<?php

namespace Glovario\Database;

defined( 'ABSPATH' ) || exit;

final class Transaction {
	private static $depth = 0;

	public static function run( $callback ) {
		global $wpdb;
		$outermost = 0 === self::$depth;
		if ( $outermost && false === $wpdb->query( 'START TRANSACTION' ) ) { // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Transaction control on the database connection; nothing to cache.
			return new \WP_Error( 'transaction_start_failed', __( 'The database transaction could not be started. No changes were applied.', 'glovario' ) );
		}

		++self::$depth;
		try {
			$result = call_user_func( $callback );
		} catch ( \Throwable $error ) {
			--self::$depth;
			if ( $outermost ) {
				self::rollback();
			}
			throw $error;
		}
		--self::$depth;

		if ( ! $outermost ) {
			return $result;
		}
		if ( is_wp_error( $result ) ) {
			self::rollback();
			return $result;
		}
		if ( false === $wpdb->query( 'COMMIT' ) ) { // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Transaction control on the database connection; nothing to cache.
			self::rollback();
			return new \WP_Error( 'transaction_commit_failed', __( 'The database transaction could not be completed. No changes were applied.', 'glovario' ) );
		}
		return $result;
	}

	private static function rollback() {
		global $wpdb;
		$wpdb->query( 'ROLLBACK' ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Transaction control on the database connection; nothing to cache. The caches the rollback may have made stale are flushed below.
		// What a rolled-back import or reference rewrite may have cached: Glovario's data,
		// posts, and widgets (options). Every other group (users, sessions, other
		// plugins' data) is kept; caches that cannot flush a group are flushed whole.
		if ( function_exists( 'wp_cache_supports' ) && wp_cache_supports( 'flush_group' ) ) {
			foreach ( array( 'glovario_variables', 'glovario_rules', 'glovario_categories', 'posts', 'post_meta', 'options' ) as $group ) {
				wp_cache_flush_group( $group );
			}
		} else {
			wp_cache_flush();
		}
		do_action( 'glovario_transaction_rolled_back' );
	}
}