<?php
namespace Academy\Classes;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Keeps curriculum post types (lessons, quizzes, and whatever addons add via
 * the `academy/private_post_types` filter) out of the places WordPress shows
 * public posts on its own: RSS feeds, site search, and the post type's own
 * single URL (/lesson/{slug}/ ...).
 *
 * Students reach this content through the course curriculum URLs
 * (/course/{course}/lesson/{slug}/, `curriculum_type` query var), which do
 * their own enrollment check, so those are left alone. Users who can edit
 * the post type (admins, instructors) keep the direct URLs for previewing.
 */
class PrivatePostTypes {

	public static function init() {
		$self = new self();
		add_action( 'pre_get_posts', array( $self, 'exclude_from_feeds_and_search' ) );
		add_action( 'template_redirect', array( $self, 'block_direct_single' ), 1 );
	}

	public static function get_post_types() {
		/**
		 * Post types whose content is enrolled-only and must never be listed
		 * in feeds/search or opened through their own single URL.
		 *
		 * @param string[] $post_types
		 */
		return (array) apply_filters( 'academy/private_post_types', array( 'academy_lessons' ) );
	}

	protected function user_can_edit_any( array $post_types ) {
		foreach ( $post_types as $post_type ) {
			$object = get_post_type_object( $post_type );
			if ( $object && current_user_can( $object->cap->edit_posts ) ) {
				return true;
			}
		}
		return false;
	}

	/**
	 * @param \WP_Query $query
	 */
	public function exclude_from_feeds_and_search( $query ) {
		if ( is_admin() || ! $query->is_main_query() || ! ( $query->is_feed() || $query->is_search() ) ) {
			return;
		}
		$private   = self::get_post_types();
		$requested = $query->get( 'post_type' );

		if ( $query->is_feed() && $requested && array_intersect( (array) $requested, $private ) ) {
			// e.g. /feed/?post_type=academy_lessons — never list these.
			$query->set( 'post__in', array( 0 ) );
			return;
		}

		if ( $query->is_search() ) {
			if ( empty( $requested ) || 'any' === $requested ) {
				$requested = get_post_types( array( 'exclude_from_search' => false ) );
			}
			$allowed = array_values( array_diff( (array) $requested, $private ) );
			$query->set( 'post_type', $allowed ? $allowed : array( 'post' ) );
		}
	}

	public function block_direct_single() {
		if ( get_query_var( 'curriculum_type' ) ) {
			return; // Course curriculum URL: gated by the curriculum template.
		}
		$private = self::get_post_types();
		if ( ! is_singular( $private ) ) {
			return;
		}
		if ( $this->user_can_edit_any( array( get_post_type() ) ) ) {
			return;
		}
		global $wp_query;
		$wp_query->set_404();
		status_header( 404 );
		nocache_headers();
	}
}