simple_menu.php

<?php namespace IET_OU\WP_Generic_Plugins;
/*
Plugin Name: Simple Menu
Plugin URI:
Description: Display a menu or sub-menu based on the shortcode `[simple_menu menu=Main sub=Help]` (JuxtaLearn)
Author:      Nick Freear
Author URI:  https://github.com/nfreear
Version:     1.2-alpha
*/

// Copyright © 2015-2016 The Open University (UK).

// NDF, 21 May 2014.
// NDF/Nick Freear, 29 November 2016 - 'display_body()'

/*
  Shortcode:  [simple_menu menu=Main sub=Help content=false]
*/


class Simple_Menu {

	const SHORTCODE = 'simple_menu';
	protected static $_post_id;

	public function __construct() {
		add_shortcode( self::SHORTCODE, [ &$this, 'shortcode_simplemenu' ] );
	}


	public function shortcode_simplemenu( $attr ) {
		extract( shortcode_atts( [
			'menu' => 'Main',
			'sub'  => null,
			'content' => false,
			'comments' => false,
			'top_link' => true,
		], $attr ) );

		// fix: vars are pulled in as strings but are queried as if they are booleans, so convert here
		$content = 'true' === $content;
		$comments = 'true' === $comments;
		$top_link = 'true' === $top_link;

		$menu_obj = wp_get_nav_menu_object( $menu ); //232 ); //'Help' ); //'Main' );
		$menu_items = wp_get_nav_menu_items( $menu_obj );

		if ( ! $menu_items ) { return;
		}

		$parent_id = null;
		$sub_menu = array();
		if ( $sub ) {
			foreach ( $menu_items as $item ) {
				if ( $sub == $item->title ) {
					$parent_id = $item->ID;
				} elseif ( $parent_id == $item->menu_item_parent ) {
					$sub_menu[] = $item;
				}
			}
		} else {
			$parent_id = $sub = 'Z';
			$sub_menu = $menu_items;
		}

		$classes = self::SHORTCODE . " menu-$menu sub-$sub";

		if ( $content ) {
			return $this->display_content( $sub_menu, $parent_id, $classes, $comments, $top_link );
		}
		return $this->display_menu( $sub_menu, $parent_id, $classes );
	}


	public static function post_id() {
		return self::$_post_id;
	}


	protected function display_menu( $sub_menu, $menu_id, $classes ) {
		ob_start();

		?><ul class="<?php echo $classes ?>" id="sm-menu-<?php echo $menu_id ?>">
		<?php foreach ( $sub_menu as $it ) :
			self::$_post_id = $it->object_id; ?>
	<li id="menu-item-<?php echo $it->ID ?>" class="<?php self::echo_classes( $it ) ?>"
	  ><a href="<?php echo $it->url ?>"><?php echo $it->title ?></a>
	<?php endforeach; ?>
		</ul><?php

		$this->end();

		return ob_get_clean();
	}


	protected function display_content( $sub_menu, $menu_id, $classes, $show_comments = false, $with_top_link = false ) {
		ob_start();

		?><div class="<?php echo $classes ?>" id="sm-menu-<?php echo $menu_id ?>">
		<?php foreach ( $sub_menu as $it ) :
			self::$_post_id = $it->object_id; ?>
	<div id="menu-item-<?php echo $it->object_id ?>" class="row <?php self::echo_classes( $it, true ) ?>"
	  data-post='<?php self::post_json( $it ) ?>' data-uri='<?php echo $it->url ?>'>
	  <div class="col-md-9 guide-inner">

	  <h2 class="item-title"><?php echo $it->title ?></h2>
		<?php echo apply_filters( 'the_content', get_post_field( 'post_content', $it->object_id ) ) ?>
		<?php self::display_comments( $it->object_id, $show_comments ) ?>
	</div>

	<?php if ( defined( 'TTTT_GUIDE_CASE_STUDY' ) ) : ?>
	<div class="col-md-3 case-study">
		<!-- Tricky topics guide -->
		<p><img src="/wp-content/themes/tttt-guide/images/default-case-study.png" alt="" /></p>
		<h4 class="cs-title"> Case study </h4>
		<?php echo apply_filters( 'lorem_small', null ) ?>
		<a href="#view-more" role="button" data-toggle="tooltip" title="View the case study.">View more</a>
	</div>
	<?php endif; ?>

	<?php if ( $with_top_link ) : ?>
		<div class="col-md-12"><a href="#site-main" class="col-md-9 tttt-to-top">Return to top of page</a></div>
	<?php endif; ?>

	</div>

	<?php endforeach ?>
		</div><?php

		$this->end();

		return ob_get_clean();
	}


	protected static function display_comments( $post_id = null, $show_comments = false ) {
		//echo $show_comments .' '. comments_open() .' '. get_comments_number();
		if ( ! $show_comments || ! comments_open( $post_id ) ) {
			return;
		}

		self::load_template( 'simple-menu-comments', false );
	}

	// https://codex.wordpress.org/Function_Reference/load_template#Loading_a_template_in_a_plugin.2C_but_allowing_theme_and_child_theme_to_override_template
	protected static function load_template( $name = 'some-template', $require_once = true ) {
		if ( $overridden_template = locate_template( $name . '.php' ) ) {
			// locate_template() returns path to file
			// if either the child theme or the parent theme have overridden the template
			load_template( $overridden_template, $require_once );
		} else {
			// If neither the child nor parent theme have overridden the template,
			// we load the template from the 'templates' sub-directory of the directory this file is in
			load_template( __DIR__ . '/templates/' . $name . '.php', $require_once );
		}
	}


	protected function end( $shortcode = null ) {
		$shortcode = $shortcode ? $shortcode : get_class( $this );
		$shortcode = str_replace( '\\', '-', $shortcode );  // Handle PHP namespaces.
		?>
	  <script>
	  document.documentElement.className += " jxl-shortcode <?php echo $shortcode ?>";
	  </script>
	<?php
	}

	protected static function echo_classes( $menu_it, $is_content = false ) {
		$classes = self::get_option( 'iet_simple_menu_item_class', '' );
		echo "menu-item $classes " . ( $is_content ? 'content ' : '' ) . implode( ' ', $menu_it->classes );
	}

	protected static function post_json( $menu_obj ) {
		echo json_encode([
			'cls'   => get_class( $menu_obj ),
			'nav_ID'   => $menu_obj->ID,
			'post_id' => $menu_obj->object_id,
			'type' => $menu_obj->object,
			# 'post_type' => $menu_obj->post_type, # 'nav_menu_item'
			'modified'  => $menu_obj->post_modified_gmt,
			#'url'  => $menu_obj->url,
			'author_id' => $menu_obj->post_author,
			'author' => get_the_author_meta( 'nickname', $menu_obj->post_author ), #Deprecated: get_author_name(..)
		]);
	}

	protected static function get_option( $key, $default = null ) {
		$_KEY = strtoupper( $key );
		$default = /*!$default &&*/ defined( $_KEY ) ? constant( $_KEY ) : $default;
		return get_option( $key, $default );
	}

}
$simple_menu = new Simple_Menu();