// Wait this many minutes after close before sending the survey email,
            // so the user has a chance to verify the fix actually held. 0 = send immediately.
            'csat_delay_minutes'              => '0',
            // GH #301: one optional reminder for an unanswered emailed survey - off by default.
            'csat_reminder'                   => '0',
            // …
            'csat_reminder_hours'             => '48',

            if ($newIsClosed && !$oldIsClosed) {
                // …
                sendTemplateEmail($conn, $ticketId, 'ticket_closed', [
                    'ticket_closed_message' => trim((string)($in['closed_message'] ?? '')),
                ]);
                require_once __DIR__ . '/../csat.php';
                try {
                    // Now, or queued for after Tickets -> Settings -> CSAT's delay (GH #301).
                    csatAutoOnClose($conn, $ticketId, $actorId);
                } catch (Exception $csEx) {
                    error_log('CSAT auto-trigger failed for ticket ' . $ticketId . ': ' . $csEx->getMessage());
                }
            }

function csatAutoOnClose(PDO $conn, int $ticketId, ?int $analystId): void {
    if (csatGetSetting($conn, 'csat_mode', 'off') !== 'auto') return;
    $delay = max(0, (int)csatGetSetting($conn, 'csat_delay_minutes', '0'));
    if ($delay > 0) {
        try {
            // The site address as it is NOW, while there may be a request to read it
            // from - the job that sends this later has none (see csatSendDue()).
            require_once __DIR__ . '/public_url.php';
            $linkBase = publicBaseUrl($conn);
            $linkBase = preg_match('#^https?://#i', $linkBase) ? mb_substr($linkBase, 0, 255) : null;
            $conn->prepare(
                "INSERT INTO csat_queue (ticket_id, due_datetime, analyst_id, link_base, created_datetime)
                 VALUES (?, UTC_TIMESTAMP() + INTERVAL ? MINUTE, ?, ?, UTC_TIMESTAMP())
                 ON DUPLICATE KEY UPDATE due_datetime = VALUES(due_datetime), analyst_id = VALUES(analyst_id),
                                         link_base = VALUES(link_base), created_datetime = VALUES(created_datetime)"
            )->execute([$ticketId, $delay, $analystId, $linkBase]);
            return;
        } catch (Throwable $e) {
            error_log('CSAT: could not queue the delayed survey for ticket ' . $ticketId . ' - sending now: ' . $e->getMessage());
        }
    }
    sendCsatSurvey($conn, $ticketId, $analystId);
}

        // GH #301: surveys held back by Tickets -> Settings -> CSAT -> "Delay before sending".
        'csat_delayed' => [
            'command' => 'php cron/csat_delayed.php', 'web' => true,
            'interval' => 5, 'grace' => 30, 'max_runtime' => 10,
            // Needed while a delay is set on "auto", while any survey is still queued,
            // or while the optional reminder is on.
            'needed'  => fn(PDO $c) => jobNeedOne($c, "SELECT 1 FROM csat_queue LIMIT 1")
                                     || (jobSettingStrict($c, 'csat_mode') === 'auto' && (int)jobSettingStrict($c, 'csat_delay_minutes') > 0)
                                     || (jobSettingStrict($c, 'csat_mode') !== 'off' && jobSettingStrict($c, 'csat_reminder') === '1'),
        ],

    $jobModules = [
        // …
        'csat_delayed' => 'csat',   // GH #301
    ];

    // GH #217: CSAT switched off for the install - nothing is sent (the queue waits).
    if (cronModuleSwitchedOff($conn, 'csat', 'csat_delayed', $trigger)) exit(0);
    if (!JobRun::lock($conn, 'csat_delayed', $trigger)) exit;

    $runId = JobRun::start($conn, 'csat_delayed', $trigger);
    $r = csatSendDue($conn);
    $rem = csatSendReminders($conn);   // the optional one reminder (Tickets -> Settings -> CSAT)
    $failed = $r['failed'] + $rem['failed'];
    $summary = "Sent {$r['sent']} survey(s); {$r['reopened']} ticket(s) reopened or gone, {$r['skipped']} not sent"
             . ($r['failed'] ? ", {$r['failed']} failed" : '')
             . "; {$rem['sent']} reminder(s)" . ($rem['failed'] ? ", {$rem['failed']} failed" : '') . '.';
    JobRun::finish($conn, $runId, $failed ? 'partial' : null,
        ['sent' => $r['sent'], 'reopened' => $r['reopened'], 'skipped' => $r['skipped'], 'failed' => $failed,
         'reminders' => $rem['sent']], $summary);
    echo "CSAT delayed surveys: $summary\n";
    if ($failed) exit(1);

function csatSendDue(PDO $conn, int $limit = 200): array {
    $out = ['sent' => 0, 'reopened' => 0, 'skipped' => 0, 'failed' => 0, 'details' => []];
    require_once __DIR__ . '/public_url.php';
    $configured = publicBaseUrlSetting($conn) !== '';
    $due = $conn->prepare("SELECT ticket_id, due_datetime, analyst_id, link_base FROM csat_queue
                            WHERE due_datetime <= UTC_TIMESTAMP() ORDER BY due_datetime ASC LIMIT " . max(1, $limit));
    $due->execute();
    $claim = $conn->prepare("DELETE FROM csat_queue WHERE ticket_id = ? AND due_datetime = ?");
    $state = $conn->prepare("SELECT t.deleted_datetime, COALESCE(s.is_closed, 0) AS is_closed
                               FROM tickets t LEFT JOIN ticket_statuses s ON s.id = t.status_id WHERE t.id = ?");
    foreach ($due->fetchAll(PDO::FETCH_ASSOC) as $row) {
        $ticketId = (int)$row['ticket_id'];
        $claim->execute([$ticketId, $row['due_datetime']]);
        if ($claim->rowCount() !== 1) continue;   // another run took it, or a new close moved it
        $state->execute([$ticketId]);
        $t = $state->fetch(PDO::FETCH_ASSOC);
        if (!$t || $t['deleted_datetime'] !== null || (int)$t['is_closed'] !== 1) {
            $out['reopened']++;
            $out['details'][] = ['ticket_id' => $ticketId, 'outcome' => $t ? 'reopened' : 'gone'];
            continue;
        }
        if (!moduleIsEnabled($conn, 'csat') || csatGetSetting($conn, 'csat_mode', 'off') !== 'auto') {
            $out['skipped']++;
            $out['details'][] = ['ticket_id' => $ticketId, 'outcome' => 'csat_off'];
            continue;
        }
        try {
            // TRAP: no request here, so with no public address configured the link
            // would be a bare path. Use the address the ticket was closed from, just
            // for this send. A configured address always wins.
            csatUseLinkBase($conn, $configured ? null : ($row['link_base'] ?? null));
            $r = sendCsatSurvey($conn, $ticketId, $row['analyst_id'] !== null ? (int)$row['analyst_id'] : null);
            publicBaseUrlForget();
            $r['result'] === CSAT_RESULT_SENT ? $out['sent']++ : $out['skipped']++;
            $out['details'][] = ['ticket_id' => $ticketId, 'outcome' => $r['result']];
        } catch (Throwable $e) {
            // … counted as failed, logged
        }
    }
    return $out;
}

function csatBuildUrl(string $token, ?PDO $conn = null): string {
    // GH #301: with a connection, the CONFIGURED public address (System -> Settings),
    // then the request's host - publicAbsoluteUrl()'s order. A delayed survey is sent
    // by a background job with no request at all, where the code below would build
    // http://localhost/... and mail it to a customer.
    if ($conn !== null) {
        require_once __DIR__ . '/public_url.php';
        return publicAbsoluteUrl($conn, 'csat?token=' . urlencode($token));
    }
    // … the old request-based build, for a caller with no connection
}

function csatUseLinkBase(PDO $conn, ?string $base): void {
    require_once __DIR__ . '/public_url.php';
    publicBaseUrlForget();
    if ($base === null || $base === '' || publicBaseUrlSetting($conn) !== '') return;
    $root = &publicBaseUrlCache();
    $root = rtrim($base, '/');
}

    // The site address this survey's link uses, so a reminder sent later from a
    // background job links to the same place (GH #301). Its own statement: the
    // column arrives with Database Verify, and a survey must still go without it.
    try {
        require_once __DIR__ . '/public_url.php';
        $base = publicBaseUrl($conn);
        if (preg_match('#^https?://#i', $base)) {
            $conn->prepare("UPDATE ticket_csat_responses SET link_base = ? WHERE id = ?")->execute([mb_substr($base, 0, 255), $responseId]);
        }
    } catch (Throwable) { /* before Database Verify */ }

    sendTemplateEmail($conn, $ticketId, 'csat_request', [
        'csat_link' => csatBuildUrl($token, $conn),
    ]);

/** Forget cached CSAT settings - for a long-running process or a test that changes them. */
function csatSettingsForget(): void {
    $cache = &csatSettingCache();
    $cache = [];
}

/** Longest wait an administrator can set before the reminder: two weeks. */
const CSAT_REMINDER_MAX_HOURS = 336;
/**
 * A survey whose reminder fell due more than this long ago gets none. It is what
 * stops switching reminders on from emailing every unanswered survey ever sent -
 * and a job that was down for days from catching up with stale ones.
 */
const CSAT_REMINDER_CATCHUP_HOURS = 48;

function csatSendReminders(PDO $conn, int $limit = 200, ?callable $send = null): array {
    $out = ['sent' => 0, 'skipped' => 0, 'failed' => 0];
    csatSettingsForget();
    if (csatGetSetting($conn, 'csat_reminder', '0') !== '1' || csatGetSetting($conn, 'csat_mode', 'off') === 'off'
        || !moduleIsEnabled($conn, 'csat')) {
        return $out;
    }
    $hours = min(CSAT_REMINDER_MAX_HOURS, max(1, (int)csatGetSetting($conn, 'csat_reminder_hours', '48')));
    // Only reminders that fall due after the reminder was switched on (csat_reminder_since,
    // written by save_csat_settings.php): ticking the box must not remind everybody surveyed in
    // the catch-up window at once. Absent on installs that switched it on before this - no limit.
    $since = csatGetSetting($conn, 'csat_reminder_since', '');
    $sinceSql = preg_match('/^\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}$/', $since) ? " AND r.sent_datetime + INTERVAL $hours HOUR >= '$since'" : '';
    $due = $conn->prepare(
        "SELECT r.id, r.ticket_id, r.token, r.link_base
           FROM ticket_csat_responses r
          WHERE r.rating IS NULL AND r.reminder_sent_datetime IS NULL AND r.channel_id IS NULL
            AND r.sent_datetime <= UTC_TIMESTAMP() - INTERVAL $hours HOUR
            AND r.sent_datetime >  UTC_TIMESTAMP() - INTERVAL " . ($hours + CSAT_REMINDER_CATCHUP_HOURS) . " HOUR$sinceSql
          ORDER BY r.sent_datetime ASC LIMIT " . max(1, $limit));
    $due->execute();
    $claim = $conn->prepare("UPDATE ticket_csat_responses SET reminder_sent_datetime = UTC_TIMESTAMP() WHERE id = ? AND reminder_sent_datetime IS NULL AND rating IS NULL");
    $state = $conn->prepare("SELECT t.deleted_datetime, COALESCE(s.is_closed, 0) AS is_closed
                               FROM tickets t LEFT JOIN ticket_statuses s ON s.id = t.status_id WHERE t.id = ?");
    $tpl = $conn->prepare("SELECT 1 FROM ticket_email_templates WHERE event_trigger = ? AND is_active = 1 LIMIT 1");
    $tpl->execute(['csat_reminder']);
    $event = $tpl->fetchColumn() ? 'csat_reminder' : 'csat_request';
    if ($event === 'csat_request') {
        // No reminder template and no survey template either: nothing could be sent,
        // so claim nothing - marking reminders "sent" would lose them for good.
        $tpl->execute(['csat_request']);
        if (!$tpl->fetchColumn()) return $out;
    }
    $send ??= fn(int $ticketId, string $ev, string $link) => sendTemplateEmail($conn, $ticketId, $ev, ['csat_link' => $link]);
    $configured = publicBaseUrlSetting($conn) !== '';
    foreach ($due->fetchAll(PDO::FETCH_ASSOC) as $r) {
        $claim->execute([(int)$r['id']]);
        if ($claim->rowCount() !== 1) continue;   // answered or reminded meanwhile, or another run took it
        $state->execute([(int)$r['ticket_id']]);
        $t = $state->fetch(PDO::FETCH_ASSOC);
        if (!$t || $t['deleted_datetime'] !== null || (int)$t['is_closed'] !== 1) { $out['skipped']++; continue; }
        try {
            csatUseLinkBase($conn, $configured ? null : ($r['link_base'] ?? null));
            $send((int)$r['ticket_id'], $event, csatBuildUrl((string)$r['token'], $conn));
            publicBaseUrlForget();
            $out['sent']++;
        } catch (Throwable $e) {
            publicBaseUrlForget();
            $out['failed']++;
            error_log('CSAT: reminder for survey ' . $r['id'] . ' failed: ' . $e->getMessage());
        }
    }
    return $out;
}

    // Switching the reminder ON (it was off): remember when, so only surveys whose reminder
    // falls due from now on are reminded - the help promises that, and an admin ticking the
    // box must not send a burst to everybody surveyed in the last two days.
    $wasOn = (string)$conn->query("SELECT setting_value FROM system_settings WHERE setting_key = 'csat_reminder'")->fetchColumn() === '1';
    // …
    $stmt->execute(['csat_reminder', $rem]);
    $stmt->execute(['csat_reminder_hours', (string)$remH]);
    if ($rem === '1' && !$wasOn) {
        $stmt->execute(['csat_reminder_since', gmdate('Y-m-d H:i:s')]);
    }

$validEvents = ['new_ticket_email', 'ticket_assigned', 'analyst_assigned', 'ticket_closed', 'csat_request', 'csat_reminder', 'note_shared'];   // csat_reminder: GH #301

<option value="csat_reminder"><?php echo htmlspecialchars(t('tickets.settings.modals.template.event_csat_reminder')); ?></option>

 * @param ?callable $send  fn(int $ticketId, string $event, string $link) that sends the email; null = sendTemplateEmail().
 *                         Only tests pass one, so they can check who would be emailed without mailing anybody.

                <div class="form-group">
                    <label for="csatDelay"><?php echo htmlspecialchars(t('tickets.settings.csat.delay_label')); ?></label>
                    <input type="number" id="csatDelay" min="0" max="10080" step="1" style="max-width: 160px;">
                    <small style="display: block; color: var(--text-muted, #666); margin-top: 4px;"><?php echo t('tickets.settings.csat_tab.delay_help'); ?></small>
                </div>

                <!-- GH #301: one optional reminder for a survey nobody has answered -->
                <div class="form-group">
                    <label style="display: flex; align-items: center; gap: 10px;">
                        <input type="checkbox" id="csatReminder" onchange="document.getElementById('csatReminderHoursWrap').hidden = !this.checked">
                        <span><?php echo htmlspecialchars(t('tickets.settings.csat_tab.reminder')); ?></span>
                    </label>
                    <div id="csatReminderHoursWrap" hidden style="margin: 8px 0 0 26px;">
                        <label for="csatReminderHours"><?php echo htmlspecialchars(t('tickets.settings.csat_tab.reminder_hours')); ?></label>
                        <input type="number" id="csatReminderHours" min="1" max="336" step="1" style="max-width: 160px;">
                    </div>
                    <small style="display: block; color: var(--text-muted, #666); margin-top: 4px; margin-left: 26px;"><?php echo t('tickets.settings.csat_tab.reminder_help'); ?></small>
                </div>

        'reminder'       => $rows['csat_reminder'] ?? '0',              // GH #301
        'reminder_hours' => isset($rows['csat_reminder_hours']) ? (int)$rows['csat_reminder_hours'] : 48,

// GH #301: one optional reminder for an unanswered survey, after this many hours.
$rem   = ($data['reminder'] ?? '0') === '1' ? '1' : '0';
$remH  = (int)($data['reminder_hours'] ?? 48);
// …
if ($remH < 1 || $remH > 336) {
    echo json_encode(['success' => false, 'error' => 'The reminder must be 1-336 hours (two weeks) after the survey']);
    exit;
}
if ($delay < 0 || $delay > 10080) {
    echo json_encode(['success' => false, 'error' => 'Delay must be 0–1 week (10080 minutes)']);
    exit;
}
// …
    $stmt->execute(['csat_reminder', $rem]);
    $stmt->execute(['csat_reminder_hours', (string)$remH]);

// TRAP: an upgrade must not stop surveys. With no delay set (0, the default), or
//   before Database Verification has made csat_queue, the survey goes at once,
//   exactly as before.
// TRAP: the job claims a row by DELETING it (rowCount 1) before sending, so two
//   overlapping runs cannot send one survey twice.

            // TRAP: no request here, so with no public address configured the link
            // would be a bare path. Use the address the ticket was closed from, just
            // for this send. A configured address always wins.

$activeTpl = $conn->query("SELECT id FROM ticket_email_templates WHERE event_trigger IN ('csat_request', 'csat_reminder') AND is_active = 1")->fetchAll(PDO::FETCH_COLUMN);
// …
    if ($activeTpl) $conn->exec("UPDATE ticket_email_templates SET is_active = 0 WHERE id IN (" . implode(',', array_map('intval', $activeTpl)) . ")");
    setSetting($conn, 'csat_in_channel', '0');      // never a real chat message (see the header)
    setSetting($conn, 'csat_reminder_since', null); // reminders below are judged without a switch-on time
``` It refuses to run if `csat_queue` already holds rows, because those would be real surveys.

The job is run as a fresh process each time, as the scheduler runs it:

```php
$runCsat = function () use (&$conn): array {
    // A fresh process each time, as the scheduler runs it - and so csatGetSetting()'s cache is fresh too.
    exec(escapeshellarg(PHP_BINARY) . ' cron/csat_delayed.php 2>&1', $out, $code);
    return [$code, implode("\n", $out)];
};

    $sent = [];
    $spy = function (int $t, string $ev, string $link) use (&$sent) { $sent[] = [$t, $ev, $link]; };

    $due     = $mk(50, null, null, 'https://desk.example.test');   // unanswered, 50h ago: due
    $young   = $mk(10);              // too soon
    $old     = $mk(200);             // fell due long ago: never caught up
    $rated   = $mk(50, 4);           // answered
    $chat    = $mk(50, null, 999);   // asked in a chat