/*
 * Copyright 2016 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
var Message = require('../message');

/**
 * Sends events to the embedded VR view IFrame via postMessage. Also handles
 * messages sent back from the IFrame:
 *
 *    click: When a hotspot was clicked.
 *    modechange: When the user changes viewing mode (VR|Fullscreen|etc).
 */
function IFrameMessageSender(iframe) {
  if (!iframe) {
    console.error('No iframe specified');
    return;
  }
  this.iframe = iframe;

  // On iOS, if the iframe is across domains, also send DeviceMotion data.
  if (this.isIOS_()) {
    window.addEventListener('devicemotion', this.onDeviceMotion_.bind(this), false);
  }
}

/**
 * Sends a message to the associated VR View IFrame.
 */
IFrameMessageSender.prototype.send = function(message) {
  var iframeWindow = this.iframe.contentWindow;
  iframeWindow.postMessage(message, '*');
};

IFrameMessageSender.prototype.onDeviceMotion_ = function(e) {
  var message = {
    type: Message.DEVICE_MOTION,
    deviceMotionEvent: this.cloneDeviceMotionEvent_(e)
  };

  this.send(message);
};

IFrameMessageSender.prototype.cloneDeviceMotionEvent_ = function(e) {
  return {
    acceleration: {
      x: e.acceleration.x,
      y: e.acceleration.y,
      z: e.acceleration.z,
    },
    accelerationIncludingGravity: {
      x: e.accelerationIncludingGravity.x,
      y: e.accelerationIncludingGravity.y,
      z: e.accelerationIncludingGravity.z,
    },
    rotationRate: {
      alpha: e.rotationRate.alpha,
      beta: e.rotationRate.beta,
      gamma: e.rotationRate.gamma,
    },
    interval: e.interval,
    timeStamp: e.timeStamp
  };
};

IFrameMessageSender.prototype.isIOS_ = function() {
  return /iPad|iPhone|iPod/.test(navigator.userAgent) && !window.MSStream;
};

module.exports = IFrameMessageSender;