, but only the first time it receives
// this command - for later 04 commands, the client will still update its client
// config but will not respond. Changing the security data at any time seems ok,
// but changing the guild card number of a client after it's initially set can
// confuse the client, and (on pre-V3 clients) possibly corrupt the character
// data. For this reason, newserv tries pretty hard to hide the remote guild
// card number when clients connect to the proxy server.
// Note: PSOBB has a handler for the 04 command, but (as of yet) I haven't
// figured out what it does.

struct S_UpdateClientConfig_DC_PC_GC_04 {
  le_uint32_t player_tag;
  le_uint32_t guild_card_number;
  // The ClientConfig structure (defined in Client.hh) describes how newserv
  // uses this command; other servers do not use the same format for the
  // following 0x20 bytes (or may not use it at all). The cfg field is opaque to
  // the client; it will send back the contents verbatim in its next 9E command.
  ClientConfig cfg;
};

struct S_Unknown_BB_04 {
  // header.flag is used too, but it's not clear what it does
  le_uint32_t unknown_a1[12];
};

// 05: Disconnect
// No arguments

// 06: Chat
// Server->client format is same as 01 command.
// Client->server format is very similar; we include a zero-length array in this
// struct to make parsing easier.

struct C_Chat_06 {
  uint64_t unused;
  union {
    char dcgc[0];
    char16_t pcbb[0];
  } text;
};

// 07 (S->C): Ship select menu

// Command is a list of these; header.flag is the entry count. The first entry
// is not included in the count and does not appear on the client. The text of
// the first entry becomes the ship name when the client joins a lobby.
template <typename CharT, int EntryLength>
struct S_MenuEntry {
  le_uint32_t menu_id;
  le_uint32_t item_id;
  le_uint16_t flags; // should be 0x0F04
  ptext<CharT, EntryLength> text;
};
struct S_MenuEntry_PC_BB_07 : S_MenuEntry<char16_t, 17> { };
struct S_MenuEntry_DC_GC_07 : S_MenuEntry<char, 18> { };

// 08 (C->S): Request game list
// No arguments

// 08 (S->C): Game list
// Client responds with 09 and 10 commands (or nothing if the player cancels).

// Command is a list of these; header.flag is the entry count. The first entry
// is not included in the count and does not appear on the client.
template <typename CharT>
struct S_GameMenuEntry {
  le_uint32_t menu_id;
  le_uint32_t game_id;
  uint8_t difficulty_tag; // 0x0A = Ep3; else difficulty + 0x22 (so 0x25 = Ult)
  uint8_t num_players;
  ptext<CharT, 0x10> name;
  uint8_t episode; // 40 = Ep1, 41 = Ep2, 43 = Ep4. Ignored on Ep3
  uint8_t flags; // 02 = locked, 04 = disabled (BB), 10 = battle, 20 = challenge
};
struct S_GameMenuEntry_PC_BB_08 : S_GameMenuEntry<char16_t> { };
struct S_GameMenuEntry_GC_08 : S_GameMenuEntry<char> { };

// 09 (C->S): Menu item info request
// Server will respond with an 11 command, or an A3 if it's the quest menu.

struct C_MenuItemInfoRequest_09 {
  le_uint32_t menu_id;
  le_uint32_t item_id;
};

// 0B: Invalid command

// 0C: Create game (DCv1)
// Format unknown

// 0D: Invalid command
// 0E: Invalid command
// 0F: Invalid command

// 10 (C->S): Menu selection

struct C_MenuSelection {
  le_uint32_t menu_id;
  le_uint32_t item_id;
  // Password is only present when client attempts to join a locked game.
  union {
    char dcgc[0];
    char16_t pcbb[0];
  } password;
};

// 11 (S->C): Ship info
// Same format as 01 command.

// 12 (S->C): Valid but ignored (BB)

// 13 (S->C): Write online quest file
// Used for downloading online quests. For download quests (to be saved to the
// memory card), use A6 instead.
// All chunks except the last must have 0x400 data bytes. When downloading an
// online quest, the .bin and .dat chunks may be interleaved (although newserv
// currently sends them sequentially).

// header.flag = file chunk index (start offset / 0x400)
struct S_WriteFile_13_A7 {
  ptext<char, 0x10> filename;
  uint8_t data[0x400];
  le_uint32_t data_size;
};

// 13 (C->S): Confirm file write
// Client sends this in response to each 13 sent by the server. It appears these
// are only sent by V3 and BB - PSO PC does not send these.
// This structure is for documentation only; newserv ignores these.

// header.flag = file chunk index (same as in the 13/A7 sent by the server)
struct C_WriteFileConfirmation_GC_BB_13_A7 {
  ptext<char, 0x10> filename;
};

// 14 (S->C): Valid but ignored (BB)
// 15: Invalid command
// 16 (S->C): Valid but ignored (BB)

// 17 (S->C): Start encryption at login server (except on BB)
// Same format as 02 command, but a different copyright string.
// V3 (PSO GC) clients will respond with a DB command the first time they
// receive a 17 command in any online session; after the first time, they will
// respond with a 9E. Non-V3 clients will respond with a 9D.
// The copyright field in the structure must contain the following text:
// "DreamCast Lobby Server. Copyright SEGA Enterprises. 1999";

// 18: Invalid command

// 19 (S->C): Reconnect to different address
// Client will disconnect, and reconnect to the given address/port.

struct S_Reconnect_19 {
  be_uint32_t address;
  le_uint16_t port;
  le_uint16_t unused;
};

// Because PSO PC and some versions of PSO GC use the same port but different
// protocols, we use a specially-crafted 19 command to send them to two
// different ports depending on the client version. I originally saw this
// technique used by Schthack; I don't know if it was his original creation.

struct S_ReconnectSplit_19 {
  be_uint32_t pc_address;
  le_uint16_t pc_port;
  parray<uint8_t, 0x0F> unused1;
  uint8_t gc_command;
  uint8_t gc_flag;
  le_uint16_t gc_size;
  be_uint32_t gc_address;
  le_uint16_t gc_port;
  parray<uint8_t, 0xB0 - 0x23> unused2;
};

// 1A: Large message box
// Client will usually respond with a D6 command (see D6 for more information).
// Contents are plain text (char on DC/GC, char16_t on PC/BB). There must be at
// least one null character ('\0') before the end of the command data.
// There is a bug in V3 (and possibly all versions) where if this command is
// sent after the client has joined a lobby, the chat log window contents will
// appear in the message box, prepended to the message text from the command.

// 1B: Invalid command
// 1C: Invalid command

// 1D: Ping
// No arguments
// When sent to the client, the client will respond with a 1D command. Data sent
// by the server is ignored; the client always sends a 1D command with no data.

// 1E: Invalid command

// 1F (S->C): Information menu
// Same format and usage as 07 command

// 20: Invalid command

// 21: GameGuard control (old versions of BB)
// Format unknown

// 22: GameGuard check (BB)
// An older version of BB used a 4-byte challenge in the flag field (and the
// command had no payload). The latest version uses this 16-byte challenge.

struct SC_GameCardCheck_BB_22 {
  parray<uint8_t, 0x10> data;
};

// 23 (S->C): Unknown (BB)
// header.flag is used, but command has no other arguments.

// 24 (S->C): Unknown (BB)

struct S_Unknown_BB_24 {
  le_uint16_t unknown_a1;
  le_uint16_t unknown_a2;
  parray<le_uint32_t, 8> values;
};

// 25 (S->C): Unknown (BB)

struct S_Unknown_BB_25 {
  le_uint16_t unknown_a1;
  uint8_t offset1;
  uint8_t value1;
  uint8_t offset2;
  uint8_t value2;
  le_uint16_t unused;
};

// 26: Invalid command
// 27: Invalid command
// 28: Invalid command
// 29: Invalid command
// 2A: Invalid command
// 2B: Invalid command
// 2C: Invalid command
// 2D: Invalid command
// 2E: Invalid command
// 2F: Invalid command
// 30: Invalid command
// 31: Invalid command
// 32: Invalid command
// 33: Invalid command
// 34: Invalid command
// 35: Invalid command
// 36: Invalid command
// 37: Invalid command
// 38: Invalid command
// 39: Invalid command
// 3A: Invalid command
// 3B: Invalid command
// 3C: Invalid command
// 3D: Invalid command
// 3E: Invalid command
// 3F: Invalid command

// 40 (C->S): Guild card search
// Server should respond with a 41 command if the target is online. If the
// target is not online, server doesn't respond at all.

struct C_GuildCardSearch_40 {
  le_uint32_t player_tag;
  le_uint32_t searcher_guild_card_number;
  le_uint32_t target_guild_card_number;
};

// 41 (S->C): Guild card search result

template <typename HeaderT, typename CharT>
struct S_GuildCardSearchResult {
  le_uint32_t player_tag;
  le_uint32_t searcher_guild_card_number;
  le_uint32_t result_guild_card_number;
  HeaderT reconnect_command_header;
  S_Reconnect_19 reconnect_command;
  // The format of this string is "GAME-NAME,Block ##,SERVER-NAME". If the
  // result player is not in a game, GAME-NAME may be a lobby name (e.g.
  // "LOBBY01") or simply blank (so the string begins with a comma).
  ptext<char, 0x44> location_string;
  le_uint32_t menu_id;
  le_uint32_t lobby_id;
  ptext<char, 0x3C> unused;
  ptext<CharT, 0x20> name;
};
struct S_GuildCardSearchResult_PC_41 : S_GuildCardSearchResult<PSOCommandHeaderPC, char16_t> { };
struct S_GuildCardSearchResult_DC_GC_41 : S_GuildCardSearchResult<PSOCommandHeaderDCGC, char> { };
struct S_GuildCardSearchResult_BB_41 : S_GuildCardSearchResult<PSOCommandHeaderBB, char16_t> { };

// 42: Invalid command
// 43: Invalid command

// 44 (S->C): Open file for download
// Used for downloading online quests. For download quests (to be saved to the
// memory card), use A6 instead.

struct S_OpenFile_PC_GC_44_A6 {
  ptext<char, 0x20> name;
  parray<uint8_t, 2> unused;
  le_uint16_t flags; // 0 = download quest, 2 = online quest, 3 = Episode 3
  ptext<char, 0x10> filename;
  le_uint32_t file_size;
};

struct S_OpenFile_BB_44_A6 {
  parray<uint8_t, 0x22> unused;
  le_uint16_t flags;
  ptext<char, 0x10> filename;
  le_uint32_t file_size;
  ptext<char, 0x18> name;
};

// 44 (C->S): Confirm open file
// Client sends this in response to each 44 sent by the server.
// This structure is for documentation only; newserv ignores these.

// header.flag = quest number (sort of - seems like the client just echoes
// whatever the server sent in its header.flag field. Also quest numbers can be
// > 0xFF so the flag is essentially meaningless)
struct C_OpenFileConfirmation_44_A6 {
  ptext<char, 0x10> filename;
};

// 45: Invalid command
// 46: Invalid command
// 47: Invalid command
// 48: Invalid command
// 49: Invalid command
// 4A: Invalid command
// 4B: Invalid command
// 4C: Invalid command
// 4D: Invalid command
// 4E: Invalid command
// 4F: Invalid command
// 50: Invalid command
// 51: Invalid command
// 52: Invalid command
// 53: Invalid command
// 54: Invalid command
// 55: Invalid command
// 56: Invalid command
// 57: Invalid command
// 58: Invalid command
// 59: Invalid command
// 5A: Invalid command
// 5B: Invalid command
// 5C: Invalid command
// 5D: Invalid command
// 5E: Invalid command
// 5F: Invalid command

// 60: Broadcast command
// When a client sends this command, the server should forward it to all players
// in the same game/lobby, except the player who originally sent the command.
// See ReceiveSubcommands or the subcommand index below for details on contents.

// 61 (C->S): Player data
// See PSOPlayerDataPC, PSOPlayerDataGC, and PSOPlayerDataBB in Player.hh for
// this command's format.
// Upon joining a game, the client assigns inventory item IDs sequentially as
// (0x00010000 + (0x00200000 * lobby_client_id) + x). So, for example, player
// 3's 8th item's ID would become 0x00610007. The item IDs from the last game
// the player was in will appear in their inventory in this command.
// Note: If the client is in a game at the time this command is received, the
// inventory sent by the client only includes items that would not disappear if
// the client crashes! Essentially, it reflects the saved state of the player's
// character rather than the live state.

// 62: Target command
// When a client sends this command, the server should forward it to the player
// identified by header.flag in the same game/lobby, even if that player is the
// player who originally sent it.
// See ReceiveSubcommands or the subcommand index below for details on contents.

// 63: Invalid command

// 64 (S->C): Join game
// This is sent to the joining player; the other players get a 65 instead.
// Note that (except on Episode 3) this comamnd does not include the player's
// disp or inventory data. The clients in the game are responsible for sending
// that data to each other during the join process with 60/62/6C/6D commands.

// Header flag = entry count
template <typename LobbyDataT, typename DispDataT>
struct S_JoinGame {
  parray<le_uint32_t, 0x20> variations;
  // Unlike lobby join commands, these are filled in in their slot positions.
  // That is, if there's only one player in a game with ID 2, then the first two
  // of these are blank and the player's data is in the third entry here.
  LobbyDataT lobby_data[4];
  uint8_t client_id;
  uint8_t leader_id;
  uint8_t disable_udp;
  uint8_t difficulty;
  uint8_t battle_mode;
  uint8_t event;
  uint8_t section_id;
  uint8_t challenge_mode;
  le_uint32_t rare_seed;
  uint8_t episode;
  uint8_t unused2; // Should be 1 for PSO PC?
  uint8_t solo_mode;
  uint8_t unused3;
  struct PlayerEntry {
    PlayerInventory inventory;
    DispDataT disp;
  };
  // This field is only present if the game (and client) is Episode 3. Similarly
  // to lobby_data above, all four of these are always present and they are
  // filled in in slot positions.
  PlayerEntry players_ep3[4];
};
struct S_JoinGame_PC_64 : S_JoinGame<PlayerLobbyDataPC, PlayerDispDataPCGC> { };
struct S_JoinGame_GC_64 : S_JoinGame<PlayerLobbyDataGC, PlayerDispDataPCGC> { };
struct S_JoinGame_BB_64 : S_JoinGame<PlayerLobbyDataBB, PlayerDispDataBB> { };

// 65 (S->C): Other player joined game

// Header flag = entry count (always 1 for 65 and 68; up to 0x0C for 67)
template <typename LobbyDataT, typename DispDataT>
struct S_JoinLobby {
  uint8_t client_id;
  uint8_t leader_id;
  uint8_t disable_udp;
  uint8_t lobby_number;
  le_uint16_t block_number;
  le_uint16_t event;
  le_uint32_t unused;
  struct Entry {
    LobbyDataT lobby_data;
    PlayerInventory inventory;
    DispDataT disp;
  };
  // Note: not all of these will be filled in and sent if the lobby isn't full
  // (the command size will be shorter than this struct's size)
  Entry entries[0x0C];

  static inline size_t size(size_t used_entries) {
    return offsetof(S_JoinLobby, entries) + used_entries * sizeof(Entry);
  }
};
struct S_JoinLobby_PC_65_67_68 : S_JoinLobby<PlayerLobbyDataPC, PlayerDispDataPCGC> { };
struct S_JoinLobby_GC_65_67_68 : S_JoinLobby<PlayerLobbyDataGC, PlayerDispDataPCGC> { };
struct S_JoinLobby_BB_65_67_68 : S_JoinLobby<PlayerLobbyDataBB, PlayerDispDataBB> { };

// 66 (S->C): Other player left game
// This is sent to all players in a game except the leaving player.

// Header flag = leaving player ID (same as client_id);
struct S_LeaveLobby_66_69 {
  uint8_t client_id;
  uint8_t leader_id;
  le_uint16_t unused;
};

// 67 (S->C): Join lobby
// This is sent to the joining player; the other players get a 68 instead.
// Same format as 65 command, but used for lobbies instead of games.

// 68 (S->C): Other player joined lobby
// Same format as 65 command, but used for lobbies instead of games.
// The command only includes the joining player's data.

// 69 (S->C): Other player left lobby
// Same format as 66 command, but used for lobbies instead of games.

// 6A: Invalid command
// 6B: Invalid command

// 6C: Broadcast command
// Same format and usage as 60 command.

// 6D: Target command
// Same format and usage as 62 command.

// 6E: Invalid command

// 6F (C->S): Set game status
// This command is sent when a player is done loading and other players can then
// join the game. On BB, this command is sent as 016F if a quest is in progress
// and the game should not be joined by anyone else.

// 70: Invalid command
// 71: Invalid command
// 72: Invalid command
// 73: Invalid command
// 74: Invalid command
// 75: Invalid command
// 76: Invalid command
// 77: Invalid command
// 78: Invalid command
// 79: Invalid command
// 7A: Invalid command
// 7B: Invalid command
// 7C: Invalid command
// 7D: Invalid command
// 7E: Invalid command
// 7F: Invalid command
// 80: Invalid command

// 81: Simple mail
// Format is the same in both directions. The server should forward the command
// to the player with to_guild_gard_number, if they are online. If they are not
// online, the server may store it for later delivery, send their auto-reply
// message back to the original sender, or simply drop the message.
// On GC (and probably other versions too) the unused space after the text
// contains uninitialized memory when the client sends this command. None of the
// unused space appears to contain anything important; newserv clears the
// uninitialized data for security reasons before forwarding and things seem to
// work fine.

struct SC_SimpleMail_GC_81 {
  le_uint32_t player_tag;
  le_uint32_t from_guild_card_number;
  ptext<char, 0x10> from_name;
  le_uint32_t to_guild_card_number;
  ptext<char, 0x200> text;
};

// 82: Invalid command

// 83 (S->C): Lobby menu
// This sets the menu item IDs that the client uses for the lobby teleport menu.
// The client expects 15 items here; sending more or fewer items does not change
// the lobby count on the client. If fewer entries are sent, the menu item IDs
// for some lobbies will not be set, and the client will likely send 84 commands
// that don't make sense if the player chooses one of lobbies with unset IDs.
// On Episode 3, the client expects 20 entries instead of 15. The CARD lobbies
// are the last five entries, even though they appear at the top of the list on
// the player's screen.

// Command is a list of these; header.flag is the entry count (15 or 20)
struct S_LobbyListEntry_83 {
  le_uint32_t menu_id;
  le_uint32_t item_id;
  le_uint32_t unused;
};

// 84 (C->S): Choose lobby

struct C_LobbySelection_84 {
  le_uint32_t menu_id;
  le_uint32_t item_id;
};

// 85: Invalid command
// 86: Invalid command
// 87: Invalid command

// 88 (S->C): Update lobby arrows

// Command is a list of these; header.flag is the entry count. There should
// be an update for every player in the lobby in this command, even if their
// arrow color isn't being changed.
struct S_ArrowUpdateEntry_88 {
  le_uint32_t player_tag;
  le_uint32_t guild_card_number;
  le_uint32_t arrow_color;
};

// The arrow color values are:
// 00 - none
// 01 - red
// 02 - blue
// 03 - green
// 04 - yellow
// 05 - purple
// 06 - cyan
// 07 - orange
// 08 - pink
// 09 - white
// 0A - white
// 0B - white
// 0C - black
// anything else - none

// 89 (C->S): Set lobby arrow
// header.flag = arrow color number (see above); no other arguments.
// Server should send an 88 command to all players in the lobby.

// 8A (C->S): Request lobby/game name
// No arguments

// 8A (S->C): Lobby/game name
// Contents is a string (char16_t on PC/BB, char on DC/GC) containing the lobby
// or game name. The client generally only sends this immediately after joining
// a game, but Sega's servers also replied to it if it was sent in a lobby. They
// would return a string like "LOBBY01" even though this would never be used
// under normal circumstances.

// 8B: Invalid command
// 8C: Invalid command
// 8D: Invalid command
// 8E: Invalid command
// 8F: Invalid command
// 90: Invalid command
// 91: Invalid command
// 92: Invalid command

// 93 (C->S): Log in (BB)

struct C_Login_BB_93 {
  le_uint32_t player_tag;
  le_uint32_t guild_card_number;
  ptext<char, 0x08> unused;
  le_uint32_t team_id;
  ptext<char, 0x10> username;
  ptext<char, 0x20> unused2;
  ptext<char, 0x10> password;
  ptext<char, 0x28> unused3;

  // Note: Unlike other versions, BB puts the version string in the client
  // config at connect time. So the first time the server gets this command, it
  // will be something like "Ver. 1.24.3". Note also that some old versions
  // (before 1.23.8?) omit the hardware_info field before the client config, so
  // the client config starts 8 bytes earlier on those versions and the entire
  // command is 8 bytes shorter, hence this odd-looking union.
  union VariableLengthSection {
    union ClientConfigFields {
      ClientConfigBB cfg;
      ptext<char, 0x28> version_string;
      le_uint32_t as_u32[10];
    };

    ClientConfigFields old_clients_cfg;
    struct NewFormat {
      le_uint32_t hardware_info[2];
      ClientConfigFields cfg;
    } new_clients;
  } var;
};

// 94: Invalid command

// 95 (S->C): Request player data
// No arguments
// For some reason, some servers send high values in the header.flag field here.
// From what I can tell, that field appears to be completely unused by the
// client - sending zero works just fine. The original Sega servers had some
// uninitialized memory bugs, of which that may have been one, and other private
// servers may have just duplicated Sega's behavior verbatim.
// Client will respond with a 61 command.

// 96 (C->S): Client checksum

struct C_ClientChecksum_GC_96 {
  // It seems only at most 48 bits of this are actually used - the highest-order
  // (last) two bytes seem to always be zero.
  le_uint64_t checksum;
};

// 97 (S->C): Save to memory card
// No arguments
// According to Sylverant's documentation, sending this command with header.flag
// == 0 will cause the client to delete a lot of the character's data. This was
// presumably intended to be used by Sega if they detected cheating. newserv
// always sends header.flag = 1 here, which saves without deleting anything.

// 98 (C->S): Leave game
// Same format as 61 command.
// Client will send an 84 when it's ready to join a lobby.

// 99 (C->S): Server time accepted
// No arguments

// 9A (C->S): Initial login (no password or client config)

struct C_Login_DC_PC_GC_9A {
  ptext<char, 0x20> unused;
  ptext<char, 0x10> serial_number;
  ptext<char, 0x10> access_key;
  uint32_t player_tag;
  uint32_t guild_card_number;
  uint32_t sub_version;
  ptext<char, 0x30> serial_number2;
  ptext<char, 0x30> access_key2;
  ptext<char, 0x30> email_address;
};

// 9A (S->C): License verification result
// The result code is sent in the header.flag field. Result codes:
// 00 = license ok (don't save to memory card; client responds with 9D/9E)
// 01 = registration required (client responds with a 9C command)
// 02 = license ok (save to memory card; client responds with 9D/9E)
// 03 = access key invalid (125)
// 04 = serial number invalid (126)
// 07 = invalid Hunter's License (117)
// 08 = Hunter's License expired (116)
// 0B = HL not registered under this serial number/access key (112)
// 0C = HL not registered under this serial number/access key (113)
// 0D = HL not registered under this serial number/access key (114)
// 0E = connection error (115)
// 0F = connection suspended (111)
// 10 = connection suspended (111)
// 11 = Hunter's License expired (116)
// 12 = invalid Hunter's License (117)
// 13 = servers under maintenance (118)
// Seems like most (all?) of the rest of the codes are "network error" (119).

// 9B (S->C): Secondary server init? (BB)
// Format is the same as 03 (and the client uses the same encryption afterward).
// The only differences that 9B has from 03:
// - 9B does not work on the data-server phase (before the client has reached
//   the ship select menu), whereas 03 does.
// - The copyright string must be
//   "PSO NEW PM Server. Copyright 1999-2002 SONICTEAM." for command 9B.
// - The client will respond with a command DB instead of a command 93.

// 9C (C->S): Register

struct C_Register_DC_PC_GC_9C {
  ptext<char, 8> unused;
  le_uint32_t sub_version;
  le_uint32_t unused2;
  ptext<char, 0x30> serial_number;
  ptext<char, 0x30> access_key;
  ptext<char, 0x30> password;
};

// 9C (S->C): Login result
// The only possible error here seems to be wrong password (127) which is
// displayed if the header.flag field is zero. If header.flag is nonzero, the
// client proceeds with the login procedure by sending a 9D/9E.

// 9D (C->S): Log in
// Not used on V3 (PSO GC) - the client sends 9E instead.
// In some cases the client sends extra unused data at the end of this command.
// This seems to only occur if the client has not yet received an 04 (guild card
// number / client config) command.

struct C_Login_PC_9D {
  le_uint32_t player_tag; // 0x00010000 if guild card is set (via 04)
  le_uint32_t guild_card_number; // 0xFFFFFFFF if not set
  le_uint64_t unused;
  le_uint32_t sub_version;
  parray<uint8_t, 0x24> unused2; // 00 01 00 00 ... (rest is 00)
  ptext<char, 0x10> serial_number;
  ptext<char, 0x10> access_key;
  ptext<char, 0x30> serial_number2;
  ptext<char, 0x30> access_key2;
  ptext<char, 0x10> name;
};
struct C_LoginWithUnusedSpace_PC_9D : C_Login_PC_9D {
  parray<uint8_t, 0x84> unused_space;
};

// 9E (C->S): Log in with client config
// Not used on versions before V3 (PSO GC).
// In some cases the client sends extra unused data at the end of this command.
// This seems to only occur if the client has not yet received an 04 (guild card
// number / client config) command.

struct C_Login_GC_9E : C_Login_PC_9D {
  union ClientConfigFields {
    ClientConfig cfg;
    parray<uint8_t, 0x20> data;
    ClientConfigFields() : data() { }
  } client_config;
};
struct C_LoginWithUnusedSpace_GC_9E : C_Login_GC_9E {
  parray<uint8_t, 0x64> unused_space;
};

// 9F (S->C): Unknown (BB)

struct S_Unknown_BB_9F {
  le_uint32_t unknown_a1[10];
};

// A0 (C->S): Change ship
// This structure is for documentation only; newserv ignores the arguments here.

struct C_ChangeShipOrBlock_A0_A1 {
  le_uint32_t player_tag;
  le_uint32_t guild_card_number;
  parray<uint8_t, 0x10> unknown; // all zeroes
};

// A0 (S->C): Ship select menu
// Same as 07 command.

// A1 (C->S): Change block
// Same format as A0. Like with A0, newserv ignores the arguments.

// A1 (S->C): Block select menu
// Same as 07 command.

// A2 (C->S): Request quest menu
// No arguments

// A2 (S->C): Quest menu
// Client will respond with an 09, 10, or A9 command. For 09, the server should
// send the category or quest description via an A3 response; for 10, the server
// should send another quest menu (if a category was chosen), or send the quest
// data with 44/13 commands; for A9, the server does not need to respond.

template <typename CharT>
struct S_QuestMenuEntry {
  le_uint32_t menu_id;
  le_uint32_t item_id;
  ptext<CharT, 0x20> name;
  ptext<CharT, 0x70> short_desc;
};
struct S_QuestMenuEntry_PC_A2_A4 : S_QuestMenuEntry<char16_t> { };
struct S_QuestMenuEntry_GC_A2_A4 : S_QuestMenuEntry<char> { };

struct S_QuestMenuEntry_BB_A2_A4 {
  le_uint32_t menu_id;
  le_uint32_t item_id;
  ptext<char16_t, 0x20> name;
  // Why is this 10 characters longer than on other versions...?
  ptext<char16_t, 0x7A> short_desc;
};

// A3 (S->C): Quest information
// Same format as 1A/D5 command (plain text)

// A4 (S->C): Download quest menu
// Same format as A2, but can be used when not in a game. The client responds
// similarly as for command A2; the primary difference is that if a quest is
// chosen, it should be sent with A6/A7 commands rather than 44/13, and it must
// be in a different encrypted format. The download quest format is documented
// in create_download_quest and create_download_quest_file in Quest.cc.

// A5 (S->C): Download quest information
// Same format as 1A/D5 command (plain text)

// A6: Open file for download
// Used for download quests and GBA games.
// Same format as 44.

// A7: Write download file
// Same format as 13.

// A8: Invalid command

// A9: Quest menu closed (canceled)
// No arguments
// This command is sent when the in-game quest menu (A2) is closed. When the
// download quest menu is closed, either by downloading a quest or canceling,
// the client sends A0 instead.

// AA (C->S): Update quest statistics
// This command is used in Maximum Attack 2, but its format is unlikely to be
// specific to that quest. The structure here represents the only instance I've
// seen so far.
// The server will respond with an AB command.

struct C_UpdateQuestStatistics_AA {
  le_uint32_t quest_internal_id;
  le_uint16_t request_token;
  le_uint16_t unknown_a1;
  le_uint32_t unknown_a2;
  le_uint32_t kill_count;
  le_uint32_t time_taken; // in seconds
  parray<uint8_t, 0x14> unknown_a3;
};

// AB (S->C): Confirm update quest statistics

struct S_ConfirmUpdateQuestStatistics_AB {
  le_uint32_t unknown_a1; // 0
  le_uint16_t request_token; // Should match token sent in AA command
  le_uint16_t unknown_a2; // Schtserv always sends 0xBFFF here
};

// AC: Quest barrier
// No arguments
// After a quest begins loading in a game (the server sends 44/13 commands to
// each player with the quest's data), each player will send an AC to the server
// when it has parsed the quest and is ready to start. When all players in a
// game have sent an AC to the server, the server should send them all an AC,
// which starts the quest for all players at (approximately) the same time.
// Sending this command to a GC client when it is not waiting to start a quest
// will cause it to crash.

// AD: Invalid command
// AE: Invalid command
// AF: Invalid command

// B0: Text message
// Same format as 01 command.
// The message appears as an overlay on the right side of the screen. The player
// doesn't do anything to dismiss it; it will disappear after a few seconds.

// B1 (C->S): Request server time
// No arguments
// Server will respond with a B1 command.

// B1 (S->C): Server time
// Contents is a string like "%Y:%m:%d: %H:%M:%S.000" (the space is not a typo).
// For example: 2022:03:30: 15:36:42.000
// This command can be sent even if it's not requested by the client (with B1).
// For example, some servers send this every time a client joins a game.
// Client will respond with a 99 command.

// B2 (S->C): Execute code and/or checksum memory
// GC v1.0/v1.1 and BB only.
// Much of this command's information came from Sylverant's documentation.
// Client will respond with a B3 command.

struct S_ExecuteCode_GC_B2 {
  // Offsets in this command are relative to the start of the header, not the
  // start of this structure! Add 4 to the offsets if computing them relative to
  // the start of this struct.
  le_uint32_t relocations_offset;
  le_uint32_t checksum_start; // CRC32; 0 = no checksum requested
  le_uint32_t checksum_size; // CRC32; 0 = no checksum requested
  // This field is big-endian on GC, little-endian on other systems. The value
  // is relative to the field itself, so e.g. 4 means that the code immediately
  // follows this field. I've seen some commands in the wild where this field is
  // set to a memory address (8xxxxxxxx) rather than an offset, but it's not
  // clear what that means.
  union {
    le_uint32_t l;
    be_uint32_t b;
  } code_offset;
  // Code (usually) immediately follows here.
};

struct S_ExecuteCode_Relocations_GC_B2 {
  le_uint32_t count_offset;
  le_uint32_t count;
  le_uint32_t unknown_a1;
  le_uint32_t unknown_a2;
  le_uint32_t offset_start;
  le_uint16_t offset_entry;
  // Variable-length field:
  // le_uint16_t offsets[count];
};

// Support exists in BB for this command, but to my knowledge it has never been
// used. Like on GC, the client will respond with a B3 command.

struct S_ExecuteCode_BB_B2 {
  // If code_size == 0, no code is executed (but checksumming may still occur).
  le_uint32_t code_size; // Size of code (following this struct) and footer
  le_uint32_t checksum_address; // May be null if size is zero
  le_uint32_t checksum_size;
};

struct S_ExecuteCode_Footer_BB_B2 {
  // Relocations is a list of words (le_uint16_t) containing the number of words
  // to skip for each relocation. The relocation pointer starts immediately
  // after the checksum_size field in the header, and advances by the value of
  // one word before each relocation. At each relocated doubleword, the address
  // of the first byte of the code (after checksum_size) is added to the
  // existing value.
  le_uint32_t relocations_offset;
  le_uint32_t num_relocations;
  le_uint32_t unknown_a1[2];
  le_uint32_t entrypoint_offset; // Relative to code base (after checksum_size)
  le_uint32_t unknown_a2[3];
};

// B3 (C->S): Execute code and/or checksum memory result
// GC v1.0/v1.1 and BB only.

struct C_ExecuteCodeResult_GC_BB_B3 {
  le_uint32_t return_value; // 0 if no code was run
  le_uint32_t checksum;
};

// B4: Invalid command
// B5: Invalid command
// B6: Invalid command

// B7 (S->C): Rank update (Episode 3)

struct S_RankUpdate_GC_Ep3_B7 {
  le_uint32_t rank;
  ptext<char, 0x0C> rank_text;
  le_uint32_t meseta;
  le_uint32_t max_meseta;
  le_uint32_t jukebox_songs_unlocked;
};

// B8 (C->S): Confirm rank update
// No arguments
// The client sends this after it receives a B8 from the server.

// B8 (S->C): Update card definitions (Episode 3)
// Contents is a single little-endian le_uint32_t specifying the size of the
// (PRS-compressed) data, followed immediately by the data.
// Note: BB has a handler for B8, but it does nothing - the client ignores B8.

// B8 (C->S): Confirm updated card definitions
// No arguments
// The client sends this after it receives a B8 from the server.

// B9: Invalid command

// BA: Meseta transaction (Episode 3)

struct C_Meseta_GC_Ep3_BA {
  le_uint32_t transaction_num;
  le_uint32_t value;
  le_uint32_t request_token;
};

struct S_Meseta_GC_Ep3_BA {
  le_uint32_t remaining_meseta;
  le_uint32_t total_meseta_awarded;
  le_uint32_t request_token; // Should match the token sent by the client
};

// BB: Invalid command
// BC: Invalid command
// BD: Invalid command
// BE: Invalid command
// BF: Invalid command

// C0 (C->S): Request choice search options
// No arguments
// Server should respond with a C0 command (described below).

// C0 (S->C): Choice search options

// Command is a list of these; header.flag is the entry count (incl. top-level).
template <typename CharT>
struct S_ChoiceSearchEntry {
  // Category IDs are nonzero; if the high byte of the ID is nonzero then the
  // category can be set by the user at any time; otherwise it can't.
  le_uint16_t parent_category_id; // 0 for top-level categories
  le_uint16_t category_id;
  ptext<CharT, 0x1C> text;
};
struct S_ChoiceSearchEntry_DC_GC_C0 : S_ChoiceSearchEntry<char> { };
struct S_ChoiceSearchEntry_PC_BB_C0 : S_ChoiceSearchEntry<char16_t> { };

// Top-level categories are things like "Level", "Class", etc.
// Choices for each top-level category immediately follow the category, so
// a reasonable order of items is (for example):
//   00 00 11 01 "Preferred difficulty"
//   11 01 01 01 "Normal"
//   11 01 02 01 "Hard"
//   11 01 03 01 "Very Hard"
//   11 01 04 01 "Ultimate"
//   00 00 22 00 "Character class"
//   22 00 01 00 "HUmar"
//   22 00 02 00 "HUnewearl"
//   etc.

// C1 (C->S): Create game

template <typename CharT>
struct C_CreateGame {
  le_uint64_t unused;
  ptext<CharT, 0x10> name;
  ptext<CharT, 0x10> password;
  uint8_t difficulty; // 0-3
  uint8_t battle_mode; // 0 or 1
  // Note: Episode 3 uses the challenge mode flag for view battle permissions.
  // 0 = view battle allowed; 1 = not allowed
  uint8_t challenge_mode; // 0 or 1
  uint8_t episode; // 1-4 on V3+; unused on DC/PC
};
struct C_CreateGame_DC_GC_C1_EC : C_CreateGame<char> { };
struct C_CreateGame_PC_C1 : C_CreateGame<char16_t> { };

struct C_CreateGame_BB_C1 : C_CreateGame<char16_t> {
  uint8_t solo_mode;
  uint8_t unused2[3];
};

// C2 (C->S): Set choice search parameters
// Server does not respond.

struct C_SetChoiceSearchParameters_C2 {
  le_uint16_t disabled; // 0 = enabled, 1 = disabled
  le_uint16_t unused;
  struct Entry {
    le_uint16_t parent_category_id;
    le_uint16_t category_id;
  };
  Entry entries[0];
};

// C3 (C->S): Execute choice search
// Server should respond with a C4 command.

struct C_ExecuteChoiceSearch_C3 {
  le_uint32_t unknown;
  struct Entry {
    le_uint16_t parent_category_id;
    le_uint16_t category_id;
  };
  Entry entries[0];
};

// C4 (S->C): Choice search results

// Command is a list of these; header.flag is the entry count
struct S_ChoiceSearchResultEntry_GC_C4 {
  le_uint32_t guild_card_number;
  ptext<char, 0x10> name; // No language marker, as usual on GC
  ptext<char, 0x20> info_string; // Usually something like "<class> Lvl <level>"
  // Format is stricter here; this is "LOBBYNAME,BLOCKNUM,SHIPNAME"
  // If target is in game, for example, "Game Name,BLOCK01,Alexandria"
  // If target is in lobby, for example, "BLOCK01-1,BLOCK01,Alexandria"
  ptext<char, 0x34> locator_string;
  // Server IP and port for "meet user" option
  le_uint32_t server_ip;
  le_uint16_t server_port;
  le_uint16_t unused1;
  le_uint32_t menu_id;
  le_uint32_t lobby_id; // These two are guesses
  le_uint32_t game_id; // Zero if target is in a lobby rather than a game
  parray<uint8_t, 0x58> unused2;
};

// C5 (S->C): Challenge rank update
// TODO: Document format and usage for this command

// C6 (C->S): Set blocked senders list

struct C_SetBlockedSenders_C6 {
  // The command always contains 30 entries, even if the entries at the end are
  // blank (zero).
  parray<le_uint32_t, 30> blocked_senders;
};

// C7 (C->S): Enable simple mail auto-reply
// Same format as 1A/D5 command (plain text).
// Server does not respond

// C8 (C->S): Disable simple mail auto-reply
// No arguments
// Server does not respond

// C9: Broadcast command (Episode 3)
// Same as 60, but only send to Episode 3 clients.

// CA (C->S): Ep3 server data request
// TODO: Document this. It does many different things.

// CB: Broadcast command (Episode 3)
// Same as 60, but only send to Episode 3 clients.

// CC: Invalid command
// CD: Invalid command
// CE: Invalid command
// CF: Invalid command

// D0 (C->S): Execute trade via trade window
// General sequence: client sends D0, server sends D1 to that client, server
// sends D3 to other client, server sends D4 to both (?) clients.
// Format unknown

// D1 (S->C): Confirm trade to initiator
// No arguments

// D2: Invalid command

// D3 (S->C): Execute trade with accepter
// Format unknown; appears to be same as D0.

// D4 (S->C): Close trade
// No arguments

// D5: Large message box
// Same as 1A command. Sylverant's documentation notes that D5 is not valid on
// pre-V3 versions (PSO DC or PSO PC).

// D6 (C->S): Large message box closed (GC)
// No arguments
// DC and PC do not send this command at all. GC v1.0 and v1.1 will send this
// command when any large message box (1A/D5) is closed; GC Plus and Episode 3
// will send D6 only for large message boxes that occur before the client has
// joined a lobby. (After joining a lobby, large message boxes will still be
// displayed if sent by the server, but the client won't send a D6 when they are
// closed.)

// D7 (C->S): Request GBA game file
// The server should send the requested file using A6/A7 commands.

struct C_GBAGameRequest_GC_D7 {
  ptext<char, 0x10> filename;
};

// D7 (S->C): Valid but ignored (BB)

// D8 (C->S): Info board request
// No arguments
// The server should respond with a D8 command (described below).

// D8 (S->C): Info board

// Command is a list of these; header.flag is the entry count. There should be
// one entry for each player in the current lobby/game.
template <typename CharT>
struct S_InfoBoardEntry_D8 {
  ptext<CharT, 0x10> name;
  ptext<CharT, 0xAC> message;
};
struct S_InfoBoardEntry_PC_BB_D8 : S_InfoBoardEntry_D8<char16_t> { };
struct S_InfoBoardEntry_DC_GC_D8 : S_InfoBoardEntry_D8<char> { };

// D9 (C->S): Write info board
// Contents are plain text, like 1A/D5.
// Server does not respond

// DA (S->C): Change lobby event
// header.flag = new event number; no other arguments.

// DB (C->S): Verify license (GC/BB)
// Server should respond with a 9A command.

struct C_VerifyLicense_GC_DB {
  ptext<char, 0x20> unused;
  ptext<char, 0x10> serial_number;
  ptext<char, 0x10> access_key;
  ptext<char, 0x08> unused2;
  le_uint32_t sub_version;
  ptext<char, 0x30> serial_number2;
  ptext<char, 0x30> access_key2;
  ptext<char, 0x30> password;
};

struct C_VerifyLicense_BB_DB {
  ptext<char, 0x10> unknown_a1;
  ptext<char, 0x10> unknown_a2;
  ptext<char, 0x10> unknown_a3;
  ptext<char, 0x10> unknown_a4;
  ptext<char, 0x30> unknown_a5;
  ptext<char, 0x30> unknown_a6;
  ptext<char, 0x30> unknown_a7;
};

// DC: Player menu state (Episode 3)
// No arguments. It seems the client expects the server to respond with another
// DC command with header.flag = 0.

// DC: Guild card data (BB)

struct S_GuildCardHeader_BB_01DC {
  le_uint32_t unknown; // should be 1
  le_uint32_t filesize; // 0x0000D590
  le_uint32_t checksum; // CRC32 of entire guild card file (0xD590 bytes)
};

struct S_GuildCardFileChunk_02DC {
  uint32_t unknown; // 0
  uint32_t chunk_index;
  uint8_t data[0x6800]; // Comamnd may be shorter if this is the last chunk
};

struct C_GuildCardDataRequest_BB_03DC {
  le_uint32_t unknown;
  le_uint32_t chunk_index;
  le_uint32_t cont;
};

// DD (S->C): Send quest state to joining player (BB)
// header.flag is the client ID that the leader should send quest state to.
// No other arguments

// DE (S->C): Rare monster configuration (BB)

struct S_RareMonsterConfig_BB_DE {
  le_uint16_t data[16];
};

// DF: Invalid command

// E0 (S->C): Tournament list (Episode 3)

// Command is a list of these; header.flag is the entry count. Some servers
// always send 0x740 bytes even if the entries don't fill the space.
struct S_TournamentEntry_GC_Ep3_E0 {
  le_uint32_t menu_id;
  le_uint32_t item_id;
  parray<uint8_t, 0x30> unknown;
};

// E0 (C->S): Request team and key config (BB)

// E1: Invalid command

// E2 (C->S): Tournament control (Episode 3)
// Flag = 0 => request tournament list (server responds with E0)
// Flag = 1 => check tournament
// Flag = 2 => cancel tournament entry
// Flag = 3 => create tournament spectator team
// Flag = 4 => join tournament spectator team

// E2 (S->C): Tournament entry control (Episode 3)

// E2 (S->C): Team and key config (BB)
// See KeyAndTeamConfigBB in Player.hh for format

// E3 (C->S): Player preview request (BB)

struct C_PlayerPreviewRequest_BB_E3 {
  le_uint32_t player_index;
  le_uint32_t unused;
};

// E4: CARD lobby game (Episode 3)
// When client sends an E4, server should respond with another E4 (but these
// commands have different formats).

// Header flag = seated state (1 = present, 0 = leaving)
struct C_CardLobbyGame_GC_E4 {
  le_uint16_t table_number;
  le_uint16_t seat_number;
};

// Header flag = 2
struct S_CardLobbyGame_GC_E4 {
  struct Entry {
    le_uint32_t present; // 1 = player present, 0 = no player
    le_uint32_t guild_card_number;
  };
  Entry entries[4];
};

// E4 (S->C): Player choice or no player present (BB)

struct S_ApprovePlayerChoice_BB_00E4 {
  le_uint32_t player_index;
  le_uint32_t result; // 1 = approved
};

struct S_PlayerPreview_NoPlayer_BB_00E4 {
  le_uint32_t player_index;
  le_uint32_t error; // 2 = no player present
};

// E5 (S->C): Player preview (BB)
// E5 (C->S): Create character (BB)

struct SC_PlayerPreview_CreateCharacter_BB_00E5 {
  le_uint32_t player_index;
  PlayerDispDataBBPreview preview;
};

// E6: Spectator team list (Episode 3)
// Same format as 08 command.

// E6 (S->C): Set guild card number and update client config (BB)

struct S_ClientInit_BB_00E6 {
  le_uint32_t error;
  le_uint32_t player_tag;
  le_uint32_t guild_card_number;
  le_uint32_t team_id;
  ClientConfigBB cfg;
  le_uint32_t caps; // should be 0x00000102
};

// E7: Save or load full player data
// See export_bb_player_data() in Player.cc for format.

// E8 (C->S): Client checksum (BB)
// E8 (S->C): Accept client checksum (BB)

struct S_AcceptClientChecksum_BB_02E8 {
  le_uint32_t verify;
  le_uint32_t unused;
};

// E9: Invalid command
// EA: Team control (BB)
// Format unknown. There are many subcommands - up to at least 14EA.

// EB (S->C): Send stream file index and chunks

// Command is a list of these; header.flag is the entry count.
struct S_StreamFileIndexEntry_BB_01EB {
  le_uint32_t size;
  le_uint32_t checksum; // CRC32 of file data
  le_uint32_t offset; // offset in stream (== sum of all previous files' sizes)
  ptext<char, 0x40> filename;
};

struct S_StreamFileChunk_BB_02EB {
  le_uint32_t chunk_index;
  uint8_t data[0x6800];
};

// EC: Create game (Episode 3)
// Same format as C1; some fields are unused (e.g. episode, difficulty).

// EC: Leave character select (BB)

// ED (C->S): Update account data (BB)
// There are several subcommands (noted in the union below) that each update a
// specific kind of account data.
// TODO: Actually define these structures and don't just treat them as raw data

union C_UpdateAccountData_BB_ED {
  le_uint32_t option; // 01ED
  parray<uint8_t, 0x4E0> symbol_chats; // 02ED
  parray<uint8_t, 0xA40> chat_shortcuts; // 03ED
  parray<uint8_t, 0x16C> key_config; // 04ED
  parray<uint8_t, 0x38> pad_config; // 05ED
  parray<uint8_t, 0x28> tech_menu; // 06ED
  parray<uint8_t, 0xE8> customize; // 07ED
};

// EE (S->C): Scrolling message (BB)
// Same format as 01. The message appears at the top of the screen and slowly
// scrolls to the left.

// EF (S->C): Unknown (BB)
// Has an unknown number of subcommands (00EF, 01EF, etc.)
// Contents are plain text (char).

// F0 (S->C): Unknown (BB)

struct S_Unknown_BB_F0 {
  le_uint32_t unknown_a1[7];
  le_uint32_t which; // Must be < 12
  ptext<char16_t, 0x10> unknown_a2;
  le_uint32_t unknown_a3;
};

// F1: Invalid command
// F2: Invalid command
// F3: Invalid command
// F4: Invalid command
// F5: Invalid command
// F6: Invalid command
// F7: Invalid command
// F8: Invalid command
// F9: Invalid command
// FA: Invalid command
// FB: Invalid command
// FC: Invalid command
// FD: Invalid command
// FE: Invalid command
// FF: Invalid command



// Now, the game subcommands (used in commands 60, 62, 6C, 6D, C9, and CB).
// These are laid out similarly as above. These structs start with G_ to
// indicate that they are (usually) bidirectional, and are (usually) generated
// by clients and consumed by clients.

// This structure is used by many commands (noted below)
struct G_ItemSubcommand {
  uint8_t command;
  uint8_t size;
  uint8_t client_id;
  uint8_t unused;
  le_uint32_t item_id;
  le_uint32_t amount;
};



// 00: Invalid subcommand
// 01: Invalid subcommand
// 02: Unknown
// 03: Unknown (same handler as 02)
// 04: Unknown

// 05: Switch state changed
// Some things that don't look like switches are implemented as switches using
// this subcommand. For example, when all enemies in a room are defeated, this
// subcommand is used to unlock the doors.

struct G_SwitchStateChanged_6x05 {
  uint8_t subcommand;
  uint8_t size;
  le_uint16_t switch_id; // 0xFFFF for room clear when all enemies defeated
  parray<uint8_t, 6> unknown;
  uint8_t area;
  uint8_t enabled;
};

// 06: Send guild card

template <typename CharT>
struct G_SendGuildCard_PC_GC {
  uint8_t subcommand;
  uint8_t size;
  le_uint16_t unused;
  le_uint32_t player_tag;
  le_uint32_t guild_card_number;
  ptext<CharT, 0x18> name;
  ptext<CharT, 0x48> desc;
  parray<uint8_t, 0x24> unused2;
  uint8_t reserved1;
  uint8_t reserved2;
  uint8_t section_id;
  uint8_t char_class;
};
struct G_SendGuildCard_PC_6x06 : G_SendGuildCard_PC_GC<char16_t> { };
struct G_SendGuildCard_GC_6x06 : G_SendGuildCard_PC_GC<char> { };

struct G_SendGuildCard_BB_6x06 {
  uint8_t subcommand;
  uint8_t size;
  le_uint16_t unused;
  le_uint32_t guild_card_number;
  ptext<char16_t, 0x18> name;
  ptext<char16_t, 0x10> team_name;
  ptext<char16_t, 0x58> desc;
  uint8_t reserved1;
  uint8_t reserved2;
  uint8_t section_id;
  uint8_t char_class;
};

// 07: Symbol chat
// 08: Invalid subcommand
// 09: Unknown

// 0A: Enemy hit

struct G_EnemyHitByPlayer_6x0A {
  uint8_t command;
  uint8_t size;
  le_uint16_t enemy_id2;
  le_uint16_t enemy_id;
  le_uint16_t damage;
  le_uint32_t flags;
};

// 0B: Box destroyed
// 0C: Add condition (poison/slow/etc.)
// 0D: Remove condition (poison/slow/etc.)
// 0E: Unknown
// 0F: Invalid subcommand
// 10: Unknown
// 11: Unknown
// 12: Dragon actions
// 13: Re Rol Le actions
// 14: Unknown (supported; game only)
// 15: Vol Opt boss actions
// 16: Vol Opt boss actions
// 17: Unknown (supported; game only)
// 18: Unknown (supported; game only)
// 19: Dark Falz actions
// 1A: Invalid subcommand
// 1B: Unknown
// 1C: Unknown (supported; game only)
// 1D: Invalid subcommand
// 1E: Invalid subcommand
// 1F: Unknown (supported; lobby & game)
// 20: Set position (existing clients send when a new client joins a lobby/game)
// 21: Inter-level warp

// 22: Set player visibility
// 23: Set player visibility

struct G_SetPlayerVisibility_6x22_6x23 {
  uint8_t subcommand; // 22 = invisible, 23 = visible
  uint8_t size;
  le_uint16_t client_id;
};

// 24: Unknown (supported; game only)

// 25: Equip item

struct G_EquipItem_6x25 {
  uint8_t command;
  uint8_t size;
  uint8_t client_id;
  uint8_t unused;
  le_uint32_t item_id;
  le_uint32_t equip_slot;
};

// 26: Unequip item

struct G_UnequipItem_6x26 {
  uint8_t command;
  uint8_t size;
  uint8_t client_id;
  uint8_t unused;
  le_uint32_t item_id;
  le_uint32_t unused2;
};

// 27: Use item

struct G_UseItem_6x27 {
  uint8_t command;
  uint8_t size;
  uint8_t client_id;
  uint8_t unused;
  le_uint32_t item_id;
};

// 28: Feed MAG

struct G_FeedMAG_6x28 {
  uint8_t subcommand;
  uint8_t size;
  le_uint16_t client_id;
  le_uint32_t mag_item_id;
  le_uint32_t fed_item_id;
};

// 29: Delete inventory item (via bank deposit / sale / feeding MAG)
// This subcommand is also used for reducing the size of stacks - if amount is
// less than the stack count, the item is not deleted and its ID remains valid.
// Format is G_ItemSubcommand

// 2A: Drop item

struct G_PlayerDropItem_6x2A {
  uint8_t command;
  uint8_t size;
  uint8_t client_id;
  uint8_t unused;
  le_uint16_t unused2; // should be 1
  le_uint16_t area;
  le_uint32_t item_id;
  le_float x;
  le_float y;
  le_float z;
};

// 2B: Create item in inventory (e.g. via tekker or bank withdraw)

struct G_PlayerCreateInventoryItem_6x2B {
  uint8_t command;
  uint8_t size;
  uint8_t client_id;
  uint8_t unused;
  ItemData item;
  le_uint32_t unknown;
};

// 2C: Talk to NPC
// 2D: Done talking to NPC
// 2E: Unknown
// 2F: Hit by enemy

// 30: Level up

struct G_LevelUp_6x30 {
  uint8_t command;
  uint8_t size;
  uint8_t client_id;
  uint8_t unused;
  le_uint16_t atp;
  le_uint16_t mst;
  le_uint16_t evp;
  le_uint16_t hp;
  le_uint16_t dfp;
  le_uint16_t ata;
  le_uint32_t level;
};

// 31: Medical center
// 32: Medical center
// 33: Revive player (e.g. with moon atomizer)
// 34: Unknown
// 35: Invalid subcommand
// 36: Unknown (supported; game only)
// 37: Photon blast
// 38: Unknown
// 39: Photon blast ready
// 3A: Unknown (supported; game only)
// 3B: Unknown (supported; lobby & game)
// 3C: Invalid subcommand
// 3D: Invalid subcommand

// 3E: Stop moving

struct G_StopAtPosition_6x3E {
  uint8_t subcommand;
  uint8_t size;
  le_uint16_t client_id;
  uint64_t unknown;
  le_float x;
  le_float y;
  le_float z;
};

// 3F: Set position

struct G_SetPosition_6x3F {
  uint8_t subcommand;
  uint8_t size;
  le_uint16_t client_id;
  le_uint32_t unknown;
  le_uint32_t area;
  le_float x;
  le_float y;
  le_float z;
};

// 40: Walk

struct G_WalkToPosition_6x40 {
  uint8_t subcommand;
  uint8_t size;
  le_uint16_t client_id;
  le_float x;
  le_float z;
  uint32_t unused;
};

// 41: Unknown

// 42: Run

struct G_RunToPosition_6x42 {
  uint8_t subcommand;
  uint8_t size;
  le_uint16_t client_id;
  le_float x;
  le_float z;
};

// 43: First attack
// 44: Second attack
// 45: Third attack
// 46: Attack finished (sent after each of 43, 44, and 45)
// 47: Cast technique
// 48: Cast technique complete
// 49: Subtract PB energy
// 4A: Fully shield attack
// 4B: Hit by enemy
// 4C: Hit by enemy
// 4D: Unknown (supported; lobby & game)
// 4E: Unknown (supported; lobby & game)
// 4F: Unknown (supported; lobby & game)
// 50: Unknown (supported; lobby & game)
// 51: Invalid subcommand
// 52: Toggle shop/bank interaction
// 53: Unknown (supported; game only)
// 54: Unknown
// 55: Intra-map warp
// 56: Unknown (supported; lobby & game)
// 57: Unknown (supported; lobby & game)
// 58: Unknown (supported; game only)

// 59: Pick up item

struct G_PickUpItem_6x59 {
  uint8_t subcommand;
  uint8_t size;
  le_uint16_t client_id;
  le_uint16_t client_id2;
  le_uint16_t area;
  le_uint32_t item_id;
};

// 5A: Request to pick up item

struct G_PickUpItemRequest_6x5A {
  uint8_t command;
  uint8_t size;
  uint8_t client_id;
  uint8_t unused;
  le_uint32_t item_id;
  uint8_t area;
  uint8_t unused2[3];
};

// 5B: Invalid subcommand
// 5C: Unknown

// 5D: Drop meseta or stacked item

struct G_DropStackedItem_6x5D {
  uint8_t subcommand;
  uint8_t size;
  uint8_t client_id;
  uint8_t unused;
  le_uint16_t area;
  le_uint16_t unused2;
  le_float x;
  le_float z;
  ItemData data;
  le_uint32_t unused3;
};

// 5E: Buy item at shop

struct G_BuyShopItem_6x5E {
  uint8_t subcommand;
  uint8_t size;
  uint8_t client_id;
  uint8_t unused;
  ItemData item;
};

// 5F: Drop item from box/enemy

struct G_DropItem_6x5F {
  uint8_t subcommand;
  uint8_t size;
  le_uint16_t unused;
  uint8_t area;
  uint8_t enemy_instance;
  le_uint16_t request_id;
  le_float x;
  le_float z;
  le_uint32_t unused2;
  ItemData data;
  le_uint32_t unused3;
};

// 60: Request for item drop (handled by the server on BB)

struct G_EnemyDropItemRequest_6x60 {
  uint8_t command;
  uint8_t size;
  le_uint16_t unused;
  uint8_t area;
  uint8_t enemy_id;
  le_uint16_t request_id;
  le_float x;
  le_float z;
  le_uint64_t unknown;
};

// 61: Feed MAG
// 62: Unknown
// 63: Destroy an item on the ground (used when too many items have been dropped)
// 64: Unknown
// 65: Unknown
// 66: Use star atomizer
// 67: Create enemy set
// 68: Telepipe/Ryuker
// 69: Unknown (supported; game only)
// 6A: Unknown (supported; game only)
// 6B: Unknown (used while loading into game)
// 6C: Unknown (used while loading into game)
// 6D: Unknown (used while loading into game)
// 6E: Unknown (used while loading into game)
// 6F: Unknown (used while loading into game)
// 70: Unknown (used while loading into game)
// 71: Unknown (used while loading into game)
// 72: Unknown (used while loading into game)
// 73: Invalid subcommand (but apparently valid on BB; function is unknown)
// 74: Word select
// 75: Unknown (supported; game only)
// 76: Enemy killed
// 77: Sync quest data
// 78: Unknown
// 79: Lobby 14/15 soccer game
// 7A: Unknown
// 7B: Unknown
// 7C: Unknown (supported; game only)
// 7D: Unknown (supported; game only)
// 7E: Unknown
// 7F: Unknown
// 80: Trigger trap
// 81: Unknown
// 82: Unknown
// 83: Place trap
// 84: Unknown (supported; game only)
// 85: Unknown (supported; game only)
// 86: Hit destructible wall
// 87: Unknown
// 88: Unknown (supported; game only)
// 89: Unknown (supported; game only)
// 8A: Unknown
// 8B: Unknown
// 8C: Unknown
// 8D: Unknown (supported; lobby & game)
// 8E: Unknown
// 8F: Unknown
// 90: Unknown
// 91: Unknown (supported; game only)
// 92: Unknown
// 93: Timed switch activated
// 94: Warp (the $warp chat command is implemented using this)
// 95: Unknown
// 96: Unknown
// 97: Unknown
// 98: Unknown
// 99: Unknown
// 9A: Update player stat ($infhp/$inftp are implemented using this)
// 9B: Unknown
// 9C: Unknown (supported; game only)
// 9D: Unknown
// 9E: Unknown
// 9F: Gal Gryphon actions
// A0: Gal Gryphon actions
// A1: Unknown

// A2: Request for item drop from box (handled by server on BB)

struct G_BoxItemDropRequest_6xA2 {
  uint8_t command;
  uint8_t size;
  le_uint16_t unused;
  uint8_t area;
  uint8_t unused2;
  le_uint16_t request_id;
  le_float x;
  le_float z;
  le_uint32_t unknown[6];
};

// A3: Episode 2 boss actions
// A4: Olga Flow phase 1 actions
// A5: Olga Flow phase 2 actions
// A6: Trade proposal
// A7: Unknown
// A8: Gol Dragon actions
// A9: Barba Ray actions
// AA: Episode 2 boss actions
// AB: Create lobby chair
// AC: Unknown
// AD: Unknown
// AE: Set chair state? (like 20, sent by existing clients at join time)
// AF: Turn in lobby chair
// B0: Move in lobby chair
// B1: Unknown
// B2: Unknown
// B3: Invalid subcommand
// B4: Invalid subcommand
// B5: Episode 3 game setup menu state sync
// B5: BB shop request (handled by the server)
// B6: Episode 3 map list (server->client only)

// B6: BB shop contents (server->client only)

struct G_ShopContents_BB_6xB6 {
  uint8_t subcommand;
  uint8_t size; // always 2C regardless of the number of items??
  le_uint16_t params; // 037F
  uint8_t shop_type;
  uint8_t num_items;
  le_uint16_t unused;
  ItemData entries[20];
};

// B7: BB buy shop item (handled by the server)

// B8: Accept tekker result (handled by the server on BB)
// Format is G_IdentifyResult

// B9: Provisional tekker result

struct G_IdentifyResult_BB_6xB9 {
  uint8_t subcommand;
  uint8_t size;
  uint8_t client_id;
  uint8_t unused;
  ItemData item;
};

// BA: Invalid subcommand
// BB: BB bank request (handled by the server)

// BC: BB bank contents (server->client only)

struct G_BankContentsHeader_BB_6xBC {
  uint8_t subcommand;
  uint8_t unused1;
  le_uint16_t unused2;
  le_uint32_t size; // same as size in overall command header
  le_uint32_t checksum; // can be random; client won't notice
  le_uint32_t numItems;
  le_uint32_t meseta;
  // Item data follows
};

// BD: BB bank action (take/deposit meseta/item) (handled by the server)

struct G_BankAction_BB_6xBD {
  uint8_t subcommand;
  uint8_t size;
  le_uint16_t unused;
  le_uint32_t item_id; // 0xFFFFFFFF = meseta; anything else = item
  le_uint32_t meseta_amount;
  uint8_t action; // 0 = deposit, 1 = take
  uint8_t item_amount;
  le_uint16_t unused2;
};

// BE: BB create inventory item (server->client only)

struct G_CreateInventoryItem_BB_6xBE {
  uint8_t subcommand;
  uint8_t size;
  le_uint16_t client_id;
  ItemData item;
  le_uint32_t unused;
};

// BF: Ep3 change music
// BF: Give EXP (BB) (server->client only)

struct G_GiveExperience_BB_6xBF {
  uint8_t subcommand;
  uint8_t size;
  uint8_t client_id;
  uint8_t unused;
  le_uint32_t amount;
};

// C0: Unknown
// C1: Unknown
// C2: Unknown

// C3: Split stacked item (not sent if entire stack is dropped) (handled by the server on BB)

struct G_SplitStackedItem_6xC3 {
  uint8_t command;
  uint8_t size;
  uint8_t client_id;
  uint8_t unused;
  le_uint16_t area;
  le_uint16_t unused2;
  le_float x;
  le_float z;
  le_uint32_t item_id;
  le_uint32_t amount;
};

// C4: Sort inventory (handled by the server on BB)

struct G_SortInventory_6xC4 {
  uint8_t command;
  uint8_t size;
  le_uint16_t unused;
  le_uint32_t item_ids[30];
};

// C5: Invalid subcommand
// C6: Invalid subcommand
// C7: Invalid subcommand

// C8: Enemy killed (handled by the server on BB)

struct G_EnemyKilled_6xC8 {
  uint8_t command;
  uint8_t size;
  le_uint16_t enemy_id2;
  le_uint16_t enemy_id;
  le_uint16_t killer_client_id;
  le_uint32_t unused;
};

// C9: Invalid subcommand
// CA: Invalid subcommand
// CB: Unknown
// CC: Unknown
// CD: Unknown
// CE: Unknown
// CF: Unknown (supported; game only) (handled by the server on BB)
// D0: Invalid subcommand
// D1: Invalid subcommand
// D2: Unknown
// D3: Invalid subcommand
// D4: Unknown
// D5: Invalid subcommand
// D6: Invalid subcommand
// D7: Invalid subcommand
// D8: Invalid subcommand
// D9: Invalid subcommand
// DA: Invalid subcommand
// DB: Unknown
// DC: Unknown
// DD: Unknown
// DE: Invalid subcommand
// DF: Invalid subcommand
// E0: Invalid subcommand
// E1: Invalid subcommand
// E2: Invalid subcommand
// E3: Unknown
// E4: Invalid subcommand
// E5: Invalid subcommand
// E6: Invalid subcommand
// E7: Invalid subcommand
// E8: Invalid subcommand
// E9: Invalid subcommand
// EA: Invalid subcommand
// EB: Invalid subcommand
// EC: Invalid subcommand
// ED: Invalid subcommand
// EE: Invalid subcommand
// EF: Invalid subcommand
// F0: Invalid subcommand
// F1: Invalid subcommand
// F2: Invalid subcommand
// F3: Invalid subcommand
// F4: Invalid subcommand
// F5: Invalid subcommand
// F6: Invalid subcommand
// F7: Invalid subcommand
// F8: Invalid subcommand
// F9: Invalid subcommand
// FA: Invalid subcommand
// FB: Invalid subcommand
// FC: Invalid subcommand
// FD: Invalid subcommand
// FE: Invalid subcommand
// FF: Invalid subcommand

#pragma pack(pop)