public function save() {
		if ( ! is_user_logged_in() ) {
			wp_send_json_error( 'unauthenticated' );
		}

		if ( ! $this->is_preview() ) {
			wp_send_json_error( 'not_preview' );
		}

		$action = 'save-customize_' . $this->get_stylesheet();
		if ( ! check_ajax_referer( $action, 'nonce', false ) ) {
			wp_send_json_error( 'invalid_nonce' );
		}

		$changeset_post_id = $this->changeset_post_id();
		$is_new_changeset  = empty( $changeset_post_id );
		if ( $is_new_changeset ) {
			if ( ! current_user_can( get_post_type_object( 'customize_changeset' )->cap->create_posts ) ) {
				wp_send_json_error( 'cannot_create_changeset_post' );
			}
		} else {
			if ( ! current_user_can( get_post_type_object( 'customize_changeset' )->cap->edit_post, $changeset_post_id ) ) {
				wp_send_json_error( 'cannot_edit_changeset_post' );
			}
		}

		if ( ! empty( $_POST['customize_changeset_data'] ) ) {
			$input_changeset_data = json_decode( wp_unslash( $_POST['customize_changeset_data'] ), true );
			if ( ! is_array( $input_changeset_data ) ) {
				wp_send_json_error( 'invalid_customize_changeset_data' );
			}
		} else {
			$input_changeset_data = array();
		}

		// Validate title.
		$changeset_title = null;
		if ( isset( $_POST['customize_changeset_title'] ) ) {
			$changeset_title = sanitize_text_field( wp_unslash( $_POST['customize_changeset_title'] ) );
		}

		// Validate changeset status param.
		$is_publish       = null;
		$changeset_status = null;
		if ( isset( $_POST['customize_changeset_status'] ) ) {
			$changeset_status = wp_unslash( $_POST['customize_changeset_status'] );
			if ( ! get_post_status_object( $changeset_status ) || ! in_array( $changeset_status, array( 'draft', 'pending', 'publish', 'future' ), true ) ) {
				wp_send_json_error( 'bad_customize_changeset_status', 400 );
			}
			$is_publish = ( 'publish' === $changeset_status || 'future' === $changeset_status );
			if ( $is_publish && ! current_user_can( get_post_type_object( 'customize_changeset' )->cap->publish_posts ) ) {
				wp_send_json_error( 'changeset_publish_unauthorized', 403 );
			}
		}

		/*
		 * Validate changeset date param. Date is assumed to be in local time for
		 * the WP if in MySQL format (YYYY-MM-DD HH:MM:SS). Otherwise, the date
		 * is parsed with strtotime() so that ISO date format may be supplied
		 * or a string like "+10 minutes".
		 */
		$changeset_date_gmt = null;
		if ( isset( $_POST['customize_changeset_date'] ) ) {
			$changeset_date = wp_unslash( $_POST['customize_changeset_date'] );
			if ( preg_match( '/^\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d$/', $changeset_date ) ) {
				$mm         = substr( $changeset_date, 5, 2 );
				$jj         = substr( $changeset_date, 8, 2 );
				$aa         = substr( $changeset_date, 0, 4 );
				$valid_date = wp_checkdate( $mm, $jj, $aa, $changeset_date );
				if ( ! $valid_date ) {
					wp_send_json_error( 'bad_customize_changeset_date', 400 );
				}
				$changeset_date_gmt = get_gmt_from_date( $changeset_date );
			} else {
				$timestamp = strtotime( $changeset_date );
				if ( ! $timestamp ) {
					wp_send_json_error( 'bad_customize_changeset_date', 400 );
				}
				$changeset_date_gmt = gmdate( 'Y-m-d H:i:s', $timestamp );
			}
		}

		$lock_user_id = null;
		$autosave     = ! empty( $_POST['customize_changeset_autosave'] );
		if ( ! $is_new_changeset ) {
			$lock_user_id = wp_check_post_lock( $this->changeset_post_id() );
		}

		// Force request to autosave when changeset is locked.
		if ( $lock_user_id && ! $autosave ) {
			$autosave           = true;
			$changeset_status   = null;
			$changeset_date_gmt = null;
		}

		if ( $autosave && ! defined( 'DOING_AUTOSAVE' ) ) { // Back-compat.
			define( 'DOING_AUTOSAVE', true );
		}

		$autosaved = false;
		$r         = $this->save_changeset_post(
			array(
				'status'   => $changeset_status,
				'title'    => $changeset_title,
				'date_gmt' => $changeset_date_gmt,
				'data'     => $input_changeset_data,
				'autosave' => $autosave,
			)
		);
		if ( $autosave && ! is_wp_error( $r ) ) {
			$autosaved = true;
		}

		// If the changeset was locked and an autosave request wasn't itself an error, then now explicitly return with a failure.
		if ( $lock_user_id && ! is_wp_error( $r ) ) {
			$r = new WP_Error(
				'changeset_locked',
				__( 'Changeset is being edited by other user.' ),
				array(
					'lock_user' => $this->get_lock_user_data( $lock_user_id ),
				)
			);
		}

		if ( is_wp_error( $r ) ) {
			$response = array(
				'message' => $r->get_error_message(),
				'code'    => $r->get_error_code(),
			);
			if ( is_array( $r->get_error_data() ) ) {
				$response = array_merge( $response, $r->get_error_data() );
			} else {
				$response['data'] = $r->get_error_data();
			}
		} else {
			$response       = $r;
			$changeset_post = get_post( $this->changeset_post_id() );

			// Dismiss all other auto-draft changeset posts for this user (they serve like autosave revisions), as there should only be one.
			if ( $is_new_changeset ) {
				$this->dismiss_user_auto_draft_changesets();
			}

			// Note that if the changeset status was publish, then it will get set to trash if revisions are not supported.
			$response['changeset_status'] = $changeset_post->post_status;
			if ( $is_publish && 'trash' === $response['changeset_status'] ) {
				$response['changeset_status'] = 'publish';
			}

			if ( 'publish' !== $response['changeset_status'] ) {
				$this->set_changeset_lock( $changeset_post->ID );
			}

			if ( 'future' === $response['changeset_status'] ) {
				$response['changeset_date'] = $changeset_post->post_date;
			}

			if ( 'publish' === $response['changeset_status'] || 'trash' === $response['changeset_status'] ) {
				$response['next_changeset_uuid'] = wp_generate_uuid4();
			}
		}

		if ( $autosave ) {
			$response['autosaved'] = $autosaved;
		}

		if ( isset( $response['setting_validities'] ) ) {
			$response['setting_validities'] = array_map( array( $this, 'prepare_setting_validity_for_js' ), $response['setting_validities'] );
		}

		/**
		 * Filters response data for a successful customize_save Ajax request.
		 *
		 * This filter does not apply if there was a nonce or authentication failure.
		 *
		 * @since 4.2.0
		 *
		 * @param array                $response Additional information passed back to the 'saved'
		 *                                       event on `wp.customize`.
		 * @param WP_Customize_Manager $this     WP_Customize_Manager instance.
		 */
		$response = apply_filters( 'customize_save_response', $response, $this );

		if ( is_wp_error( $r ) ) {
			wp_send_json_error( $response );
		} else {
			wp_send_json_success( $response );
		}
	}