<?php

//Add a new field to menu edit screen
add_filter( 'wp_setup_nav_menu_item', 'antreas_menu_fields' );
function antreas_menu_fields( $menu ) {
	$menu->icon  = get_post_meta( $menu->ID, '_menu_item_icon', true );
	$menu->style = get_post_meta( $menu->ID, '_menu_item_style', true );
	return $menu;
}


//Save the field data
add_action( 'wp_update_nav_menu_item', 'antreas_menu_fields_update', 10, 3 );
function antreas_menu_fields_update( $menu_id, $db_id, $args ) {
	if ( isset( $_REQUEST['menu-item-icon'] ) && is_array( $_REQUEST['menu-item-icon'] ) ) {
		$icon_value = isset( $_REQUEST['menu-item-icon'][ $db_id ] ) ? $_REQUEST['menu-item-icon'][ $db_id ] : '';
		update_post_meta( $db_id, '_menu_item_icon', $icon_value );
	}
	if ( isset( $_REQUEST['menu-item-style'] ) && is_array( $_REQUEST['menu-item-style'] ) ) {
		$style_value = $_REQUEST['menu-item-style'][ $db_id ];
		update_post_meta( $db_id, '_menu_item_style', $style_value );
	}
}


//Print the field using a custom walker
add_filter( 'wp_edit_nav_menu_walker', 'antreas_menu_fields_walker', 10, 2 );
function antreas_menu_fields_walker( $walker, $menu_id ) {
	return 'Antreas_Menu_Edit_Walker';
}


//Change the default walker for custom menu widgets
// add_filter('wp_nav_menu_args', 'antreas_menu_walker');
function antreas_menu_walker( $args ) {
	//Widgets do not use a theme_location
	if ( $args['theme_location'] == '' ) {
		$args = array_merge( $args, array( 'walker' => new Antreas_Menu_Walker() ) );
	}
	return $args;
}