<?php

/**
 *
 * Adapted from Edward McIntyre's wp_bootstrap_navwalker class. 
 * Removed support for glyphicon and added support for Font Awesome
 *
 */
/**
 * Class Name: wp_bootstrap_navwalker
 * GitHub URI: https://github.com/twittem/wp-bootstrap-navwalker
 * Description: A custom WordPress nav walker class to implement the Bootstrap 3 navigation style in a custom theme using the WordPress built in menu manager.
 * Version: 2.0.4
 * Author: Edward McIntyre - @twittem
 * License: GPL-2.0+
 * License URI: http://www.gnu.org/licenses/gpl-2.0.txt
 */
//exit if accessed directly
if ( !defined( 'ABSPATH' ) )
	exit;
if ( !class_exists( 'wp_bootstrap_navwalker' ) ) {

	class wp_bootstrap_navwalker extends Walker_Nav_Menu {

		/**
		 * @see Walker::start_lvl()
		 * @since 3.0.0
		 *
		 * @param string $output Passed by reference. Used to append additional content.
		 * @param int $depth Depth of page. Used for padding.
		 */
		public function start_lvl( &$output, $depth = 0, $args = array() ) {
			$indent = str_repeat( "\t", $depth );
			$output .= "\n$indent<ul role=\"menu\" class=\" dropdown-menu\">\n";
		}

		/**
		 * @see Walker::start_el()
		 * @since 3.0.0
		 *
		 * @param string $output Passed by reference. Used to append additional content.
		 * @param object $item Menu item data object.
		 * @param int $depth Depth of menu item. Used for padding.
		 * @param int $current_page Menu item ID.
		 * @param object $args
		 */
		public function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ) {
			$indent = ( $depth ) ? str_repeat( "\t", $depth ) : '';
			/**
			 * Dividers, Headers or Disabled
			 * =============================
			 * Determine whether the item is a Divider, Header, Disabled or regular
			 * menu item. To prevent errors we use the strcasecmp() function to so a
			 * comparison that is not case sensitive. The strcasecmp() function returns
			 * a 0 if the strings are equal.
			 */
			if ( strcasecmp( $item->attr_title, 'divider' ) == 0 && $depth === 1 ) {
				$output .= $indent . '<li role="presentation" class="divider">';
			} else if ( strcasecmp( $item->title, 'divider' ) == 0 && $depth === 1 ) {
				$output .= $indent . '<li role="presentation" class="divider">';
			} else if ( strcasecmp( $item->attr_title, 'dropdown-header' ) == 0 && $depth === 1 ) {
				$output .= $indent . '<li role="presentation" class="dropdown-header">' . esc_attr( $item->title );
			} else if ( strcasecmp( $item->attr_title, 'disabled' ) == 0 ) {
				$output .= $indent . '<li role="presentation" class="disabled"><a href="#">' . esc_attr( $item->title ) . '</a>';
			} else {
				$class_names = $value		 = '';
				$classes	 = empty( $item->classes ) ? array() : (array) $item->classes;
				$classes[]	 = 'menu-item-' . $item->ID;
				$class_names = join( ' ', apply_filters( 'nav_menu_css_class', array_filter( $classes ), $item, $args ) );
				/*
				  if ( $args->has_children )
				  $class_names .= ' dropdown';
				 */
				if ( $args->has_children && $depth === 0 ) {
					$class_names .= ' dropdown';
				} elseif ( $args->has_children && $depth > 0 ) {
					$class_names .= ' dropdown-submenu';
				}
				if ( in_array( 'current-menu-item', $classes ) )
					$class_names .= ' active';
				// remove Font Awesome icon from classes array and save the icon
				// we will add the icon back in via a <span> below so it aligns with
				// the menu item
				if ( in_array( 'fa', $classes ) ) {
					$key		 = array_search( 'fa', $classes );
					$icon		 = $classes[ $key + 1 ];
					$class_names = str_replace( $classes[ $key + 1 ], '', $class_names );
					$class_names = str_replace( $classes[ $key ], '', $class_names );
				}

				$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 . '>';
				$atts			 = array();
				$atts[ 'title' ]	 = !empty( $item->title ) ? $item->title : '';
				$atts[ 'target' ]	 = !empty( $item->target ) ? $item->target : '';
				$atts[ 'rel' ]	 = !empty( $item->xfn ) ? $item->xfn : '';
				// If item has_children add atts to a.
				// if ( $args->has_children && $depth === 0 ) {
				if ( $args->has_children ) {
					$atts[ 'href' ]		 = !empty( $item->url ) ? $item->url : '';
					$atts[ 'data-toggle' ] = 'dropdown';
					$atts[ 'class' ]		 = 'dropdown-toggle';
				} else {
					$atts[ 'href' ] = !empty( $item->url ) ? $item->url : '';
				}
				$atts		 = apply_filters( 'nav_menu_link_attributes', $atts, $item, $args );
				$attributes	 = '';
				foreach ( $atts as $attr => $value ) {
					if ( !empty( $value ) ) {
						$value = ( 'href' === $attr ) ? esc_url( $value ) : esc_attr( $value );
						$attributes .= ' ' . $attr . '="' . $value . '"';
					}
				}
				$item_output = $args->before;
				/*
				 * Glyphicons/Font-Awesome
				 * ===========
				 * Since the the menu item is NOT a Divider or Header we check the see
				 * if there is a value in the attr_title property. If the attr_title
				 * property is NOT null we apply it as the class name for the glyphicon.
				 */
				if ( ! empty( $item->attr_title ) ) :
								$pos = strpos( esc_attr( $item->attr_title ), 'glyphicon' );
					if ( false !== $pos ) :
						$item_output .= '<a' . $attributes . '><span class="glyphicon ' . esc_attr( $item->attr_title ) . '" aria-hidden="true"></span>&nbsp;';
								else :
									$item_output .= '<a' . $attributes . '><i class="fa ' . esc_attr( $item->attr_title ) . '" aria-hidden="true"></i>&nbsp;';
											endif;
				else :
					$item_output .= '<a' . $attributes . '>';
				endif;
				$item_output .= $args->link_before . apply_filters( 'the_title', $item->title, $item->ID ) . $args->link_after;
				$item_output .= ( $args->has_children && 0 === $depth ) ? ' <span class="caret"></span></a>' : '</a>';
				$item_output .= $args->after;
				$output .= apply_filters( 'walker_nav_menu_start_el', $item_output, $item, $depth, $args );
			}
		}

		/**
		 * Traverse elements to create list from elements.
		 *
		 * Display one element if the element doesn't have any children otherwise,
		 * display the element and its children. Will only traverse up to the max
		 * depth and no ignore elements under that depth.
		 *
		 * This method shouldn't be called directly, use the walk() method instead.
		 *
		 * @see Walker::start_el()
		 * @since 2.5.0
		 *
		 * @param object $element Data object
		 * @param array $children_elements List of elements to continue traversing.
		 * @param int $max_depth Max depth to traverse.
		 * @param int $depth Depth of current element.
		 * @param array $args
		 * @param string $output Passed by reference. Used to append additional content.
		 * @return null Null on failure with no changes to parameters.
		 */
		public function display_element( $element, &$children_elements, $max_depth, $depth, $args, &$output ) {
			if ( ! $element ) {
				return; }
			$id_field = $this->db_fields['id'];
			// Display this element.
			if ( is_object( $args[0] ) ) {
				$args[0]->has_children = ! empty( $children_elements[ $element->$id_field ] ); }
			parent::display_element( $element, $children_elements, $max_depth, $depth, $args, $output );
		}


		/**
		 * 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( 'edit_theme_options' ) ) {
				/* Get Arguments. */
				$container = $args['container'];
				$container_id = $args['container_id'];
				$container_class = $args['container_class'];
				$menu_class = $args['menu_class'];
				$menu_id = $args['menu_id'];
				if ( $container ) {
					echo '<' . esc_attr( $container );
					if ( $container_id ) {
						echo ' id="' . esc_attr( $container_id ) . '"';
					}
					if ( $container_class ) {
						echo ' class="' . sanitize_html_class( $container_class ) . '"'; }
					echo '>';
				}
				echo '<ul';
				if ( $menu_id ) {
					echo ' id="' . esc_attr( $menu_id ) . '"'; }
				if ( $menu_class ) {
					echo ' class="' . esc_attr( $menu_class ) . '"'; }
				echo '>';
				echo '<li><a href="' . esc_url( admin_url( 'nav-menus.php' ) ) . '" title="">' . esc_attr__( 'Add a menu', 'head-blog' ) . '</a></li>';
				echo '</ul>';
				if ( $container ) {
					echo '</' . esc_attr( $container ) . '>'; }
			}
		}

	}

}