%%%-------------------------------------------------------------------
%%% @author Evgeny Khramtsov <ekhramtsov@process-one.net>
%%% Created : 13 Sep 2017 by Evgeny Khramtsov <ekhramtsov@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(mod_avatar).
-behaviour(gen_mod).

%% gen_mod API
-export([start/2, stop/1, reload/3, depends/2, mod_opt_type/1]).
%% Hooks
-export([pubsub_publish_item/6, vcard_iq_convert/1, vcard_iq_publish/1]).

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

-type convert_rules() :: {default | eimp:img_type(), eimp:img_type()}.

%%%===================================================================
%%% API
%%%===================================================================
start(Host, _Opts) ->
    ejabberd_hooks:add(pubsub_publish_item, Host, ?MODULE,
		       pubsub_publish_item, 50),
    ejabberd_hooks:add(vcard_iq_set, Host, ?MODULE,
		       vcard_iq_convert, 30),
    ejabberd_hooks:add(vcard_iq_set, Host, ?MODULE,
		       vcard_iq_publish, 100).

stop(Host) ->
    ejabberd_hooks:delete(pubsub_publish_item, Host, ?MODULE,
			  pubsub_publish_item, 50),
    ejabberd_hooks:delete(vcard_iq_set, Host, ?MODULE, vcard_iq_convert, 30),
    ejabberd_hooks:delete(vcard_iq_set, Host, ?MODULE, vcard_iq_publish, 100).

reload(_Host, _NewOpts, _OldOpts) ->
    ok.

depends(_Host, _Opts) ->
    [{mod_vcard, hard}, {mod_vcard_xupdate, hard}, {mod_pubsub, hard}].

%%%===================================================================
%%% Hooks
%%%===================================================================
pubsub_publish_item(LServer, ?NS_AVATAR_METADATA,
		    #jid{luser = LUser, lserver = LServer} = From,
		    #jid{luser = LUser, lserver = LServer} = Host,
		    ItemId, [Payload|_]) ->
    try xmpp:decode(Payload) of
	#avatar_meta{info = []} ->
	    delete_vcard_avatar(From);
	#avatar_meta{info = Info} ->
	    Rules = get_converting_rules(LServer),
	    case get_meta_info(Info, Rules) of
		#avatar_info{type = MimeType, id = ID, url = <<"">>} = I ->
		    case get_avatar_data(Host, ID) of
			{ok, Data} ->
			    Meta = #avatar_meta{info = [I]},
			    Photo = #vcard_photo{type = MimeType,
						 binval = Data},
			    set_vcard_avatar(From, Photo,
					     #{avatar_meta => {ID, Meta}});
			{error, _} ->
			    ok
		    end;
		#avatar_info{type = MimeType, url = URL} ->
		    Photo = #vcard_photo{type = MimeType,
					 extval = URL},
		    set_vcard_avatar(From, Photo, #{})
	    end;
	_ ->
	    ?WARNING_MSG("invalid avatar metadata of ~s@~s published "
			 "with item id ~s",
			 [LUser, LServer, ItemId])
    catch _:{xmpp_codec, Why} ->
	    ?WARNING_MSG("failed to decode avatar metadata of ~s@~s: ~s",
			 [LUser, LServer, xmpp:format_error(Why)])
    end;
pubsub_publish_item(_, _, _, _, _, _) ->
    ok.

-spec vcard_iq_convert(iq()) -> iq() | {stop, stanza_error()}.
vcard_iq_convert(#iq{from = From, lang = Lang, sub_els = [VCard]} = IQ) ->
    #jid{luser = LUser, lserver = LServer} = From,
    case convert_avatar(LUser, LServer, VCard) of
	{ok, MimeType, Data} ->
	    VCard1 = VCard#vcard_temp{
		       photo = #vcard_photo{type = MimeType,
					    binval = Data}},
	    IQ#iq{sub_els = [VCard1]};
	pass ->
	    IQ;
	{error, Reason} ->
	    stop_with_error(Lang, Reason)
    end;
vcard_iq_convert(Acc) ->
    Acc.

-spec vcard_iq_publish(iq()) -> iq() | {stop, stanza_error()}.
vcard_iq_publish(#iq{sub_els = [#vcard_temp{photo = undefined}]} = IQ) ->
    publish_avatar(IQ, #avatar_meta{}, <<>>, <<>>, <<>>);
vcard_iq_publish(#iq{sub_els = [#vcard_temp{
				   photo = #vcard_photo{
					      type = MimeType,
					      binval = Data}}]} = IQ)
  when is_binary(Data), Data /= <<>> ->
    SHA1 = str:sha(Data),
    M = get_avatar_meta(IQ),
    case M of
	{ok, SHA1, _} ->
	    IQ;
	{ok, _ItemID, #avatar_meta{info = Info} = Meta} ->
	    case lists:keyfind(SHA1, #avatar_info.id, Info) of
		#avatar_info{} ->
		    IQ;
		false ->
		    Info1 = lists:filter(
			      fun(#avatar_info{url = URL}) -> URL /= <<"">> end,
			      Info),
		    Meta1 = Meta#avatar_meta{info = Info1},
		    publish_avatar(IQ, Meta1, MimeType, Data, SHA1)
	    end;
	{error, _} ->
	    publish_avatar(IQ, #avatar_meta{}, MimeType, Data, SHA1)
    end;
vcard_iq_publish(Acc) ->
    Acc.

%%%===================================================================
%%% Internal functions
%%%===================================================================
-spec get_meta_info([avatar_info()], convert_rules()) -> avatar_info().
get_meta_info(Info, Rules) ->
    case lists:foldl(
	   fun(_, #avatar_info{} = Acc) ->
		   Acc;
	      (#avatar_info{url = URL}, Acc) when URL /= <<"">> ->
		   Acc;
	      (#avatar_info{} = I, _) when Rules == [] ->
		   I;
	      (#avatar_info{type = MimeType} = I, Acc) ->
		   T = decode_mime_type(MimeType),
		   case lists:keymember(T, 2, Rules) of
		       true ->
			   I;
		       false ->
			   case convert_to_type(T, Rules) of
			       undefined ->
				   Acc;
			       _ ->
				   [I|Acc]
			   end
		   end
	   end, [], Info) of
	#avatar_info{} = I -> I;
	[] -> hd(Info);
	Is -> hd(lists:reverse(Is))
    end.

-spec get_avatar_data(jid(), binary()) -> {ok, binary()} |
					  {error,
					   notfound | invalid_data | internal_error}.
get_avatar_data(JID, ItemID) ->
    {LUser, LServer, _} = LBJID = jid:remove_resource(jid:tolower(JID)),
    case mod_pubsub:get_item(LBJID, ?NS_AVATAR_DATA, ItemID) of
	#pubsub_item{payload = [Payload|_]} ->
	    try xmpp:decode(Payload) of
		#avatar_data{data = Data} ->
		    {ok, Data};
		_ ->
		    ?WARNING_MSG("invalid avatar data detected "
				 "for ~s@~s with item id ~s",
				 [LUser, LServer, ItemID]),
		    {error, invalid_data}
	    catch _:{xmpp_codec, Why} ->
		    ?WARNING_MSG("failed to decode avatar data for "
				 "~s@~s with item id ~s: ~s",
				 [LUser, LServer, ItemID,
				  xmpp:format_error(Why)]),
		    {error, invalid_data}
	    end;
	{error, #stanza_error{reason = 'item-not-found'}} ->
	    {error, notfound};
	{error, Reason} ->
	    ?WARNING_MSG("failed to get item for ~s@~s at node ~s "
			 "with item id ~s: ~p",
			 [LUser, LServer, ?NS_AVATAR_METADATA, ItemID, Reason]),
	    {error, internal_error}
    end.

-spec get_avatar_meta(iq()) -> {ok, binary(), avatar_meta()} |
			       {error,
				notfound | invalid_metadata | internal_error}.
get_avatar_meta(#iq{meta = #{avatar_meta := {ItemID, Meta}}}) ->
    {ok, ItemID, Meta};
get_avatar_meta(#iq{from = JID}) ->
    {LUser, LServer, _} = LBJID = jid:remove_resource(jid:tolower(JID)),
    case mod_pubsub:get_items(LBJID, ?NS_AVATAR_METADATA) of
	[#pubsub_item{itemid = {ItemID, _}, payload = [Payload|_]}|_] ->
	    try xmpp:decode(Payload) of
		#avatar_meta{} = Meta ->
		    {ok, ItemID, Meta};
		_ ->
		    ?WARNING_MSG("invalid metadata payload detected "
				 "for ~s@~s with item id ~s",
				 [LUser, LServer, ItemID]),
		    {error, invalid_metadata}
	    catch _:{xmpp_codec, Why} ->
		    ?WARNING_MSG("failed to decode metadata for "
				 "~s@~s with item id ~s: ~s",
				 [LUser, LServer, ItemID,
				  xmpp:format_error(Why)]),
		    {error, invalid_metadata}
	    end;
	{error, #stanza_error{reason = 'item-not-found'}} ->
	    {error, notfound};
	{error, Reason} ->
	    ?WARNING_MSG("failed to get items for ~s@~s at node ~s: ~p",
			 [LUser, LServer, ?NS_AVATAR_METADATA, Reason]),
	    {error, internal_error}
    end.

-spec publish_avatar(iq(), avatar_meta(), binary(), binary(), binary()) ->
			    iq() | {stop, stanza_error()}.
publish_avatar(#iq{from = JID} = IQ, Meta, <<>>, <<>>, <<>>) ->
    {_, LServer, _} = LBJID = jid:remove_resource(jid:tolower(JID)),
    case mod_pubsub:publish_item(
	   LBJID, LServer, ?NS_AVATAR_METADATA,
	   JID, <<>>, [xmpp:encode(Meta)]) of
	{result, _} ->
	    IQ;
	{error, StanzaErr} ->
	    {stop, StanzaErr}
    end;
publish_avatar(#iq{from = JID} = IQ, Meta, MimeType, Data, ItemID) ->
    #avatar_meta{info = Info} = Meta,
    {_, LServer, _} = LBJID = jid:remove_resource(jid:tolower(JID)),
    Payload = xmpp:encode(#avatar_data{data = Data}),
    case mod_pubsub:publish_item(
	   LBJID, LServer, ?NS_AVATAR_DATA,
	   JID, ItemID, [Payload]) of
	{result, _} ->
	    {W, H} = case eimp:identify(Data) of
			 {ok, ImgInfo} ->
			     {proplists:get_value(width, ImgInfo),
			      proplists:get_value(height, ImgInfo)};
			 _ ->
			     {undefined, undefined}
		     end,
	    I = #avatar_info{id = ItemID,
			     width = W,
			     height = H,
			     type = MimeType,
			     bytes = size(Data)},
	    Meta1 = Meta#avatar_meta{info = [I|Info]},
	    case mod_pubsub:publish_item(
		   LBJID, LServer, ?NS_AVATAR_METADATA,
		   JID, ItemID, [xmpp:encode(Meta1)]) of
		{result, _} ->
		    IQ;
		{error, StanzaErr} ->
		    ?ERROR_MSG("Failed to publish avatar metadata for ~s: ~p",
			       [jid:encode(JID), StanzaErr]),
		    {stop, StanzaErr}
	    end;
	{error, StanzaErr} ->
	    ?ERROR_MSG("Failed to publish avatar data for ~s: ~p",
		       [jid:encode(JID), StanzaErr]),
	    {stop, StanzaErr}
    end.

-spec convert_avatar(binary(), binary(), vcard_temp()) ->
			    {ok, binary(), binary()} |
			    {error, eimp:error_reason() | base64_error} |
			    pass.
convert_avatar(LUser, LServer, VCard) ->
    case get_converting_rules(LServer) of
	[] ->
	    pass;
	Rules ->
	    case VCard#vcard_temp.photo of
		#vcard_photo{binval = Data} when is_binary(Data) ->
		    convert_avatar(LUser, LServer, Data, Rules);
		_ ->
		    pass
	    end
    end.

-spec convert_avatar(binary(), binary(), binary(), convert_rules()) ->
			    {ok, eimp:img_type(), binary()} |
			    {error, eimp:error_reason()} |
			    pass.
convert_avatar(LUser, LServer, Data, Rules) ->
    Type = get_type(Data),
    NewType = convert_to_type(Type, Rules),
    if NewType == undefined orelse Type == NewType ->
	    pass;
       true ->
	    ?DEBUG("Converting avatar of ~s@~s: ~s -> ~s",
		   [LUser, LServer, Type, NewType]),
	    case eimp:convert(Data, NewType) of
		{ok, NewData} ->
		    {ok, encode_mime_type(NewType), NewData};
		{error, Reason} = Err ->
		    ?ERROR_MSG("Failed to convert avatar of "
			       "~s@~s (~s -> ~s): ~s",
			       [LUser, LServer, Type, NewType,
				eimp:format_error(Reason)]),
		    Err
	    end
    end.

-spec set_vcard_avatar(jid(), vcard_photo() | undefined, map()) -> ok.
set_vcard_avatar(JID, VCardPhoto, Meta) ->
    case get_vcard(JID) of
	{ok, #vcard_temp{photo = VCardPhoto}} ->
	    ok;
	{ok, VCard} ->
	    VCard1 = VCard#vcard_temp{photo = VCardPhoto},
	    IQ = #iq{from = JID, to = JID, id = randoms:get_string(),
		     type = set, sub_els = [VCard1], meta = Meta},
	    LServer = JID#jid.lserver,
	    ejabberd_hooks:run_fold(vcard_iq_set, LServer, IQ, []),
	    ok;
	{error, _} ->
	    ok
    end.

-spec delete_vcard_avatar(jid()) -> ok.
delete_vcard_avatar(JID) ->
    set_vcard_avatar(JID, undefined, #{}).

-spec get_vcard(jid()) -> {ok, vcard_temp()} | {error, invalid_vcard}.
get_vcard(#jid{luser = LUser, lserver = LServer}) ->
    VCardEl = case mod_vcard:get_vcard(LUser, LServer) of
		  [El] -> El;
		  _ -> #vcard_temp{}
	      end,
    try xmpp:decode(VCardEl, ?NS_VCARD, []) of
	#vcard_temp{} = VCard ->
	    {ok, VCard};
	_ ->
	    ?ERROR_MSG("invalid vCard of ~s@~s in the database",
		       [LUser, LServer]),
	    {error, invalid_vcard}
    catch _:{xmpp_codec, Why} ->
	    ?ERROR_MSG("failed to decode vCard of ~s@~s: ~s",
		       [LUser, LServer, xmpp:format_error(Why)]),
	    {error, invalid_vcard}
    end.

-spec stop_with_error(binary(), eimp:error_reason()) ->
			     {stop, stanza_error()}.
stop_with_error(Lang, Reason) ->
    Txt = eimp:format_error(Reason),
    {stop, xmpp:err_internal_server_error(Txt, Lang)}.

-spec get_converting_rules(binary()) -> convert_rules().
get_converting_rules(LServer) ->
    gen_mod:get_module_opt(LServer, ?MODULE, convert, []).

-spec get_type(binary()) -> eimp:img_type() | unknown.
get_type(Data) ->
    eimp:get_type(Data).

-spec convert_to_type(eimp:img_type() | unknown, convert_rules()) ->
			     eimp:img_type() | undefined.
convert_to_type(unknown, _Rules) ->
    undefined;
convert_to_type(Type, Rules) ->
    case proplists:get_value(Type, Rules) of
	undefined ->
	    proplists:get_value(default, Rules);
	T ->
	    T
    end.

-spec decode_mime_type(binary()) -> eimp:img_type() | unknown.
decode_mime_type(MimeType) ->
    case str:to_lower(MimeType) of
	<<"image/jpeg">> -> jpeg;
	<<"image/png">> -> png;
	<<"image/webp">> -> webp;
	<<"image/gif">> -> gif;
	_ -> unknown
    end.

-spec encode_mime_type(eimp:img_type()) -> binary().
encode_mime_type(Type) ->
    <<"image/", (atom_to_binary(Type, latin1))/binary>>.

-spec fail(atom()) -> no_return().
fail(Format) ->
    FormatS = case Format of
		  webp -> "WebP";
		  png -> "PNG";
		  jpeg -> "JPEG";
		  gif -> "GIF";
		  _ -> ""
	      end,
    if FormatS /= "" ->
	    ?WARNING_MSG("ejabberd is not compiled with ~s support", [FormatS]);
       true ->
	    ok
    end,
    erlang:error(badarg).

mod_opt_type({convert, From}) ->
    fun(To) when is_atom(To), To /= From ->
	    case eimp:is_supported(From) orelse From == default of
		false ->
		    fail(From);
		true ->
		    case eimp:is_supported(To) of
			false -> fail(To);
			true -> To
		    end
	    end
    end;
mod_opt_type(_) ->
    [{convert, T} || T <- [default|eimp:supported_formats()]].
