telegram-purple.c

/*
    This file is part of telegram-purple
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02111-1301  USA
 
    Copyright Matthias Jentsch, Vitaly Valtman, Ben Wiederhake, Christopher Althaus 2014-2015
*/

#include <mtproto-key.h>

#include "telegram-purple.h"
#include "commit.h"

#ifdef WIN32
#include "win32/win32dep.h"
#endif

static void update_message_handler (struct tgl_state *TLS, struct tgl_message *M);
static void update_marked_read (struct tgl_state *TLS, int num, struct tgl_message *list[]);
static void update_on_logged_in (struct tgl_state *TLS);
static void update_on_ready (struct tgl_state *TLS);
static void update_user_typing (struct tgl_state *TLS, struct tgl_user *U, enum tgl_typing_status status);
static void update_secret_chat_typing (struct tgl_state *TLS, struct tgl_secret_chat *E);
static void update_user_status_handler (struct tgl_state *TLS, struct tgl_user *U);
static void update_user_handler (struct tgl_state *TLS, struct tgl_user *U, unsigned flags);
static void update_secret_chat_handler (struct tgl_state *TLS, struct tgl_secret_chat *C, unsigned flags);
static void update_on_failed_login (struct tgl_state *TLS);

struct tgl_update_callback tgp_callback = {
  .new_msg = update_message_handler,
  .marked_read = update_marked_read,
  .logprintf = debug,
  .get_values = request_value,
  .logged_in = update_on_logged_in,
  .started = update_on_ready,
  .type_notification = update_user_typing,
  
  // FIXME: what about user_registred, user_activated, new_authorization, our_id ?
  .type_in_secret_chat_notification = update_secret_chat_typing,
  .type_in_chat_notification = update_chat_typing,
  .chat_update = update_chat_handler,
  .channel_update = update_channel_handler,
  .user_update = update_user_handler,
  .secret_chat_update = update_secret_chat_handler,
  .msg_receive = update_message_handler,
  .user_status_update = update_user_status_handler,
  .create_print_name = tgp_blist_create_print_name,
  .on_failed_login = update_on_failed_login
};

static void _update_buddy (struct tgl_state *TLS, tgl_peer_t *user, unsigned flags) {
  PurpleBuddy *buddy = tgp_blist_buddy_find (TLS, user->id);
  if (buddy) {
    if (flags & TGL_UPDATE_DELETED) {
      debug ("update deleted");
      purple_blist_remove_buddy (buddy);
    } else {
      if (flags & TGL_UPDATE_CONTACT) {
        debug ("update contact");
        purple_blist_alias_buddy (buddy, user->print_name);
      }
      if (flags & TGL_UPDATE_PHOTO) {
        debug ("update photo");
        tgp_info_update_photo (&buddy->node, user);
      }
    }
  }
}

static void update_user_handler (struct tgl_state *TLS, struct tgl_user *user, unsigned flags) {
  debug ("update_user_handler() (%s)", print_flags_update (flags));
  
  if (tgl_get_peer_id (TLS->our_id) == tgl_get_peer_id (user->id) && (flags & (TGL_UPDATE_NAME | TGL_UPDATE_CONTACT))) {
    // own user object, do not add that user to the buddy list but make the ID known to the name lookup and
    // set the print name as the name to be displayed in IM chats instead of the login name (the phone number)
    purple_connection_set_display_name (tls_get_conn (TLS), user->print_name);
    tgp_blist_lookup_add (TLS, user->id, user->print_name);
    return;
  }
  
  if (flags & TGL_UPDATE_CREATED) {
    // user was allocated, fetch the corresponding buddy from the buddy list
    PurpleBuddy *buddy = tgp_blist_buddy_find (TLS, user->id);
    debug ("new user %s allocated (%s)", user->print_name, print_flags_user (user->flags));
    
    if (user->flags & TGLUF_DELETED) {
      if (buddy) {
        info ("user %d was deleted, removing from buddy list ...", tgl_get_peer_id (user->id));
        purple_blist_remove_buddy (buddy);
      }
    } else {
      g_return_if_fail(user->print_name);
      
      if (! buddy) {
        // if the buddy is still stored in the legacy naming format find and migrate it. This
        // should only happen when making the switch from a version < 1.2.2 to a version >= 1.2.2
        char *id = g_strdup_printf ("%d", tgl_get_peer_id (user->id));
        buddy = purple_find_buddy (tls_get_pa (TLS), id);
        g_free (id);
        
        if (buddy) {
          info ("migrating buddy from old name %s to %s", purple_buddy_get_name (buddy), user->print_name);
          buddy = tgp_blist_buddy_migrate (TLS, buddy, user);
        }
        
        // the id isn't known to the lookup yet since the user is not in the buddy list. Add the id to the
        // lookup to allow sending messages to this user based on the purple name.
        tgp_blist_lookup_add (TLS, user->id, user->print_name);
        
      } else {
        // Keep the users name up-to-date. Changing the actual user name would imply making the history
        // inacessible, therefore name changes should only affect the alias.
        if (strcmp (purple_buddy_get_alias (buddy), user->print_name)) {
          serv_got_alias (tls_get_conn (TLS), purple_buddy_get_name (buddy), user->print_name);
        }
      }

      if (user->flags & TGLUF_CONTACT) {
        if (! buddy) {
          tgp_blist_contact_add (TLS, user);
        }
      }
      
      if (buddy) {
        p2tgl_prpl_got_user_status (TLS, user->id, &user->status);
        tgp_info_update_photo (&buddy->node, tgl_peer_get (TLS, user->id));
      }
    }
  } else {
    // peer was not created, but altered in some way
    _update_buddy (TLS, (tgl_peer_t *)user, flags);
  }
}

static void update_secret_chat_handler (struct tgl_state *TLS, struct tgl_secret_chat *U, unsigned flags) {
  debug ("update_secret_chat_handler() (%s)", print_flags_update (flags));
  PurpleBuddy *buddy = tgp_blist_buddy_find (TLS, U->id);

  if (flags & TGL_UPDATE_CREATED) {
    tgp_blist_lookup_add (TLS, U->id, U->print_name);
  } else {
    if (flags & TGL_UPDATE_WORKING) {
      write_secret_chat_file (TLS);
      if (U->state == sc_ok) {
        tgp_msg_special_out (TLS , _("Secret chat ready.") , U->id, PURPLE_MESSAGE_NO_LOG | PURPLE_MESSAGE_SYSTEM);
      }
    }
    if (buddy) {
      if (flags & TGL_UPDATE_DELETED) {
        U->state = sc_deleted;
        write_secret_chat_file (TLS);

        tgp_msg_special_out (TLS , _("Secret chat terminated.") , U->id, PURPLE_MESSAGE_SYSTEM);
        purple_prpl_got_user_status (tls_get_pa (TLS), tgp_blist_lookup_purple_name (TLS, U->id), "offline", NULL);
        purple_blist_remove_buddy (buddy);
      } else {
        _update_buddy (TLS, (tgl_peer_t *)U, flags);
      }
    }
  }
  
  if (!(flags & TGL_UPDATE_DELETED)) {
    if (! buddy) {
      buddy = tgp_blist_buddy_new (TLS, (tgl_peer_t *)U);
      purple_blist_add_buddy (buddy, NULL, tgp_blist_group_init (_("Telegram")), NULL);
      purple_blist_alias_buddy (buddy, U->print_name);
    }
    purple_prpl_got_user_status (tls_get_pa (TLS), tgp_blist_lookup_purple_name (TLS, U->id), "mobile", NULL);
  }

  if (flags & TGL_UPDATE_REQUESTED) {
    const char* choice = purple_account_get_string (tls_get_pa (TLS), TGP_KEY_ACCEPT_SECRET_CHATS, "ask");
    if (! strcmp (choice, "always")) {
      tgl_do_accept_encr_chat_request (TLS, U, write_secret_chat_gw, 0);
    } else if (! strcmp (choice, "ask")) {
      request_accept_secret_chat (TLS, U);
    }
  }
}

static void update_user_status_handler (struct tgl_state *TLS, struct tgl_user *U) {
  p2tgl_prpl_got_user_status (TLS, U->id, &U->status);
}

static void update_message_handler (struct tgl_state *TLS, struct tgl_message *M) {
  write_files_schedule (TLS);
  tgp_msg_recv (TLS, M, NULL);
}

static void update_secret_chat_typing (struct tgl_state *TLS, struct tgl_secret_chat *E) {
  g_return_if_fail (tgp_blist_lookup_purple_name (TLS, E->id));
  serv_got_typing (tls_get_conn (TLS), tgp_blist_lookup_purple_name (TLS, E->id), 2, PURPLE_TYPING);
}

static void update_user_typing (struct tgl_state *TLS, struct tgl_user *U, enum tgl_typing_status status) {
  g_return_if_fail (tgp_blist_lookup_purple_name (TLS, U->id));
  if (status == tgl_typing_typing) {
    serv_got_typing (tls_get_conn (TLS), tgp_blist_lookup_purple_name (TLS, U->id), 2, PURPLE_TYPING);
  }
}

static void update_marked_read (struct tgl_state *TLS, int num, struct tgl_message *list[]) {
  if (! purple_account_get_bool (tls_get_pa (TLS), TGP_KEY_DISPLAY_READ_NOTIFICATIONS, FALSE)) {
    return;
  }
  int i;
  for (i = 0; i < num; i++) {
    if (list[i]) {
      // only display the read recipes for messages that we sent ourselves
      if (tgl_get_peer_id (list[i]->from_id) == tgl_get_peer_id (TLS->our_id)) {
        debug ("update_mark_read to=%d", tgl_get_peer_id (list[i]->to_id));
        tgp_msg_special_out (TLS , _("Message marked as read."), list[i]->to_id, PURPLE_MESSAGE_SYSTEM);
      }
    }
  }
}

static void on_get_dialog_list_done (struct tgl_state *TLS, void *extra, int success, int size,
    tgl_peer_id_t peers[], tgl_message_id_t *last_msg_id[], int unread_count[]) {
  info ("Fetched dialogue list of size: %d", size);
  
  connection_data *conn = tls_get_data(TLS);
  if (tgp_error_if_false (TLS, success, "Fetching dialogue list failed", TLS->error)) {
    return;
  }
  
  // add all peers in the dialogue list to the buddy list
  int i;
  for (i = size - 1; i >= 0; i--) {
    tgl_peer_t *UC = tgl_peer_get (TLS, peers[i]);
    if (! UC) {
      g_warn_if_reached ();
      continue;
    }
    // our own contact shouldn't show up in our buddy list
    if (tgl_get_peer_id (UC->id) == tgl_get_peer_id (TLS->our_id)) {
      continue;
    }
    if (tgl_get_peer_type (UC->id) == TGL_PEER_USER) {
      if (! (UC->user.flags & TGLUF_DELETED)) {
        tgp_blist_contact_add (TLS, &UC->user);
      }
    }
  }
  
  // handle pending roomlist request
  if (conn->roomlist != NULL && purple_roomlist_get_in_progress (conn->roomlist)) {
    tgp_chat_roomlist_populate (TLS);
  }
  
  // handle all pending chat joins
  tls_get_data (TLS)->dialogues_ready = TRUE;
  tgp_chat_join_all_pending (TLS);
}

static void on_get_channel_list_done (struct tgl_state *TLS, void *callback_extra, int success, int size,
                tgl_peer_id_t peers[], tgl_message_id_t *last_msg_id[], int unread_count[]) {
  int i;
  for (i = 0; i < size; i ++) {
    if (! tgp_channel_loaded (TLS, peers[i])) {
      tgp_channel_load (TLS, tgl_peer_get (TLS, peers[i]), NULL, NULL);
    }
  }
}

static const char *tgprpl_list_icon (PurpleAccount *acct, PurpleBuddy *buddy) {
  return "telegram";
}

static void tgprpl_tooltip_text (PurpleBuddy *buddy, PurpleNotifyUserInfo *info, gboolean full) {
  // buddy in old format that didn't migrate
  if (! tgp_blist_buddy_has_id (buddy)) {
    return;
  }
  
  tgl_peer_t *P = tgl_peer_get (pbn_get_data (&buddy->node)->TLS, tgp_blist_buddy_get_id (buddy));
  g_return_if_fail (P);

  gchar *status = tgp_format_user_status (&P->user.status);
  purple_notify_user_info_add_pair (info, "last online: ", status);
  g_free (status);
}

static GList *tgprpl_status_types (PurpleAccount *acct) {
  debug ("tgprpl_status_types()");
  GList *types = NULL;
  PurpleStatusType *type;
  
  type = purple_status_type_new_full (PURPLE_STATUS_AVAILABLE, NULL, NULL, FALSE, TRUE, FALSE);
  types = g_list_prepend (types, type);
  
  type = purple_status_type_new_full (PURPLE_STATUS_MOBILE, NULL, NULL, FALSE, TRUE, FALSE);
  types = g_list_prepend (types, type);

  type = purple_status_type_new_full (PURPLE_STATUS_OFFLINE, NULL, NULL, FALSE, TRUE, FALSE);
  types = g_list_prepend (types, type);
  
  /*
    The states below are only registered internally so that we get notified about 
    state changes to away and unavailable. This is useful for deciding when to send 
    No other peer should ever have those states.
   */
  type = purple_status_type_new_full (PURPLE_STATUS_AWAY, NULL, NULL, FALSE, TRUE, FALSE);
  types = g_list_prepend (types, type);
  
  type = purple_status_type_new_full (PURPLE_STATUS_UNAVAILABLE, NULL, NULL, FALSE, TRUE, FALSE);
  types = g_list_prepend (types, type);
  
  return g_list_reverse (types);
}

static void create_secret_chat_done (struct tgl_state *TLS, void *callback_extra, int success,
    struct tgl_secret_chat *E) {
  if (! success) {
    tgp_notify_on_error_gw (TLS, NULL, success);
    return;
  }
  write_secret_chat_file (TLS);
}

static void start_secret_chat (PurpleBlistNode *node, gpointer data) {
  tgl_do_create_secret_chat (pbn_get_data (node)->TLS, tgp_blist_buddy_get_id ((PurpleBuddy *)node),
      create_secret_chat_done, NULL);
}

static void create_chat_link_done (struct tgl_state *TLS, void *extra, int success, const char *url) {
  tgl_peer_t *P = extra;
  if (success) {
    char *msg = g_strdup_printf (_("Invite link: %s"), url);
    tgp_chat_got_in (TLS, P, P->id, msg, PURPLE_MESSAGE_SYSTEM, time(NULL));
    g_free (msg);
  } else {
    tgp_notify_on_error_gw (TLS, NULL, success);
  }
}

void export_chat_link (struct tgl_state *TLS, tgl_peer_t *P) {
  if (! (P->flags & (TGLPF_ADMIN | TGLPF_CREATOR))) {
    // FIXME: Can TGLCHF_MODERATOR export links?
    purple_notify_error (_telegram_protocol, _("Creating chat link failed"), _("Creating chat link failed"),
        _("You need to be admin of the group  to do that."));
    return;
  }
  
  if (tgl_get_peer_type (P->id) == TGL_PEER_CHAT) {
    tgl_do_export_chat_link (TLS, P->id, create_chat_link_done, P);
  } else if (tgl_get_peer_type(P->id) == TGL_PEER_CHANNEL) {
    tgl_do_export_channel_link (TLS, P->id, create_chat_link_done, P);
  } else {
    g_warn_if_reached();
  }
}

static void export_chat_link_checked_gw (PurpleBlistNode *node, gpointer data) {
  PurpleChat *chat = (PurpleChat*)node;
  export_chat_link_by_name (pbn_get_data (node)->TLS, purple_chat_get_name (chat));
}

void export_chat_link_by_name (struct tgl_state *TLS, const char *name) {
  g_return_if_fail(name);
  tgl_peer_t *C = tgp_blist_lookup_peer_get (TLS, name);
  g_warn_if_fail(C != NULL);
  export_chat_link (TLS, C);
}

static void leave_and_delete_chat_gw (PurpleBlistNode *node, gpointer data) {
  PurpleChat *C = (PurpleChat *)node;
  g_return_if_fail(tgp_chat_has_id (C));
  
  leave_and_delete_chat (pbn_get_data (node)->TLS, tgl_peer_get (pbn_get_data (node)->TLS, tgp_chat_get_id (C)));
}

void leave_and_delete_chat (struct tgl_state *TLS, tgl_peer_t *P) {
  g_return_if_fail (P);

  if (tgl_get_peer_type(P->id) == TGL_PEER_CHAT) {
    if (!(P->chat.flags & TGLCHF_LEFT)) {
      tgl_do_del_user_from_chat (TLS, P->id, TLS->our_id, tgp_notify_on_error_gw, NULL);
    }
  } else if (tgl_get_peer_type(P->id) == TGL_PEER_CHANNEL) {
    tgl_do_leave_channel (TLS, P->id, tgp_notify_on_error_gw, NULL);
  } else {
    g_return_if_reached();
  }

  serv_got_chat_left (tls_get_conn (TLS), tgl_get_peer_id (P->id));

  PurpleChat *PC = tgp_blist_chat_find (TLS, P->id);
  if (PC) {
    purple_blist_remove_chat (PC);
  }
}

void leave_and_delete_chat_by_name (struct tgl_state *TLS, const char *name) {
  g_return_if_fail(name);
  tgl_peer_t *P = tgp_blist_lookup_peer_get (TLS, name);
  g_return_if_fail(P);
  leave_and_delete_chat (TLS, P);
}

static PurpleCmdRet tgprpl_cmd_kick(PurpleConversation *conv, const gchar *cmd, gchar **args, gchar **error, void *data)
{
  PurpleConnection *pc = NULL;
  int id = -1;
  gchar *who;
  
  pc = conv->account->gc;
  id = purple_conv_chat_get_id(PURPLE_CONV_CHAT(conv));
  
  if (pc == NULL || id == -1) {
    return PURPLE_CMD_RET_FAILED;
  }
  
  who = g_strjoinv(" ", args);
  tgprpl_kick_from_chat(pc, id, who);
  g_free(who);
  
  return PURPLE_CMD_RET_OK;
}

static void import_chat_link_done (struct tgl_state *TLS, void *extra, int success) {
  if (! success) {
    tgp_notify_on_error_gw (TLS, NULL, success);
    return;
  }
  purple_notify_info (_telegram_protocol, _("Chat joined"), _("Chat joined"),
      _("Chat added to list of chat rooms."));
}

void import_chat_link (struct tgl_state *TLS, const char *link) {
  tgl_do_import_chat_link (TLS, link, (int) strlen(link), import_chat_link_done, NULL);
}

static GList* tgprpl_blist_node_menu (PurpleBlistNode *node) {
  debug ("tgprpl_blist_node_menu()");

  // skip orphaned buddies in "old" format that didn't migrate and don't have an ID
  if (PURPLE_BLIST_NODE_IS_BUDDY(node) && ! tgp_blist_buddy_has_id ((PurpleBuddy *)node)) {
    return NULL;
  }
  
  // chats that don't have a proper ID aren't usable
  if (PURPLE_BLIST_NODE_IS_CHAT(node) && ! tgp_chat_has_id ((PurpleChat *)node)) {
    return NULL;
  }
  
  GList* menu = NULL;
  if (PURPLE_BLIST_NODE_IS_BUDDY(node) &&
      tgl_get_peer_type (tgp_blist_buddy_get_id ((PurpleBuddy *)node)) == TGL_PEER_USER) {
    // Add encrypted chat option to the right click menu of all buddies
    PurpleBuddy* buddy = (PurpleBuddy *)node;
    PurpleMenuAction* action = purple_menu_action_new (_("Start secret chat..."), PURPLE_CALLBACK(start_secret_chat),
        buddy, NULL);
    menu = g_list_append (menu, (gpointer)action);
  }
  if (PURPLE_BLIST_NODE_IS_CHAT(node)) {

     // Generate Public Link
    PurpleMenuAction* action = purple_menu_action_new (_("Invite users by link..."),
        PURPLE_CALLBACK(export_chat_link_checked_gw), NULL, NULL);
    menu = g_list_append (menu, (gpointer)action);
  }
  
  if (PURPLE_BLIST_NODE_IS_CHAT(node)) {
    
    // Delete self from chat
    PurpleMenuAction* action = purple_menu_action_new (_("Delete and exit..."), PURPLE_CALLBACK(leave_and_delete_chat_gw),
        NULL, NULL);
    menu = g_list_append (menu, (gpointer)action);
  }
  return menu;
}

static void update_on_logged_in (struct tgl_state *TLS) {
  info ("update_on_logged_in(): The account is signed in");
  write_auth_file (TLS);
  
  debug ("state: seq = %d, pts = %d, date = %d", TLS->seq, TLS->pts, TLS->date);
  purple_connection_set_state (tls_get_conn (TLS), PURPLE_CONNECTED);
  
  purple_blist_add_account (tls_get_pa (TLS));
  tgp_blist_lookup_init (TLS);
  
  // It is important to load secret chats exactly at this point during login, cause if it was done earlier,
  // the update function wouldn't find existing chats and create duplicate entries. If it was done later, eventual
  // updates for those secret chats wouldn't be able to be decrypted due to missing secret keys.
  read_secret_chat_file (TLS);
}

static void update_on_ready (struct tgl_state *TLS) {
  info ("update_on_ready(): The account is done fetching new history");
  
  tgl_peer_t *P = tgl_peer_get (TLS, TLS->our_id);
  g_warn_if_fail(P);
  if (P) {
    purple_connection_set_display_name (tls_get_conn (TLS), P->print_name);
  }
  
  tgl_do_get_dialog_list (TLS, 200, 0, on_get_dialog_list_done, NULL);
  tgl_do_get_channels_dialog_list (TLS, 50, 0, on_get_channel_list_done, NULL);
  tgl_do_update_contact_list (TLS, 0, 0);
}

static void update_on_failed_login (struct tgl_state *TLS) {
  info ("update_on_failed_login(): Login to telegram failed.");
  
  // 401: SESSION_REVOKED is called when the session is cancelled during runtime
  // 401: AUTH_KEY_UNREGISTERED is called when logging into a revoked session
  if (strstr (TLS->error, "SESSION_REVOKED") ||
      strstr (TLS->error, "AUTH_KEY_UNREGISTERED")) {
    purple_account_set_bool (tls_get_pa (TLS), TGP_KEY_RESET_AUTH, TRUE);
  }
  purple_connection_error (tls_get_conn (TLS), TLS->error);
}

static gulong chat_conversation_typing_signal = 0;

static void tgprpl_login (PurpleAccount * acct) {
  info ("tgprpl_login(): Purple is telling the prpl to connect the account");
  
  struct tgl_state *TLS = tgl_state_alloc ();
  PurpleConnection *gc = purple_account_get_connection (acct);
  gc->flags |= PURPLE_CONNECTION_NO_BGCOLOR;
  connection_data *conn = connection_data_init (TLS, gc, acct);
  purple_connection_set_protocol_data (gc, conn);
  tgl_set_ev_base (TLS, conn);

  TLS->base_path = get_config_dir (purple_account_get_username (acct));
  debug ("base configuration path: '%s'", TLS->base_path);
  g_mkdir_with_parents (TLS->base_path, 0700);

  const gchar *base = !g_strcmp0 (purple_core_get_ui(), "BitlBee")
                    ? g_get_tmp_dir() : TLS->base_path;
  conn->download_dir = g_build_filename (base, "downloads", NULL);
  debug ("telegram download directory: '%s'", conn->download_dir);
  tgl_set_download_directory (TLS, conn->download_dir);
  g_mkdir_with_parents (conn->download_dir, 0700);
#ifdef DOWNLOAD_URI_BASE
  conn->download_uri = g_strdup (DOWNLOAD_URI_BASE);
#else
  conn->download_uri = g_strconcat ("file://", conn->download_dir, NULL);
#endif
  debug ("telegram download uri base: '%s'", conn->download_uri);

  tgl_set_rsa_key_direct (TLS, tglmp_get_default_e(),
                               tglmp_get_default_key_len(),
                               tglmp_get_default_key());
  tgl_set_net_methods (TLS, &tgp_conn_methods);
  tgl_set_timer_methods (TLS, &tgp_timers);
  tgl_set_callback (TLS, &tgp_callback);
  tgl_register_app_id (TLS, TGP_APP_ID, TGP_APP_HASH);
  tgl_set_app_version (TLS, PACKAGE_VERSION);

  if (tgl_init (TLS) != 0) {
    debug ("Call to tgl_init failed.\n");
    char *cause = g_strdup_printf (_("Unable to sign on as %s: problem in the underlying library"
                                     " 'tgl'. Please submit a bug report with the debug log."),
                    purple_account_get_username (acct));
    purple_connection_error_reason (gc, PURPLE_CONNECTION_ERROR_INVALID_SETTINGS, cause);
    purple_notify_message (_telegram_protocol, PURPLE_NOTIFY_MSG_ERROR, _("Problem in tgl"),
        cause, NULL, NULL, NULL);
    g_free (cause);
    return;
  }

  if (purple_account_get_bool (acct, TGP_KEY_USE_IPV6, FALSE)) {
    tgl_enable_ipv6(TLS);
  }

  if (! tgp_startswith (purple_account_get_username (acct), "+")) {
    // TRANSLATORS: Please fill in your own prefix!
    char *cause = g_strdup_printf (_("Unable to sign on as %s: phone number lacks country prefix."
                                     " Numbers must start with the full international"
                                     " prefix code, e.g. +1 for USA."),
                                   purple_account_get_username (acct));
    purple_connection_error_reason (gc, PURPLE_CONNECTION_ERROR_INVALID_SETTINGS, cause);
    purple_notify_message (_telegram_protocol, PURPLE_NOTIFY_MSG_ERROR, _("Incomplete phone number"),
        cause, NULL, NULL, NULL);
    g_free (cause);
    return;
  }

  read_auth_file (TLS);
  read_state_file (TLS);

  if (purple_account_get_bool (acct, TGP_KEY_RESET_AUTH, FALSE)) {
    info ("last login attempt failed, resetting authorization ...");
    purple_account_set_bool (tls_get_pa (TLS), TGP_KEY_RESET_AUTH, FALSE);
    bl_do_reset_authorization (TLS);
  }
  
  purple_connection_set_state (conn->gc, PURPLE_CONNECTING);
  tgl_login (TLS);
    
  if (!chat_conversation_typing_signal) {
    chat_conversation_typing_signal = purple_signal_connect(purple_conversations_get_handle(), "chat-conversation-typing", 
      purple_connection_get_prpl (gc), PURPLE_CALLBACK(tgprpl_send_chat_typing), NULL);
  }
}

static void tgprpl_close (PurpleConnection *gc) {
  debug ("tgprpl_close()");
  connection_data_free (purple_connection_get_protocol_data (gc));
}

static int tgprpl_send_im (PurpleConnection *gc, const char *who, const char *message, PurpleMessageFlags flags) {
  debug ("tgprpl_send_im()");

  // workaround to support clients without the request API (request.h), see tgp-request.c:request_code()
  if (gc_get_data (gc)->request_code_data) {
    // OTR plugins may try to insert messages that don't contain the code
    if (tgp_startswith (message, "?OTR")) {
      info ("Fallback SMS auth, skipping OTR message: '%s'", message);
      return -1;
    }
    struct request_values_data *data = gc_get_data (gc)->request_code_data;
    data->callback (gc_get_tls (gc), &message, data->arg);
    free (data);

    gc_get_data (gc)->request_code_data = NULL;
    return 1;
  }

  // check receiver to give immediate feedback in case sending a message is not possible
  tgl_peer_t *peer = tgp_blist_lookup_peer_get (gc_get_tls (gc), who);
  if (! peer) {
    warning ("peer not found");
    return -1;
  }

  // secret chat not yet usable
  if (tgl_get_peer_type (peer->id) == TGL_PEER_ENCR_CHAT && peer->encr_chat.state != sc_ok) {
    const char *msg;
    if (peer->encr_chat.state == sc_deleted) {
      msg = _("Secret chat was already deleted");
    } else {
      msg = _("Secret chat is not ready");
    }
    tgp_msg_special_out (gc_get_tls (gc), msg, peer->id, PURPLE_MESSAGE_NO_LOG | PURPLE_MESSAGE_ERROR);
    return -1;
  }

  // channel owned by someone else (TEST: why does it work with supergroups?)
  if (tgl_get_peer_type (peer->id) == TGL_PEER_CHANNEL && ! (peer->flags & TGLCHF_CREATOR)) {
    tgp_msg_special_out (gc_get_tls (gc), _("Only the creator of a channel can post messages."), peer->id,
        PURPLE_MESSAGE_NO_LOG | PURPLE_MESSAGE_ERROR);
    return -1;
  }
  
  // when the other peer receives a message it is obvious that the previous messages were read
  pending_reads_send_user (gc_get_tls (gc), peer->id);
  
  return tgp_msg_send (gc_get_tls (gc), message, peer->id);
}

static unsigned int tgprpl_send_typing (PurpleConnection *gc, const char *who, PurpleTypingState typing) {
  debug ("tgprpl_send_typing()");
  tgl_peer_t *peer = tgp_blist_lookup_peer_get (gc_get_tls (gc), who);
  if (peer) {
    tgl_do_send_typing (gc_get_tls (gc), peer->id, typing == PURPLE_TYPING ? tgl_typing_typing : tgl_typing_cancel,
        0, 0);
    
    // when the other peer sees that the current user is typing it is obvious that the previous messages were read
    pending_reads_send_user (gc_get_tls (gc), peer->id);
  }
  return 0;
}

static void tgprpl_set_status (PurpleAccount *acct, PurpleStatus *status) {
  debug ("tgprpl_set_status(%s)", purple_status_get_name (status));
  
  pending_reads_send_all (pa_get_data (acct)->TLS);
}

static void tgprpl_add_buddy (PurpleConnection *gc, PurpleBuddy *buddy, PurpleGroup *group) {
  tgl_peer_t *P = tgl_peer_get_by_name (gc_get_tls (gc), buddy->name);
  if (P) {
    tgp_blist_contact_add (gc_get_tls (gc), &P->user);
  }
}

static void tgprpl_chat_invite (PurpleConnection *gc, int id, const char *message, const char *who) {
  debug ("tgprpl_chat_invite()");
  tgl_peer_t *chat = tgl_peer_get (gc_get_tls (gc), TGL_MK_CHAT (id));
  tgl_peer_t *user = tgp_blist_lookup_peer_get (gc_get_tls (gc), who);
  
  if (! chat || ! user) {
    purple_notify_error (_telegram_protocol, _("Cannot invite buddy to chat"), _("Cannot invite buddy to chat"),
        _("Specified user does not exist."));
    return;
  }
  tgl_do_add_user_to_chat (gc_get_tls (gc), chat->id, user->id, 0, tgp_notify_on_error_gw, chat);
}

static gboolean tgprpl_can_receive_file (PurpleConnection *gc, const char *who) {
  return TRUE;
}

static GHashTable *tgprpl_get_account_text_table (PurpleAccount *pa) {
  GHashTable *HT;
  HT = g_hash_table_new (g_str_hash, g_str_equal);
  g_hash_table_insert(HT, "login_label", (gpointer) _("phone no. (+ country prefix)"));
  return HT;
}

PurplePlugin *_telegram_protocol = NULL;

static PurplePluginProtocolInfo prpl_info = {
  OPT_PROTO_NO_PASSWORD | OPT_PROTO_IM_IMAGE,
  NULL,                    // user_¡splits, initialized in tgprpl_init()
  NULL,                    // protocol_options, initialized in tgprpl_init()
  {
    "png",
    1,                     // min_width
    1,                     // min_height
    512,                   // max_width
    512,                   // max_height
    64000,                 // max_filesize
    PURPLE_ICON_SCALE_SEND,
  },
  tgprpl_list_icon,
  NULL,
  NULL,
  tgprpl_tooltip_text,
  tgprpl_status_types,
  tgprpl_blist_node_menu,
  tgprpl_chat_join_info,
  tgprpl_chat_info_defaults,
  tgprpl_login,
  tgprpl_close,
  tgprpl_send_im,
  NULL,                    // set_info
  tgprpl_send_typing,
  tgprpl_info_show,
  tgprpl_set_status,
  NULL,                    // set_idle
  NULL,                    // change_passwd
  tgprpl_add_buddy,
  NULL,                    // add_buddies
  tgprpl_request_delete_contact,
  NULL,                    // remove_buddies
  NULL,                    // add_permit
  NULL,                    // add_deny
  NULL,                    // rem_permit
  NULL,                    // rem_deny
  NULL,                    // set_permit_deny
  tgprpl_chat_join,
  NULL,                    // reject_chat
  tgprpl_get_chat_name,
  tgprpl_chat_invite,
  NULL,                    // chat_leave
  NULL,                    // chat_whisper
  tgprpl_send_chat,
  NULL,                    // keepalive
  NULL,                    // register_user
  NULL,                    // get_cb_info
  NULL,                    // get_cb_away
  NULL,                    // alias_buddy
  NULL,                    // group_buddy
  NULL,                    // rename_group
  NULL,                    // buddy_free
  NULL,                    // convo_closed
  NULL,                    // normalize
  NULL,                    // tgprpl_set_buddy_icon
  NULL,                    // remove_group
  NULL,
  NULL,                    // set_chat_topic
  NULL,                    // find_blist_chat
  tgprpl_roomlist_get_list,
  tgprpl_roomlist_cancel,
  NULL,                    // roomlist_expand_category
  tgprpl_can_receive_file,
  tgprpl_send_file,       
  tgprpl_new_xfer,        
  NULL,                    // offline_message
  NULL,                    // whiteboard_prpl_ops
  NULL,                    // send_raw
  NULL,                    // roomlist_room_serialize
  NULL,                    // unregister_user
  NULL,                    // send_attention
  NULL,                    // get_attention_types
  sizeof(PurplePluginProtocolInfo),
  tgprpl_get_account_text_table, // get_account_text_table
  NULL,                    // initiate_media
  NULL,                    // get_media_caps
  NULL,                    // get_moods
  NULL,                    // set_public_alias
  NULL,                    // get_public_alias
  NULL,                    // add_buddy_with_invite
  NULL                     // add_buddies_with_invite
};

static gboolean tgprpl_load (PurplePlugin *plugin) {				
  purple_cmd_register("kick", "s", PURPLE_CMD_P_PLUGIN, PURPLE_CMD_FLAG_CHAT |
                      PURPLE_CMD_FLAG_PRPL_ONLY | PURPLE_CMD_FLAG_ALLOW_WRONG_ARGS,
                      PLUGIN_ID, tgprpl_cmd_kick,
                      _("kick <user>:  Kick a user from the room."), NULL);
  
  return TRUE;
}

static void tgprpl_init (PurplePlugin *plugin) {
  PurpleAccountOption *opt;
  
  // set domain name that is used for translation
#if ENABLE_NLS
  bindtextdomain (GETTEXT_PACKAGE, LOCALEDIR);
  bind_textdomain_codeset (GETTEXT_PACKAGE, "UTF-8");
#endif
  
#define ADD_VALUE(list, desc, v) { \
  PurpleKeyValuePair *kvp = g_new0(PurpleKeyValuePair, 1); \
  kvp->key = g_strdup((desc)); \
  kvp->value = g_strdup((v)); \
  list = g_list_prepend(list, kvp); \
}
  
  // Login
  opt = purple_account_option_string_new (_("Password (two factor authentication)"), TGP_KEY_PASSWORD_TWO_FACTOR, NULL);
  purple_account_option_set_masked (opt, TRUE);
  prpl_info.protocol_options = g_list_append(prpl_info.protocol_options, opt);
  
  opt = purple_account_option_bool_new (
      _("Fallback SMS verification\n(Helps when not using Pidgin and you aren't being prompted for the code)"),
      "compat-verification", 0);
  prpl_info.protocol_options = g_list_append(prpl_info.protocol_options, opt);

  // Messaging
  GList *choices = NULL;
  // Whether to do fallback SMS verification
  ADD_VALUE(choices, _("Always"), "always");
  // Whether to do fallback SMS verification
  ADD_VALUE(choices, _("Never"), "never");
  // Whether to do fallback SMS verification
  ADD_VALUE(choices, _("Ask"), "ask");

  opt = purple_account_option_list_new (_("Accept secret chats"),
      TGP_KEY_ACCEPT_SECRET_CHATS, choices);
  prpl_info.protocol_options = g_list_append(prpl_info.protocol_options, opt);

  opt = purple_account_option_int_new (_("Display buddies offline after (days)"),
      TGP_KEY_INACTIVE_DAYS_OFFLINE, TGP_DEFAULT_INACTIVE_DAYS_OFFLINE);
  prpl_info.protocol_options = g_list_append (prpl_info.protocol_options, opt);

  opt = purple_account_option_int_new (_("Don't fetch history older than (days)\n(0 for unlimited)"),
      TGP_KEY_HISTORY_RETRIEVAL_THRESHOLD, TGP_DEFAULT_HISTORY_RETRIEVAL_THRESHOLD);
  prpl_info.protocol_options = g_list_append (prpl_info.protocol_options, opt);

  // Media and documents
  choices = NULL;
  // How to handle "large" files
  ADD_VALUE(choices, _("Discard"), "discard");
  // How to handle "large" files
  ADD_VALUE(choices, _("Auto load"), "autoload");
  // How to handle "large" files
  ADD_VALUE(choices, _("Ask"), "ask");

  opt = purple_account_option_int_new (_("Auto load file transfers up to (kb)"), TGP_KEY_MEDIA_SIZE,
                                       TGP_DEFAULT_MEDIA_SIZE);
  prpl_info.protocol_options = g_list_append (prpl_info.protocol_options, opt);
  
  opt = purple_account_option_list_new (_("Bigger file transfers"), TGP_KEY_FT_HANDLING, choices);
  prpl_info.protocol_options = g_list_append (prpl_info.protocol_options, opt);

  // Chats
  opt = purple_account_option_bool_new (_("Add all group chats to buddy list"),
      TGP_KEY_JOIN_GROUP_CHATS, TGP_DEFAULT_JOIN_GROUP_CHATS);
  prpl_info.protocol_options = g_list_append (prpl_info.protocol_options, opt);

  // Receipts
  opt = purple_account_option_bool_new (_("Display notices of receipt"),
      TGP_KEY_DISPLAY_READ_NOTIFICATIONS, TGP_DEFAULT_DISPLAY_READ_NOTIFICATIONS);
  prpl_info.protocol_options = g_list_append (prpl_info.protocol_options, opt);

  opt = purple_account_option_bool_new (_("Send notices of receipt when present"),
      TGP_KEY_SEND_READ_NOTIFICATIONS, TGP_DEFAULT_SEND_READ_NOTIFICATIONS);
  prpl_info.protocol_options = g_list_append (prpl_info.protocol_options, opt);

  // IPv6
  opt = purple_account_option_bool_new (_("Use IPv6 for connecting (restart required)"),
      TGP_KEY_USE_IPV6, TGP_DEFAULT_USE_IPV6);
  prpl_info.protocol_options = g_list_append (prpl_info.protocol_options, opt);

  _telegram_protocol = plugin;
  debug ("tgprpl_init finished: This is " PACKAGE_VERSION "+g" GIT_COMMIT " on libtgl " TGL_VERSION);
}

static GList *tgprpl_actions (PurplePlugin *plugin, gpointer context) {
  return (GList *)NULL;
}

static PurplePluginInfo plugin_info = {
  PURPLE_PLUGIN_MAGIC,
  PURPLE_MAJOR_VERSION,
  PURPLE_MINOR_VERSION,
  PURPLE_PLUGIN_PROTOCOL,
  NULL,
  0,
  NULL,
  PURPLE_PRIORITY_DEFAULT,
  PLUGIN_ID,
  "Telegram",
  PACKAGE_VERSION "\n\t\t\tcommit: " GIT_COMMIT "\n\t\t\tlibtgl: " TGL_VERSION,
  "Telegram",
  N_("Telegram Protocol Plugin."),
  PLUGIN_AUTHOR,
  "https://github.com/majn/telegram-purple",
  tgprpl_load,    // on load
  NULL,           // on unload
  NULL,           // on destroy
  NULL,           // ui specific struct
  &prpl_info,
  NULL,           // prefs info
  tgprpl_actions,
  NULL,           // reserved
  NULL,           // reserved
  NULL,           // reserved
  NULL            // reserved
};

PURPLE_INIT_PLUGIN (telegram, tgprpl_init, plugin_info)