'use strict';
/* global ForwardLock, MozActivity */

(function(exports) {

  function Wallpaper() {
    // Do nothing...
  }

  Wallpaper.prototype = {
    change: function() {
      // Ask for the locked content key first, because if it does not exist
      // we know there is no locked content on the phone and we don't have
      // to show the Locked Content app in the activity request.
      ForwardLock.getKey(function(secret) {
        var activity = new MozActivity({
          name: 'pick',
          data: {
            type: ['wallpaper', 'image/*'],
            includeLocked: (secret !== null),
            // XXX: This will not work with Desktop Fx / Simulator.
            width: Math.ceil(window.screen.width * window.devicePixelRatio),
            height: Math.ceil(window.screen.height * window.devicePixelRatio)
          }
        });

        activity.onsuccess = function onWallpaperSuccess() {
          var blob = activity.result.blob;

          if (!blob) {
            return;
          }

          // If this is a locked image from the locked content app, unlock it
          if (blob.type.split('/')[1] === ForwardLock.mimeSubtype) {
            ForwardLock.unlockBlob(secret, blob, function(unlocked) {
              setWallpaper(unlocked);
            });
          } else {
            setWallpaper(blob);
          }

          function setWallpaper(blob) {
            navigator.mozSettings.createLock().set({
              'wallpaper.image': blob
            });
          }
        };

        activity.onerror = function onWallpaperError() {
          console.warn('pick failed!');
        };
      });
    }
  };

  exports.wallpaper = new Wallpaper();

}(window));