Create / Delete / Check cookies

functions.php

add_action( 'wp', 'action_cookies' );

function action_cookies() {

    global $post;

    // abort if not a page/post
    if(! $post)
    {
        return;
    }

    // list of page slugs to protect (must have same format as below)
    $protected_slugs = [
        '1-reveal',
    ];

    // default page that user is redirected to after subscribing
    $default_protected_slug = '1-reveal';

    // "success" page after subscribing to set cookie
    $cookie_create_page_slug = 'cookie-create';

    // page to delete cookies (for testing purposes only)
    $cookie_delete_page_slug = 'cookie-delete';


    // cookie actions >>>
    if( $post->post_name === $cookie_create_page_slug ) {

        // set cookie to expire in 10 years
        setcookie( 'manna-anglican-subscribed', TRUE, time() + ( 10 * 365 * 24 * 60 * 60 ) );

        // redirect to protected page
        $slug = ( isset( $_COOKIE['manna-anglican-page-requested'] ) ? $_COOKIE['manna-anglican-page-requested'] : $default_protected_slug );

        wp_redirect( get_permalink( get_page_by_path( $slug ) ) );

        exit;

    } else if( $post->post_name === $cookie_delete_page_slug ) {

        // delete cookies (for testing purposes only)
        setcookie( 'manna-anglican-subscribed', null, time() - 3600 );
        setcookie( 'manna-anglican-page-requested', null, time() - 3600 );

    } else if( in_array( $post->post_name, $protected_slugs ) ) {

        // prevent access to protected pages
        if( ! isset( $_COOKIE['manna-anglican-subscribed'] ) ) {

            // set cookie to expire in 1 day
            setcookie( 'manna-anglican-page-requested', $post->post_name, time() + ( 24 * 60 * 60 ) );

            // convert "1-reveal” to "1-sign-up”
            $subscribe_page_slug = str_replace('-reveal', '-sign-up', $post->post_name );

            // redirect to page to allow user to subscribe
            wp_redirect( get_permalink( get_page_by_path( $subscribe_page_slug ) ) ); exit;

        }

    }

}