<?

// User login bruteforce protect
function catch_failed_logins($username) {
    
    global $wpdb;
    
    // Check if logging table exists
    $sql = "
    SELECT * 
    FROM information_schema.tables
    WHERE table_schema = '".DB_NAME."' 
        AND table_name = '".$wpdb->prefix."bruteforce_logger'
    LIMIT 1;";
    
    $result = $wpdb->query($sql);
    
    // Table doesn't exist. Create it!
    if (!$result) {
        
        $sql = "
        CREATE TABLE IF NOT EXISTS `".$wpdb->prefix."bruteforce_logger` (
          `id` int(11) NOT NULL,
          `ip` char(15) NOT NULL,
          `username` varchar(30) NOT NULL,
          `date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
        ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=1;";
        
        $wpdb->query($sql);
        
        $sql = "
        ALTER TABLE `".$wpdb->prefix."bruteforce_logger`
        ADD PRIMARY KEY (`id`);";
        
        $wpdb->query($sql);
        
        $sql = "
        ALTER TABLE `".$wpdb->prefix."bruteforce_logger`
        MODIFY `id` int(11) NOT NULL AUTO_INCREMENT;";
        
        $wpdb->query($sql);
        
    }
    
    // Add failed attempt to logs
    $sql = "
    INSERT INTO `".$wpdb->prefix."bruteforce_logger` (
        `ip`,
        `username`,
        `date`
    ) VALUES (
        '".esc_sql($_SERVER['REMOTE_ADDR'])."',
        '".esc_sql($username)."',
        NOW()
    )";
    $wpdb->query($sql);
    
}
add_action( 'wp_login_failed', 'catch_failed_logins' );

function protect_wordpress_login() {
    
    global $wpdb;
    
    // Get number of failed attempts from last 5 minutes
    $sql = "SELECT COUNT(*) AS `amount` FROM `".$wpdb->prefix."bruteforce_logger` WHERE `ip` = '".esc_sql($_SERVER['REMOTE_ADDR'])."' AND `date` > DATE_SUB(NOW(),INTERVAL 5 MINUTE)";
    $result = $wpdb->get_results($sql);
    
    // There is a result!
    if ($result) {
        
        // Result exceeds 5. Block the user.
        if ($result[0]->amount > 5) {
            
            // Show message
            echo 'You are blocked for 5 minutes due to too many failed login attempts.';
            exit;
            
        }
        
    }
    
}
add_action('login_init','protect_wordpress_login');<?

function register_menus() {
  register_nav_menu('header-menu',__( 'Header Menu' ));
  register_nav_menu('subheader-menu',__( 'Subheader Menu' ));
  register_nav_menu('menu-footer',__( 'Footer Menu' ));
  register_nav_menu('menu-footer-zoekwoorden',__( 'SEO Menu' ));

}
add_action( 'init', 'register_menus' );<?

if (is_admin()) {

    add_filter( 'admin_footer_text', 'my_admin_footer_text' );

    function my_admin_footer_text( $default_text ) {

        return '<span id="footer-thankyou">Website ontwikkeld door <a href="http://www.yellowlemontree.nl">Yellow Lemon Tree</a><span> | Mede mogelijk gemaakt door <a href="http://www.wordpress.org">WordPress</a>';

    }

}<?

add_action('init','register_post_types');

function register_post_types() {
   
    // Producten
    register_post_type('references_posts',
        array(
        'label' => __('References'),
        'labels' => array(
                'name'                  => __('Referenties'),
                'singular_name'         => __('Referentie'),
                'add_new'               => __('Referentie toevoegen'),
                'add_new_item'          => __('Nieuwe referentie'),
                'edit_item'             => __('Wijzig referentie'),
                'new_item'              => __('Nieuwe referentie'),
                'all_items'             => __('Alle referenties'),
                'view_item'             => __('Bekijk referentie'),
                'search_items'          => __('Zoek referentie'),
                'not_found'             => __('Er zijn geen referenties gevonden'),
                'not_found_in_trash'    => __('Geen referenties gevonden in de prullenbak')
        ),
        'public'            => false,
        'can_export'        => false,
        'show_ui'           => true,
        '_builtin'          => false,
        '_edit_link'        => 'post.php?post=%d',
		'menu_icon'			=> 'dashicons-groups',
        'capability_type'   => 'post',
        'hierarchical'      => false,
        'rewrite'           => array("slug" => 'referenties'), // Permalinks
        'supports'          => array(
            'title',
        ),
        'show_in_menu'      => true,
        'taxonomies'        => array("references_taxo")
        )
    );
    
   register_taxonomy("references_taxo", array('references_posts'), 
    array(
        "hierarchical" => true,
        "label" => "Categorieën",
        'labels' => array(
            'name' => __('Categorie'),
            'singular_name' => __('Categorie'),
            'search_items' => __('Categorieën zoeken'),
            'popular_items' => __('Populaire categorieën'),
            'all_items' => __('Alle categorieën'),
            'parent_item' => __('Huidige categorie'),
            'parent_item_colon' => __('Huidige categorie:'),
            'edit_item' => __('Wijzig categorie'),
            'update_item' => __('Wijzig categorie'),
            'add_new_item' => __('Nieuwe categorie toevoegen'),
            'new_item_name' => __('Nieuwe categorie')),
        'public' => false,
        'query_var' => true,
        'rewrite' => array('slug' => 'accommodaties'),
        'show_ui' => true,
        'with_front' => false
    )
);
}<?
add_action( 'cmb2_admin_init', 'homepage_partnerslider_metabox' );
add_action( 'cmb2_admin_init', 'homepage_infobox_meta' );
add_action( 'cmb2_admin_init', 'homepage_headerslider_meta' );
add_action( 'cmb2_admin_init', 'pagesettings_meta' );
add_action( 'cmb2_admin_init', 'pagesettings_default_meta' );
add_action( 'cmb2_admin_init', 'pagesettings_default2_meta' );
add_action( 'cmb2_admin_init', 'pagepreview_meta' );
add_action( 'cmb2_admin_init', 'custombuttons_meta' );
add_action( 'cmb2_admin_init', 'references_meta' );
add_action( 'cmb2_admin_init', 'product_meta' );

function product_meta () {
    $prefix = '_product_';
    
    $cmb = new_cmb2_box( array(
            'id'            => $prefix,
            'title'         => "Product eigenschappen",
            'object_types'  => array( 'page'),
            'show_on'       => array( 'key' => 'page-template', 'value' => array('productpage.php')),
            'show_names'    => true,
    ) );
    
    $cmb->add_field( array(
            'name'       => __( 'Materiaal', 'cmb2' ),
            'id'         => $prefix . 'material',
            'type'       => 'text',
    ) );
    
    $cmb->add_field( array(
            'name'       => __( 'Gewicht', 'cmb2' ),
            'id'         => $prefix . 'weight',
            'type'       => 'text',
    ) );
    
    $cmb->add_field( array(
            'name'       => __( 'Brandwerend', 'cmb2' ),
            'id'         => $prefix . 'fireproof',
            'type'       => 'text',
    ) );

    $cmb->add_field( array(
            'name'       => __( 'Bedrukking', 'cmb2' ),
            'id'         => $prefix . 'printing',
            'type'       => 'text',
    ) );
    
    $cmb->add_field( array(
            'name'       => __( 'Max. rolbreedte', 'cmb2' ),
            'id'         => $prefix . 'rollwidth',
            'type'       => 'text_small',
    ) );
    
    $cmb->add_field( array(
            'name'       => __( 'Max. rollengte', 'cmb2' ),
            'id'         => $prefix . 'rolllength',
            'type'       => 'text_small',
    ) );
    
    $cmb->add_field( array(
            'name'       => __( 'Textuur', 'cmb2' ),
            'id'         => $prefix . 'texture',
            'type'       => 'text_small',
    ) );
    
    $cmb->add_field( array(
            'name'       => __( 'Afwerking', 'cmb2' ),
            'id'         => $prefix . 'finish',
            'type'       => 'text',
    ) );
    
    $cmb->add_field( array(
            'name'       => __( 'Toepassingen', 'cmb2' ),
            'id'         => $prefix . 'uses',
            'type'       => 'text',
    ) );
    
    $cmb->add_field( array(
            'name'       => __( 'Indoor / outdoor', 'cmb2' ),
            'id'         => $prefix . 'indoor',
            'type'       => 'text_medium',
    ) );
        
    $cmb->add_field( array(
            'name'       => __( 'Waterafstotend', 'cmb2' ),
            'id'         => $prefix . 'waterproof',
            'type'       => 'text_small',
    ) );
        
    $cmb->add_field( array(
            'name'       => __( 'Translucent', 'cmb2' ),
            'id'         => $prefix . 'translucent',
            'type'       => 'text_small',
    ) );
    
    $cmb->add_field( array(
            'name' => __( 'Detail afbeelding 1', 'cmb2' ),
            'desc' => __( 'Afbeelding dient minimaal 190px breed bij 190px hoog te zijn', 'cmb2' ),
            'id'   => $prefix . 'detailimg_1',
            'type' => 'file',
    ) );
	
	$cmb->add_field( array(
            'name' => __( 'Detail afbeelding 1 ALT tekst', 'cmb2' ),
            'id'   => $prefix . 'detailimg_1_alt',
            'type' => 'text',
    ) );
    
    $cmb->add_field( array(
            'name' => __( 'Detail afbeelding 2', 'cmb2' ),
            'desc' => __( 'Afbeelding dient minimaal 190px breed bij 190px hoog te zijn', 'cmb2' ),
            'id'   => $prefix . 'detailimg_2',
            'type' => 'file',
    ) );
	
	$cmb->add_field( array(
            'name' => __( 'Detail afbeelding 2 ALT tekst', 'cmb2' ),
            'id'   => $prefix . 'detailimg_2_alt',
            'type' => 'text',
    ) );
}

function references_meta () {
    $prefix = '_reference_';
    
    $cmb = new_cmb2_box( array(
            'id'            => $prefix,
            'title'         => "Referentie gegevens",
            'object_types'  => array( 'references_posts'), 
            'show_names'    => true,
    ) );
    
    $cmb->add_field( array(
		'name' => __( 'Website URL', 'cmb2' ),
		'id'   => $prefix . 'url',
		'type' => 'text_url',
		'protocols' => array('http', 'https')
	) );
    
    $cmb->add_field( array(
            'name' => __( 'Logo', 'cmb2' ),
            'id'   => $prefix . 'logo',
            'type' => 'file',
    ) );
}

function custombuttons_meta () {
    $prefix = '_custombutton';
    $post_id = !empty($_GET['post']) ? $_GET['post'] : null;
    
    if($post_id == 89){
        return false;
    }
    
    $cmb = new_cmb2_box( array(
            'id'            => $prefix,
            'title'         => "Custom knoppen",
            'object_types'  => array( 'page', ), // Post type
            'show_names'    => true,
    ) );
    
    $group_field_id = $cmb->add_field( array(
            'id'          => $prefix . 'groupfield',
            'type'        => 'group',
            'description' => __( 'Maak hier eigen knoppen aan welke u op de pagina kunt gebruiken. Gebruik een knop door b.v. [button id=1] in uw bericht te plaatsen.', 'cmb2' ),
            'options'     => array(
                    'group_title'   => __( '[button id={#}]', 'cmb2' ),
                    'add_button'    => __( 'Nieuwe knop toevoegen', 'cmb2' ),
                    'remove_button' => __( 'Verwijder knop', 'cmb2' ),
                    'sortable'      => false,
            ),
    ) );
    
    $cmb->add_group_field($group_field_id, array(
            'name'       => __( 'Knoplabel', 'cmb2' ),
            'id'         => 'buttontxt',
            'type'       => 'text_medium',
    ) );
    
    $cmb->add_group_field($group_field_id, array(
            'name'             => __( 'Pagina', 'cmb2' ),
            'desc'             => __( 'Selecteer een pagina waarnaar de knop moet linken', 'cmb2' ),
            'id'               => 'page',
            'type'             => 'select',
            'show_option_none' => true,
            'options'          => get_pageselect_options(),
    ) );
    $cmb->add_group_field($group_field_id, array(
            'name'             => __( 'Knoptype', 'cmb2' ),
            'id'               => 'type',
            'type'             => 'select',
            'show_option_none' => false,
            'options'          => array("full" => "Volledig kleur", "empty" => "Witte binnenkant"),
    ) );
}

function homepage_headerslider_meta () {
    $prefix = '_hmp_headerslider';
    $post_id = !empty($_GET['post']) ? $_GET['post'] : null;
    
    if(!empty($post_id) && $post_id != 89){
        return false;
    }
    
    $cmb = new_cmb2_box( array(
            'id'            => $prefix,
            'title'         => "Hoofdafbeelding slider afbeeldingen",
            'object_types'  => array( 'page', ), // Post type
            'show_names'    => true,
    ) );
    
    $group_field_id = $cmb->add_field( array(
            'id'          => $prefix . 'left_groupfield',
            'type'        => 'group',
            'options'     => array(
                    'group_title'   => __( 'Slider links', 'cmb2' ),
                    'add_button'    => __( 'Nieuwe afbeelding toevoegen', 'cmb2' ),
                    'remove_button' => __( 'Verwijder afbeelding', 'cmb2' ),
                    'sortable'      => false,
            ),
    ) );

    $cmb->add_group_field($group_field_id, array(
            'name' => __( 'Afbeelding', 'cmb2' ),
            'desc' => __( 'Afmeting afbeelding minimaal 250px breedte bij 250px hoog', 'cmb2' ),
            'id'   => $prefix . 'image',
            'type' => 'file',
    ) );
    
    
    $rgroup_field_id = $cmb->add_field( array(
            'id'          => $prefix . 'right_groupfield',
            'type'        => 'group',
            'options'     => array(
                    'group_title'   => __( 'Slider rechts', 'cmb2' ),
                    'add_button'    => __( 'Nieuwe afbeelding toevoegen', 'cmb2' ),
                    'remove_button' => __( 'Verwijder afbeelding', 'cmb2' ),
                    'sortable'      => false,
            ),
    ) );

    $cmb->add_group_field($rgroup_field_id, array(
            'name' => __( 'Afbeelding', 'cmb2' ),
            'desc' => __( 'Afmeting afbeelding minimaal 250px breedte bij 250px hoog', 'cmb2' ),
            'id'   => $prefix . 'image',
            'type' => 'file',
    ) );
}

function pagepreview_meta () {
    $prefix = '_pagepreview';
    
    $cmb = new_cmb2_box( array(
            'id'            => $prefix,
            'title'         => "Pagina voorvertoning",
            'object_types'  => array( 'page'), // Post type
            'show_names'    => true,
    ) );
    
    $cmb->add_field( array(
            'name'       => __( 'Omschrijving', 'cmb2' ),
            'id'         => $prefix . 'desc',
            'type'       => 'textarea_small',
            'desc'          => 'Omschrijf hier in het kort waar de pagina over gaat. Deze informatie wordt op de overzichtpagina\'s getoond',
    ) );
    
    $cmb->add_field( array(
            'name' => __( 'Afbeelding 1', 'cmb2' ),
            'desc' => __( 'Afmeting afbeelding minimaal 500px breedte bij 300px hoog', 'cmb2' ),
            'id'   => $prefix . 'image1',
            'type' => 'file',
    ) );
    
    $cmb->add_field( array(
            'name' => __( 'Afbeelding 2', 'cmb2' ),
            'desc' => __( 'Afmeting afbeelding minimaal 500px breedte bij 300px hoog', 'cmb2' ),
            'id'   => $prefix . 'image2',
            'type' => 'file',
    ) );
    
    $cmb->add_field( array(
            'name' => __( 'Afbeelding 3', 'cmb2' ),
            'desc' => __( 'Afmeting afbeelding minimaal 500px breedte bij 300px hoog', 'cmb2' ),
            'id'   => $prefix . 'image3',
            'type' => 'file',
    ) );
}

function pagesettings_meta() {
    $prefix = '_pagesettings_';
    $post_id = !empty($_GET['post']) ? $_GET['post'] : null;
    
    $cmb = new_cmb2_box( array(
            'id'            => $prefix . 'metabox',
            'title'         => __( 'Pagina instellingen', 'cmb2' ),
            'object_types'  => array( 'page'), // Post type
            'show_on'       => array( 'key' => 'page-template', 'value' => array('groupoverview.php', 'contactpage.php', 'homepage_20160526_1649_original-oktober2018.php') ),
            'show_names'    => true,
    ) );
    
    $cmb->add_field( array(
            'name'       => __( 'Titel op afbeelding', 'cmb2' ),
            'id'         => $prefix . 'title',
            'type'       => 'text',
    ) );
    
    if($post_id != 89){
        $cmb->add_field( array(
                'name'       => __( 'Subtitel 1', 'cmb2' ),
                'id'         => $prefix . 'subtitle1',
                'type'       => 'text',
        ) );

        $cmb->add_field( array(
                'name'       => __( 'Subtitel 2', 'cmb2' ),
                'id'         => $prefix . 'subtitle2',
                'type'       => 'text',
        ) );

        $cmb->add_field( array(
                'name'       => __( 'Subtitel 3', 'cmb2' ),
                'id'         => $prefix . 'subtitle3',
                'type'       => 'text',
        ) );

        $cmb->add_field( array(
                'name'       => __( 'Subtitel 4', 'cmb2' ),
                'id'         => $prefix . 'subtitle4',
                'type'       => 'text',
        ) );
    }   
        
    $cmb->add_field( array(
            'name' => __( 'Hoofdafbeelding', 'cmb2' ),
            'desc' => __( 'Afbeelding dient minimaal 1250px breed te zijn', 'cmb2' ),
            'id'   => $prefix . 'image',
            'type' => 'file',
    ) );
	
	$cmb->add_field( array(
            'name' => __( 'Hoofdafbeelding ALT tekst', 'cmb2' ),
            'desc' => __( 'SEO-vriendelijke tekst voor de hoofdafbeelding', 'cmb2' ),
            'id'   => $prefix . 'image_alt',
            'type' => 'text',
    ) );
    
    if($post_id != 89){
        $cmb->add_field( array(
                'name'             => __( 'Kleurenschema', 'cmb2' ),
                'id'               => $prefix . 'color',
                'type'             => 'select',
                'options'          => array("lightblue" => "Licht blauw", "blue" => "Blauw", "purple" => "Paars", "grey" => "Grijs"),
        ) );
    }    
}

function pagesettings_default_meta() {
    $prefix = '_pagesettingsdefault_';
    $post_id = !empty($_GET['post']) ? $_GET['post'] : null;
    $ancestor_id = end(get_ancestors( $post_id, 'page' ));
    
    $cmb = new_cmb2_box( array(
            'id'            => $prefix . 'metabox',
            'title'         => __( 'Pagina instellingen', 'cmb2' ),
            'object_types'  => array( 'page', ), // Post type
            'show_on'       => array( 'key' => 'page-template', 'value' => array('default', 'productpage.php', 'fullpage.php') ),
            'show_names'    => true,
    ) );
    
    $cmb->add_field( array(
            'name'       => __( 'Titel op afbeelding', 'cmb2' ),
            'id'         => $prefix . 'title',
            'type'       => 'text',
    ) );
    
    $cmb->add_field( array(
            'name' => __( 'Hoofdafbeelding', 'cmb2' ),
            'desc' => __( 'Afbeelding dient minimaal 1250px breed te zijn', 'cmb2' ),
            'id'   => $prefix . 'image',
            'type' => 'file',
    ) );
	
	$cmb->add_field( array(
            'name' => __( 'Hoofdafbeelding ALT tekst', 'cmb2' ),
            'desc' => __( 'SEO-vriendelijke ALT tekst voor de hoofdafbeelding', 'cmb2' ),
            'id'   => $prefix . 'image_alt_algemeen',
            'type' => 'text',
    ) );
    
    $cmb->add_field( array(
            'name'             => __( 'Kleurenschema', 'cmb2' ),
            'id'               => $prefix . 'color',
            'type'             => 'select',
            'options'          => array("lightblue" => "Licht blauw", "blue" => "Blauw", "purple" => "Paars", "grey" => "Grijs"),
    ) );
    
    if (empty($post_id) || $ancestor_id == 8) {
        $cmb->add_field( array(
                'name'     => __( 'Referentiecategorie', 'cmb2' ),
                'id'       => $prefix . 'referencecat',
                'type'     => 'select',
                'show_option_none' => true,
		'options' => getReferenceCategories(),
        ) );
    }
}


function pagesettings_default2_meta() {
    $prefix = '_pagesettingsdefault2_';
    $post_id = !empty($_GET['post']) ? $_GET['post'] : null;
    $ancestor_id = end(get_ancestors( $post_id, 'page' ));
    
    $cmb = new_cmb2_box( array(
            'id'            => $prefix . 'metabox2',
            'title'         => __( 'Header afbeelding - SEO vriendelijke ALT tekst', 'cmb2' ),
            'object_types'  => array( 'page'), // Post type
            'show_on'       => array( 'key' => 'page-template', 'value' => array('contactpage_old_.php', 'contactpage_old_original.php', 'homepage_20160526_1649_original-oktober2018.php', 									'pricelist.php', 'productpage.php', 'references.php') ),
            'show_names'    => true,
    ) );
	
	$cmb->add_field( array(
            'name' => __( 'SEO vriendelijke alt tekst', 'cmb2' ),
            'desc' => __( 'SEO vriendelijke ALT tekst voor de header afbeelding op deze pagina', 'cmb2' ),
            'id'   => $prefix . 'image_alt_algemeen2',
            'type' => 'text',
    ) );
    

}


function homepage_infobox_meta() {
    $prefix = '_home_infobox_';
    
    $cmb = new_cmb2_box( array(
            'id'            => $prefix . 'metabox',
            'title'         => __( 'Informatieblok', 'cmb2' ),
            'object_types'  => array( 'page', ), // Post type
            'show_on'       => array( 'key' => 'page-template', 'value' => 'homepage_20160526_1649_original-oktober2018.php' ),
            'show_names'    => true,
    ) );
    
    $cmb->add_field( array(
            'name'       => __( 'Titel', 'cmb2' ),
            'id'         => $prefix . 'title',
            'type'       => 'text',
    ) );
    
    $cmb->add_field( array(
            'name'       => __( 'Tekstveld', 'cmb2' ),
            'id'         => $prefix . 'description',
            'type'       => 'textarea_small',
    ) );
        
    $cmb->add_field( array(
            'name'       => __( 'Knoplabel', 'cmb2' ),
            'id'         => $prefix . 'buttontxt',
            'type'       => 'text_medium',
    ) );
    
    $cmb->add_field( array(
            'name'             => __( 'Pagina', 'cmb2' ),
            'desc'             => __( 'Selecteer een pagina waarnaar de knop moet linken', 'cmb2' ),
            'id'               => $prefix . 'page',
            'type'             => 'select',
            'show_option_none' => true,
            'options'          => get_pageselect_options(),
    ) );

    $cmb->add_field(array(
            'name' => __( 'Afbeelding', 'cmb2' ),
            'desc' => __( 'Afmeting afbeelding minimaal 500px breedte bij 300px hoog', 'cmb2' ),
            'id'   => $prefix . 'image',
            'type' => 'file',
    ) );
}

function homepage_partnerslider_metabox() {
	$prefix = '_referenceslider_';
	$cmb = new_cmb2_box( array(
		'id'           => $prefix . 'metabox',
		'title'        => __( 'Referentie slider', 'cmb2' ),
		'object_types' => array( 'page'),
        'show_on'      => array( 'key' => 'page-template', 'value' => 'homepage_20160526_1649_original-oktober2018.php' ),
	) );
	
	$cmb->add_field( array(
		'name'    => __( 'Referenties', 'cmb2' ),
		'id'      => $prefix . 'multicheckbox',
		'type'    => 'multicheck',
		'options' => get_references()
        ) );
}


function get_references () {
    $arr = array();

    $query = new WP_Query(array('post_type' => 'references_posts','posts_per_page' => -1));

    if(empty($query->posts)) {
        return array();
    }
    
    foreach ($query->posts as $partner) {
        $arr[$partner->ID] = $partner->post_title;
    }
    
    wp_reset_query(); 
    return $arr;
}

function get_pageselect_options() {
    $return = array();
    $arr_pages = get_pages(array('orderby' => 'post_title','order' => 'ASC', 'post_status' => 'publish'));
    
    foreach ($arr_pages as $page) {
        if($page->ID != 89){
            $return[$page->ID] = $page->post_title;
        }
    }
    
    return $return;
}


/**
 * Metabox for Children of Parent ID
 * @author Kenneth White (GitHub: sprclldr)
 * @link https://github.com/WebDevStudios/CMB2/wiki/Adding-your-own-show_on-filters
 *
 * @param bool $display
 * @param array $meta_box
 * @return bool display metabox
 */
function be_metabox_show_on_child_of( $display, $meta_box ) {
    if ( ! isset( $meta_box['show_on']['key'], $meta_box['show_on']['value'] ) ) {
        return $display;
    }

    if ( 'child_of' !== $meta_box['show_on']['key'] ) {
        return $display;
    }

    $post_id = 0;

    // If we're showing it based on ID, get the current ID
    if ( isset( $_GET['post'] ) ) {
        $post_id = $_GET['post'];
    } elseif ( isset( $_POST['post_ID'] ) ) {
        $post_id = $_POST['post_ID'];
    }

    if ( ! $post_id ) {
        return $display;
    }

    $pageids = array();
    foreach( (array) $meta_box['show_on']['value'] as $parent_id ) {
        $pages = get_pages( array(
            'child_of'    => $parent_id,
            'post_status' => 'publish,draft,pending',
        ) );

        if ( $pages ) {
            foreach( $pages as $page ){
                if ($page->post_parent == $parent_id)
                    $pageids[] = $page->ID;
            }
        }
    }
    $pageids_unique = array_unique( $pageids );

    return in_array( $post_id, $pageids_unique );
}
add_filter( 'cmb2_show_on', 'be_metabox_show_on_child_of', 10, 2 );

/**
 * Get reference Categories
 * 
 * @global object $wpdb
 * @return array $arr
 */
function getReferenceCategories() {  
    global $wpdb;
    $arr = array();
  
    $sql = "SELECT      t.`term_id`, t.`name`
            FROM        `wp_term_taxonomy` as ta 
            LEFT JOIN   `wp_terms` as t
                ON ta.`term_id` = t.`term_id`
            WHERE       ta.`taxonomy` = 'references_taxo'"; 
    
    $result = $wpdb->get_results($sql);
    
    if(!empty($result)) {
        foreach($result as $term) {
            $arr[$term->term_id] = $term->name; 
        }
    }
    return $arr;
}
<?

add_filter( 'tiny_mce_before_init', 'register_editor_styles' );

function register_editor_styles( $settings ) {
    
    $style_formats = array(
        array(
        	'title' => 'Introductie',
        	'block' => 'div',
        	'classes' => 'intro'
        )
    );

    $settings['style_formats'] = json_encode( $style_formats );

    return $settings;

}
// Callback function to insert 'styleselect' into the $buttons array
function register_tiny_mce_buttons( $buttons ) {
	array_unshift( $buttons, 'styleselect' );
	return $buttons;
}
// Register our callback to the appropriate filter
add_filter('mce_buttons_2', 'register_tiny_mce_buttons');