var H5P = H5P || {};

H5P.JoubelProgressbar = (function ($) {

  /**
   * Joubel progressbar class
   * @method JoubelProgressbar
   * @constructor
   * @param  {number}          steps Number of steps
   * @param {Object} [options] Additional options
   * @param {boolean} [options.disableAria] Disable readspeaker assistance
   * @param {string} [options.progressText] A progress text for describing
   *  current progress out of total progress for readspeakers.
   *  e.g. "Slide :num of :total"
   */
  function JoubelProgressbar(steps, options) {
    H5P.EventDispatcher.call(this);
    var self = this;
    this.options = $.extend({
      progressText: 'Slide :num of :total'
    }, options);
    this.currentStep = 0;
    this.steps = steps;

    this.$progressbar = $('<div>', {
      'class': 'h5p-joubelui-progressbar'
    });
    this.$background = $('<div>', {
      'class': 'h5p-joubelui-progressbar-background'
    }).appendTo(this.$progressbar);
  }

  JoubelProgressbar.prototype = Object.create(H5P.EventDispatcher.prototype);
  JoubelProgressbar.prototype.constructor = JoubelProgressbar;

  JoubelProgressbar.prototype.updateAria = function () {
    var self = this;
    if (this.options.disableAria) {
      return;
    }

    if (!this.$currentStatus) {
      this.$currentStatus = $('<div>', {
        'class': 'h5p-joubelui-progressbar-slide-status-text',
        'aria-live': 'assertive'
      }).appendTo(this.$progressbar);
    }
    var interpolatedProgressText = self.options.progressText
      .replace(':num', self.currentStep)
      .replace(':total', self.steps);
    this.$currentStatus.html(interpolatedProgressText);
  };

  /**
   * Appends to a container
   * @method appendTo
   * @param  {H5P.jquery} $container
   */
  JoubelProgressbar.prototype.appendTo = function ($container) {
    this.$progressbar.appendTo($container);
  };

  /**
   * Update progress
   * @method setProgress
   * @param  {number}    step
   */
  JoubelProgressbar.prototype.setProgress = function (step) {
    // Check for valid value:
    if (step > this.steps || step < 0) {
      return;
    }
    this.currentStep = step;
    this.$background.css({
      width: ((this.currentStep/this.steps)*100) + '%'
    });

    this.updateAria();
  };

  /**
   * Increment progress with 1
   * @method next
   */
  JoubelProgressbar.prototype.next = function () {
    this.setProgress(this.currentStep+1);
  };

  /**
   * Reset progressbar
   * @method reset
   */
  JoubelProgressbar.prototype.reset = function () {
    this.setProgress(0);
  };

  /**
   * Check if last step is reached
   * @method isLastStep
   * @return {Boolean}
   */
  JoubelProgressbar.prototype.isLastStep = function () {
    return this.steps === this.currentStep;
  };

  return JoubelProgressbar;
})(H5P.jQuery);