Course content stay in sync whenever a course's main instructor is changed

classes/Course.php

@@ -328,7 +328,7 @@
 		global $wp_query;
 		$course_coming_soon_enabled = (int) get_post_meta( $content->ID, '_tutor_course_enable_coming_soon', true );
 		$is_instructor              = tutor_utils()->is_instructor_of_this_course( get_current_user_id(), $content->ID, true );
 		if ( ! CourseModel::get_post_types( $content ) || current_user_can( 'administrator' ) || $is_instructor || $course_coming_soon_enabled ) {
 			return $content;
 		}
 
@@ -659,7 +659,7 @@
 						} else {
 							$errors['pricing'] = __( 'Invalid product', 'tutor' );
 						}
 					} else {
 						/**
 						 * If user does not select WC product
 						 * Then automatic WC product will be create name with course title.
@@ -796,7 +796,7 @@
 					update_post_meta( $post_id, self::COURSE_PRICE_TYPE_META, $params['pricing']['type'] );
 				}
 			} catch ( \Throwable $th ) {
 				throw new \Exception( $th->getMessage() );
 			}
 		}
 
@@ -1977,10 +1977,21 @@
 		/**
 		 * Adding author to instructor automatically
 		 */
+		$requested_author_id = Input::post( 'post_author_override', 0, Input::TYPE_INT );
 
-		// Override post author id.
-		$author_id = isset( $_POST['post_author_override'] ) ? $_POST['post_author_override'] : $post->post_author; //phpcs:ignore
-		$attached  = (int) $wpdb->get_var(
+		/**
+		 * Only accept the requested author override if it targets a real,approved instructor or admin
+		 *
+		 * @since 4.0.4
+		 */
+		$author_id = $post->post_author;
+		if ( $requested_author_id && ( User::is_admin() || User::is_instructor() ) ) {
+			if ( User::is_admin( $requested_author_id ) || User::is_instructor( $requested_author_id, true ) ) {
+				$author_id = $requested_author_id;
+			}
+		}
+
+		$attached = (int) $wpdb->get_var(
 			$wpdb->prepare(
 				"SELECT COUNT(umeta_id) FROM {$wpdb->usermeta}
 					WHERE user_id = %d
@@ -2007,6 +2018,18 @@
 			}
 		}
 
+		/**
+		 * Update course content if main author is changed and multi-instructor addon is disabled.
+		 *
+		 * @since 4.0.4
+		 */
+		if ( ! $attached && ! tutor_utils()->is_addon_enabled( 'tutor-multi-instructors' ) ) {
+			CourseModel::update_course_content_author( $post_ID, (int) $author_id );
+			// Remove all existing instructors from the course and add the new one.
+			delete_metadata( 'user', 0, '_tutor_instructor_course_id', $post_ID, true );
+			add_user_meta( $author_id, '_tutor_instructor_course_id', $post_ID );
+		}
+
 		do_action( 'tutor_save_course_after', $post_ID, $post );
 	}
 
@@ -2420,7 +2443,7 @@
 		/**
 		 * Only admin can change main author
 		 */
 		if ( $courses_post_type === $post_type && ! current_user_can( 'administrator' ) ) {
 			global $wpdb;
 			$post_ID     = (int) tutor_utils()->avalue_dot( 'ID', $postarr );
 			$post_author = (int) $wpdb->get_var( $wpdb->prepare( "SELECT post_author FROM {$wpdb->posts} WHERE ID = %d ", $post_ID ) );

models/CourseModel.php

@@ -743,7 +743,7 @@
 		);
 
 		// Check if the current user is an admin.
 		if ( ! current_user_can( 'administrator' ) ) {
 			$args['author'] = $current_user->ID;
 		}
 
@@ -1180,7 +1180,7 @@
 			),
 		);
 
 		$courses = current_user_can( 'administrator' ) ? self::get_courses() : self::get_courses_by_instructor();
 		if ( ! empty( $courses ) ) {
 			foreach ( $courses as $course ) {
 				$course_options[] = array(
@@ -1520,7 +1520,7 @@
 		$args = wp_parse_args( $args, $defaults );
 
 		if ( ! $args['course_id'] || ! $args['current_post_id'] || ! $args['current_post_type'] ) {
 			throw new InvalidArgumentException( __( 'Invalid argument passed', 'tutor' ) );
 		}
 
 		$has_access = false;
@@ -1750,4 +1750,74 @@
 			+ ( $duration['durationMinutes'] * MINUTE_IN_SECONDS )
 			+ ( $duration['durationSeconds'] );
 	}
+
+	/**
+	 * Update the post_author of a course's content (topics, lessons,
+	 * quizzes and assignments) to a given user.
+	 *
+	 * @since 4.0.3
+	 *
+	 * @param int $course_id course id.
+	 * @param int $author_id new author (user) id.
+	 *
+	 * @return bool
+	 */
+	public static function update_course_content_author( int $course_id, int $author_id ): bool {
+		global $wpdb;
+
+		$content_ids = get_posts(
+			array(
+				'post_parent'    => $course_id,
+				'post_type'      => tutor()->topics_post_type,
+				'fields'         => 'ids',
+				'posts_per_page' => -1,
+				'post_status'    => 'any',
+			)
+		);
+
+		$content_ids        = is_array( $content_ids ) ? $content_ids : array();
+		$default_post_types = array( tutor()->lesson_post_type, tutor()->quiz_post_type );
+		$content_post_types = array_unique( apply_filters( 'tutor_course_contents_post_types', $default_post_types ) );
+
+		$primary_table = 'posts as course';
+		$topic_table   = 'posts as topic';
+		$content_table = 'posts as content';
+
+		$joined_data = QueryHelper::get_joined_data(
+			$primary_table,
+			array(
+				array(
+					'type'  => 'INNER',
+					'table' => $topic_table,
+					'on'    => 'course.ID = topic.post_parent',
+				),
+				array(
+					'type'  => 'INNER',
+					'table' => $content_table,
+					'on'    => 'topic.ID = content.post_parent',
+				),
+			),
+			array( 'content.ID' ),
+			array(
+				'course.ID'         => $course_id,
+				'content.post_type' => array( 'IN', $content_post_types ),
+			),
+			array(),
+			'',
+			-1
+		);
+
+		$content_ids = array_merge( $content_ids, wp_list_pluck( $joined_data['results'], 'ID' ) );
+		$content_ids = array_filter( array_unique( array_map( 'absint', $content_ids ) ) );
+
+		if ( empty( $content_ids ) ) {
+			return false;
+		}
+
+		return (bool) QueryHelper::update_where_in(
+			$wpdb->posts,
+			array( 'post_author' => $author_id ),
+			implode( ',', $content_ids )
+		);
+	}
 }