VulpesOS/gaia/apps/video/js/forward_rewind_controller.js

/* exported ForwardRewindController */
/* globals pause */

/**
   * This file is used for forward and rewind funtionality of Gaia Video app.
   *
   * If the user taps the forward or rewind icons,
   * the video will jump forward or back by 10 seconds.
   *
   * When the user presses and holds on the forward or rewind icons,
   * the video time will move forward or back at 10 times the regular speed.
   */

'use strict';

var ForwardRewindController = (function() {

  var isLongPressing = false;
  var intervalId = null;
  var forwardButton;
  var backwardButton;
  var videoToolbar;
  var player;
  var seekHelper;

  function init(video, forward, backward, seeker) {
    forwardButton = forward;
    backwardButton = backward;
    player = video;
    seekHelper = seeker;

    videoToolbar = forward.parentElement;
    videoToolbar.addEventListener('click', handleButtonClick);
    videoToolbar.addEventListener('contextmenu', handlePlayerLongPress);
    videoToolbar.addEventListener('touchend', stopFastSeeking);
  }

  function uninit(video, forward, backward) {
    videoToolbar.removeEventListener('click', handleButtonClick);
    videoToolbar.removeEventListener('contextmenu', handlePlayerLongPress);
    videoToolbar.removeEventListener('touchend', stopFastSeeking);

    forwardButton = null;
    backwardButton = null;
    player = null;
  }

  function handleButtonClick(event) {

    if (event.target === forwardButton) {
      startFastSeeking(1);
    } else if (event.target === backwardButton) {
      startFastSeeking(-1);
    } else {
      return;
    }
  }

  function handlePlayerLongPress(event) {

    if (event.target === forwardButton) {
      isLongPressing = true;
      startFastSeeking(1);
    } else if (event.target === backwardButton) {
      isLongPressing = true;
      startFastSeeking(-1);
    } else {
      return;
    }
  }

  function startFastSeeking(direction) {

    // direction can be 1 or -1, 1 means forward and -1 means rewind.
    var offset = direction * 10;

    if (isLongPressing) {
      intervalId = window.setInterval(function() {
        seekVideo(player.currentTime + offset);
      }, 1000);
    } else {
      seekVideo(player.currentTime + offset);
    }
  }

  function stopFastSeeking() {
    if (intervalId) {
     window.clearInterval(intervalId);
     intervalId = null;
     isLongPressing = false;
    }
  }

  function seekVideo(seekTime) {
    if (seekTime >= player.duration || seekTime < 0) {
      if (isLongPressing) {
        stopFastSeeking();
      }
      if (seekTime >= player.duration) {
        seekTime = player.duration;
        // If the user tries to seek past the end then pause playback
        // because otherwise when we get the 'ended' event we'll skip
        // to the beginning of the movie. Even though we pause, we'll
        // still get the ended event, but the handler sees that we're
        // paused and does not skip back to the beginning.
        pause();
      }
      else {
        seekTime = 0;
      }
    }

    if (seekHelper) {
      seekHelper.seekTo(seekTime);
    }
    else {
      player.fastSeek(seekTime);
    }
  }

  return {
   init: init,
   uninit: uninit,
   stopFastSeeking: stopFastSeeking
  };

}());