/**
 * Copyright 2017 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.
 */

class EmulationManager {
  /**
   * @param {!Puppeteer.CDPSession} client
   */
  constructor(client) {
    this._client = client;
    this._emulatingMobile = false;
    this._hasTouch = false;
  }

  /**
   * @param {!Puppeteer.Viewport} viewport
   * @return {Promise<boolean>}
   */
  /* async */ emulateViewport(viewport) {return (fn => {
  const gen = fn.call(this);
  return new Promise((resolve, reject) => {
    function step(key, arg) {
      let info, value;
      try {
        info = gen[key](arg);
        value = info.value;
      } catch (error) {
        reject(error);
        return;
      }
      if (info.done) {
        resolve(value);
      } else {
        return Promise.resolve(value).then(
            value => {
              step('next', value);
            },
            err => {
              step('throw', err);
            });
      }
    }
    return step('next');
  });
})(function*(){
    const mobile = viewport.isMobile || false;
    const width = viewport.width;
    const height = viewport.height;
    const deviceScaleFactor = viewport.deviceScaleFactor || 1;
    /** @type {Protocol.Emulation.ScreenOrientation} */
    const screenOrientation = viewport.isLandscape ? { angle: 90, type: 'landscapePrimary' } : { angle: 0, type: 'portraitPrimary' };
    const hasTouch = viewport.hasTouch || false;

    (yield Promise.all([
      this._client.send('Emulation.setDeviceMetricsOverride', { mobile, width, height, deviceScaleFactor, screenOrientation }),
      this._client.send('Emulation.setTouchEmulationEnabled', {
        enabled: hasTouch
      })
    ]));

    const reloadNeeded = this._emulatingMobile !== mobile || this._hasTouch !== hasTouch;
    this._emulatingMobile = mobile;
    this._hasTouch = hasTouch;
    return reloadNeeded;
  });}
}

module.exports = {EmulationManager};