%%%----------------------------------------------------------------------
%%% File    : gen_iq_handler.erl
%%% Author  : Alexey Shchepin <alexey@process-one.net>
%%% Purpose : IQ handler support
%%% Created : 22 Jan 2003 by Alexey Shchepin <alexey@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2018   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(gen_iq_handler).

-author('alexey@process-one.net').

-behaviour(ejabberd_config).

%% API
-export([add_iq_handler/5, remove_iq_handler/3, handle/4,
	 process_iq/4, check_type/1, transform_module_options/1,
	 opt_type/1]).
%% Deprecated functions
-export([add_iq_handler/6, handle/5, iqdisc/1]).
-deprecated([{add_iq_handler, 6}, {handle, 5}, {iqdisc, 1}]).

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

-type component() :: ejabberd_sm | ejabberd_local.

%%====================================================================
%% API
%%====================================================================
-spec add_iq_handler(module(), binary(), binary(), module(), atom()) -> ok.
add_iq_handler(Component, Host, NS, Module, Function) ->
    Component:register_iq_handler(Host, NS, Module, Function).

-spec remove_iq_handler(component(), binary(), binary()) -> ok.
remove_iq_handler(Component, Host, NS) ->
    Component:unregister_iq_handler(Host, NS).

-spec handle(binary(), atom(), atom(), iq()) -> any().
handle(Host, Module, Function, IQ) ->
    process_iq(Host, Module, Function, IQ).

-spec process_iq(binary(), atom(), atom(), iq()) -> any().
process_iq(_Host, Module, Function, IQ) ->
    try
	ResIQ = case erlang:function_exported(Module, Function, 1) of
		    true ->
			process_iq(Module, Function, IQ);
		    false ->
			From = xmpp:get_from(IQ),
			To = xmpp:get_to(IQ),
			process_iq(Module, Function, From, To,
				   jlib:iq_query_info(xmpp:encode(IQ)))
		end,
	if ResIQ /= ignore ->
		ejabberd_router:route(ResIQ);
	   true ->
		ok
	end
    catch E:R ->
	    ?ERROR_MSG("failed to process iq:~n~s~nReason = ~p",
		       [xmpp:pp(IQ), {E, {R, erlang:get_stacktrace()}}]),
	    Txt = <<"Module failed to handle the query">>,
	    Err = xmpp:err_internal_server_error(Txt, IQ#iq.lang),
	    ejabberd_router:route_error(IQ, Err)
    end.

-spec process_iq(module(), atom(), iq()) -> ignore | iq().
process_iq(Module, Function, #iq{lang = Lang, sub_els = [El]} = IQ) ->
    try
	Pkt = case erlang:function_exported(Module, decode_iq_subel, 1) of
		  true -> Module:decode_iq_subel(El);
		  false -> xmpp:decode(El)
	      end,
	Module:Function(IQ#iq{sub_els = [Pkt]})
    catch error:{xmpp_codec, Why} ->
	    Txt = xmpp:io_format_error(Why),
	    xmpp:make_error(IQ, xmpp:err_bad_request(Txt, Lang))
    end.

-spec process_iq(module(), atom(), jid(), jid(), term()) -> iq().
process_iq(Module, Function, From, To, IQ) ->
    case Module:Function(From, To, IQ) of
	ignore -> ignore;
	ResIQ ->
	    xmpp:set_from_to(
	      xmpp:decode(jlib:iq_to_xml(ResIQ), ?NS_CLIENT, [ignore_els]),
	      To, From)
    end.

-spec check_type(any()) -> no_queue.
check_type(_Type) ->
    ?WARNING_MSG("Option 'iqdisc' is deprecated and has no effect anymore", []),
    no_queue.

-spec iqdisc(binary() | global) -> no_queue.
iqdisc(_Host) ->
    no_queue.

-spec transform_module_options([{atom(), any()}]) -> [{atom(), any()}].

transform_module_options(Opts) ->
    lists:map(
      fun({iqdisc, {queues, N}}) ->
              {iqdisc, N};
         (Opt) ->
              Opt
      end, Opts).

-spec opt_type(iqdisc) -> fun((any()) -> no_queue);
	      (atom()) -> [atom()].
opt_type(iqdisc) -> fun check_type/1;
opt_type(_) -> [iqdisc].

%%====================================================================
%% Deprecated API
%%====================================================================
-spec add_iq_handler(module(), binary(), binary(), module(), atom(), any()) -> ok.
add_iq_handler(Component, Host, NS, Module, Function, _Type) ->
    add_iq_handler(Component, Host, NS, Module, Function).

-spec handle(binary(), atom(), atom(), any(), iq()) -> any().
handle(Host, Module, Function, _Opts, IQ) ->
    handle(Host, Module, Function, IQ).