%%%----------------------------------------------------------------------
%%% File    : rpc_listen.erl
%%% Author  : shinde local account <otpuser@tiger>
%%% Purpose : Act as a tcp/ip server and spawn processes for socket connections
%%% Created : 26 May 1999 by ottuser local account <otpuser@tiger>
%%%----------------------------------------------------------------------
-module(rpc_listen).
-vsn(1).
-author('shinde@one2one.co.uk').

-export([start_link/1]).
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
-export([create/2]).

-behaviour(gen_server).

-record(state,{listen_socket = []}).		% Listener socket reference
%%%----------------------------------------------------------------------
%%% API
%%%----------------------------------------------------------------------
start_link(Port) ->
    Name = list_to_atom(lists:flatten(io_lib:format("rpc_server_~w",[Port]))),
    gen_server:start_link({local, Name}, ?MODULE, Port, []).


%% Access to this server from socket servers
create(ServerPid, Pid) ->
    gen_server:cast(ServerPid, {create, Pid}).


%%%----------------------------------------------------------------------
%%% Callback functions from gen_server
%%%----------------------------------------------------------------------

%%----------------------------------------------------------------------
%% Func: init/1
%% Returns: {ok, State}          |
%%          {ok, State, Timeout} |
%%          ignore               |
%%          {stop, Reason}
%%----------------------------------------------------------------------
init(Port) ->
    process_flag(trap_exit, true),
    case gen_tcp:listen(Port,[binary,{packet,2},{active, true},
			      {reuseaddr,true}]) of
	{ok, ListenSocket} ->
	    {ok, Pid} = rpc_socket:start(self(), ListenSocket),	% Start acceptor process
	    rpc_socket:get_connection(Pid),	% Tell it to start accepting
	    {ok, #state{listen_socket = ListenSocket}};
	{error, Reason} ->
	    {stop, Reason}
    end.

%%----------------------------------------------------------------------
%% Func: handle_call/3
%% Returns: {reply, Reply, State}          |
%%          {reply, Reply, State, Timeout} |
%%          {noreply, State}               |
%%          {noreply, State, Timeout}      |
%%          {stop, Reason, Reply, State}   | (terminate/2 is called)
%%          {stop, Reason, State}            (terminate/2 is called)
%%----------------------------------------------------------------------
handle_call(Request,From,State) ->
    {reply,ok,State}.


%%----------------------------------------------------------------------
%% Func: handle_cast/2
%% Returns: {noreply, State}          |
%%          {noreply, State, Timeout} |
%%          {stop, Reason, State}            (terminate/2 is called)
%%----------------------------------------------------------------------
handle_cast({create,Pid}, State) ->
    {ok, NewPid} = rpc_socket:start(self(), State#state.listen_socket),
    rpc_socket:get_connection(NewPid),
    {noreply, State}.

%%----------------------------------------------------------------------
%% Func: handle_info/2
%% Returns: {noreply, State}          |
%%          {noreply, State, Timeout} |
%%          {stop, Reason, State}            (terminate/2 is called)
%%----------------------------------------------------------------------
% 
handle_info({'EXIT', Pid, {error, accept_failed}}, State) ->
    create(self(), self()),			% Start off new acceptor as listen socket is still open
    {noreply,State};

% normal shutdown of socket process
handle_info({'EXIT', Pid, normal}, State) ->
    {noreply,State};

handle_info(Info, State) ->
    io:format("Unexpected info: ~p~n",[Info]),
    {noreply,State}.

%%----------------------------------------------------------------------
%% Func: terminate/2
%% Purpose: Shutdown the server
%% Returns: any (ignored by gen_server)
%%----------------------------------------------------------------------
terminate(Reason,State) ->
    gen_tcp:close(State#state.listen_socket),
    ok.

%%----------------------------------------------------------------------
%% Func: code_change/3
%% Purpose: Convert process state when code is changed
%% Returns: {ok, NewState}
%%----------------------------------------------------------------------
code_change(OldVsn, State, Extra) ->
    {ok, State}.

%%%----------------------------------------------------------------------
%%% Internal functions
%%%----------------------------------------------------------------------