Paid Memberships Pro + LearnDash: Courses per Membership Level

if ( ! function_exists( 'pmpro_hasMembershipLevel' ) || ! function_exists( 'ld_update_course_access' ) ) {
    return;
}

// Level ID => LearnDash course IDs.
$wpide_pmpro_ld_courses = array(
    1 => array( 1001 ),
    2 => array( 1001, 1002, 1003 ),
);

add_action( 'pmpro_after_change_membership_level', function ( $level_id, $user_id ) use ( $wpide_pmpro_ld_courses ) {
    $keep = array();

    foreach ( $wpide_pmpro_ld_courses as $level => $courses ) {
        if ( pmpro_hasMembershipLevel( $level, $user_id ) ) {
            $keep = array_merge( $keep, array_map( 'intval', $courses ) );
        }
    }

    // Only courses this snippet granted are ever removed, never ones bought separately.
    $granted = array_map( 'intval', (array) get_user_meta( $user_id, 'wpide_pmpro_ld_granted', true ) );

    foreach ( array_unique( $keep ) as $course_id ) {
        if ( ! sfwd_lms_has_access( $course_id, $user_id ) ) {
            ld_update_course_access( (int) $user_id, $course_id );
            $granted[] = $course_id;
        }
    }

    foreach ( array_diff( $granted, $keep ) as $course_id ) {
        ld_update_course_access( (int) $user_id, $course_id, true );
    }

    update_user_meta( $user_id, 'wpide_pmpro_ld_granted', array_values( array_intersect( array_unique( $granted ), $keep ) ) );
}, 10, 2 );