<?php
/*
 * REGISTER NAVIATION MENUS
 *************************************************************/
add_action( 'after_setup_theme', 'register_make_nav_menus' );
function register_make_nav_menus() {
	register_nav_menus( array(
		'header-menu' => 'Main Header Menu',
	) );
}

class make_submenu_class extends Walker_Nav_Menu {
    /**
     * [start_lvl Starts the list before the elements are added.]
     * The $args parameter holds additional values that may be used with the child class methods.
     * This method is called at the start of the output list.
     * The start level refers to the start of a sub-level. Mening that the output does not effect the initial wrapping around the whole navigation, but only the list of childerns children.
     *
     * @param   [string]  &$output  (Required) Used  to append additional content (passed by reference).
     * @param   [int]     $depth    (Required) Depth of the item.
     * @param   [array]   $args     (Optional) An array of additional arguments. Default value: array()
     *
     */
    function start_lvl(&$output, $depth = 0, $args = array()) {
        $output .= ($depth == 0) ? "<div class=\"megamenu\">\n" : ''; // Wrap the sub-menu items with the megamenu wrapper

        $indent = str_repeat("\t", $depth);
        $output .= "\n$indent<ul class=\"sub-menu\">\n"; // add a numeric value to determin the level of submenu
    }
    public function end_lvl( &$output, $depth = 0, $args = array() ) {
		$output .= ($depth == 0) ? "</div><!-- /.megamenu -->\n" : ''; // Close the megamenu wrapper at the end of the first level

    }

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

        $classes     = empty ( $item->classes ) ? array () : (array) $item->classes;
        $class_names = join( ' ',   apply_filters(
                'nav_menu_css_class',   array_filter( $classes ), $item
            )
        );

        ! empty ( $class_names )
        and $class_names = ' class="'. esc_attr( $class_names ) . '"';

        if ( in_array( 'featured', $item->classes ) ) {
            // Wrap the featured items to seperate them from the main sub items
            $output .= "</ul>\n<ul class=\"sub-menu-featured\">\n";
        }
        $output .= "<li id='menu-item-$item->ID' $class_names>";

        $attributes  = '';

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

        $title = apply_filters( 'the_title', $item->title, $item->ID );

        $item_output = $args->before
            . "<a $attributes>"
            . $args->link_before
            . $title
            . '</a> '
            . $args->link_after
            . $args->after;

        // Since $output is called by reference we don't need to return anything.
        $output .= apply_filters(
            'walker_nav_menu_start_el'
            ,   $item_output
            ,   $item
            ,   $depth
            ,   $args
        );
    }
    function end_el( &$output, $item, $depth = 0, $args = array() ) {
        if ( in_array( 'featured', $item->classes ) ) {
            // Close off the .feature item
            $output .= "</ul>";
        }
    }
}

/**
* Add the images submenu items with the featured class
*
* @param [array] $items List of menu objects (WP_Post).
* @return [array]
*/
function make_featured_submenu_items( $items ) {
	$featured_item_ids = array();
    //echo '<pre>' . var_export($items, true) . '</pre>';
    foreach ( $items as $item ) {
        if ( $item->menu_item_parent != 0 ) { // Don't add the featured image if it's a parent item.
            if ( in_array( 'featured', $item->classes, true )
                    && isset( $item->ID )
                        && has_post_thumbnail( $item->object_id )) {

                $item->title = sprintf(
                    '%1$s %2$s %3$s %4$s',
                    '<span class="featured-title">' . $item->title .'</span>',
                    get_the_post_thumbnail( $item->object_id, 'thumbnail', array( 'alt' => esc_attr( $item->title ) ) ),
                    '<span class="featured-excerpt">' . wp_trim_words(get_the_excerpt($item->object_id), 5) . '</span>', // Limit to 5 words, doesn't need to be too lengthy
                    '<a href="' . get_post_type_archive_link( $item->object ) . '">See all ' . $item->type_label . '<span class="arrow-button"></span></a>'
                );
            }
        }
    }

	return $items;
}
add_filter( 'wp_nav_menu_objects', 'make_featured_submenu_items' );