-module(mappingserver).

-behaviour(gen_server).
-export([start/0]).
%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
         terminate/2, code_change/3]).
-compile(export_all).


start() -> gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
stop()  -> gen_server:call(?MODULE, stop).

lookup_port(Host)     -> gen_server:call(?MODULE, {port, Host}).
lookup_command(Host)  -> gen_server:call(?MODULE, {command, Host}).
refresh()  -> gen_server:call(?MODULE, {refresh}).


refresh_file() ->
    {ok,List} = file:consult("mapping.dat"),
    dict:from_list([{Host,{Port,Command}} || {Host,Port,Command} <- List]).

init([]) ->
    State = refresh_file(),
    timer:apply_interval(60*1000,?MODULE,refresh,[]),
    {ok, State}.

handle_call({port,Host}, _From, State) ->
    {Reply,_} = dict:fetch(Host,State),
    {reply, Reply, State};
handle_call({command,Host}, _From, State) ->
    {_,Reply} = dict:fetch(Host,State),
    {reply, Reply, State};
handle_call({refresh}, _From, State) ->
    NewState = refresh_file(),
    {reply, ok, NewState};

handle_call(stop, _From, State) ->
    {stop, normal, stopped, State}.

handle_cast(_Msg, State) -> {noreply, State}.
handle_info(_Info, State) -> {noreply, State}.
terminate(_Reason, _State) -> ok.
code_change(_OldVsn, State, Extra) -> {ok, State}.