function llms_page_restricted( $post_id, $user_id = null ) {

	$results = array(
		'content_id'     => $post_id,
		'is_restricted'  => false,
		'reason'         => 'accessible',
		'restriction_id' => 0,
	);

	if ( ! $user_id ) {
		$user_id = get_current_user_id();
	}

	$student = false;
	if ( $user_id ) {
		$student = new LLMS_Student( $user_id );
	}

	$post_type = get_post_type( $post_id );

	/**
	 * Do checks to determine if the content should be restricted.
	 */
	$sitewide_membership_id = llms_is_post_restricted_by_sitewide_membership( $post_id, $user_id );
	$membership_id          = llms_is_post_restricted_by_membership( $post_id, $user_id );

	if ( is_home() && $sitewide_membership_id ) {
		$restriction_id = $sitewide_membership_id;
		$reason         = 'sitewide_membership';
		// if it's a search page and the site isn't restricted to a membership bypass restrictions.
	} elseif ( ( is_search() ) && ! get_option( 'lifterlms_membership_required', '' ) ) {
		return apply_filters( 'llms_page_restricted', $results, $post_id );
	} elseif ( is_singular() && $sitewide_membership_id ) {
		$restriction_id = $sitewide_membership_id;
		$reason         = 'sitewide_membership';
	} elseif ( is_singular() && $membership_id ) {
		$restriction_id = $membership_id;
		$reason         = 'membership';
	} elseif ( is_singular() && 'lesson' === $post_type ) {
		$lesson = new LLMS_Lesson( $post_id );
		// if lesson is free, return accessible results and skip the rest of this function.
		if ( $lesson->is_free() ) {
			return $results;
		} else {
			$restriction_id = $lesson->get( 'parent_course' );
			$reason         = 'enrollment_lesson';
		}
	} elseif ( is_singular() && 'course' === $post_type ) {
		$restriction_id = $post_id;
		$reason         = 'enrollment_course';
	} elseif ( is_singular() && 'llms_membership' === $post_type ) {
		$restriction_id = $post_id;
		$reason         = 'enrollment_membership';
	} else {

		/**
		 * Allow filtering of results before checking if the student has access.
		 *
		 * @since Unknown.
		 *
		 * @param array $results Restriction check result data.
		 * @param int   $post_id WordPress Post ID of the content.
		 */
		$results = apply_filters( 'llms_page_restricted_before_check_access', $results, $post_id );
		extract( $results ); // phpcs:ignore

	}

	/**
	 * Content should be restricted, so we'll do the restriction checks
	 * and return restricted results.
	 *
	 * This is run if we have a restriction and a reason for restriction
	 * and we either don't have a logged in student or the logged in student doesn't have access.
	 */
	if ( ! empty( $restriction_id ) && ! empty( $reason ) && ( ! $student || ! $student->is_enrolled( $restriction_id ) ) ) {

		$results['is_restricted']  = true;
		$results['reason']         = $reason;
		$results['restriction_id'] = $restriction_id;

		/**
		 * Allow filtering of the restricted results.
		 *
		 * @since Unknown
		 *
		 * @param array $results Restriction check result data.
		 * @param int   $post_id WordPress Post ID of the content.
		 */
		return apply_filters( 'llms_page_restricted', $results, $post_id );

	}

	/**
	 * At this point student has access or the content isn't supposed to be restricted
	 * we need to do some additional checks for specific post types.
	 */
	if ( is_singular() ) {

		if ( 'llms_quiz' === $post_type ) {

			$quiz_id = llms_is_quiz_accessible( $post_id, $user_id );
			if ( $quiz_id ) {

				$results['is_restricted']  = true;
				$results['reason']         = 'quiz';
				$results['restriction_id'] = $post_id;
				/* This filter is documented above. */
				return apply_filters( 'llms_page_restricted', $results, $post_id );

			}
		}

		if ( 'lesson' === $post_type || 'llms_quiz' === $post_type ) {

			$course_id = llms_is_post_restricted_by_time_period( $post_id, $user_id );
			if ( $course_id ) {

				$results['is_restricted']  = true;
				$results['reason']         = 'course_time_period';
				$results['restriction_id'] = $course_id;
				/* This filter is documented above. */
				return apply_filters( 'llms_page_restricted', $results, $post_id );

			}

			$prereq_data = llms_is_post_restricted_by_prerequisite( $post_id, $user_id );
			if ( $prereq_data ) {

				$results['is_restricted']  = true;
				$results['reason']         = sprintf( '%s_prerequisite', $prereq_data['type'] );
				$results['restriction_id'] = $prereq_data['id'];
				/* This filter is documented above. */
				return apply_filters( 'llms_page_restricted', $results, $post_id );

			}

			$lesson_id = llms_is_post_restricted_by_drip_settings( $post_id, $user_id );
			if ( $lesson_id ) {

				$results['is_restricted']  = true;
				$results['reason']         = 'lesson_drip';
				$results['restriction_id'] = $lesson_id;
				/* This filter is documented above. */
				return apply_filters( 'llms_page_restricted', $results, $post_id );

			}
		}
	}

	/* This filter is documented above. */
	return apply_filters( 'llms_page_restricted', $results, $post_id );

}