var Client = require('./client');
var util = require('./util');

function StreamClient(options) {
  options.server = {
    stream: options.server,
    buffer: [],
    full: false
  };
  Client.apply(this, arguments);

  this._callbacks = {};

  this._server.stream.on('data', this._onData.bind(this));
  this._server.stream.on('drain', this._onDrain.bind(this));
}

StreamClient.prototype = new Client({
  server: true
});
StreamClient.prototype.constructor = StreamClient;

StreamClient.prototype._send = function (request) {
  var success;

  if (this._server.full) {
    this._server.buffer.push(request);
  } else {
    try {
      request = JSON.stringify(request);
    } catch (e) {
      throw 'Could not serialize request to JSON';
    }

    this._server.full = !this._server.stream.write(request);
  }
};

StreamClient.prototype.request = function () {
  var request = this._makeRequest.apply(this, arguments);
  var callback;
  var response;

  request.id = this._nextId++;

  if (request.callback) {
    callback = request.callback;
    delete request.callback;
  } else if (util.isArray(request.params) &&
    util.isFunction(request.params[request.params.length - 1])
  ) {
    callback = request.params.pop();
  }

  this._send(request);

  if (callback && util.isNumber(request.id)) {
    this._callbacks[request.id] = callback;
  }
};

StreamClient.prototype._onData = function (response) {
  response = JSON.parse(response);

  if (!util.isUndefined(response.id) && this._callbacks[response.id]) {
    this._callbacks[response.id](response.error || null,
      response.result || null);
    delete this._callbacks[response.id];
  }
};

StreamClient.prototype._onDrain = function (request) {
  var buffer = this._server.buffer.slice().reverse();

  this._server.full = false;
  while (buffer.length > 0) {
    this._send(buffer.pop());
  }
};

module.exports = StreamClient;