<?php
defined('ABSPATH') || exit;

/** Cross-request leases for OrderWorth writes; also works without an object cache. */
final class OWWC_Lock {
    public static function acquire(string $key, int $ttl = 300): string {
        global $wpdb;
        self::invalidate($key);
        $previous = get_option($key, null);
        $at = is_array($previous) ? ($previous['at'] ?? null) : $previous;
        // Recognize the integer leases used by older import versions too.
        if (is_numeric($at) && (int) $at < time() - $ttl) { self::remove($key, $previous); }
        $token = wp_generate_password(32, false, false);
        // add_option uses an upsert after a cache check. INSERT IGNORE leaves an
        // existing owner's lease intact, even with two stale negative caches.
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Atomic insert without replacement; these private options are non-autoloaded and both relevant caches are invalidated below.
        $inserted = $wpdb->query($wpdb->prepare("INSERT IGNORE INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, %s)", $key, maybe_serialize(['at'=>time(), 'token'=>$token]), 'no'));
        self::invalidate($key);
        return $inserted === 1 ? $token : '';
    }
    public static function release(string $key, string $token): void {
        $current = get_option($key, null);
        if (is_array($current) && is_string($current['token'] ?? null) && hash_equals($current['token'], $token)) {
            self::remove($key, $current);
        }
    }
    private static function remove(string $key, $expected): void {
        global $wpdb;
        // delete_option cannot compare the lease value. A conditional delete
        // prevents an expired/finished request from deleting its successor's lock.
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Atomic compare-and-delete for a non-autoloaded option; both relevant caches are invalidated immediately below.
        $wpdb->query($wpdb->prepare("DELETE FROM {$wpdb->options} WHERE option_name = %s AND option_value = %s", $key, maybe_serialize($expected)));
        self::invalidate($key);
    }
    private static function invalidate(string $key): void {
        wp_cache_delete($key, 'options');
        wp_cache_delete('notoptions', 'options');
    }
}