<?php
/**
 * Fixed-window rate limiter backed by a small table (works without object cache).
 *
 * @package LoyaltySpin
 */

namespace LoyaltyPress;

defined( 'ABSPATH' ) || exit;

/**
 * Rate limiter.
 */
class Rate_Limiter {

	/**
	 * Register a hit and say whether it is allowed.
	 *
	 * @param string $key    Bucket key (e.g. "spin:12").
	 * @param int    $max    Max hits per window.
	 * @param int    $window Window in seconds.
	 * @return bool True when allowed.
	 */
	public static function hit( $key, $max, $window ) {
		global $wpdb;
		$table = $wpdb->prefix . 'loyaltypress_rate_limits';
		$now   = time();
		$key   = substr( $key, 0, 100 );

		// Atomic upsert: reset the window if it has elapsed, otherwise increment.
		// phpcs:disable WordPress.DB.DirectDatabaseQuery,WordPress.DB.PreparedSQL.InterpolatedNotPrepared
		$wpdb->query(
			$wpdb->prepare(
				'INSERT INTO %i (rl_key, hits, window_start) VALUES (%s, 1, %d)
				ON DUPLICATE KEY UPDATE
					hits = IF(window_start + %d <= %d, 1, hits + 1),
					window_start = IF(window_start + %d <= %d, %d, window_start)',
				$table,
				$key,
				$now,
				$window,
				$now,
				$window,
				$now,
				$now
			)
		);
		$hits = (int) $wpdb->get_var( $wpdb->prepare( 'SELECT hits FROM %i WHERE rl_key = %s', $table, $key ) );
		// phpcs:enable
		return $hits <= $max;
	}
}