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

final class FormGuard_Receipts {
    private static array $fresh = [];
    private const LOCK = 'formguard_receipts_worker';
    public static function register(): void {
        add_action('shutdown', [self::class, 'flushNew'], 100);
    }

    public static function confirm(array $decision): void {
        if (($decision['capture']['status'] ?? '') !== 'stored' || ($decision['capture']['receipt_required'] ?? false) !== true || !in_array($decision['decision']['action'] ?? '', ['block', 'review'], true)) {
            return;
        }
        $id = $decision['request_id'] ?? '';
        $config = get_option('formguard_connection', []);
        if (!is_string($id) || !preg_match('/^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i', $id) || empty($config['site_id'])) {
            return;
        }
        // An independent atomic option avoids losing concurrent confirmations.
        // No inquiry text or credentials are saved in the retry queue.
        $name = 'formguard_receipt_' . str_replace('-', '', $id);
        if (add_option($name, ['request_id' => $id, 'site_id' => $config['site_id'], 'at' => time()], '', false)) { self::$fresh[] = $name; }
    }

    public static function flushNew(): void {
        $names = self::$fresh;
        self::$fresh = [];
        if ($names) { self::flush($names); }
    }

    // Direct SQL avoids stale object caches. Unique option_name plus a
    // compare-and-swap prevents a stale worker from replacing a newer lease.
    private static function acquire(): ?string {
        global $wpdb;
        $token = (time() + 30) . ':' . wp_generate_uuid4();
        $inserted = $wpdb->query($wpdb->prepare("INSERT IGNORE INTO {$wpdb->options} (option_name,option_value,autoload) VALUES (%s,%s,'no')", self::LOCK, $token));
        wp_cache_delete(self::LOCK, 'options');
        wp_cache_delete('notoptions', 'options');
        if ($inserted === 1) { return $token; }
        $old = $wpdb->get_var($wpdb->prepare("SELECT option_value FROM {$wpdb->options} WHERE option_name=%s", self::LOCK));
        if (!is_string($old) || (int) $old > time()) { return null; }
        $updated = $wpdb->query($wpdb->prepare("UPDATE {$wpdb->options} SET option_value=%s WHERE option_name=%s AND option_value=%s", $token, self::LOCK, $old));
        wp_cache_delete(self::LOCK, 'options');
        return $updated === 1 ? $token : null;
    }

    public static function flush(?array $names = null): void {
        global $wpdb;
        $config = get_option('formguard_connection', []);
        if (empty($config['site_id'])) { return; }
        $token = self::acquire();
        if ($token === null) { return; }
        $failed = false;
        $deadline = microtime(true) + 5;
        try {
        // Old retries run through the existing five-minute Cron, not page views.
        $names = $names ?? $wpdb->get_col($wpdb->prepare("SELECT option_name FROM {$wpdb->options} WHERE option_name LIKE %s ORDER BY option_id LIMIT 10", $wpdb->esc_like('formguard_receipt_') . '%'));
        $names = array_slice($names, 0, 10);
        foreach ($names as $name) {
            $pending = get_option($name, []);
            if (!is_array($pending) || !is_string($pending['request_id'] ?? null) || ($pending['at'] ?? 0) <= time() - 1800 || ($pending['site_id'] ?? '') !== $config['site_id']) {
                delete_option($name);
                continue;
            }
            $remaining = $deadline - microtime(true);
            if ($remaining < 0.1) { break; }
            $response = FormGuard_Releases::request('/v1/receipts', ['decision_request_id' => $pending['request_id']], $remaining);
            if (($response['acknowledged'] ?? false) === true || ($response['reason'] ?? '') === 'not_confirmable') {
                delete_option($name);
            } else {
                $failed = true;
                break;
            }
        }
        } catch (\Throwable $error) {
            // Keep the confirmation queued if transport or a WP hook fails.
            $failed = true;
        } finally {
            $next = ($failed ? time() + 60 : 0) . ':' . wp_generate_uuid4();
            $wpdb->query($wpdb->prepare("UPDATE {$wpdb->options} SET option_value=%s WHERE option_name=%s AND option_value=%s", $next, self::LOCK, $token));
            wp_cache_delete(self::LOCK, 'options');
        }
    }
}