(function ($) {

/**

 * Attach the machine-readable name form element behavior.

 */

Drupal.behaviors.machineName = {

  /**

   * Attaches the behavior.

   *

   * @param settings.machineName

   *   A list of elements to process, keyed by the HTML ID of the form element

   *   containing the human-readable value. Each element is an object defining

   *   the following properties:

   *   - target: The HTML ID of the machine name form element.

   *   - suffix: The HTML ID of a container to show the machine name preview in

   *     (usually a field suffix after the human-readable name form element).

   *   - label: The label to show for the machine name preview.

   *   - replace_pattern: A regular expression (without modifiers) matching

   *     disallowed characters in the machine name; e.g., '[^a-z0-9]+'.

   *   - replace: A character to replace disallowed characters with; e.g., '_'

   *     or '-'.

   *   - standalone: Whether the preview should stay in its own element rather

   *     than the suffix of the source element.

   *   - field_prefix: The #field_prefix of the form element.

   *   - field_suffix: The #field_suffix of the form element.

   */

  attach: function (context, settings) {

    var self = this;

    $.each(settings.machineName, function (source_id, options) {

      var $source = $(source_id, context).addClass('machine-name-source');

      var $target = $(options.target, context).addClass('machine-name-target');

      var $suffix = $(options.suffix, context);

      var $wrapper = $target.closest('.form-item');

      // All elements have to exist.

      if (!$source.length || !$target.length || !$suffix.length || !$wrapper.length) {

        return;

      }

      // Skip processing upon a form validation error on the machine name.

      if ($target.hasClass('error')) {

        return;

      }

      // Figure out the maximum length for the machine name.

      options.maxlength = $target.attr('maxlength');

      // Hide the form item container of the machine name form element.

      $wrapper.hide();

      // Determine the initial machine name value. Unless the machine name form

      // element is disabled or not empty, the initial default value is based on

      // the human-readable form element value.

      if ($target.is(':disabled') || $target.val() != '') {

        var machine = $target.val();

      }

      else {

        var machine = self.transliterate($source.val(), options);

      }

      // Append the machine name preview to the source field.

      var $preview = $('<span class="machine-name-value">' + options.field_prefix + Drupal.checkPlain(machine) + options.field_suffix + '</span>');

      $suffix.empty();

      if (options.label) {

        $suffix.append(' ').append('<span class="machine-name-label">' + options.label + ':</span>');

      }

      $suffix.append(' ').append($preview);

      // If the machine name cannot be edited, stop further processing.

      if ($target.is(':disabled')) {

        return;

      }

      // If it is editable, append an edit link.

      var $link = $('<span class="admin-link"><a href="#">' + Drupal.t('Edit') + '</a></span>')

        .click(function () {

          $wrapper.show();

          $target.focus();

          $suffix.hide();

          $source.unbind('.machineName');

          return false;

        });

      $suffix.append(' ').append($link);

      // Preview the machine name in realtime when the human-readable name

      // changes, but only if there is no machine name yet; i.e., only upon

      // initial creation, not when editing.

      if ($target.val() == '') {

        $source.bind('keyup.machineName change.machineName input.machineName', function () {

          machine = self.transliterate($(this).val(), options);

          // Set the machine name to the transliterated value.

          if (machine != '') {

            if (machine != options.replace) {

              $target.val(machine);

              $preview.html(options.field_prefix + Drupal.checkPlain(machine) + options.field_suffix);

            }

            $suffix.show();

          }

          else {

            $suffix.hide();

            $target.val(machine);

            $preview.empty();

          }

        });

        // Initialize machine name preview.

        $source.keyup();

      }

    });

  },

  /**

   * Transliterate a human-readable name to a machine name.

   *

   * @param source

   *   A string to transliterate.

   * @param settings

   *   The machine name settings for the corresponding field, containing:

   *   - replace_pattern: A regular expression (without modifiers) matching

   *     disallowed characters in the machine name; e.g., '[^a-z0-9]+'.

   *   - replace: A character to replace disallowed characters with; e.g., '_'

   *     or '-'.

   *   - maxlength: The maximum length of the machine name.

   *

   * @return

   *   The transliterated source string.

   */

  transliterate: function (source, settings) {

    var rx = new RegExp(settings.replace_pattern, 'g');

    return source.toLowerCase().replace(rx, settings.replace).substr(0, settings.maxlength);

  }

};

})(jQuery);