%%%-------------------------------------------------------------------
%%% File    : eldap_pool.erl
%%% Author  : Evgeniy Khramtsov <xram@jabber.ru>
%%% Purpose : LDAP connections pool
%%% Created : 12 Nov 2006 by Evgeniy Khramtsov <xram@jabber.ru>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2022   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(eldap_pool).

-author('xram@jabber.ru').

%% API
-export([start_link/7, bind/3, search/2,
	 modify_passwd/3]).

-include("logger.hrl").

-ifdef(USE_OLD_PG2).
pg_create(PoolName) -> pg2:create(PoolName).
pg_join(PoolName, Pid) -> pg2:join(PoolName, Pid).
pg_get_closest_pid(Name) -> pg2:get_closest_pid(Name).
-else.
pg_create(_) -> pg:start_link().
pg_join(PoolName, Pid) -> pg:join(PoolName, Pid).
pg_get_closest_pid(Group) ->
    case pg:get_local_members(Group) of
        [] ->
            case pg:get_members(Group) of
                [] -> {error, {no_process, Group}};
                [Pid | _] -> Pid
            end;
        [Pid | _] -> Pid
    end.
-endif.

%%====================================================================
%% API
%%====================================================================
bind(PoolName, DN, Passwd) ->
    do_request(PoolName, {bind, [DN, Passwd]}).

search(PoolName, Opts) ->
    do_request(PoolName, {search, [Opts]}).

modify_passwd(PoolName, DN, Passwd) ->
    do_request(PoolName, {modify_passwd, [DN, Passwd]}).

start_link(Name, Hosts, Backups, Port, Rootdn, Passwd,
	   Opts) ->
    PoolName = make_id(Name),
    pg_create(PoolName),
    lists:foreach(fun (Host) ->
			  ID = list_to_binary(erlang:ref_to_list(make_ref())),
			  case catch eldap:start_link(ID, [Host | Backups],
						      Port, Rootdn, Passwd,
						      Opts)
			      of
			    {ok, Pid} -> pg_join(PoolName, Pid);
			    Err ->
                                  ?ERROR_MSG("Err = ~p", [Err]),
                                  error
			  end
		  end,
		  Hosts).

%%====================================================================
%% Internal functions
%%====================================================================
do_request(Name, {F, Args}) ->
    case pg_get_closest_pid(make_id(Name)) of
      Pid when is_pid(Pid) ->
	  case catch apply(eldap, F, [Pid | Args]) of
	    {'EXIT', {timeout, _}} ->
		?ERROR_MSG("LDAP request failed: timed out", []);
	    {'EXIT', Reason} ->
		?ERROR_MSG("LDAP request failed: eldap:~p(~p)~nReason: ~p",
			   [F, Args, Reason]),
		{error, Reason};
	    Reply -> Reply
	  end;
      Err -> Err
    end.

make_id(Name) ->
    misc:binary_to_atom(<<"eldap_pool_", Name/binary>>).