%%%----------------------------------------------------------------------
%%% File    : mod_register.erl
%%% Author  : Alexey Shchepin <alexey@process-one.net>
%%% Purpose : Inband registration support
%%% Created :  8 Dec 2002 by Alexey Shchepin <alexey@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2011   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
%%%
%%%----------------------------------------------------------------------

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

-behaviour(gen_mod).

-export([start/2,
	 stop/1,
	 stream_feature_register/2,
	 unauthenticated_iq_register/4,
	 try_register/5,
	 process_iq/3]).

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

start(Host, Opts) ->
    IQDisc = gen_mod:get_opt(iqdisc, Opts, one_queue),
    gen_iq_handler:add_iq_handler(ejabberd_local, Host, ?NS_REGISTER,
				  ?MODULE, process_iq, IQDisc),
    gen_iq_handler:add_iq_handler(ejabberd_sm, Host, ?NS_REGISTER,
				  ?MODULE, process_iq, IQDisc),
    ejabberd_hooks:add(c2s_stream_features, Host,
 		       ?MODULE, stream_feature_register, 50),
    ejabberd_hooks:add(c2s_unauthenticated_iq, Host,
 		       ?MODULE, unauthenticated_iq_register, 50),
    mnesia:create_table(mod_register_ip,
			[{ram_copies, [node()]},
			 {local_content, true},
			 {attributes, [key, value]}]),
    mnesia:add_table_copy(mod_register_ip, node(), ram_copies),
    ok.

stop(Host) ->
    ejabberd_hooks:delete(c2s_stream_features, Host,
 			  ?MODULE, stream_feature_register, 50),
    ejabberd_hooks:delete(c2s_unauthenticated_iq, Host,
			  ?MODULE, unauthenticated_iq_register, 50),
    gen_iq_handler:remove_iq_handler(ejabberd_local, Host, ?NS_REGISTER),
    gen_iq_handler:remove_iq_handler(ejabberd_sm, Host, ?NS_REGISTER).


stream_feature_register(Acc, _Host) ->
    [{xmlelement, "register",
      [{"xmlns", ?NS_FEATURE_IQREGISTER}], []} | Acc].

unauthenticated_iq_register(_Acc,
			    Server, #iq{xmlns = ?NS_REGISTER} = IQ, IP) ->
    Address = case IP of
		 {A, _Port} -> A;
		  _ -> undefined
	      end,
    ResIQ = process_iq(jlib:make_jid("", "", ""),
 		       jlib:make_jid("", Server, ""),
 		       IQ,
		       Address),
    Res1 = jlib:replace_from_to(jlib:make_jid("", Server, ""),
 				jlib:make_jid("", "", ""),
 				jlib:iq_to_xml(ResIQ)),
    jlib:remove_attr("to", Res1);

unauthenticated_iq_register(Acc, _Server, _IQ, _IP) ->
    Acc.

process_iq(From, To, IQ) ->
    process_iq(From, To, IQ, jlib:jid_tolower(From)).

process_iq(From, To,
	   #iq{type = Type, lang = Lang, sub_el = SubEl, id = ID} = IQ,
	   Source) ->
    IsCaptchaEnabled = case gen_mod:get_module_opt(
			      To#jid.lserver, ?MODULE, captcha_protected, false) of
			   true ->
			       true;
			   _ ->
			       false
		       end,
    case Type of
	set ->
	    UTag = xml:get_subtag(SubEl, "username"),
	    PTag = xml:get_subtag(SubEl, "password"),
	    RTag = xml:get_subtag(SubEl, "remove"),
	    Server = To#jid.lserver,
	    Access = gen_mod:get_module_opt(Server, ?MODULE, access, all),
	    AllowRemove = (allow == acl:match_rule(Server, Access, From)),
	    if
		(UTag /= false) and (RTag /= false) and AllowRemove ->
		    User = xml:get_tag_cdata(UTag),
		    case From of
			#jid{user = User, lserver = Server} ->
			    ejabberd_auth:remove_user(User, Server),
			    IQ#iq{type = result, sub_el = [SubEl]};
			_ ->
			    if
				PTag /= false ->
				    Password = xml:get_tag_cdata(PTag),
				    case ejabberd_auth:remove_user(User,
								   Server,
								   Password) of
					ok ->
					    IQ#iq{type = result,
						  sub_el = [SubEl]};
					%% TODO FIXME: This piece of
					%% code does not work since
					%% the code have been changed
					%% to allow several auth
					%% modules.  lists:foreach can
					%% only return ok:
					not_allowed ->
					    IQ#iq{type = error,
						  sub_el =
						  [SubEl, ?ERR_NOT_ALLOWED]};
					not_exists ->
					    IQ#iq{type = error,
						  sub_el =
						  [SubEl, ?ERR_ITEM_NOT_FOUND]};
					_ ->
					    IQ#iq{type = error,
						  sub_el =
						  [SubEl,
						   ?ERR_INTERNAL_SERVER_ERROR]}
				    end;
				true ->
				    IQ#iq{type = error,
					  sub_el = [SubEl, ?ERR_BAD_REQUEST]}
			    end
		    end;
		(UTag == false) and (RTag /= false) and AllowRemove ->
		    case From of
			#jid{user = User,
			     lserver = Server,
			     resource = Resource} ->
			    ResIQ = #iq{type = result, xmlns = ?NS_REGISTER,
					id = ID,
					sub_el = [SubEl]},
			    ejabberd_router:route(
			      jlib:make_jid(User, Server, Resource),
			      jlib:make_jid(User, Server, Resource),
			      jlib:iq_to_xml(ResIQ)),
			    ejabberd_auth:remove_user(User, Server),
			    ignore;
			_ ->
			    IQ#iq{type = error,
				  sub_el = [SubEl, ?ERR_NOT_ALLOWED]}
		    end;
		(UTag /= false) and (PTag /= false) ->
		    User = xml:get_tag_cdata(UTag),
		    Password = xml:get_tag_cdata(PTag),
		    try_register_or_set_password(
		      User, Server, Password, From,
		      IQ, SubEl, Source, Lang, not IsCaptchaEnabled);
		IsCaptchaEnabled ->
		    case ejabberd_captcha:process_reply(SubEl) of
			ok ->
			    case process_xdata_submit(SubEl) of
				{ok, User, Password} ->
				    try_register_or_set_password(
				      User, Server, Password, From,
				      IQ, SubEl, Source, Lang, true);
				_ ->
				    IQ#iq{type = error,
					  sub_el = [SubEl, ?ERR_BAD_REQUEST]}
			    end;
			{error, malformed} ->
			    IQ#iq{type = error,
				  sub_el = [SubEl, ?ERR_BAD_REQUEST]};
			_ ->
			    ErrText = "The CAPTCHA verification has failed",
			    IQ#iq{type = error,
				  sub_el = [SubEl,
					    ?ERRT_NOT_ALLOWED(Lang, ErrText)]}
		    end;
		true ->
		    IQ#iq{type = error,
			  sub_el = [SubEl, ?ERR_BAD_REQUEST]}
	    end;
	get ->
	    {IsRegistered, UsernameSubels, QuerySubels} =
		case From of
		    #jid{user = User, lserver = Server} ->
			case ejabberd_auth:is_user_exists(User,Server) of
			    true ->
				{true, [{xmlcdata, User}],
				 [{xmlelement, "registered", [], []}]};
			    false ->
				{false, [{xmlcdata, User}], []}
			end;
		    _ ->
			{false, [], []}
		end,
	    if IsCaptchaEnabled and not IsRegistered ->
		    TopInstrEl = {xmlelement, "instructions", [],
				  [{xmlcdata,
				    translate:translate(
				      Lang, "You need a client that supports x:data "
				      "and CAPTCHA to register")}]},
		    InstrEl = {xmlelement, "instructions", [],
			       [{xmlcdata,
				 translate:translate(
				   Lang,
				   "Choose a username and password "
				   "to register with this server")}]},
		    UField = {xmlelement, "field",
			      [{"type", "text-single"},
			       {"label", translate:translate(Lang, "User")},
			       {"var", "username"}],
			      [{xmlelement, "required", [], []}]},
		    PField = {xmlelement, "field",
			      [{"type", "text-private"},
			       {"label", translate:translate(Lang, "Password")},
			       {"var", "password"}],
			      [{xmlelement, "required", [], []}]},
		    case ejabberd_captcha:create_captcha_x(
			   ID, To, Lang, Source, [InstrEl, UField, PField]) of
			{ok, CaptchaEls} ->
			    IQ#iq{type = result,
				  sub_el = [{xmlelement, "query",
					     [{"xmlns", "jabber:iq:register"}],
					     [TopInstrEl | CaptchaEls]}]};
                        {error, limit} ->
                            ErrText = "Too many CAPTCHA requests",
                            IQ#iq{type = error,
				  sub_el = [SubEl, ?ERRT_RESOURCE_CONSTRAINT(
                                                      Lang, ErrText)]};
			_Err ->
			    ErrText = "Unable to generate a CAPTCHA",
			    IQ#iq{type = error,
				  sub_el = [SubEl, ?ERRT_INTERNAL_SERVER_ERROR(
						      Lang, ErrText)]}
		    end;
	       true ->
		    IQ#iq{type = result,
			  sub_el = [{xmlelement,
				     "query",
				     [{"xmlns", "jabber:iq:register"}],
				     [{xmlelement, "instructions", [],
				       [{xmlcdata,
					 translate:translate(
					   Lang,
					   "Choose a username and password "
					   "to register with this server")}]},
				      {xmlelement, "username", [], UsernameSubels},
				      {xmlelement, "password", [], []}
				      | QuerySubels]}]}
	    end
    end.

try_register_or_set_password(User, Server, Password, From, IQ,
			     SubEl, Source, Lang, CaptchaSucceed) ->
    case From of
	#jid{user = User, lserver = Server} ->
	    try_set_password(User, Server, Password, IQ, SubEl, Lang);
	_ when CaptchaSucceed ->
	    case check_from(From, Server) of
		allow ->
		    case try_register(User, Server, Password,
				      Source, Lang) of
			ok ->
			    IQ#iq{type = result,
				  sub_el = [SubEl]};
			{error, Error} ->
			    IQ#iq{type = error,
				  sub_el = [SubEl, Error]}
		    end;
		deny ->
		    IQ#iq{type = error,
			  sub_el = [SubEl, ?ERR_FORBIDDEN]}
	    end;
	_ ->
	    IQ#iq{type = error,
		  sub_el = [SubEl, ?ERR_NOT_ALLOWED]}
    end.

%% @doc Try to change password and return IQ response
try_set_password(User, Server, Password, IQ, SubEl, Lang) ->
    case is_strong_password(Server, Password) of
	true ->
	    case ejabberd_auth:set_password(User, Server, Password) of
		ok ->
		    IQ#iq{type = result, sub_el = [SubEl]};
		{error, empty_password} ->
		    IQ#iq{type = error, sub_el = [SubEl, ?ERR_BAD_REQUEST]};
		{error, not_allowed} ->
		    IQ#iq{type = error, sub_el = [SubEl, ?ERR_NOT_ALLOWED]};
		{error, invalid_jid} ->
		    IQ#iq{type = error, sub_el = [SubEl, ?ERR_ITEM_NOT_FOUND]};
		_ ->
		    IQ#iq{type = error, sub_el = [SubEl, ?ERR_INTERNAL_SERVER_ERROR]}
	    end;
	false ->
	    ErrText = "The password is too weak",
	    IQ#iq{type = error,
		  sub_el = [SubEl, ?ERRT_NOT_ACCEPTABLE(Lang, ErrText)]}
    end.

try_register(User, Server, Password, SourceRaw, Lang) ->
    case jlib:is_nodename(User) of
	false ->
	    {error, ?ERR_BAD_REQUEST};
	_ ->
	    JID = jlib:make_jid(User, Server, ""),
	    Access = gen_mod:get_module_opt(Server, ?MODULE, access, all),
	    IPAccess = get_ip_access(Server),
	    case {acl:match_rule(Server, Access, JID),
		  check_ip_access(SourceRaw, IPAccess)} of
		{deny, _} ->
		    {error, ?ERR_FORBIDDEN};
		{_, deny} ->
		    {error, ?ERR_FORBIDDEN};
		{allow, allow} ->
		    Source = may_remove_resource(SourceRaw),
		    case check_timeout(Source) of
			true ->
			    case is_strong_password(Server, Password) of
				true ->
				    case ejabberd_auth:try_register(
					   User, Server, Password) of
					{atomic, ok} ->
					    send_welcome_message(JID),
					    send_registration_notifications(JID, Source),
					    ok;
					Error ->
					    remove_timeout(Source),
					    case Error of
						{atomic, exists} ->
						    {error, ?ERR_CONFLICT};
						{error, invalid_jid} ->
						    {error, ?ERR_JID_MALFORMED};
						{error, not_allowed} ->
						    {error, ?ERR_NOT_ALLOWED};
						{error, _Reason} ->
						    {error, ?ERR_INTERNAL_SERVER_ERROR}
					    end
				    end;
				false ->
				    ErrText = "The password is too weak",
				    {error, ?ERRT_NOT_ACCEPTABLE(Lang, ErrText)}
			    end;
			false ->
			    ErrText = "Users are not allowed to register "
				"accounts so quickly",
			    {error, ?ERRT_RESOURCE_CONSTRAINT(Lang, ErrText)}
		    end
	    end
    end.


send_welcome_message(JID) ->
    Host = JID#jid.lserver,
    case gen_mod:get_module_opt(Host, ?MODULE, welcome_message, {"", ""}) of
	{"", ""} ->
	    ok;
	{Subj, Body} ->
	    ejabberd_router:route(
	      jlib:make_jid("", Host, ""),
	      JID,
	      {xmlelement, "message", [{"type", "normal"}],
	       [{xmlelement, "subject", [], [{xmlcdata, Subj}]},
		{xmlelement, "body", [], [{xmlcdata, Body}]}]});
	_ ->
	    ok
    end.

send_registration_notifications(UJID, Source) ->
    Host = UJID#jid.lserver,
    case gen_mod:get_module_opt(Host, ?MODULE, registration_watchers, []) of
	[] -> ok;
	JIDs when is_list(JIDs) ->
	    Body = lists:flatten(
		     io_lib:format(
		       "[~s] The account ~s was registered from IP address ~s "
		       "on node ~w using ~p.",
		       [get_time_string(), jlib:jid_to_string(UJID),
			ip_to_string(Source), node(), ?MODULE])),
	    lists:foreach(
	      fun(S) ->
		      case jlib:string_to_jid(S) of
			  error -> ok;
			  JID ->
			      ejabberd_router:route(
				jlib:make_jid("", Host, ""),
				JID,
				{xmlelement, "message", [{"type", "chat"}],
				 [{xmlelement, "body", [],
				   [{xmlcdata, Body}]}]})
		      end
	      end, JIDs);
	_ ->
	    ok
    end.

check_from(#jid{user = "", server = ""}, _Server) ->
    allow;
check_from(JID, Server) ->
    Access = gen_mod:get_module_opt(Server, ?MODULE, access_from, none),
    acl:match_rule(Server, Access, JID).

check_timeout(undefined) ->
    true;
check_timeout(Source) ->
    Timeout = case ejabberd_config:get_local_option(registration_timeout) of
		  undefined -> 600;
		  TO -> TO
	      end,
    if
	is_integer(Timeout) ->
	    {MSec, Sec, _USec} = now(),
	    Priority = -(MSec * 1000000 + Sec),
	    CleanPriority = Priority + Timeout,
	    F = fun() ->
			Treap = case mnesia:read(mod_register_ip, treap,
						 write) of
				    [] ->
					treap:empty();
				    [{mod_register_ip, treap, T}] -> T
				end,
			Treap1 = clean_treap(Treap, CleanPriority),
			case treap:lookup(Source, Treap1) of
			    error ->
				Treap2 = treap:insert(Source, Priority, [],
						      Treap1),
				mnesia:write({mod_register_ip, treap, Treap2}),
				true;
			    {ok, _, _} ->
				mnesia:write({mod_register_ip, treap, Treap1}),
				false
			end
		end,
	    case mnesia:transaction(F) of
		{atomic, Res} ->
		    Res;
		{aborted, Reason} ->
		    ?ERROR_MSG("mod_register: timeout check error: ~p~n",
			       [Reason]),
		    true
	    end;
	true ->
	    true
    end.

clean_treap(Treap, CleanPriority) ->
    case treap:is_empty(Treap) of
	true ->
	    Treap;
	false ->
	    {_Key, Priority, _Value} = treap:get_root(Treap),
	    if
		Priority > CleanPriority ->
		    clean_treap(treap:delete_root(Treap), CleanPriority);
		true ->
		    Treap
	    end
    end.

remove_timeout(undefined) ->
    true;
remove_timeout(Source) ->
    Timeout = case ejabberd_config:get_local_option(registration_timeout) of
		  undefined -> 600;
		  TO -> TO
	      end,
    if
	is_integer(Timeout) ->
	    F = fun() ->
			Treap = case mnesia:read(mod_register_ip, treap,
						 write) of
				    [] ->
					treap:empty();
				    [{mod_register_ip, treap, T}] -> T
				end,
			Treap1 = treap:delete(Source, Treap),
			mnesia:write({mod_register_ip, treap, Treap1}),
			ok
		end,
	    case mnesia:transaction(F) of
		{atomic, ok} ->
		    ok;
		{aborted, Reason} ->
		    ?ERROR_MSG("mod_register: timeout remove error: ~p~n",
			       [Reason]),
		    ok
	    end;
	true ->
	    ok
    end.

ip_to_string(Source) when is_tuple(Source) -> inet_parse:ntoa(Source);
ip_to_string(undefined) -> "undefined";
ip_to_string(_) -> "unknown".

get_time_string() -> write_time(erlang:localtime()).
%% Function copied from ejabberd_logger_h.erl and customized
write_time({{Y,Mo,D},{H,Mi,S}}) ->
    io_lib:format("~w-~.2.0w-~.2.0w ~.2.0w:~.2.0w:~.2.0w",
		  [Y, Mo, D, H, Mi, S]).

process_xdata_submit(El) ->
    case xml:get_subtag(El, "x") of
        false ->
	    error;
        Xdata ->
            Fields = jlib:parse_xdata_submit(Xdata),
            case catch {proplists:get_value("username", Fields),
			proplists:get_value("password", Fields)} of
                {[User|_], [Pass|_]} ->
		    {ok, User, Pass};
		_ ->
		    error
	    end
    end.

is_strong_password(Server, Password) ->
    LServer = jlib:nameprep(Server),
    case gen_mod:get_module_opt(LServer, ?MODULE, password_strength, 0) of
	Entropy when is_number(Entropy), Entropy >= 0 ->
	    if Entropy == 0 ->
		    true;
	       true ->
		    ejabberd_auth:entropy(Password) >= Entropy
	    end;
	Wrong ->
	    ?WARNING_MSG("Wrong value for password_strength option: ~p",
			 [Wrong]),
	    true
    end.

%%%
%%% ip_access management
%%%

may_remove_resource({_, _, _} = From) ->
    jlib:jid_remove_resource(From);
may_remove_resource(From) ->
    From.

get_ip_access(Host) ->
    IPAccess = gen_mod:get_module_opt(Host, ?MODULE, ip_access, []),
    lists:flatmap(
      fun({Access, S}) ->
	      case parse_ip_netmask(S) of
		  {ok, IP, Mask} ->
		      [{Access, IP, Mask}];
		  error ->
		      ?ERROR_MSG("mod_register: invalid "
				 "network specification: ~p",
				 [S]),
		      []
	      end
      end, IPAccess).

parse_ip_netmask(S) ->
    case string:tokens(S, "/") of
	[IPStr] ->
	    case inet_parse:address(IPStr) of
		{ok, {_, _, _, _} = IP} ->
		    {ok, IP, 32};
		{ok, {_, _, _, _, _, _, _, _} = IP} ->
		    {ok, IP, 128};
		_ ->
		    error
	    end;
	[IPStr, MaskStr] ->
	    case catch list_to_integer(MaskStr) of
		Mask when is_integer(Mask),
			  Mask >= 0 ->
		    case inet_parse:address(IPStr) of
			{ok, {_, _, _, _} = IP} when Mask =< 32 ->
			    {ok, IP, Mask};
			{ok, {_, _, _, _, _, _, _, _} = IP} when Mask =< 128 ->
			    {ok, IP, Mask};
			_ ->
			    error
		    end;
		_ ->
		    error
	    end;
	_ ->
	    error
    end.

check_ip_access(_Source, []) ->
    allow;
check_ip_access({User, Server, Resource}, IPAccess) ->
    case ejabberd_sm:get_user_ip(User, Server, Resource) of
	{IPAddress, _PortNumber} -> check_ip_access(IPAddress, IPAccess);
	_ -> true
    end;
check_ip_access({_, _, _, _} = IP,
		[{Access, {_, _, _, _} = Net, Mask} | IPAccess]) ->
    IPInt = ip_to_integer(IP),
    NetInt = ip_to_integer(Net),
    M = bnot ((1 bsl (32 - Mask)) - 1),
    if
	IPInt band M =:= NetInt band M ->
	    Access;
	true ->
	    check_ip_access(IP, IPAccess)
    end;
check_ip_access({_, _, _, _, _, _, _, _} = IP,
		[{Access, {_, _, _, _, _, _, _, _} = Net, Mask} | IPAccess]) ->
    IPInt = ip_to_integer(IP),
    NetInt = ip_to_integer(Net),
    M = bnot ((1 bsl (128 - Mask)) - 1),
    if
	IPInt band M =:= NetInt band M ->
	    Access;
	true ->
	    check_ip_access(IP, IPAccess)
    end;
check_ip_access(IP, [_ | IPAccess]) ->
    check_ip_access(IP, IPAccess).

ip_to_integer({IP1, IP2, IP3, IP4}) ->
    (((((IP1 bsl 8) bor IP2) bsl 8) bor IP3) bsl 8) bor IP4;
ip_to_integer({IP1, IP2, IP3, IP4, IP5, IP6, IP7, IP8}) ->
    (((((((((((((IP1 bsl 16) bor IP2) bsl 16) bor IP3) bsl 16) bor IP4)
	   bsl 16) bor IP5) bsl 16) bor IP6) bsl 16) bor IP7) bsl 16) bor IP8.