%%%-------------------------------------------------------------------
%%% @author Evgeny Khramtsov <ekhramtsov@process-one.net>
%%% Created : 30 Mar 2017 by Evgeny Khramtsov <ekhramtsov@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2017   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.,
%%% 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
%%%
%%%-------------------------------------------------------------------
-module(mod_carboncopy_redis).
-behaviour(mod_carboncopy).

%% API
-export([init/2, enable/4, disable/3, list/2]).

-include("ejabberd.hrl").
-include("logger.hrl").

%%%===================================================================
%%% API
%%%===================================================================
init(_Host, _Opts) ->
    clean_table().

enable(LUser, LServer, LResource, NS) ->
    USKey = us_key(LUser, LServer),
    NodeKey = node_key(),
    JID = jid:encode({LUser, LServer, LResource}),
    case ejabberd_redis:multi(
	   fun() ->
		   ejabberd_redis:hset(USKey, LResource, NS),
		   ejabberd_redis:sadd(NodeKey, [JID])
	   end) of
	{ok, _} ->
	    ok;
	{error, _} ->
	    {error, db_failure}
    end.

disable(LUser, LServer, LResource) ->
    USKey = us_key(LUser, LServer),
    NodeKey = node_key(),
    JID = jid:encode({LUser, LServer, LResource}),
    case ejabberd_redis:multi(
	   fun() ->
		   ejabberd_redis:hdel(USKey, [LResource]),
		   ejabberd_redis:srem(NodeKey, [JID])
	   end) of
	{ok, _} ->
	    ok;
	{error, _} ->
	    {error, db_failure}
    end.

list(LUser, LServer) ->
    USKey = us_key(LUser, LServer),
    case ejabberd_redis:hgetall(USKey) of
	{ok, Vals} ->
	    Vals;
	{error, _} ->
	    []
    end.

%%%===================================================================
%%% Internal functions
%%%===================================================================
clean_table() ->
    ?INFO_MSG("Cleaning Redis 'carboncopy' table...", []),
    NodeKey = node_key(),
    case ejabberd_redis:smembers(NodeKey) of
	{ok, JIDs} ->
	    ejabberd_redis:multi(
	      fun() ->
		      lists:foreach(
			fun(JID) ->
				{U, S, R} = jid:split(jid:decode(JID)),
				USKey = us_key(U, S),
				ejabberd_redis:hdel(USKey, [R])
			end, JIDs)
	      end);
	{error, _} ->
	    ok
    end,
    ejabberd_redis:del([NodeKey]),
    ok.

us_key(LUser, LServer) ->
    <<"ejabberd:carboncopy:users:", LUser/binary, $@, LServer/binary>>.

node_key() ->
    Node = erlang:atom_to_binary(node(), latin1),
    <<"ejabberd:carboncopy:nodes:", Node/binary>>.