%%% @author     Max Lapshin <max@maxidoors.ru> [http://erlyvideo.org]
%%% @copyright  2010 Max Lapshin
%%% @doc        RTSP socket module
%%%
%%%
%%% 1. connect
%%% 2. describe
%%% 3. each setup
%%% 4. play, possible Rtp-Sync
%%% 5. get each packet
%%% 6. decode
%%%
%%%
%%% @end
%%% @reference  See <a href="http://erlyvideo.org/rtsp" target="_top">http://erlyvideo.org</a> for common information.
%%% @end
%%%
%%% This file is part of erlang-rtsp.
%%%
%%% erlang-rtsp 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 3 of the License, or
%%% (at your option) any later version.
%%%
%%% erlang-rtsp 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 erlang-rtsp.  If not, see <http://www.gnu.org/licenses/>.
%%%
%%%---------------------------------------------------------------------------------------
-module(rtsp_socket).
-author('Max Lapshin <max@maxidoors.ru>').
-behaviour(gen_server).

-include("log.hrl").
-include_lib("erlmedia/include/video_frame.hrl").
-include_lib("erlmedia/include/media_info.hrl").
-include_lib("erlmedia/include/sdp.hrl").
-include("rtsp.hrl").

-export([start_link/1, set_socket/2]).
%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).

-export([read/2, connect/3, options/2, describe/2, setup/3, play/2, teardown/1]).

-export([handle_sdp/3, reply/3, reply/4, save_media_info/2, generate_session/0]).

read(URL, Options) when is_binary(URL) ->
  read(binary_to_list(URL), Options);

read(URL, Options) when is_list(URL) ->
  % try read_raw(URL, Options) of
  %   {ok, RTSP, MediaInfo} -> {ok, RTSP, MediaInfo}
  % catch
  %   _Class:{error,Reason} -> {error, Reason};
  %   exit:Reason -> {error, Reason};
  %   Class:Reason -> {Class, Reason}
  % end.
  read_raw(URL, Options).

read_raw(URL, Options) ->
  {ok, RTSP} = rtsp_sup:start_rtsp_socket([{consumer, proplists:get_value(consumer, Options, self())}]),
  ConnectResult = rtsp_socket:connect(RTSP, URL, Options),
  ok == ConnectResult orelse erlang:throw(ConnectResult),
  {ok, _Methods} = rtsp_socket:options(RTSP, Options),
  {ok, MediaInfo, AvailableTracks} = rtsp_socket:describe(RTSP, Options),
  Tracks = 
    case proplists:get_value(tracks, Options) of
      undefined -> AvailableTracks;
      RequestedTracks -> [T || T <- AvailableTracks, lists:member(T,RequestedTracks)]
  end,
  [ok = rtsp_socket:setup(RTSP, Track, Options) || Track <- Tracks],
  ok = rtsp_socket:play(RTSP, Options),
  {ok,RTSP,MediaInfo}.

options(RTSP, Options) ->
  Timeout = proplists:get_value(timeout, Options, 5000)*2,
  gen_server:call(RTSP, {request, options}, Timeout).

describe(RTSP, Options) -> 
  Timeout = proplists:get_value(timeout, Options, 5000)*2,
  gen_server:call(RTSP, {request, describe}, Timeout).

setup(RTSP, Stream, Options) ->
  Timeout = proplists:get_value(timeout, Options, 5000)*2,
  gen_server:call(RTSP, {request, setup, Stream}, Timeout).

play(RTSP, Options) ->
  Timeout = proplists:get_value(timeout, Options, 5000)*2,
  gen_server:call(RTSP, {request, play}, Timeout).

connect(RTSP, URL, Options) ->
  Timeout = proplists:get_value(timeout, Options, 10000)*2,
  gen_server:call(RTSP, {connect, URL, Options}, Timeout).

teardown(RTSP) ->
  gen_server:call(RTSP, teardown).

start_link(Options) ->
  gen_server:start_link(?MODULE, [Options], []).


set_socket(Pid, Socket) when is_pid(Pid), is_port(Socket) ->
  gen_tcp:controlling_process(Socket, Pid),
  gen_server:cast(Pid, {socket_ready, Socket}).


init([Options]) ->
  Callback = proplists:get_value(callback, Options),
  Consumer = proplists:get_value(consumer, Options),
  case Consumer of
    undefined -> ok;
    _ -> erlang:monitor(process, Consumer)
  end,
  {ok, #rtsp_socket{callback = Callback, options = Options, media = Consumer, auth = fun empty_auth/2, timeout = ?DEFAULT_TIMEOUT}}.


%%-------------------------------------------------------------------------
%% @spec (Request, From, State) -> {reply, Reply, State}          |
%%                                 {reply, Reply, State, Timeout} |
%%                                 {noreply, State}               |
%%                                 {noreply, State, Timeout}      |
%%                                 {stop, Reason, Reply, State}   |
%%                                 {stop, Reason, State}
%% @doc Callback for synchronous server calls.  If `{stop, ...}' tuple
%%      is returned, the server is stopped and `terminate/2' is called.
%% @end
%% @private
%%-------------------------------------------------------------------------


handle_call({connect, _, Options} = Call, From, #rtsp_socket{} = RTSP) ->
  rtsp_inbound:handle_call(Call, From, RTSP#rtsp_socket{dump_traffic = proplists:get_value(dump_traffic, Options, true)});

handle_call({consume, _Consumer} = Call, From, RTSP) ->
  rtsp_inbound:handle_call(Call, From, RTSP);

handle_call({request, _Request} = Call, From, RTSP) ->
  rtsp_inbound:handle_call(Call, From, RTSP);

handle_call({request, setup, _Num} = Call, From, RTSP) ->
  rtsp_inbound:handle_call(Call, From, RTSP);

handle_call(teardown, _From, RTSP) ->
  send_teardown(RTSP),
  {stop, normal, ok, RTSP};

handle_call(Request, _From, #rtsp_socket{} = RTSP) ->
  {stop, {unknown_call, Request}, RTSP}.



%%-------------------------------------------------------------------------
%% @spec (Msg, State) ->{noreply, State}          |
%%                      {noreply, State, Timeout} |
%%                      {stop, Reason, State}
%% @doc Callback for asyncrous server calls.  If `{stop, ...}' tuple
%%      is returned, the server is stopped and `terminate/2' is called.
%% @end
%% @private
%%-------------------------------------------------------------------------
handle_cast({socket_ready, Socket}, #rtsp_socket{timeout = Timeout} = State) ->
  {ok, {IP, Port}} = inet:peername(Socket),
  inet:setopts(Socket, [{active, once}]),
  {noreply, State#rtsp_socket{socket = Socket, addr = IP, port = Port}, Timeout};

handle_cast(Request, #rtsp_socket{} = Socket) ->
  {stop, {unknown_cast, Request}, Socket}.


%%-------------------------------------------------------------------------
%% @spec (Msg, State) ->{noreply, State}          |
%%                      {noreply, State, Timeout} |
%%                      {stop, Reason, State}
%% @doc Callback for messages sent directly to server's mailbox.
%%      If `{stop, ...}' tuple is returned, the server is stopped and
%%      `terminate/2' is called.
%% @end
%% @private
%%-------------------------------------------------------------------------


handle_info({tcp_closed, _Socket}, State) ->
  ?D({"RTSP socket closed"}),
  {stop, normal, State};

handle_info({udp, _Socket, Addr, Port, Bin}, #rtsp_socket{media = Consumer, timeout = Timeout, rtp = RTP} = RTSP) ->
  {ok, RTP1, NewFrames} = rtp:handle_data(RTP, {Addr, Port}, Bin),
  [Consumer ! Frame || Frame <- NewFrames],
  {noreply, RTSP#rtsp_socket{rtp = RTP1}, Timeout};

handle_info({tcp, Socket, Bin}, #rtsp_socket{buffer = Buf, timeout = Timeout} = RTSPSocket) ->
  inet:setopts(Socket, [{active, once}]),
  {noreply, handle_packet(RTSPSocket#rtsp_socket{buffer = <<Buf/binary, Bin/binary>>}), Timeout};

% handle_info({'DOWN', _, process, Consumer, _Reason}, #rtsp_socket{rtp = Consumer} = Socket) ->
%   ?D({"RTSP RTP process died", Consumer}),
%   {stop, normal, Socket};

handle_info({'DOWN', _, process, Consumer, _Reason}, #rtsp_socket{media = Consumer} = Socket) ->
  ?D({"RTSP consumer died", Consumer}),
  {stop, normal, Socket};

handle_info(#video_frame{} = Frame, #rtsp_socket{timeout = Timeout} = Socket) ->
  {noreply, rtsp_outbound:encode_frame(Frame, Socket), Timeout};

handle_info({ems_stream, _, play_complete, _}, Socket) ->
  {stop, normal, Socket};

handle_info(timeout, #rtsp_socket{} = Socket) ->
  {stop, timeout, Socket};

handle_info(send_sr, #rtsp_socket{rtp = RTP} = Socket) ->
  rtp:send_rtcp(RTP, sender_report, []),
  {noreply, Socket};

handle_info({ems_stream,_Num,_}, #rtsp_socket{} = Socket) ->
  {noreply, Socket};

handle_info({ems_stream,_Num,_Key,_}, #rtsp_socket{} = Socket) ->
  {noreply, Socket};

handle_info({'EXIT', _, _}, RTSP) ->
  {noreply, RTSP};

handle_info(Message, #rtsp_socket{} = Socket) ->
  {stop, {unknown_message, Message}, Socket}.

dump_io(false, _) -> ok;
dump_io(true, IO) -> dump_io(IO).

dump_io({request, Method, URL, Headers, undefined}) ->
  HeaderS = lists:flatten([io_lib:format("~p: ~p~n", [K, V]) || {K,V} <- Headers]),
  io:format("<<<<<< RTSP IN (~p:~p)  <<<<<~n~s ~s RTSP/1.0~n~s~n", [?MODULE, ?LINE, Method, URL, HeaderS]);

dump_io({request, Method, URL, Headers, Body}) ->
  HeaderS = lists:flatten([io_lib:format("~p: ~p~n", [K, V]) || {K,V} <- Headers]),
  io:format("<<<<<< RTSP IN (~p:~p)  <<<<<~n~s ~s RTSP/1.0~n~s~n~s~n", [?MODULE, ?LINE, Method, URL, HeaderS, Body]);

dump_io({response, Code, Message, Headers, undefined}) ->
  HeaderS = lists:flatten([io_lib:format("~p: ~p~n", [K, V]) || {K,V} <- Headers]),
  io:format("<<<<<< RTSP IN (~p:~p)  <<<<<~nRTSP/1.0 ~p ~s~n~s~n", [?MODULE, ?LINE, Code, Message, HeaderS]);

dump_io({response, Code, Message, Headers, Body}) ->
  HeaderS = lists:flatten([io_lib:format("~p: ~p~n", [K, V]) || {K,V} <- Headers]),
  io:format("<<<<<< RTSP IN (~p:~p)  <<<<<~nRTSP/1.0 ~p ~s~n~s~n~s~n", [?MODULE, ?LINE, Code, Message, HeaderS, Body]).

-define(DUMP_REQUEST(Flag, X), dump_io(Flag, X)).
-define(DUMP_RESPONSE(Flag, X), dump_io(Flag, X)).

handle_packet(#rtsp_socket{buffer = Data, rtp = RTP, media = Consumer, dump_traffic = Dump} = Socket) ->
  case packet_codec:decode(Data) of
    {more, Data} ->
      Socket;
    {ok, {rtp, Channel, Packet}, Rest} ->
      {ok, RTP1, NewFrames} = rtp:handle_data(RTP, Channel, Packet),
      Socket1 = case NewFrames of
        [#video_frame{dts = DTS}|_] when Socket#rtsp_socket.sent_sdp_config == false ->
          [Consumer ! Frame#video_frame{dts = DTS, pts = DTS} || Frame <- video_frame:config_frames(Socket#rtsp_socket.media_info)],
          Socket#rtsp_socket{sent_sdp_config = true};
        _ ->
          Socket
      end,
      [Consumer ! Frame || Frame <- NewFrames],
      handle_packet(Socket1#rtsp_socket{buffer = Rest, rtp = RTP1});
    {ok, {response, _Code, _Message, Headers, _Body} = Response, Rest} ->
      ?DUMP_RESPONSE(Dump, Response),
      Socket1 = handle_response(extract_session(Socket#rtsp_socket{buffer = Rest}, Headers), Response),
      handle_packet(Socket1);
    {ok, {request, _Method, _URL, _Headers, _Body} = Request, Rest} ->
      ?DUMP_REQUEST(Dump, Request),
      Socket1 = handle_request(Request, Socket#rtsp_socket{buffer = Rest}),
      handle_packet(Socket1)
  end.

% Special case for server, rejecting Basic auth
handle_response(#rtsp_socket{state = Request, auth_type = basic, auth_info = AuthInfo, pending = From} = Socket, {response, 401, _Message, Headers, _Body}) ->
  case proplists:get_value('Www-Authenticate', Headers) of
    [digest|Digest] ->
      [Username, Password] = string:tokens(AuthInfo, ":"),

      DigestAuth = fun(ReqName, URL) ->
        digest_auth(Digest, Username, Password, URL, ReqName)
      end,
      {noreply, Socket1, _T} = rtsp_inbound:handle_call({request,Request}, From, Socket#rtsp_socket{auth_type = digest, auth = DigestAuth}),
      Socket1;
    _ ->
      reply_pending(Socket#rtsp_socket{state = undefined, pending_reply = {error, unauthorized}})
  end;


handle_response(#rtsp_socket{state = options} = Socket, {response, _Code, _Message, Headers, _Body}) ->
  Available = string:tokens(binary_to_list(proplists:get_value('Public', Headers, <<"">>)), ", "),
  reply_pending(Socket#rtsp_socket{pending_reply = {ok, Available}});

handle_response(#rtsp_socket{state = describe} = Socket, {response, 200, _Message, Headers, Body}) ->
  Socket1 = handle_sdp(Socket, Headers, Body),
  reply_pending(Socket1#rtsp_socket{state = undefined});

handle_response(#rtsp_socket{state = play} = Socket, {response, 200, _Message, Headers, _Body}) ->
  Socket1 = rtsp_inbound:sync_rtp(Socket, Headers),
  reply_pending(Socket1#rtsp_socket{state = undefined});

handle_response(#rtsp_socket{state = {setup, StreamId}, rtp = RTP, transport = Transport} = Socket, {response, 200, _Message, Headers, _Body}) ->
  TransportHeader = proplists:get_value('Transport', Headers, []),
  PortOpts = case proplists:get_value(server_port, TransportHeader) of
    {SPort1,SPort2} -> [{remote_rtp_port,SPort1},{remote_rtcp_port,SPort2}];
    undefined -> []
  end,
  {ok, RTP1, _} = rtp:setup_channel(RTP, StreamId, [{proto,Transport}]++PortOpts),
  reply_pending(Socket#rtsp_socket{state = undefined, pending_reply = ok, rtp = RTP1});

handle_response(Socket, {response, 401, _Message, _Headers, _Body}) ->
  reply_pending(Socket#rtsp_socket{state = undefined, pending_reply = {error, unauthorized}});

handle_response(Socket, {response, 404, _Message, _Headers, _Body}) ->
  reply_pending(Socket#rtsp_socket{state = undefined, pending_reply = {error, not_found}});

handle_response(Socket, {response, _Code, _Message, _Headers, _Body}) ->
  reply_pending(Socket#rtsp_socket{state = undefined, pending_reply = {error, _Code}}).


reply_pending(#rtsp_socket{pending = undefined} = Socket) ->
  Socket;

reply_pending(#rtsp_socket{state = {Method, Count}} = Socket) when Count > 1 ->
  Socket#rtsp_socket{state = {Method, Count - 1}};

reply_pending(#rtsp_socket{pending = From, pending_reply = Reply} = Socket) ->
  gen_server:reply(From, Reply),
  Socket#rtsp_socket{pending = undefined, pending_reply = ok}.

handle_sdp(#rtsp_socket{media = Consumer, content_base = OldContentBase, url = URL} = Socket, Headers, Body) ->
  <<"application/sdp">> = proplists:get_value('Content-Type', Headers),
  MI1 = #media_info{streams = Streams} = sdp:decode(Body),
  MI2 = MI1#media_info{streams = [S || #stream_info{content = Content, codec = Codec} = S <- Streams, 
    (Content == audio orelse Content == video) andalso Codec =/= undefined]},
  MediaInfo = MI2,
  RTP = rtp:init(local, MediaInfo),
  ContentBase = case proplists:get_value('Content-Base', Headers) of
    undefined -> OldContentBase;
    NewContentBase -> % Here we must handle important case when Content-Base is given with local network
      {match, [_Host, BasePath]} = re:run(NewContentBase, "rtsp://([^/]+)(/.*)$", [{capture,all_but_first,list}]),
      {match, [Host, _Path]} = re:run(URL, "rtsp://([^/]+)(/.*)$", [{capture,all_but_first,list}]),
      "rtsp://" ++ Host ++ "/" ++ BasePath
  end,
  Socket1 = save_media_info(Socket#rtsp_socket{rtp = RTP, content_base = ContentBase}, MediaInfo),
  case Consumer of
    undefined -> ok;
    _ -> Consumer ! Socket1#rtsp_socket.media_info
  end,
  Socket1.
  

save_media_info(#rtsp_socket{options = Options} = Socket, #media_info{streams = Streams1} = MediaInfo) ->
  StreamNums = lists:seq(1, length(Streams1)),

  Streams2 = lists:sort(fun(#stream_info{track_id = Id1}, #stream_info{track_id = Id2}) ->
    Id1 =< Id2
  end, Streams1),
  
  Streams3 = [lists:nth(Track, Streams2) || Track <- proplists:get_value(tracks, Options, lists:seq(1,length(Streams2)))],  
  
  Streams = Streams3,

  StreamInfos = list_to_tuple(Streams3),
  ControlMap = [{proplists:get_value(control, Opt),S} || #stream_info{options = Opt, track_id = S} <- Streams],
  MediaInfo1 = MediaInfo#media_info{streams = Streams},

  % ?D({"Streams", StreamInfos, StreamNums, ControlMap}),
  Socket#rtsp_socket{rtp_streams = StreamInfos, media_info = MediaInfo1, control_map = ControlMap, pending_reply = {ok, MediaInfo1, StreamNums}}.


generate_session() ->
  {_A1, A2, A3} = now(),
  lists:flatten(io_lib:format("~p~p", [A2*1000,A3 div 1000])).

seq(Headers) ->
  proplists:get_value('Cseq', Headers, 1).

%
% Wirecast goes:
%
% ANNOUNCE with SDP
% OPTIONS
% SETUP

user_agents() ->
  [
    {"RealMedia", mplayer},
    {"LibVLC", vlc}
  ].

detect_user_agent(Headers) ->
  case proplists:get_value('User-Agent', Headers) of
    undefined -> undefined;
    UA -> find_user_agent(UA, user_agents())
  end.

find_user_agent(_UA, []) -> undefined;
find_user_agent(UA, [{Match, Name}|Matches]) ->
  case re:run(UA, Match, [{capture,all_but_first,list}]) of
    {match, _} -> Name;
    _ -> find_user_agent(UA, Matches)
  end.


setup_user_agent_preferences(#rtsp_socket{} = Socket, Headers) ->
  UserAgent = detect_user_agent(Headers),
  Socket#rtsp_socket{user_agent = UserAgent}.


handle_request({request, 'DESCRIBE', URL, Headers, Body}, Socket) ->
  rtsp_outbound:handle_describe_request(Socket, URL, Headers, Body);


handle_request({request, 'RECORD', URL, Headers, Body}, #rtsp_socket{callback = Callback} = State) ->
  case Callback:record(URL, Headers, Body) of
    ok ->
      reply(State, "200 OK", [{'Cseq', seq(Headers)}]);
    {error, authentication} ->
      reply(State, "401 Unauthorized", [{"WWW-Authenticate", "Basic realm=\"Erlyvideo Streaming Server\""}, {'Cseq', seq(Headers)}])
  end;


handle_request({request, 'PLAY', URL, Headers, Body}, #rtsp_socket{direction = in} = State) ->
  handle_request({request, 'RECORD', URL, Headers, Body}, State);

handle_request({request, 'PLAY', URL, Headers, Body}, #rtsp_socket{} = Socket) ->
  rtsp_outbound:handle_play_request(Socket, URL, Headers, Body);

handle_request({request, 'OPTIONS', _URL, Headers, _Body}, State) ->
  reply(setup_user_agent_preferences(State, Headers), "200 OK",
      [{'Server', ?SERVER_NAME}, {'Cseq', seq(Headers)}, {"Supported", "play.basic, con.persistent"},
       {'Public', "SETUP, TEARDOWN, PLAY, PAUSE, OPTIONS, ANNOUNCE, DESCRIBE, RECORD, GET_PARAMETER"}]);

handle_request({request, 'ANNOUNCE', URL, Headers, Body}, Socket) ->
  rtsp_inbound:handle_announce_request(Socket, URL, Headers, Body);

handle_request({request, 'PAUSE', _URL, Headers, _Body}, #rtsp_socket{direction = in} = State) ->
  rtsp_inbound:handle_pause(State, _URL, Headers, _Body);

handle_request({request, 'PAUSE', _URL, Headers, _Body}, #rtsp_socket{direction = out} = State) ->
  rtsp_outbound:handle_pause_request(State, _URL, Headers, _Body);
%
% handle_request({request, 'PAUSE', _URL, Headers, _Body}, #rtsp_socket{rtp = Consumer} = State) ->
%   gen_server:call(Consumer, {pause, self()}),
%   reply(State, "200 OK", [{'Cseq', seq(Headers)}]);

handle_request({request, 'SETUP', URL, Headers, Body}, #rtsp_socket{} = Socket) ->
  Transport = proplists:get_value('Transport', Headers),
  case proplists:get_value(mode, Transport) of
    'receive' -> rtsp_inbound:handle_receive_setup(Socket, URL, Headers, Body);
    _ -> rtsp_outbound:handle_play_setup(Socket, URL, Headers, Body)
  end;

handle_request({request, 'GET_PARAMETER', URL, Headers, Body}, #rtsp_socket{} = Socket) ->
  handle_request({request, 'OPTIONS', URL, Headers, Body}, Socket);

handle_request({request, 'TEARDOWN', _URL, Headers, _Body}, #rtsp_socket{} = State) ->
  reply(State, "200 OK", [{'Cseq', seq(Headers)}]).



reply(State, Code, Headers) ->
  reply(State, Code, Headers, undefined).

reply(#rtsp_socket{socket = Socket} = State, Code, Headers, Body) ->
  {State1, Headers1} = append_session(State, Headers),
  Headers2 = case Body of
    undefined -> Headers1;
    _ -> [{'Content-Length', iolist_size(Body)}, {'Content-Type', <<"application/sdp">>}|Headers1]
  end,
  Reply = iolist_to_binary(["RTSP/1.0 ", Code, <<"\r\n">>, packet_codec:encode_headers(Headers2), <<"\r\n">>,
  case Body of
    undefined -> <<>>;
    _ -> Body
  end]),
  io:format("[RTSP Response to Client]~n~s", [Reply]),
  gen_tcp:send(Socket, Reply),
  State1.



extract_session(Socket, Headers) ->
  case proplists:get_value('Session', Headers) of
    undefined ->
      Socket;
    FullSession ->
      Socket#rtsp_socket{session = "Session: "++hd(string:tokens(binary_to_list(FullSession), ";"))++"\r\n"}
  end.

parse_session(Session) when is_binary(Session) -> parse_session(binary_to_list(Session));
parse_session(Session) -> hd(string:tokens(Session, ";")).

append_session(#rtsp_socket{session = undefined} = Socket, Headers) ->
  case proplists:get_value('Session', Headers) of
    undefined -> {Socket, Headers};
    Session -> {Socket#rtsp_socket{session = parse_session(Session)}, Headers}
  end;

append_session(#rtsp_socket{session = Session, timeout = Timeout} = Socket, Headers) ->
  Sess = lists:flatten(io_lib:format("~s;timeout=~p", [Session, Timeout div 1000])),
  {Socket#rtsp_socket{session = Session}, [{'Session', Sess}|Headers]}.



send_teardown(#rtsp_socket{socket = undefined}) ->
  % ?D({warning, teardown,"on closed socket"}),
  ok;

send_teardown(#rtsp_socket{socket = Socket, url = URL, auth = Auth, seq = Seq} = RTSP) ->
  Call = io_lib:format("TEARDOWN ~s RTSP/1.0\r\nCSeq: ~p\r\nAccept: application/sdp\r\n"++Auth("TEARDOWN", URL)++"\r\n", [URL, Seq+1]),
  gen_tcp:send(Socket, Call),
  rtsp_inbound:dump_io(RTSP, Call),
  gen_tcp:close(Socket).


%%-------------------------------------------------------------------------
%% @spec (Reason, State) -> any
%% @doc  Callback executed on server shutdown. It is only invoked if
%%       `process_flag(trap_exit, true)' is set by the server process.
%%       The return value is ignored.
%% @end
%% @private
%%-------------------------------------------------------------------------
terminate(_Reason, RTSP) ->
  send_teardown(RTSP),
  ok.

%%-------------------------------------------------------------------------
%% @spec (OldVsn, State, Extra) -> {ok, NewState}
%% @doc  Convert process state when code is changed.
%% @end
%% @private
%%-------------------------------------------------------------------------
code_change(_OldVsn, State, _Extra) ->
  {ok, State}.



to_hex(L) when is_binary(L) ->
  to_hex(binary_to_list(L));

to_hex(L) when is_list(L) -> 
  list_to_binary(lists:flatten(lists:map(fun(X) -> int_to_hex(X) end, L))).

int_to_hex(N) when N < 256 ->
  [hex(N div 16), hex(N rem 16)].

hex(N) when N < 10 ->
  $0+N;
hex(N) when N >= 10, N < 16 ->
  $a + (N-10).

empty_auth(_Method, _URL) ->
  "".


digest_auth(Digest, Username, Password, URL, Request) ->
  Realm = proplists:get_value(realm, Digest),
  Nonce = proplists:get_value(nonce, Digest),
  % CNonce = to_hex(crypto:md5(iolist_to_binary([Username, ":erlyvideo:", Password]))),
  % CNonce = <<>>,
  % NonceCount = <<"00000000">>,
  _Qop = proplists:get_value(qop, Digest),

  % <<"auth">> == Qop orelse erlang:throw({unsupported_digest_auth, Qop}),
  HA1 = to_hex(crypto:md5(iolist_to_binary([Username, ":", Realm, ":", Password]))),
  HA2 = to_hex(crypto:md5(iolist_to_binary([Request, ":", URL]))),
  Response = to_hex(crypto:md5(iolist_to_binary([HA1, ":", Nonce, ":", HA2]))),


  DigestAuth = io_lib:format("Authorization: Digest username=\"~s\", realm=\"~s\", nonce=\"~s\", uri=\"~s\", response=\"~s\"\r\n",
  [Username, Realm, Nonce, URL, Response]),
  lists:flatten(DigestAuth).



-include_lib("eunit/include/eunit.hrl").

digest_auth_test() ->
  ?assertEqual("Authorization: Digest username=\"admin\", realm=\"Avigilon-12045784\", nonce=\"dh9U5wffmjzbGZguCeXukieLz277ckKgelszUk86230000\", uri=\"rtsp://admin:admin@94.80.16.122:554/defaultPrimary0?streamType=u\", response=\"99a9e6b080a96e25547b9425ff5d68bf\"\r\n",
  digest_auth([{realm, <<"Avigilon-12045784">>}, {nonce, <<"dh9U5wffmjzbGZguCeXukieLz277ckKgelszUk86230000">>}, {qop, <<"auth">>}], "admin", "admin", "rtsp://admin:admin@94.80.16.122:554/defaultPrimary0?streamType=u", "OPTIONS")).