-behavior(shackle_client).
-export([
    init/0,
    setup/2,
    handle_request/2,
    handle_data/2,
    terminate/1
]).

-record(state, {
    buffer =       <<>> :: binary(),
    request_counter = 0 :: non_neg_integer()
}).

-spec init(Options :: term()) ->
    {ok, State :: term()} |
    {error, Reason :: term()}.

init(_Options) ->
    {ok, #state {}}.

-spec setup(Socket :: inet:socket(), State :: term()) ->
    {ok, State :: term()} |
    {error, Reason :: term(), State :: term()}.

setup(Socket, State) ->
    case gen_tcp:send(Socket, <<"INIT">>) of
        ok ->
            case gen_tcp:recv(Socket, 0) of
                {ok, <<"OK">>} ->
                    {ok, State};
                {error, Reason} ->
                    {error, Reason, State}
            end;
        {error, Reason} ->
            {error, Reason, State}
    end.

-spec handle_request(Request :: term(), State :: term()) ->
    {ok, RequestId :: external_request_id(), Data :: iodata(), State :: term()}.

handle_request(noop,  State) ->
    Data = arithmetic_protocol:request(0, noop, 0, 0),

    {ok, undefined, Data, State};
handle_request({Operation, A, B}, #state {
        request_counter = RequestCounter
    } = State) ->

    RequestId = request_id(RequestCounter),
    Data = request(RequestId, Operation, A, B),

    {ok, RequestId, Data, State#state {
        request_counter = RequestCounter + 1
    }}.

-spec handle_data(Data :: binary(), State :: term()) ->
    {ok, [{RequestId :: external_request_id(), Reply :: term()}], State :: term()}.

handle_data(Data, #state {
        buffer = Buffer
    } = State) ->

    Data2 = <<Buffer/binary, Data/binary>>,
    {Replies, Buffer2} = parse_replies(Data2, []),

    {ok, Replies, State#state {
        buffer = Buffer2
    }}.

-spec terminate(State :: term()) -> ok.

terminate(_State) -> ok.

shackle_pool:start(shackle_pool:name(), client(), client_options(), pool_options())

1> shackle:call(pool_name, {get, <<"test">>}).
{ok, <<"bar">>}

2> {ok, ReqId} = shackle:cast(pool_name, {get, <<"foo">>}, 500).
{ok, {anchor, anchor_client, #Ref<0.0.0.2407>}}

3> shackle:receive_response(ReqId).
{ok, <<"bar">>}