<?php

class Kai_Menu_Walker extends Walker {

  var $db_fields = array( 'parent' =>'menu_item_parent', 'id' => 'db_id' );

  function start_lvl( &$output, $depth = 0, $args = array() ) {
    $indent = str_repeat("\t", $depth);
    $output .= "\n$indent<ul>\n";
  }

  function end_lvl( &$output, $depth = 0, $args = array() ) {
    $indent = str_repeat("\t", $depth);
    $output .= "$indent</ul>\n";
  }

  function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ) {

    global $wp_query;
    $indent = ( $depth ) ? str_repeat( "\t", $depth ) : '';
    $class_names = $value = '';
    $classes = empty( $item->classes ) ? array() : (array) $item->classes;

    /* Add active class */
    if(in_array('current-menu-item', $classes)) {
      $classes[] = 'active';
      unset($classes['current-menu-item']);
    }

    /* Check for children */
    $children = get_posts(array('post_type' => 'nav_menu_item', 'nopaging' => true, 'numberposts' => 1, 'meta_key' =>'_menu_item_menu_item_parent', 'meta_value' => $item->ID));
    if (!empty($children)) {
      $classes[] = 'has-sub';
    }

    $class_names = join( ' ', apply_filters( 'nav_menu_css_class', array_filter( $classes ), $item, $args ) );
    $class_names = $class_names ? ' class="' . esc_attr( $class_names ) . '"' : '';

    $id = apply_filters( 'nav_menu_item_id', 'menu-item-'. $item->ID, $item, $args );
    $id = $id ? ' id="' . esc_attr( $id ) . '"' : '';

    $output .= $indent . '<li' . $id . $value . $class_names .'>';

    $attributes  = ! empty( $item->attr_title ) ? ' title="'  . esc_attr( $item->attr_title ) .'"' : '';
    $attributes .= ! empty( $item->target )     ? ' target="' . esc_attr( $item->target     ) .'"' : '';
    $attributes .= ! empty( $item->xfn )        ? ' rel="'    . esc_attr( $item->xfn        ) .'"' : '';
    $attributes .= ! empty( $item->url )        ? ' href="'   . esc_attr( $item->url        ) .'"' : '';

    $item_output = $args->before;
    $item_output .= '<a'. $attributes .'><span>';
    $item_output .= $args->link_before . apply_filters( 'the_title', $item->title, $item->ID ) . $args->link_after;
    $item_output .= '</span></a>';
    $item_output .= $args->after;

    $output .= apply_filters( 'walker_nav_menu_start_el', $item_output, $item, $depth, $args );
  }

  function end_el( &$output, $item, $depth = 0, $args = array() ) {
    $output .= "</li>\n";
  }
  /**
     * Menu Fallback
     * =============
     * If this function is assigned to the wp_nav_menu's fallback_cb variable
     * and a manu has not been assigned to the theme location in the WordPress
     * menu manager the function with display nothing to a non-logged in user,
     * and will add a link to the WordPress menu manager if logged in as an admin.
     *
     * @param array $args passed from the wp_nav_menu function.
     *
     */
    public static function fallback( $args ) {
        if ( current_user_can( 'manage_options' ) ) {

            extract( $args );

            $fb_output = null;

            if ( $container ) {
                $fb_output = '<' . $container;

                if ( $container_id )
                    $fb_output .= ' id="' . $container_id . '"';

                if ( $container_class )
                    $fb_output .= ' class="' . $container_class . '"';

                $fb_output .= '>';
            }

            $fb_output .= '<ul';

            if ( $menu_id )
                $fb_output .= ' id="' . $menu_id . '"';

            if ( $menu_class )
                $fb_output .= ' class="' . $menu_class . '"';

            $fb_output .= '>';
            $fb_output .= '<li><a href="' . admin_url( 'nav-menus.php' ) . '">'.esc_attr__('Add a menu','kai') .'</a></li>';
            $fb_output .= '</ul>';

            if ( $container )
                $fb_output .= '</' . $container . '>';

            //echo esc_html($fb_output);
        }
    }

}