%%%----------------------------------------------------------------------
 %%% File    : mod_last.erl
 %%% Author  : Alexey Shchepin <alexey@process-one.net>
 %%% Purpose : jabber:iq:last support (XEP-0012)
 %%% Created : 24 Oct 2003 by Alexey Shchepin <alexey@process-one.net>
 %%%
 %%%
 %%% ejabberd, Copyright (C) 2002-2012   ProcessOne
 %%%
 %%% 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., 59 Temple Place, Suite 330, Boston, MA
 %%% 02111-1307 USA
 %%%
 %%%----------------------------------------------------------------------
 
 
 %%% Database schema (version / storage / table)
 %%%
 %%% 2.1.x / mnesia / last_activity
 %%%  us = {Username::string(), Host::string()}
 %%%  timestamp = now()
 %%%  status = string()
 %%%
 %%% 2.1.x / odbc / last
 %%%  username = varchar250
 %%%  seconds = text
 %%%  state = text
 %%%
 %%% 3.0.0-prealpha / mnesia / last_activity
 %%%  us = {Username::binary(), Host::binary()}
 %%%  timestamp = now()
 %%%  status = binary()
 %%%
 %%% 3.0.0-prealpha / odbc / last
 %%%  Same as 2.1.x
 %%%
 %%% 3.0.0-alpha / mnesia / last_activity
 %%%  user_host = {Username::binary(), Host::binary()}
 %%%  timestamp = now()
 %%%  status = binary()
 %%%
 %%% 3.0.0-alpha / odbc / last_activity
 %%%  user = varchar150
 %%%  host = varchar150
 %%%  timestamp = bigint
 %%%  status = text
 
 
 -module(mod_last).
 
 -author('alexey@process-one.net').
 
 -behaviour(gen_mod).
 
 -export([start/2, stop/1, process_local_iq/3, process_sm_iq/3, on_presence_update/4,
 	 store_last_info/4, get_last_info/2, remove_user/2]).
 
 -include_lib("exmpp/include/exmpp.hrl").
 
 -include("ejabberd.hrl").
 
 -include("mod_privacy.hrl").
 
 -record(last_activity, {user_host, timestamp, status}).
 
 start(Host, Opts) when is_list(Host) -> start(list_to_binary(Host), Opts);
 start(HostB, Opts) ->
     IQDisc = gen_mod:get_opt(iqdisc, Opts, one_queue),
     Backend = gen_mod:get_opt(backend, Opts, mnesia),
     gen_storage:create_table(Backend, HostB, last_activity,
 			     [{disc_copies, [node()]}, {odbc_host, HostB},
 			      {attributes, record_info(fields, last_activity)},
 			      {types, [{user_host, {text, text}}, {timestamp, bigint}]}]),
     update_table(HostB, Backend),
     gen_iq_handler:add_iq_handler(ejabberd_local, HostB, ?NS_LAST_ACTIVITY, ?MODULE,
 				  process_local_iq, IQDisc),
     gen_iq_handler:add_iq_handler(ejabberd_sm, HostB, ?NS_LAST_ACTIVITY, ?MODULE,
 				  process_sm_iq, IQDisc),
     ejabberd_hooks:add(remove_user, HostB, ?MODULE, remove_user, 50),
     ejabberd_hooks:add(unset_presence_hook, HostB, ?MODULE, on_presence_update, 50).
 
 stop(Host) when is_list(Host) -> stop(list_to_binary(Host));
 stop(HostB) ->
     ejabberd_hooks:delete(remove_user, HostB, ?MODULE, remove_user, 50),
     ejabberd_hooks:delete(unset_presence_hook, HostB, ?MODULE, on_presence_update, 50),
     gen_iq_handler:remove_iq_handler(ejabberd_local, HostB, ?NS_LAST_ACTIVITY),
     gen_iq_handler:remove_iq_handler(ejabberd_sm, HostB, ?NS_LAST_ACTIVITY).
 
 %%%
 %%% Uptime of ejabberd node
 %%%
 
 
 process_local_iq(_From, _To, #iq{type = get} = IQ_Rec) ->
     Sec = get_node_uptime(),
     Response = #xmlel{ns = ?NS_LAST_ACTIVITY, name = 'query',
 		      attrs = [?XMLATTR(<<"seconds">>, Sec)]},
     exmpp_iq:result(IQ_Rec, Response);
 process_local_iq(_From, _To, #iq{type = set} = IQ_Rec) ->
     exmpp_iq:error(IQ_Rec, 'not-allowed').
 
 %% @spec () -> integer()
 %% @doc Get the uptime of the ejabberd node, expressed in seconds.
 %% When ejabberd is starting, ejabberd_config:start/0 stores the datetime.
 get_node_uptime() ->
     case ejabberd_config:get_local_option(node_start) of
       {_, _, _} = StartNow -> now_to_seconds(now()) - now_to_seconds(StartNow);
       _undefined -> trunc(element(1, erlang:statistics(wall_clock)) / 1000)
     end.
 
 now_to_seconds({MegaSecs, Secs, _MicroSecs}) -> MegaSecs * 1000000 + Secs.
 
 %%%
 %%% Serve queries about user last online
 %%%
 
 
 process_sm_iq(From, To, #iq{type = get} = IQ_Rec) ->
     {Subscription, _Groups} = ejabberd_hooks:run_fold(roster_get_jid_info,
 						      exmpp_jid:prep_domain(To),
 						      {none, []},
 						      [exmpp_jid:prep_node(To),
 						       exmpp_jid:prep_domain(To), From]),
     SameUser = exmpp_jid:bare_compare(From, To),
     if (Subscription == both) or (Subscription == from) or SameUser ->
 	   UserListRecord = ejabberd_hooks:run_fold(privacy_get_user_list,
 						    exmpp_jid:prep_domain(To),
 						    #userlist{},
 						    [exmpp_jid:prep_node(To),
 						     exmpp_jid:prep_domain(To)]),
 	   case ejabberd_hooks:run_fold(privacy_check_packet, exmpp_jid:prep_domain(To),
 					allow,
 					[exmpp_jid:prep_node(To),
 					 exmpp_jid:prep_domain(To), UserListRecord,
 					 {To, From, exmpp_presence:available()}, out])
 	       of
 	     allow ->
 		 get_last_iq(IQ_Rec, exmpp_jid:prep_node(To), exmpp_jid:prep_domain(To));
 	     deny -> exmpp_iq:error(IQ_Rec, forbidden)
 	   end;
        true -> exmpp_iq:error(IQ_Rec, forbidden)
     end;
 process_sm_iq(_From, _To, #iq{type = set} = IQ_Rec) ->
     exmpp_iq:error(IQ_Rec, 'not-allowed').
 
 %% TODO: This function could use get_last_info/2
 %% @spec (LUser::string(), LServer::string()) ->
 %%      {ok, TimeStamp::integer(), Status::string()} | not_found | {error, Reason}
 get_last(LUser, LServer) ->
     case catch gen_storage:dirty_read(LServer, last_activity, {LUser, LServer}) of
       {'EXIT', Reason} -> {error, Reason};
       [] -> not_found;
       [#last_activity{timestamp = TimeStamp, status = Status}] -> {ok, TimeStamp, Status}
     end.
 
 get_last_iq(IQ_Rec, LUser, LServer) ->
     case ejabberd_sm:get_user_resources(LUser, LServer) of
       [] -> get_last_iq_disconnected(IQ_Rec, LUser, LServer);
       _ ->
 	  Sec = 0,
 	  #xmlel{ns = ?NS_LAST_ACTIVITY, name = 'query',
 		 attrs = [?XMLATTR(<<"seconds">>, Sec)]}
     end.
 
 get_last_iq_disconnected(IQ_Rec, LUser, LServer) ->
     case get_last(LUser, LServer) of
       {error, _Reason} -> exmpp_iq:error(IQ_Rec, 'internal-server-error');
       not_found -> exmpp_iq:error(IQ_Rec, 'service-unavailable');
       {ok, TimeStamp, Status} ->
 	  TimeStamp2 = now_to_seconds(now()),
 	  Sec = TimeStamp2 - TimeStamp,
 	  Response = #xmlel{ns = ?NS_LAST_ACTIVITY, name = 'query',
 			    attrs = [?XMLATTR(<<"seconds">>, Sec)],
 			    children = [#xmlcdata{cdata = Status}]},
 	  exmpp_iq:result(IQ_Rec, Response)
     end.
 
 on_presence_update(User, Server, _Resource, Status) ->
     {MegaSecs, Secs, _MicroSecs} = now(),
     TimeStamp = MegaSecs * 1000000 + Secs,
     store_last_info(User, Server, TimeStamp, Status).
 
 store_last_info(User, Server, TimeStamp, Status)
     when is_binary(User), is_binary(Server) ->
     try US = {User, Server},
 	F = fun () ->
 		    gen_storage:write(Server,
 				      #last_activity{user_host = US,
 						     timestamp = TimeStamp,
 						     status = Status})
 	    end,
 	gen_storage:transaction(Server, last_activity, F)
     catch
       _ -> ok
     end.
 
 %% @spec (LUser::string(), LServer::string()) ->
 %%      {ok, Timestamp::integer(), Status::string()} | not_found
 get_last_info(LUser, LServer) when is_list(LUser), is_list(LServer) ->
     get_last_info(list_to_binary(LUser), list_to_binary(LServer));
 get_last_info(LUser, LServer) when is_binary(LUser), is_binary(LServer) ->
     case get_last(LUser, LServer) of
       {error, _Reason} -> not_found;
       Res -> Res
     end.
 
 remove_user(User, Server) when is_binary(User), is_binary(Server) ->
     try LUser = exmpp_stringprep:nodeprep(User),
 	LServer = exmpp_stringprep:nameprep(Server),
 	US = {LUser, LServer},
 	F = fun () -> gen_storage:delete(LServer, {last_activity, US}) end,
 	gen_storage:transaction(LServer, last_activity, F)
     catch
       _ -> ok
     end.
 
 update_table(global, Storage) ->
     [update_table(HostB, Storage) || HostB <- ejabberd_hosts:get_hosts(ejabberd)];
 update_table(HostB, mnesia) ->
     gen_storage_migration:migrate_mnesia(HostB, last_activity,
 					 [{last_activity, [us, timestamp, status],
 					   fun ({last_activity, {U, S}, Timestamp,
 						 Status}) ->
 						   U1 = case U of
 							  "" -> undefined;
 							  V -> V
 							end,
 						   #last_activity{user_host =
 								      {list_to_binary(U1),
 								       list_to_binary(S)},
 								  timestamp = Timestamp,
 								  status =
 								      list_to_binary(Status)}
 					   end}]);
 update_table(HostB, odbc) ->
     gen_storage_migration:migrate_odbc(HostB, [last_activity],
 				       [{"last", ["username", "seconds", "state"],
 					 fun (_, Username, STimeStamp, Status) ->
 						 case catch list_to_integer(STimeStamp) of
 						   TimeStamp when is_integer(TimeStamp) ->
 						       [#last_activity{user_host =
 									   {Username,
 									    HostB},
 								       timestamp =
 									   TimeStamp,
 								       status = Status}];
 						   _ ->
 						       ?WARNING_MSG("Omitting last_activity migration item with timestamp=~p",
 								    [STimeStamp])
 						 end
 					 end}]).