nt_family_post ) || empty( $font_family_post->ID )
		|| 'wp_font_family' !== $font_family_post->post_type
		) {
			return $error;
		}

		return $font_family_post;
	}

	/**
	 * Prepares links for the request.
	 *
	 * @since 6.5.0
	 *
	 * @param WP_Post $post Post object.
	 * @return array Links for the given post.
	 */
	protected function prepare_links( $post ) {
		// Entity meta.
		return array(
			'self'       => array(
				'href' => rest_url( $this->namespace . '/font-families/' . $post->post_parent . '/font-faces/' . $post->ID ),
			),
			'collection' => array(
				'href' => rest_url( $this->namespace . '/font-families/' . $post->post_parent . '/font-faces' ),
			),
			'parent'     => array(
				'href' => rest_url( $this->namespace . '/font-families/' . $post->post_parent ),
			),
		);
	}

	/**
	 * Prepares a single font face post for creation.
	 *
	 * @since 6.5.0
	 *
	 * @param WP_REST_Request $request Request object.
	 * @return stdClass Post object.
	 */
	protected function prepare_item_for_database( $request ) {
		$prepared_post = new stdClass();

		// Settings have already been decoded by ::sanitize_font_face_settings().
		$settings = $request->get_param( 'font_face_settings' );

		// Store this "slug" as the post_title rather than post_name, since it uses the fontFamily setting,
		// which may contain multibyte characters.
		$title = WP_Font_Utils::get_font_face_slug( $settings );

		$prepared_post->post_type    = $this->post_type;
		$prepared_post->post_parent  = $request['font_family_id'];
		$prepared_post->post_status  = 'publish';
		$prepared_post->post_title   = $title;
		$prepared_post->post_name    = sanitize_title( $title );
		$prepared_post->post_content = wp_json_encode( $settings );

		return $prepared_post;
	}

	/**
	 * Sanitizes a single src value for a font face.
	 *
	 * @since 6.5.0
	 *
	 * @param string $value Font face src that is a URL or the key for a $_FILES array item.
	 * @return string Sanitized value.
	 */
	protected function sanitize_src( $value ) {
		$value = ltrim( $value );
		return false === wp_http_validate_url( $value ) ? (string) $value : sanitize_url( $value );
	}

	/**
	 * Handles the upload of a font file using wp_handle_upload().
	 *
	 * @since 6.5.0
	 *
	 * @param array $file Single file item from $_FILES.
	 * @return array|WP_Error Array containing uploaded file attributes on success, or WP_Error object on failure.
	 */
	protected function handle_font_file_upload( $file ) {
		add_filter( 'upload_mimes', array( 'WP_Font_Utils', 'get_allowed_font_mime_types' ) );
		// Filter the upload directory to return the fonts directory.
		add_filter( 'upload_dir', '_wp_filter_font_directory' );

		$overrides = array(
			'upload_error_handler' => array( $this, 'handle_font_file_upload_error' ),
			// Not testing a form submission.
			'test_form'            => false,
			// Only allow uploading font files for this request.
			'mimes'                => WP_Font_Utils::get_allowed_font_mime_types(),
		);

		// Bypasses is_uploaded_file() when running unit tests.
		if ( defined( 'DIR_TESTDATA' ) && DIR_TESTDATA ) {
			$overrides['action'] = 'wp_handle_mock_upload';
		}

		$uploaded_file = wp_handle_upload( $file, $overrides );

		remove_filter( 'upload_dir', '_wp_filter_font_directory' );
		remove_filter( 'upload_mimes', array( 'WP_Font_Utils', 'get_allowed_font_mime_types' ) );

		return $uploaded_file;
	}

	/**
	 * Handles file upload error.
	 *
	 * @since 6.5.0
	 *
	 * @param array  $file    File upload data.
	 * @param string $message Error message from wp_handle_upload().
	 * @return WP_Error WP_Error object.
	 */
	public function handle_font_file_upload_error( $file, $message ) {
		$status = 500;
		$code   = 'rest_font_upload_unknown_error';

		if ( __( 'Sorry, you are not allowed to upload this file type.' ) === $message ) {
			$status = 400;
			$code   = 'rest_font_upload_invalid_file_type';
		}

		return new WP_Error( $code, $message, array( 'status' => $status ) );
	}

	/**
	 * Returns relative path to an uploaded font file.
	 *
	 * The path is relative to the current fonts directory.
	 *
	 * @since 6.5.0
	 * @access private
	 *
	 * @param string $path Full path to the file.
	 * @return string Relative path on success, unchanged path on failure.
	 */
	protected function relative_fonts_path( $path ) {
		$new_path = $path;

		$fonts_dir = wp_get_font_dir();
		if ( str_starts_with( $new_path, $fonts_dir['basedir'] ) ) {
			$new_path = str_replace( $fonts_dir['basedir'], '', $new_path );
			$new_path = ltrim( $new_path, '/' );
		}

		return $new_path;
	}

	/**
	 * Gets the font face's settings from the post.
	 *
	 * @since 6.5.0
	 *
	 * @param WP_Post $post Font face post object.
	 * @return array Font face settings array.
	 */
	protected function get_settings_from_post( $post ) {
		$settings   = json_decode( $post->post_content, true );
		$properties = $this->get_item_schema()['properties']['font_face_settings']['properties'];

		// Provide required, empty settings if needed.
		if ( null === $settings ) {
			$settings = array(
				'fontFamily' => '',
				'src'        => array(),
			);
		}

		// Only return the properties defined in the schema.
		return array_intersect_key( $settings, $properties );
	}
}