%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2003-2020. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%%     http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%

-module(ct_telnet).

-export([open/1, open/2, open/3, open/4, close/1]).
-export([cmd/2, cmd/3, cmdf/3, cmdf/4, get_data/1, 
	 send/2, send/3, sendf/3, sendf/4,
	 expect/2, expect/3]).

%% Callbacks
-export([init/3,handle_msg/2,reconnect/2,terminate/2]).

%% Tool internals
-export([silent_teln_expect/6, teln_receive_until_prompt/3,
	 format_data/2]).
-export([start_gen_log/1, end_gen_log/0, log/3, log/4]).

-define(RECONNS,3).
-define(RECONN_TIMEOUT,5000).
-define(DEFAULT_TIMEOUT,10000).
-define(DEFAULT_PORT,23).
-define(POLL_LIMIT,0).
-define(POLL_INTERVAL,1000).

-include("ct_util.hrl").

-record(state,{host,
	       port,
	       teln_pid,
	       prx,
	       buffer=[],
	       prompt=false,
	       name,
	       type,
	       target_mod,
	       keep_alive,
	       poll_limit=?POLL_LIMIT,
	       poll_interval=?POLL_INTERVAL,
	       extra,
	       conn_to=?DEFAULT_TIMEOUT, 
	       com_to=?DEFAULT_TIMEOUT, 
	       reconns=?RECONNS,
	       reconn_int=?RECONN_TIMEOUT,
	       tcp_nodelay=false}).

open(Name) ->
    open(Name,telnet).

open(Name,ConnType) ->
    case ct_util:get_key_from_name(Name) of
	{ok, unix} -> % unix host
	    open(Name, ConnType, unix_telnet, Name);
	{ok, Key} -> % any other, e.g. interwatch (iw), etc.
	    open(Name, ConnType, Key, Name);
	Error ->
	    Error
    end.

open(KeyOrName,ConnType,TargetMod) ->
    open(KeyOrName,ConnType,TargetMod,KeyOrName).

open(KeyOrName,ConnType,TargetMod,Extra) ->
    case ct:get_config({KeyOrName,ConnType}) of
	undefined ->
	    log(undefined,open,"Failed: ~tp",[{not_available,KeyOrName}]),
	    {error,{not_available,KeyOrName,ConnType}};
	Addr ->
	    Addr1 =
		case Addr of
		    {_IP,_Port} ->
			Addr;
		    IP ->
			case ct:get_config({KeyOrName,port}) of
			    undefined -> IP;
			    P -> {IP,P}
			end
		end,
	    KeepAlive =
		case ct:get_config({KeyOrName,keep_alive}) of
		    undefined -> 
			case ct:get_config({telnet_settings,keep_alive}) of
			    undefined -> true;
			    Bool -> Bool
			end;
		    Bool -> Bool
		end,
	    log(undefined,open,"Connecting to ~tp(~tp)",
		[KeyOrName,Addr1]),
	    Reconnect =
		case ct:get_config({telnet_settings,reconnection_attempts}) of
		    0 -> false;
		    _ -> true
		end,
	    ct_gen_conn:start(full_addr(Addr1,ConnType),
			      {TargetMod,KeepAlive,Extra},
			      ?MODULE, [{name,KeyOrName},
					{reconnect,Reconnect},
					{old,true}])
    end.

close(Connection) ->
    case get_handle(Connection) of
	{ok,Pid} ->
	    log(undefined,close,"Connection closed, handle: ~w",[Pid]),
	    case ct_gen_conn:stop(Pid) of
		{error,{process_down,Pid,_}} ->
		    {error,already_closed};
		Result ->
		    Result
	    end;
	Error ->
	    Error
    end.

%%%=================================================================
%%% Test suite interface
%%%-----------------------------------------------------------------

cmd(Connection,Cmd) ->
    cmd(Connection,Cmd,[]).

cmd(Connection,Cmd,Opts) when is_list(Opts) ->
    case check_cmd_opts(Opts) of
	ok ->
	    case get_handle(Connection) of
		{ok,Pid} ->
		    call(Pid,{cmd,Cmd,Opts});
		Error ->
		    Error
	    end;
	Error ->
	    Error
    end;
cmd(Connection,Cmd,Timeout) when is_integer(Timeout); Timeout==default ->
    %% This clause is kept for backwards compatibility only
    cmd(Connection,Cmd,[{timeout,Timeout}]).

check_cmd_opts([{timeout,Timeout}|Opts]) when is_integer(Timeout);
					      Timeout==default ->
    check_cmd_opts(Opts);
check_cmd_opts([]) ->
    ok;
check_cmd_opts(Opts) ->
    check_send_opts(Opts).

cmdf(Connection,CmdFormat,Args) ->
    cmdf(Connection,CmdFormat,Args,[]).

cmdf(Connection,CmdFormat,Args,Opts) when is_list(Args) ->
    Cmd = lists:flatten(io_lib:format(CmdFormat,Args)),
    cmd(Connection,Cmd,Opts).

get_data(Connection) ->
    case get_handle(Connection) of
	{ok,Pid} ->
	    call(Pid,get_data);
	Error ->
	    Error
    end.

send(Connection,Cmd) ->
    send(Connection,Cmd,[]).

send(Connection,Cmd,Opts) ->
    case check_send_opts(Opts) of
	ok ->
	    case get_handle(Connection) of
		{ok,Pid} ->
		    call(Pid,{send,Cmd,Opts});
		Error ->
		    Error
	    end;
	Error ->
	    Error
    end.

check_send_opts([{newline,Bool}|Opts]) when is_boolean(Bool) ->
    check_send_opts(Opts);
check_send_opts([{newline,String}|Opts]) when is_list(String) ->
    case lists:all(fun(I) when is_integer(I), I>=0, I=<127 -> true;
                      (_) -> false
                   end, String) of
        true ->
            check_send_opts(Opts);
        false ->
            {error,{invalid_option,{newline,String}}}
    end;
check_send_opts([Invalid|_]) ->
    {error,{invalid_option,Invalid}};
check_send_opts([]) ->
    ok.

sendf(Connection,CmdFormat,Args) when is_list(Args) ->
    sendf(Connection,CmdFormat,Args,[]).

sendf(Connection,CmdFormat,Args,Opts) when is_list(Args) ->
    Cmd = lists:flatten(io_lib:format(CmdFormat,Args)),
    send(Connection,Cmd,Opts).

expect(Connection,Patterns) ->
    expect(Connection,Patterns,[]).

expect(Connection,Patterns,Opts) ->
    case get_handle(Connection) of
        {ok,Pid} ->
            case call(Pid,{expect,Patterns,Opts}) of
                {error,Reason} when element(1,Reason)==bad_pattern ->
                    %% Faulty user input - should fail the test case
                    exit({Reason,{?MODULE,?FUNCTION_NAME,3}});
                Other ->
                    Other
            end;
        Error ->
            Error
    end.

%%%=================================================================
%%% Callback functions

init(Name,{Ip,Port,Type},{TargetMod,KeepAlive,Extra}) ->
    S0 = case ct:get_config(telnet_settings) of
	     undefined ->
		 #state{};
	     Settings ->
		 set_telnet_defaults(Settings,#state{})				    
	 end,
    %% Handle old user versions of TargetMod
    _ = code:ensure_loaded(TargetMod),
    try
	case erlang:function_exported(TargetMod,connect,7) of
	    true ->
		TargetMod:connect(Name,Ip,Port,S0#state.conn_to,
				  KeepAlive,S0#state.tcp_nodelay,Extra);
	    false ->
		TargetMod:connect(Name,Ip,Port,S0#state.conn_to,
				  KeepAlive,Extra)
	end
    of
	{ok,TelnPid} ->
	    put({ct_telnet_pid2name,TelnPid},Name),
	    S1 = S0#state{host=Ip,
			  port=Port,
			  teln_pid=TelnPid,
			  name=Name,
			  type=type(Type),
			  target_mod=TargetMod,
			  keep_alive=KeepAlive,
			  extra=Extra,
			  prx=TargetMod:get_prompt_regexp()},
	    log(S1,open,
		"Opened telnet connection\n"
		"IP: ~p\n"
		"Port: ~p\n"
		"Command timeout: ~p\n"
		"Reconnection attempts: ~p\n"
		"Reconnection interval: ~p\n"
		"Connection timeout: ~p\n"
		"Keep alive: ~w\n"
		"Poll limit: ~w\n"
		"Poll interval: ~w\n"
		"TCP nodelay: ~w",
		[Ip,Port,S1#state.com_to,S1#state.reconns,
		 S1#state.reconn_int,S1#state.conn_to,KeepAlive,
		 S1#state.poll_limit,S1#state.poll_interval,
		 S1#state.tcp_nodelay]),
	    {ok,TelnPid,S1};
	Error ->
	    Error
    catch
	_:Reason ->
	    {error,Reason}
    end.

type(telnet) -> ip;
type(TS) when TS==ts1;TS==ts2 -> ts.

set_telnet_defaults([{connect_timeout,CnTo}|Ss],S) ->
    set_telnet_defaults(Ss,S#state{conn_to=CnTo});
set_telnet_defaults([{command_timeout,CmTo}|Ss],S) ->
    set_telnet_defaults(Ss,S#state{com_to=CmTo});
set_telnet_defaults([{reconnection_attempts,Rs}|Ss],S) ->
    set_telnet_defaults(Ss,S#state{reconns=Rs});
set_telnet_defaults([{reconnection_interval,RInt}|Ss],S) ->
    set_telnet_defaults(Ss,S#state{reconn_int=RInt});
set_telnet_defaults([{keep_alive,_}|Ss],S) ->
    set_telnet_defaults(Ss,S);
set_telnet_defaults([{poll_limit,PL}|Ss],S) ->
    set_telnet_defaults(Ss,S#state{poll_limit=PL});
set_telnet_defaults([{poll_interval,PI}|Ss],S) ->
    set_telnet_defaults(Ss,S#state{poll_interval=PI});
set_telnet_defaults([{tcp_nodelay,NoDelay}|Ss],S) ->
    set_telnet_defaults(Ss,S#state{tcp_nodelay=NoDelay});
set_telnet_defaults([Unknown|Ss],S) ->
    force_log(S,error,
	      "Bad element in telnet_settings: ~tp",[Unknown]),
    set_telnet_defaults(Ss,S);
set_telnet_defaults([],S) ->
    S.

handle_msg({cmd,Cmd,Opts},State) ->
    start_gen_log(heading(cmd,State#state.name)),
    log(State,cmd,"Cmd: ~tp",[Cmd]),

    %% whatever is in the buffer from previous operations
    %% will be ignored as we go ahead with this telnet cmd

    debug_cont_gen_log("Throwing Buffer:",[]),
    debug_log_lines(State#state.buffer),

    _ = case {State#state.type,State#state.prompt} of
	{ts,_} ->
	    silent_teln_expect(State#state.name,
			       State#state.teln_pid,
			       State#state.buffer,
			       prompt,
			       State#state.prx,
			       [{idle_timeout,2000}]);
	{ip,false} ->
	    silent_teln_expect(State#state.name,
			       State#state.teln_pid,
			       State#state.buffer,
			       prompt,
			       State#state.prx,
			       [{idle_timeout,200}]);
	{ip,true} ->
	    ok
    end,
    TO = case proplists:get_value(timeout,Opts,default) of
	     default -> State#state.com_to;
	     Timeout -> Timeout
	 end,
    Newline = proplists:get_value(newline,Opts,true),
    {Return,NewBuffer,Prompt} = 
	case teln_cmd(State#state.teln_pid, Cmd, State#state.prx,
		      Newline, TO) of
	    {ok,Data,_PromptType,Rest} ->
		log(State,recv,"Return: ~tp",[{ok,Data}]),
		{{ok,Data},Rest,true};
	    Error ->
		Retry = {retry,{Error,
				{State#state.name,
				 State#state.type},
				State#state.teln_pid,
				{cmd,Cmd,Opts}}},
		log(State,recv,"Return: ~tp",[Error]),
		{Retry,[],false}
	end,
    end_gen_log(),
    {Return,State#state{buffer=NewBuffer,prompt=Prompt}};
handle_msg({send,Cmd,Opts},State) ->
    start_gen_log(heading(send,State#state.name)),
    log(State,send,"Sending: ~tp",[Cmd]),
    
    debug_cont_gen_log("Throwing Buffer:",[]),
    debug_log_lines(State#state.buffer),
    
    _ = case {State#state.type,State#state.prompt} of
	{ts,_} -> 
	    silent_teln_expect(State#state.name,
			       State#state.teln_pid,
			       State#state.buffer,
			       prompt,
			       State#state.prx,
			       [{idle_timeout,2000}]);
	{ip,false} -> 
	    silent_teln_expect(State#state.name,
			       State#state.teln_pid,
			       State#state.buffer,
			       prompt,
			       State#state.prx,
			       [{idle_timeout,200}]);
	{ip,true} ->
	    ok
    end,
    Newline = proplists:get_value(newline,Opts,true),
    ct_telnet_client:send_data(State#state.teln_pid,Cmd,Newline),
    end_gen_log(),
    {ok,State#state{buffer=[],prompt=false}};
handle_msg(get_data,State) ->
    start_gen_log(heading(get_data,State#state.name)),
    log(State,cmd,"Reading data...",[]),
    {ok,Data,Buffer} = teln_get_all_data(State,State#state.buffer,[],[],
					 State#state.poll_limit),
    log(State,recv,"Return: ~tp",[{ok,Data}]),
    end_gen_log(),
    {{ok,Data},State#state{buffer=Buffer}};
handle_msg({expect,Pattern,Opts},State) ->
    start_gen_log(heading(expect,State#state.name)),
    log(State,expect,"Expect: ~tp\nOpts = ~tp\n",[Pattern,Opts]),
    {Return,NewBuffer,Prompt} = 
	case teln_expect(State#state.name,
			 State#state.teln_pid,
			 State#state.buffer,
			 Pattern,
			 State#state.prx,
			 Opts) of
	    {ok,Data,Rest} ->
		P = check_if_prompt_was_reached(Data,[]),
		{{ok,Data},Rest,P};
	    {ok,Data,HaltReason,Rest} ->
		force_log(State,expect,"HaltReason: ~tp",[HaltReason]),
		P = check_if_prompt_was_reached(Data,HaltReason),
		{{ok,Data,HaltReason},Rest,P};
	    {error,Reason,Rest} ->
		force_log(State,expect,"Expect failed\n~tp",[{error,Reason}]),
		P = check_if_prompt_was_reached([],Reason),
		{{error,Reason},Rest,P};
	    {error,Reason} ->
		force_log(State,expect,"Expect failed\n~tp",[{error,Reason}]),
		P = check_if_prompt_was_reached([],Reason),
		{{error,Reason},[],P}
	end,
    end_gen_log(),
    Return1 = case Return of
		  {error,_} -> {retry,{Return,
				       {State#state.name,
					State#state.type},
				       State#state.teln_pid,
				       {expect,Pattern,Opts}}};
		  _ -> Return
	      end,	    
    {Return1,State#state{buffer=NewBuffer,prompt=Prompt}}.


reconnect({Ip,Port,_Type},State) ->
    reconnect(Ip,Port,State#state.reconns,State).
reconnect(Ip,Port,N,State=#state{name=Name,
				 target_mod=TargetMod,
				 keep_alive=KeepAlive,
				 extra=Extra,
				 conn_to=ConnTo,
				 reconn_int=ReconnInt,
				 tcp_nodelay=NoDelay}) ->
    %% Handle old user versions of TargetMod
    ConnResult =
	case erlang:function_exported(TargetMod,connect,7) of
	    true ->
		TargetMod:connect(Name,Ip,Port,ConnTo,KeepAlive,NoDelay,Extra);
	    false ->
		TargetMod:connect(Name,Ip,Port,ConnTo,KeepAlive,Extra)
	end,
    case ConnResult of
	{ok,NewPid} ->
	    put({ct_telnet_pid2name,NewPid},Name),
	    {ok, NewPid, State#state{teln_pid=NewPid}};
	Error when N==0 ->
	    Error;
	_Error ->
	    log(State,reconnect,"Reconnect failed!","Retries left: ~w",[N]),
	    timer:sleep(ReconnInt),
	    reconnect(Ip,Port,N-1,State)
    end.


terminate(TelnPid,State) ->
    Result = ct_telnet_client:close(TelnPid),
    log(State,close,"Telnet connection for ~w closed.",[TelnPid]),
    Result.

%%%=================================================================
%%% Internal function
get_handle(Pid) when is_pid(Pid) ->
    {ok,Pid};
get_handle({Name,Type}) when Type==telnet;Type==ts1;Type==ts2 ->
    case ct_util:get_connection(Name,?MODULE) of
	{ok,Conn} ->
	    case get_handle(Type,Conn) of
		{ok,Pid} -> 
		    {ok,Pid};
		_Error ->
		    case ct_util:get_key_from_name(Name) of
			{ok,node} ->
			    open(Name,Type,ct_telnet_cello_node);
			{ok,unix} -> % unix host
			    open(Name,Type,unix_telnet,Name);
			{ok,Key} -> % any other, e.g. interwatch (iw)
			    open(Name,Type,Key,Name);
			Error ->
			    Error
		    end
	    end;
	Error ->
	    Error
    end;
get_handle(Name) ->
    get_handle({Name,telnet}).

get_handle(Type,{Pid,{_,_,Type}}) ->
    {ok,Pid};
get_handle(Type,_) ->
    {error,{no_such_connection,Type}}.

full_addr({Ip,Port},Type) ->
    {Ip,Port,Type};
full_addr(Ip,Type) ->
    {Ip,?DEFAULT_PORT,Type}.

call(Pid,Msg) ->
    ct_gen_conn:call(Pid,Msg).

check_if_prompt_was_reached({prompt,_},_) ->
    true;
check_if_prompt_was_reached(_,{prompt,_}) ->
    true;
check_if_prompt_was_reached(Data,_) when is_list(Data) ->
    lists:keymember(prompt,1,Data);
check_if_prompt_was_reached(_,_) ->
    false.

%%%-----------------------------------------------------------------
%%% Functions for logging ct_telnet reports and telnet data 

heading(Action,undefined) ->
    io_lib:format("~w ~w",[?MODULE,Action]);
heading(Action,Name) ->
    io_lib:format("~w ~w for ~tp",[?MODULE,Action,Name]).

force_log(State,Action,String,Args) ->
    log(State,Action,String,Args,true).

%%%-----------------------------------------------------------------
log(State,Action,String,Args) when is_record(State, state) ->
    log(State,Action,String,Args,false);
log(Name,Action,String,Args) when is_atom(Name) ->
    log(#state{name=Name},Action,String,Args,false);
log(TelnPid,Action,String,Args) when is_pid(TelnPid) ->
    log(#state{teln_pid=TelnPid},Action,String,Args,false).

%%%-----------------------------------------------------------------
log(undefined,String,Args) ->
    log(#state{},undefined,String,Args,false);
log(Name,String,Args) when is_atom(Name) ->
    log(#state{name=Name},undefined,String,Args,false);
log(TelnPid,String,Args) when is_pid(TelnPid) ->
    log(#state{teln_pid=TelnPid},undefined,String,Args).

%%%-----------------------------------------------------------------
log(#state{name=Name,teln_pid=TelnPid,host=Host,port=Port},
    Action,String,Args,ForcePrint) ->
    Name1 = if Name == undefined -> get({ct_telnet_pid2name,TelnPid});
	       true              -> Name
	    end,
    Silent = get(silent),

    if Action == general_io ->
	    case ct_util:get_testdata({cth_conn_log,?MODULE}) of
		HookMode when HookMode /= undefined, HookMode /= silent,
			      Silent /= true ->
		    error_logger:info_report(#conn_log{header=false,
						       client=self(),
						       conn_pid=TelnPid,
						       address={Host,Port},
						       name=Name1,
						       action=Action,
						       module=?MODULE},
					     {String,Args});
		_ -> %% hook inactive or silence requested
		    ok
	    end;

       true ->	    
	    if Action == open; Action == close; Action == reconnect;
	       Action == info; Action == error ->
		    ct_gen_conn:log(heading(Action,Name1),String,Args);

	       ForcePrint == false ->
		    case ct_util:is_silenced(telnet) of
			true  ->
			    ok;
			false ->
			    ct_gen_conn:cont_log_no_timestamp(String,Args)
		    end;
	       
	       ForcePrint == true ->
		    case ct_util:is_silenced(telnet) of
			true ->
			    %% call log/3 now instead of cont_log/2 since 
			    %% start_gen_log/1 will not have been previously
			    %% called
			    ct_gen_conn:log(heading(Action,Name1),String,Args);
			false ->
			    ct_gen_conn:cont_log_no_timestamp(String,Args)
		    end
	    end
    end.

%%%-----------------------------------------------------------------
start_gen_log(Heading) ->
    %% check if output is suppressed
    case ct_util:is_silenced(telnet) of
	true  -> ok;
	false -> ct_gen_conn:start_log(Heading)
    end.

%%%-----------------------------------------------------------------
end_gen_log() -> 
    %% check if output is suppressed
    case ct_util:is_silenced(telnet) of
	true  -> ok;
	false -> ct_gen_conn:end_log()
    end.

%% Debug printouts.
debug_cont_gen_log(Str,Args) ->
    Old = put(silent,true),
    ct_gen_conn:cont_log(Str,Args),
    put(silent,Old).

%% Log callback - called from the error handler process
format_data(_How,{String,Args}) ->
    io_lib:format(String,Args).

%%%=================================================================
%%% Abstraction layer on top of ct_telnet_client.erl
teln_cmd(Pid,Cmd,Prx,Newline,Timeout) ->
    ct_telnet_client:send_data(Pid,Cmd,Newline),
    teln_receive_until_prompt(Pid,Prx,Timeout).

teln_get_all_data(State=#state{teln_pid=Pid,prx=Prx},Data,Acc,LastLine,Polls) ->
    case check_for_prompt(Prx,LastLine++Data) of
	{prompt,Lines,_PromptType,Rest} ->
	    teln_get_all_data(State,Rest,[Lines|Acc],[],State#state.poll_limit);
	{noprompt,Lines,LastLine1} ->
	    case ct_telnet_client:get_data(Pid) of
		{ok,[]} when LastLine1 /= [], Polls > 0 ->
		    %% No more data from server but the last string is not
		    %% a complete line (maybe because of a slow connection),
		    timer:sleep(State#state.poll_interval),
		    NewPolls = if Polls == infinity -> infinity;
				  true              -> Polls-1
			       end,
		    teln_get_all_data(State,[],[Lines|Acc],LastLine1,NewPolls);
		{ok,[]} ->
		    {ok,lists:reverse(lists:append([Lines|Acc])),LastLine1};
		{ok,Data1} ->
		    teln_get_all_data(State,Data1,[Lines|Acc],LastLine1,
				      State#state.poll_limit)
	    end
    end.
    
%% Expect options record
-record(eo,{teln_pid,
	    prx,
	    idle_timeout,
	    total_timeout,
	    haltpatterns=[],
	    seq=false,
	    repeat=false,
	    found_prompt=false,
	    prompt_check=true}).

%% Externally the silent_teln_expect function shall only be used
%% by the TargetModule, i.e. the target specific module which
%% implements connect/2 and get_prompt_regexp/0.
silent_teln_expect(Name,Pid,Data,Pattern,Prx,Opts) ->
    Old = put(silent,true),
    Result = teln_expect(Name,Pid,Data,Pattern,Prx,Opts),
    put(silent,Old),
    Result.

%% teln_expect/6
%%
%% This function implements the expect functionality over telnet. In
%% general there are three possible ways to go:
%% 1) Single: One or more patterns are given, and the function return
%% when one of the patterns are matched.
%% 2) Sequence: Several patterns are given, and they are matched in
%% the order they appear in the pattern list.
%% 3a) Repeat (single): 1) is repeated either N times or until a halt
%% condition is fulfilled.
%% 3b) Repeat (sequence): 2) is repeated either N times or until a
%% halt condition is fulfilled.
teln_expect(Name,Pid,Data,Pattern0,Prx,Opts) ->
    HaltPatterns0 =
	case get_ignore_prompt(Opts) of
	    true ->
		get_haltpatterns(Opts);
	    false ->
		[prompt | get_haltpatterns(Opts)]
	end,
    case convert_pattern(HaltPatterns0,false) of
        {ok,HaltPatterns} ->
            {WaitForPrompt,Pattern1,Opts1} = wait_for_prompt(Pattern0,Opts),
            Seq = get_seq(Opts1),
            case convert_pattern(Pattern1,Seq) of
                {ok,Pattern2} ->
                    {IdleTimeout,TotalTimeout} = get_timeouts(Opts1),
                    PromptCheck = get_prompt_check(Opts1),

                    EO = #eo{teln_pid=Pid,
                             prx=Prx,
                             idle_timeout=IdleTimeout,
                             total_timeout=TotalTimeout,
                             seq=Seq,
                             haltpatterns=HaltPatterns,
                             prompt_check=PromptCheck},
    
                    case get_repeat(Opts1) of
                        false ->
                            case teln_expect1(Name,Pid,Data,Pattern2,[],EO) of
                                {ok,Matched,Rest} when WaitForPrompt ->
                                    case lists:reverse(Matched) of
                                        [{prompt,_},Matched1] ->
                                            {ok,Matched1,Rest};
                                        [{prompt,_}|Matched1] ->
                                            {ok,lists:reverse(Matched1),Rest}
                                    end;
                                {ok,Matched,Rest} ->
                                    {ok,Matched,Rest};
                                {halt,Why,Rest} ->
                                    {error,Why,Rest};
                                {error,Reason} ->
                                    {error,Reason}
                            end;
                        N ->
                            EO1 = EO#eo{repeat=N},
                            repeat_expect(Name,Pid,Data,Pattern2,[],EO1)
                    end;
               Error ->
                    Error
            end;
        Error ->
            Error
    end.

convert_pattern(Pattern0,Seq)
  when Pattern0==[] orelse (is_list(Pattern0) and not is_integer(hd(Pattern0))) ->
    Pattern =
        case Seq of
            true -> Pattern0;
            false -> rm_dupl(Pattern0,[])
        end,
    compile_pattern(Pattern,[]);
convert_pattern(Pattern,_Seq) ->
    compile_pattern([Pattern],[]).

rm_dupl([P|Ps],Acc) ->
    case lists:member(P,Acc) of
	true ->
	    rm_dupl(Ps,Acc);
	false ->
	    rm_dupl(Ps,[P|Acc])
    end;
rm_dupl([],Acc) ->
    lists:reverse(Acc).

compile_pattern([prompt|Patterns],Acc) ->
    compile_pattern(Patterns,[prompt|Acc]);
compile_pattern([{prompt,_}=P|Patterns],Acc) ->
    compile_pattern(Patterns,[P|Acc]);
compile_pattern([{Tag,Pattern}|Patterns],Acc) ->
    try re:compile(Pattern,[unicode]) of
        {ok,MP} -> compile_pattern(Patterns,[{Tag,MP}|Acc]);
        {error,Error} -> {error,{bad_pattern,{Tag,Pattern},Error}}
    catch error:badarg -> {error,{bad_pattern,{Tag,Pattern}}}
    end;
compile_pattern([Pattern|Patterns],Acc) ->
    try re:compile(Pattern,[unicode]) of
        {ok,MP} -> compile_pattern(Patterns,[MP|Acc]);
        {error,Error} -> {error,{bad_pattern,Pattern,Error}}
    catch error:badarg -> {error,{bad_pattern,Pattern}}
    end;
compile_pattern([],Acc) ->
    {ok,lists:reverse(Acc)}.

get_timeouts(Opts) ->
    {case lists:keysearch(idle_timeout,1,Opts) of
	 {value,{_,T}} ->
	     T;
	 false ->
	     %% this check is for backwards compatibility (pre CT v1.8)
	     case lists:keysearch(timeout,1,Opts) of
		 {value,{_,T}} -> T;
		 false -> ?DEFAULT_TIMEOUT
	     end
     end,
     case lists:keysearch(total_timeout,1,Opts) of
	 {value,{_,T}} -> T;
	 false -> infinity
     end}.

get_repeat(Opts) ->
    case lists:keysearch(repeat,1,Opts) of
	{value,{repeat,N}} when is_integer(N) ->
	    N;
	false ->
	    case lists:member(repeat,Opts) of
		true ->
		    -1;
		false ->
		    false
	    end
    end.
get_seq(Opts) ->
    lists:member(sequence,Opts).
get_haltpatterns(Opts) ->
    case lists:keysearch(halt,1,Opts) of
	{value,{halt,HaltPatterns}} ->
	    HaltPatterns;
	false ->
	    []
    end.
get_ignore_prompt(Opts) ->    
    lists:member(ignore_prompt,Opts).
get_prompt_check(Opts) ->
    not lists:member(no_prompt_check,Opts).

wait_for_prompt(Pattern, Opts) ->
    case lists:member(wait_for_prompt, Opts) of
	true ->
	    wait_for_prompt1(prompt, Pattern,
			     lists:delete(wait_for_prompt,Opts));
	false ->
	    case proplists:get_value(wait_for_prompt, Opts) of
		undefined ->
		    {false,Pattern,Opts};
		PromptStr ->
		    wait_for_prompt1({prompt,PromptStr}, Pattern,
				     proplists:delete(wait_for_prompt,Opts))
	    end
    end.

wait_for_prompt1(Prompt, [Ch|_] = Pattern, Opts) when is_integer(Ch) ->
    wait_for_prompt2(Prompt, [Pattern], Opts);
wait_for_prompt1(Prompt, Pattern, Opts) when is_list(Pattern) ->
    wait_for_prompt2(Prompt, Pattern, Opts);
wait_for_prompt1(Prompt, Pattern, Opts) ->
    wait_for_prompt2(Prompt, [Pattern], Opts).

wait_for_prompt2(Prompt, Pattern, Opts) ->
    Pattern1 = case lists:reverse(Pattern) of
		   [prompt|_]     -> Pattern;
		   [{prompt,_}|_] -> Pattern;
		   _              -> Pattern ++ [Prompt]
	       end,
    Opts1 = case lists:member(sequence, Opts) of
		true ->  Opts;
		false -> [sequence|Opts]
	    end,
    {true,Pattern1,Opts1}.

%% Repeat either single or sequence. All match results are accumulated
%% and returned when a halt condition is fulfilled.
repeat_expect(_Name,_Pid,Rest,_Pattern,Acc,#eo{repeat=0}) ->
    {ok,lists:reverse(Acc),done,Rest};
repeat_expect(Name,Pid,Data,Pattern,Acc,EO) ->
    case teln_expect1(Name,Pid,Data,Pattern,[],EO) of
	{ok,Matched,Rest} ->
	    EO1 = EO#eo{repeat=EO#eo.repeat-1},
	    repeat_expect(Name,Pid,Rest,Pattern,[Matched|Acc],EO1);
	{halt,Why,Rest} ->
	    {ok,lists:reverse(Acc),Why,Rest};
	{error,Reason} ->
	    {error,Reason}
    end.

teln_expect1(Name,Pid,Data,Pattern,Acc,EO=#eo{idle_timeout=IdleTO,
					      total_timeout=TotalTO}) ->
    %% TotalTO is a float value in this loop (unless it's 'infinity'),
    %% but an integer value will be passed to the other functions
    EOMod = if TotalTO /= infinity -> EO#eo{total_timeout=trunc(TotalTO)};
	       true                -> EO
	    end,
    ExpectFun = case EOMod#eo.seq of
		    true -> fun() ->
				    seq_expect(Name,Pid,Data,Pattern,Acc,EOMod)
			    end;
		    false -> fun() ->
				     one_expect(Name,Pid,Data,Pattern,EOMod)
			     end
		end,
    case ExpectFun() of
	{match,Match,Rest} ->
	    {ok,Match,Rest};
	{halt,Why,Rest} ->
	    {halt,Why,Rest};
	NotFinished ->
	    %% Get more data
	    Fun = fun() -> get_data1(EOMod#eo.teln_pid) end,
	    BreakAfter = if TotalTO < IdleTO ->
				 %% use the integer value
				 EOMod#eo.total_timeout;
			    true ->
				 IdleTO
			 end,
	    {PatOrPats1,Acc1,Rest1} = case NotFinished of
					 {nomatch,Rest0} ->
					     %% one expect
					     {Pattern,[],Rest0};
					 {continue,Pats0,Acc0,Rest0} ->
					     %% sequence
					     {Pats0,Acc0,Rest0}
				     end,
	    case timer:tc(ct_gen_conn, do_within_time, [Fun,BreakAfter]) of
		{_,{error,Reason}} ->
		    %% A timeout will occur when the telnet connection
		    %% is idle for EO#eo.idle_timeout milliseconds.
		    if Rest1 /= [] ->
			    log(name_or_pid(Name,Pid),"       ~ts",[Rest1]);
		       true ->
			    ok
		    end,
		    {error,Reason};
		{_,{ok,Data1}} when TotalTO == infinity ->
		    teln_expect1(Name,Pid,Rest1++Data1,PatOrPats1,Acc1,EOMod);
		{Elapsed,{ok,Data1}} ->
		    TVal = TotalTO - (Elapsed/1000),
		    if TVal =< 0 ->
			    {error,timeout};
		       true ->
			    EO1 = EO#eo{total_timeout = TVal},
			    teln_expect1(Name,Pid,Rest1++Data1,
					 PatOrPats1,Acc1,EO1)
		    end
	    end
    end.

get_data1(Pid) ->
    case ct_telnet_client:get_data(Pid) of
	{ok,[]} ->
	    get_data1(Pid);
	{ok,Data} ->
	    {ok,Data}
    end.

%% 1) Single expect.
%% First the whole data chunk is searched for a prompt (to avoid doing
%% a regexp match for the prompt at each line).
%% If we are searching for anything else, the datachunk is split into
%% lines and each line is matched against each pattern.

%% one_expect: split data chunk at prompts
one_expect(Name,Pid,Data,Pattern,EO) when EO#eo.prompt_check==false ->
%    io:format("Raw Data ~tp Pattern ~tp EO ~tp ",[Data,Pattern,EO]),
    one_expect1(Name,Pid,Data,Pattern,[],EO#eo{found_prompt=false});
one_expect(Name,Pid,Data,Pattern,EO) ->
    case match_prompt(Data,EO#eo.prx) of
	{prompt,UptoPrompt,PromptType,Rest} ->
	    case Pattern of 
		[Prompt] when Prompt==prompt; Prompt=={prompt,PromptType} ->
		    %% Only searching for prompt
		    log_lines(Name,Pid,UptoPrompt),
		    log(name_or_pid(Name,Pid),"PROMPT: ~ts",[PromptType]),
		    {match,{prompt,PromptType},Rest};
		[{prompt,_OtherPromptType}] ->
		    %% Only searching for one specific prompt, not this one
		    log_lines(Name,Pid,UptoPrompt),
		    {nomatch,Rest};
		_ ->
		    one_expect1(Name,Pid,UptoPrompt,Pattern,Rest,
				EO#eo{found_prompt=PromptType})
	    end;
	noprompt ->
	    case Pattern of
		[Prompt] when Prompt==prompt; element(1,Prompt)==prompt ->
		    %% Only searching for prompt
		    LastLine = log_lines_not_last(Name,Pid,Data),
		    {nomatch,LastLine};
		_ ->
		    one_expect1(Name,Pid,Data,Pattern,[],
				EO#eo{found_prompt=false})
	    end
    end.

%% one_expect1: split data chunk at lines
one_expect1(Name,Pid,Data,Pattern,Rest,EO) ->
    case match_lines(Name,Pid,Data,Pattern,EO) of
	{match,Match,MatchRest} ->
	    {match,Match,MatchRest++Rest};
	{nomatch,prompt} ->
	    one_expect(Name,Pid,Rest,Pattern,EO);
	{nomatch,NoMatchRest} ->
	    {nomatch,NoMatchRest++Rest};
	{halt,Why,HaltRest} ->
	    {halt,Why,HaltRest++Rest}
    end.
    

%% 2) Sequence.
%% First the whole data chunk is searched for a prompt (to avoid doing
%% a regexp match for the prompt at each line).
%% If we are searching for anything else, the datachunk is split into
%% lines and each line is matched against the first pattern in the list.
%% When a match is found, the match result is accumulated, and we keep
%% searching for the next pattern in the list.

%% seq_expect: Split data chunk at prompts
seq_expect(_Name,_Pid,Data,[],Acc,_EO) ->
    {match,lists:reverse(Acc),Data};
seq_expect(_Name,_Pid,[],Patterns,Acc,_EO) ->
    {continue,Patterns,lists:reverse(Acc),[]};
seq_expect(Name,Pid,Data,Patterns,Acc,EO) when EO#eo.prompt_check==false ->
    seq_expect1(Name,Pid,Data,Patterns,Acc,[],EO#eo{found_prompt=false});
seq_expect(Name,Pid,Data,Patterns,Acc,EO) ->
    case match_prompt(Data,EO#eo.prx) of
	{prompt,UptoPrompt,PromptType,Rest} ->
	    seq_expect1(Name,Pid,UptoPrompt,Patterns,Acc,Rest,
			EO#eo{found_prompt=PromptType});
	noprompt ->
	    seq_expect1(Name,Pid,Data,Patterns,Acc,[],EO#eo{found_prompt=false})
    end.

%% seq_expect1: For one prompt-chunk, match each pattern - line by
%% line if it is other than the prompt we are seaching for.
seq_expect1(Name,Pid,Data,[prompt|Patterns],Acc,Rest,EO) ->
    case EO#eo.found_prompt of
	false ->
	    LastLine = log_lines_not_last(Name,Pid,Data),
	    %% Rest==[] because no prompt is found
	    {continue,[prompt|Patterns],Acc,LastLine};
	PromptType ->
	    log_lines(Name,Pid,Data),
	    log(name_or_pid(Name,Pid),"PROMPT: ~ts",[PromptType]),
	    seq_expect(Name,Pid,Rest,Patterns,[{prompt,PromptType}|Acc],EO)
    end;
seq_expect1(Name,Pid,Data,[{prompt,PromptType}|Patterns],Acc,Rest,EO) ->
    case EO#eo.found_prompt of
	false ->
	    LastLine = log_lines_not_last(Name,Pid,Data),
	    %% Rest==[] because no prompt is found
	    {continue,[{prompt,PromptType}|Patterns],Acc,LastLine};
	PromptType ->
	    log_lines(Name,Pid,Data),
	    log(name_or_pid(Name,Pid),"PROMPT: ~ts", [PromptType]),
	    seq_expect(Name,Pid,Rest,Patterns,[{prompt,PromptType}|Acc],EO);
	_OtherPromptType ->
	    log_lines(Name,Pid,Data),
	    seq_expect(Name,Pid,Rest,[{prompt,PromptType}|Patterns],Acc,EO)
    end;
seq_expect1(Name,Pid,Data,[Pattern|Patterns],Acc,Rest,EO) ->
    case match_lines(Name,Pid,Data,[Pattern],EO) of
	{match,Match,MatchRest} ->
	    seq_expect1(Name,Pid,MatchRest,Patterns,[Match|Acc],Rest,EO);
	{nomatch,prompt} ->
	    seq_expect(Name,Pid,Rest,[Pattern|Patterns],Acc,EO);
	{nomatch,NoMatchRest} when Rest==[] ->
	    %% The data did not end with a prompt
	    {continue,[Pattern|Patterns],Acc,NoMatchRest};
	{halt,Why,HaltRest} ->
	    {halt,Why,HaltRest++Rest}
    end;
seq_expect1(_Name,_Pid,Data,[],Acc,Rest,_EO) ->
    {match,lists:reverse(Acc),Data++Rest}.

%% Split prompt-chunk at lines
match_lines(Name,Pid,Data,Patterns,EO) ->
    FoundPrompt = EO#eo.found_prompt,
    case one_line(Data,[]) of
	{noline,Rest} when FoundPrompt=/=false ->
	    %% This is the line including the prompt
	    case match_line(Name,Pid,Rest,Patterns,FoundPrompt,false,EO) of
		nomatch ->
		    {nomatch,prompt};
		{Tag,Match} ->
		    {Tag,Match,[]}
	    end;
	{noline,Rest} when EO#eo.prompt_check==false ->
	    case match_line(Name,Pid,Rest,Patterns,false,false,EO) of
		nomatch ->
		    {nomatch,Rest};
		{Tag,Match} ->
		    {Tag,Match,[]}
	    end;
	{noline,Rest} ->
	    {nomatch,Rest};
	{Line,Rest} ->
	    case match_line(Name,Pid,Line,Patterns,false,true,EO) of
		nomatch ->
		    match_lines(Name,Pid,Rest,Patterns,EO);
		{Tag,Match} ->
		    {Tag,Match,Rest}
	    end
    end.
    
%% For one line, match each pattern
match_line(Name,Pid,Line,Patterns,FoundPrompt,Terminated,EO) ->
    match_line(Name,Pid,Line,Patterns,FoundPrompt,Terminated,EO,match).

match_line(Name,Pid,Line,[prompt|Patterns],false,Term,EO,RetTag) ->
    match_line(Name,Pid,Line,Patterns,false,Term,EO,RetTag);
match_line(Name,Pid,Line,[prompt|_Patterns],FoundPrompt,_Term,_EO,RetTag) ->
    log(name_or_pid(Name,Pid),"       ~ts",[Line]),
    log(name_or_pid(Name,Pid),"PROMPT: ~ts",[FoundPrompt]),
    {RetTag,{prompt,FoundPrompt}};
match_line(Name,Pid,Line,[{prompt,PromptType}|_Patterns],FoundPrompt,_Term,
	   _EO,RetTag) when PromptType==FoundPrompt ->
    log(name_or_pid(Name,Pid),"       ~ts",[Line]),
    log(name_or_pid(Name,Pid),"PROMPT: ~ts",[FoundPrompt]),
    {RetTag,{prompt,FoundPrompt}};
match_line(Name,Pid,Line,[{prompt,PromptType}|Patterns],FoundPrompt,Term,
	   EO,RetTag) 
  when PromptType=/=FoundPrompt ->
    match_line(Name,Pid,Line,Patterns,FoundPrompt,Term,EO,RetTag);
match_line(Name,Pid,Line,[{Tag,Pattern}|Patterns],FoundPrompt,Term,EO,RetTag) ->
    case re:run(Line,Pattern,[{capture,all,list}]) of
	nomatch ->
	    match_line(Name,Pid,Line,Patterns,FoundPrompt,Term,EO,RetTag);
	{match,Match} ->
	    log(name_or_pid(Name,Pid),"MATCH: ~ts",[Line]),
	    {RetTag,{Tag,Match}}
    end;
match_line(Name,Pid,Line,[Pattern|Patterns],FoundPrompt,Term,EO,RetTag) ->
    case re:run(Line,Pattern,[{capture,all,list}]) of
	nomatch ->
	    match_line(Name,Pid,Line,Patterns,FoundPrompt,Term,EO,RetTag);
	{match,Match} ->
	    log(name_or_pid(Name,Pid),"MATCH: ~ts",[Line]),
	    {RetTag,Match}
    end;
match_line(Name,Pid,Line,[],FoundPrompt,Term,EO,match) ->
    match_line(Name,Pid,Line,EO#eo.haltpatterns,FoundPrompt,Term,EO,halt);
%% print any terminated line that cannot be matched
match_line(Name,Pid,Line,[],_FoundPrompt,true,_EO,halt) ->
    log(name_or_pid(Name,Pid),"       ~ts",[Line]),
    nomatch;
%% if there's no line termination, Line is saved as Rest (above) and will
%% be printed later
match_line(_Name,_Pid,_Line,[],_FoundPrompt,false,_EO,halt) ->
    nomatch.

one_line([$\n|Rest],Line) ->
    {lists:reverse(Line),Rest};
one_line([$\r|Rest],Line) ->
    one_line(Rest,Line);
one_line([0|Rest],Line) ->
    one_line(Rest,Line);
one_line([Char|Rest],Line) ->
    one_line(Rest,[Char|Line]);
one_line([],Line) ->
    {noline,lists:reverse(Line)}.

debug_log_lines(String) ->
    Old = put(silent,true),
    log_lines(undefined,undefined,String),
    put(silent,Old).

log_lines(Name,Pid,String) ->
    case log_lines_not_last(Name,Pid,String) of
	[] ->
	    ok;
	LastLine ->
	    log(name_or_pid(Name,Pid),"       ~ts",[LastLine])
    end.

log_lines_not_last(Name,Pid,String) ->
    case add_tabs(String,[],[]) of
	{[],LastLine} ->
	    LastLine;
	{String1,LastLine} ->
	    log(name_or_pid(Name,Pid),"~ts",[String1]),
	    LastLine
    end.

name_or_pid(undefined,Pid) -> Pid;
name_or_pid(Name,_) -> Name.

add_tabs([0|Rest],Acc,LastLine) ->
    add_tabs(Rest,Acc,LastLine);
add_tabs([$\r|Rest],Acc,LastLine) ->
    add_tabs(Rest,Acc,LastLine);
add_tabs([$\n|Rest],Acc,LastLine) ->
    add_tabs(Rest,[$\n|LastLine] ++ [$\s,$\s,$\s,$\s,$\s,$\s,$\s|Acc],[]);
add_tabs([Ch|Rest],Acc,LastLine) ->
    add_tabs(Rest,Acc,[Ch|LastLine]);
add_tabs([],[$\n|Acc],LastLine) ->
    {lists:reverse(Acc),lists:reverse(LastLine)};
add_tabs([],[],LastLine) ->
    {[],lists:reverse(LastLine)}.

teln_receive_until_prompt(Pid,Prx,Timeout) ->
    Fun = fun() -> teln_receive_until_prompt(Pid,Prx,[],[]) end,
    ct_gen_conn:do_within_time(Fun, Timeout).

teln_receive_until_prompt(Pid,Prx,Acc,LastLine) ->
    {ok,Data} = ct_telnet_client:get_data(Pid),
    case check_for_prompt(Prx,LastLine++Data) of
	{prompt,Lines,PromptType,Rest} ->
	    Return = lists:reverse(lists:append([Lines|Acc])),
	   {ok,Return,PromptType,Rest};
	{noprompt,Lines,LastLine1} ->
	    teln_receive_until_prompt(Pid,Prx,[Lines|Acc],LastLine1)
   end.

check_for_prompt(Prx,Data) ->
    case match_prompt(Data,Prx) of
	{prompt,UptoPrompt,PromptType,Rest} ->
	    {RevLines,LastLine} = split_lines(UptoPrompt),
	    {prompt,[LastLine|RevLines],PromptType,Rest};
	noprompt ->
	    {RevLines,Rest} = split_lines(Data),
	    {noprompt,RevLines,Rest}
    end.

split_lines(String) ->
    split_lines(String,[],[]).
split_lines([$\n|Rest],Line,Lines) when Line /= [] ->
    split_lines(Rest,[],[lists:reverse(Line)|Lines]);
split_lines([$\n|Rest],[],Lines) ->
    split_lines(Rest,[],Lines);
split_lines([$\r|Rest],Line,Lines) ->
    split_lines(Rest,Line,Lines);
split_lines([0|Rest],Line,Lines) ->
    split_lines(Rest,Line,Lines);
split_lines([Char|Rest],Line,Lines) ->
    split_lines(Rest,[Char|Line],Lines);
split_lines([],Line,Lines) ->
    {Lines,lists:reverse(Line)}.


match_prompt(Str,Prx) ->
    match_prompt(Str,Prx,[]).
match_prompt(Str,Prx,Acc) ->
    case re:run(Str,Prx,[unicode]) of
	nomatch ->
	    noprompt;
	{match,[{Start,Len}]} ->
	    case split_prompt_string(Str,Start+1,Start+Len,1,[],[]) of
		{noprompt,Done,Rest} ->
		    match_prompt(Rest,Prx,Done);
		{prompt,UptoPrompt,Prompt,Rest} ->
		    {prompt,lists:reverse(UptoPrompt++Acc),
		     lists:reverse(Prompt),Rest}
	    end
    end.

split_prompt_string([Ch|Str],Start,End,N,UptoPrompt,Prompt) when N<Start ->
    split_prompt_string(Str,Start,End,N+1,[Ch|UptoPrompt],Prompt);
split_prompt_string([Ch|Str],Start,End,N,UptoPrompt,Prompt) 
  when N>=Start, N<End->
    split_prompt_string(Str,Start,End,N+1,UptoPrompt,[Ch|Prompt]);
split_prompt_string([Ch|Rest],_Start,End,N,UptoPrompt,Prompt) when N==End ->
    case UptoPrompt of
	[$",$=,$T,$P,$M,$O,$R,$P|_] ->
	    %% This is a line from "listenv", it is not a real prompt
	    {noprompt,[Ch|Prompt]++UptoPrompt,Rest};
	[$\s,$t,$s,$a|_] when Prompt==":nigol" ->
	    %% This is probably the "Last login:" statement which is
	    %% written when telnet connection is openend.
	    {noprompt,[Ch|Prompt]++UptoPrompt,Rest};
	_ ->
	    {prompt,[Ch|Prompt]++UptoPrompt,[Ch|Prompt],Rest}
    end.