private function generate_export( $filepath, $certificate_id ) {

		$html = $this->get_export_html( $certificate_id );

		if ( is_wp_error( $html ) ) {
			return $html;
		}

		/**
		 * Run actions prior to certificate export generation.
		 *
		 * @param string $filepath       Full path where the created file will be stored. Passed as a reference.
		 * @param string $html           Certificate HTML. Passed as a reference.
		 * @param int    $certificate_id WP_Post ID of the earned certificate.
		 */
		do_action_ref_array( 'llms_certificate_generate_export', array( &$filepath, &$html, $certificate_id ) );

		$file = fopen( $filepath, 'w' );
		if ( false === $file ) {
			return new WP_Error( 'llms_certificate_error', __( 'Unable to open export file (HTML certificate) for writing.', 'lifterlms' ) );
		}

		if ( false === fwrite( $file, $html ) ) {
			return new WP_Error( 'llms_certificate_error', __( 'Unable to write to export file (HTML certificate).', 'lifterlms' ) );
		}

		fclose( $file );

		return $filepath;

	}