-module(erlcount_counter).
-behaviour(gen_server).
-export([start_link/4]).
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
        terminate/2, code_change/3]).

-record(state, {dispatcher, ref, file, re}).

start_link(DispatcherPid, Ref, FileName, Regex) ->
    gen_server:start_link(?MODULE, [DispatcherPid, Ref, FileName, Regex], []).

init([DispatcherPid, Ref, FileName, Regex]) ->
    self() ! start,
    {ok, #state{dispatcher=DispatcherPid,
                ref = Ref,
                file = FileName,
                re = Regex}}.

handle_call(_Msg, _From, State) ->
    {noreply, State}.

handle_cast(_Msg, State) ->
    {noreply, State}.

handle_info(start, S = #state{re=Re, ref=Ref}) ->
    {ok, Bin} = file:read_file(S#state.file),
    Count = erlcount_lib:regex_count(Re, Bin),
    erlcount_dispatch:complete(S#state.dispatcher, Re, Ref, Count),
    {stop, normal, S}.

terminate(_Reason, _State) ->
    ok.

code_change(_OldVsn, State, _Extra) ->
    {ok, State}.