ring $table_name Table name.
	 * @param string $index_name Index name, empty string for the primary key.
	 * @return array The index columns. Empty array if the table or the index don't exist.
	 */
	public function get_index_columns( string $table_name, string $index_name = '' ): array {
		global $wpdb;

		if ( empty( $index_name ) ) {
			$index_name = 'PRIMARY';
		}

		// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
		$results = $wpdb->get_results( $wpdb->prepare( "SHOW INDEX FROM $table_name WHERE Key_name = %s", $index_name ) );

		if ( empty( $results ) ) {
			return array();
		}

		return array_column( $results, 'Column_name' );
	}

	/**
	 * Formats an object value of type `$type` for inclusion in the database.
	 *
	 * @param mixed  $value Raw value.
	 * @param string $type  Data type.
	 * @return mixed
	 * @throws \Exception When an invalid type is passed.
	 */
	public function format_object_value_for_db( $value, string $type ) {
		switch ( $type ) {
			case 'decimal':
				$value = wc_format_decimal( $value, false, true );
				break;
			case 'int':
				$value = (int) $value;
				break;
			case 'bool':
				$value = wc_string_to_bool( $value );
				break;
			case 'string':
				$value = strval( $value );
				break;
			case 'date':
				// Date properties are converted to the WP timezone (see WC_Data::set_date_prop() method), however
				// for our own tables we persist dates in GMT.
				$value = $value ? ( new DateTime( $value ) )->setTimezone( new DateTimeZone( '+00:00' ) )->format( 'Y-m-d H:i:s' ) : null;
				break;
			case 'date_epoch':
				$value = $value ? ( new DateTime( "@{$value}" ) )->format( 'Y-m-d H:i:s' ) : null;
				break;
			default:
				throw new \Exception( 'Invalid type received: ' . $type );
		}

		return $value;
	}

	/**
	 * Returns the `$wpdb` placeholder to use for data type `$type`.
	 *
	 * @param string $type Data type.
	 * @return string
	 * @throws \Exception When an invalid type is passed.
	 */
	public function get_wpdb_format_for_type( string $type ) {
		static $wpdb_placeholder_for_type = array(
			'int'        => '%d',
			'decimal'    => '%f',
			'string'     => '%s',
			'date'       => '%s',
			'date_epoch' => '%s',
			'bool'       => '%d',
		);

		if ( ! isset( $wpdb_placeholder_for_type[ $type ] ) ) {
			throw new \Exception( 'Invalid column type: ' . $type );
		}

		return $wpdb_placeholder_for_type[ $type ];
	}

	/**
	 * Generates ON DUPLICATE KEY UPDATE clause to be used in migration.
	 *
	 * @param array $columns List of column names.
	 *
	 * @return string SQL clause for INSERT...ON DUPLICATE KEY UPDATE
	 */
	public function generate_on_duplicate_statement_clause( array $columns ): string {
		$update_value_statements = array();
		foreach ( $columns as $column ) {
			$update_value_statements[] = "`$column` = VALUES( `$column` )";
		}
		$update_value_clause = implode( ', ', $update_value_statements );

		return "ON DUPLICATE KEY UPDATE $update_value_clause";
	}

	/**
	 * Hybrid of $wpdb->update and $wpdb->insert. It will try to update a row, and if it doesn't exist, it will insert it. This needs unique constraints to be set on the table on all ID columns.
	 *
	 * You can use this function only when:
	 * 1. There is only one unique constraint on the table. The constraint can contain multiple columns, but it must be the only one unique constraint.
	 * 2. The complete unique constraint must be part of the $data array.
	 * 3. You do not need the LAST_INSERT_ID() value.
	 *
	 * @param string $table_name Table name.
	 * @param array  $data Unescaped data to update (in column => value pairs).
	 * @param array  $format An array of formats to be mapped to each of the values in $data.
	 *
	 * @return int Returns the value of DB's  ON DUPLICATE KEY UPDATE clause.
	 */
	public function insert_on_duplicate_key_update( $table_name, $data, $format ) : int {
		global $wpdb;
		if ( empty( $data ) ) {
			return 0;
		}

		$columns      = array_keys( $data );
		$value_format = array();
		$values       = array();
		$index        = 0;
		// Directly use NULL for placeholder if the value is NULL, since otherwise $wpdb->prepare will convert it to empty string.
		foreach ( $data as $key => $value ) {
			if ( is_null( $value ) ) {
				$value_format[] = 'NULL';
			} else {
				$values[]       = $value;
				$value_format[] = $format[ $index ];
			}
			$index++;
		}
		$column_clause       = '`' . implode( '`, `', $columns ) . '`';
		$value_format_clause = implode( ', ', $value_format );
		$on_duplicate_clause = $this->generate_on_duplicate_statement_clause( $columns );
		// phpcs:disable WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQLPlaceholders.UnfinishedPrepare -- Values are escaped in $wpdb->prepare.
		$sql = $wpdb->prepare(
			"
INSERT INTO $table_name ( $column_clause )
VALUES ( $value_format_clause )
$on_duplicate_clause
",
			$values
		);
		// phpcs:enable
		// phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared -- $sql is prepared.
		return $wpdb->query( $sql );
	}

	/**
	 * Get max index length.
	 *
	 * @return int Max index length.
	 */
	public function get_max_index_length() : int {
		/**
		 * Filters the maximum index length in the database.
		 *
		 * Indexes have a maximum size of 767 bytes. Historically, we haven't need to be concerned about that.
		 * As of WP 4.2, however, they moved to utf8mb4, which uses 4 bytes per character. This means that an index which
		 * used to have room for floor(767/3) = 255 characters, now only has room for floor(767/4) = 191 characters.
		 *
		 * Additionally, MyISAM engine also limits the index size to 1000 bytes. We add this filter so that interested folks on InnoDB engine can increase the size till allowed 3071 bytes.
		 *
		 * @param int $max_index_length Maximum index length. Default 191.
		 *
		 * @since 8.0.0
		 */
		$max_index_length = apply_filters( 'woocommerce_database_max_index_length', 191 );
		// Index length cannot be more than 768, which is 3078 bytes in utf8mb4 and max allowed by InnoDB engine.
		return min( absint( $max_index_length ), 767 );
	}
}
get_formatted();
			}
		}

		$this->restore_storing_document_settings();
		return $data;
	}

	public function generate_document_shortcode( $atts, $content = null, $shortcode_tag = '' ) {
		global $wp;

		if ( is_admin() ) {
			return;
		}

		// Default values
		$values = shortcode_atts( array(
			'order_id'      => '',
			'link_text'     => '',
			'id'            => '',
			'class'         => 'wpo_wcpdf_document_link',
			'document_type' => 'invoice',
		), $atts );

		$is_document_type_valid = false;
		$documents              = WPO_WCPDF()->documents->get_documents();
		foreach ( $documents as $document ) {
			if ( $document->get_type() === $values['document_type'] ) {
				$is_document_type_valid = true;

				if ( ! empty( $values['link_text'] ) ) {
					$link_text = $values['link_text'];
				} else {
					$link_text = sprintf(
						/* translators: %s: Document type */
						__( 'Download %s (PDF)', 'woocommerce-pdf-invoices-packing-slips' ),
						wp_kses_post( $document->get_type() )
					);
				}

				break;
			}
		}

		if ( ! $is_document_type_valid ) {
			return;
		}

		// Get $order
		if ( empty( $values['order_id'] ) ) {
			if ( is_checkout() && is_wc_endpoint_url( 'order-received' ) && isset( $wp->query_vars['order-received'] ) ) {
				$order = wc_get_order( $wp->query_vars['order-received'] );
			} elseif ( is_account_page() && is_wc_endpoint_url( 'view-order' ) && isset( $wp->query_vars['view-order'] ) ) {
				$order = wc_get_order( $wp->query_vars['view-order'] );
			}
		} else {
			$order = wc_get_order( $values['order_id'] );
		}

		if ( empty( $order ) || ! is_object( $order ) ) {
			return;
		}

		$document = wcpdf_get_document( $values['document_type'], $order );

		if ( ! $document || ! $document->is_allowed() ) {
			return;
		}

		$pdf_url = WPO_WCPDF()->endpoint->get_document_link( $order, $values['document_type'], [ 'shortcode' => 'true' ] );

		if ( 'wcpdf_document_link' === $shortcode_tag ) {
			return esc_url( $pdf_url );
		}

		return sprintf(
			'<p><a %s class="%s" href="%s" target="_blank">%s</a></p>',
			( ! empty( $values['id'] ) ? 'id="' . esc_attr( $values['id'] ) . '"' : '' ),
			esc_attr( $values['class'] ),
			esc_url( $pdf_url ),
			esc_html( $link_text )
		);
	}

	/**
	 * Document objects are created in order to check for existence and retrieve data,
	 * but we don't want to store the settings for uninitialized documents.
	 * Only use in frontend/backed (page requests), otherwise settings will never be stored!
	 */
	public function disable_storing_document_settings() {
		add_filter( 'wpo_wcpdf_document_store_settings', array( $this, 'return_false' ), 9999 );
	}

	public function restore_storing_document_settings() {
		remove_filter( 'wpo_wcpdf_document_store_settings', array( $this, 'return_false' ), 9999 );
	}

	public function return_false(){
		return false;
	}
}

endif; // class_exists