var H5P = H5P || {};

/**
 * Class responsible for creating a help text dialog
 */
H5P.JoubelHelpTextDialog = (function ($) {

  var numInstances = 0;
  /**
   * Display a pop-up containing a message.
   *
   * @param {H5P.jQuery}  $container  The container which message dialog will be appended to
   * @param {string}      message     The message
   * @param {string}      closeButtonTitle The title for the close button
   * @return {H5P.jQuery}
   */
  function JoubelHelpTextDialog(header, message, closeButtonTitle) {
    H5P.EventDispatcher.call(this);

    var self = this;

    numInstances++;
    var headerId = 'joubel-help-text-header-' + numInstances;
    var helpTextId = 'joubel-help-text-body-' + numInstances;

    var $helpTextDialogBox = $('<div>', {
      'class': 'joubel-help-text-dialog-box',
      'role': 'dialog',
      'aria-labelledby': headerId,
      'aria-describedby': helpTextId
    });

    $('<div>', {
      'class': 'joubel-help-text-dialog-background'
    }).appendTo($helpTextDialogBox);

    var $helpTextDialogContainer = $('<div>', {
      'class': 'joubel-help-text-dialog-container'
    }).appendTo($helpTextDialogBox);

    $('<div>', {
      'class': 'joubel-help-text-header',
      'id': headerId,
      'role': 'header',
      'html': header
    }).appendTo($helpTextDialogContainer);

    $('<div>', {
      'class': 'joubel-help-text-body',
      'id': helpTextId,
      'html': message,
      'role': 'document',
      'tabindex': 0
    }).appendTo($helpTextDialogContainer);

    var handleClose = function () {
      $helpTextDialogBox.remove();
      self.trigger('closed');
    };

    var $closeButton = $('<div>', {
      'class': 'joubel-help-text-remove',
      'role': 'button',
      'title': closeButtonTitle,
      'tabindex': 1,
      'click': handleClose,
      'keydown': function (event) {
        // 32 - space, 13 - enter
        if ([32, 13].indexOf(event.which) !== -1) {
          event.preventDefault();
          handleClose();
        }
      }
    }).appendTo($helpTextDialogContainer);

    /**
     * Get the DOM element
     * @return {HTMLElement}
     */
    self.getElement = function () {
      return $helpTextDialogBox;
    };

    self.focus = function () {
      $closeButton.focus();
    };
  }

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

  return JoubelHelpTextDialog;
}(H5P.jQuery));