<?php

/*
 * Tickets - loading one, checking what it may link to, drawing it wherever
 * another page lists tickets, deleting it for good, and the recurring
 * schedules that raise them.
 *
 * A ticket belongs to a client (or to none, for internal work). What it
 * links to - its contact, asset and other assets, site, vendor and project -
 * must be that client's own; ticketClientOwnedId() is the one check, used by
 * the handlers, the API and the cron alike. The change functions for
 * priority, assignee, status and billing are in functions/ticket_fields.php.
 */

/** The built-in statuses (ticket_statuses rows 1-5) - the system sets New and Closed; Resolve sets Resolved. */
const TICKET_STATUS_NEW = 1;
const TICKET_STATUS_OPEN = 2;
const TICKET_STATUS_ON_HOLD = 3;
const TICKET_STATUS_RESOLVED = 4;
const TICKET_STATUS_CLOSED = 5;

/** How often a recurring ticket can run - what is stored, and how far one run is from the next. */
const RECURRING_TICKET_FREQUENCIES = [
    'Three Days' => ['days' => 3],
    'Weekly' => ['days' => 7],
    'Biweekly' => ['days' => 14],
    'Monthly' => ['months' => 1],
    'Quarterly' => ['months' => 3],
    'Biannually' => ['months' => 6],
    'Annually' => ['months' => 12],
];

/** May this agent do this with tickets? 1 is to see them, 2 to work them, 3 to delete them. */
function ticketCan($level) {
    return lookupUserPermission('module_support') >= $level;
}

/** One ticket by id, with its client, contact, status and agent - raw, or null. */
function ticketRow($ticket_id) {
    global $mysqli;
    $ticket_id = intval($ticket_id);
    if (!$ticket_id) {
        return null;
    }
    $row = mysqli_fetch_assoc(mysqli_query($mysqli, "SELECT tickets.*, client_name, contact_name, contact_email,
            ticket_status_name, ticket_status_color, user_name, user_avatar
        FROM tickets
        LEFT JOIN clients ON client_id = ticket_client_id
        LEFT JOIN contacts ON contact_id = ticket_contact_id
        LEFT JOIN ticket_statuses ON ticket_status_id = ticket_status
        LEFT JOIN users ON user_id = ticket_assigned_to
        WHERE ticket_id = $ticket_id LIMIT 1"));
    return $row ?: null;
}

/**
 * For post handlers: the ticket a request names, after the module and client
 * checks (a ticket with no client is internal work any agent may reach) - or
 * back with an error if it is gone. Sets the global $client_id.
 */
function ticketForRequest($ticket_id, $level) {
    global $client_id;
    enforceUserPermission('module_support', $level);
    $row = ticketRow($ticket_id);
    if (!$row) {
        flashAlert('That ticket no longer exists.', 'error');
        redirect();
    }
    $client_id = intval($row['ticket_client_id']);
    if ($client_id) {
        enforceClientAccess();
    }
    return $row;
}

/**
 * For modals: the ticket a modal is opened for, after the module and client
 * checks - or the modal's error, and nothing more. $open_only refuses a
 * closed ticket. Sets the global $client_id.
 */
function ticketForModal($ticket_id, $level = 2, $open_only = false) {
    global $client_id;
    enforceUserPermission('module_support', $level);
    $row = ticketRow($ticket_id);
    if (!$row) {
        echo json_encode(['error' => 'That ticket no longer exists.']);
        exit;
    }
    $client_id = intval($row['ticket_client_id']);
    if ($client_id) {
        enforceClientAccess();
    }
    if ($open_only && !empty($row['ticket_closed_at'])) {
        echo json_encode(['error' => 'Ticket ' . ticketReference($row) . ' is closed.']);
        exit;
    }
    return $row;
}

/** For post handlers: the tickets a bulk action names (ticket_ids[]) that this agent may act on - [id => row]. */
function ticketsForBulk($level) {
    global $client_id;
    enforceUserPermission('module_support', $level);
    $rows = [];
    foreach (array_unique(array_map('intval', (array) ($_POST['ticket_ids'] ?? []))) as $ticket_id) {
        $row = ticketRow($ticket_id);
        if (!$row) {
            continue;
        }
        $client_id = intval($row['ticket_client_id']);
        if ($client_id) {
            enforceClientAccess();
        }
        $rows[$ticket_id] = $row;
    }
    return $rows;
}

/** Its reference - TCK-1234. */
function ticketReference($row) {
    return ($row['ticket_prefix'] ?? '') . intval($row['ticket_number'] ?? 0);
}

/** Is it still being worked - neither resolved nor closed? */
function ticketIsOpen($row) {
    return empty($row['ticket_resolved_at']) && empty($row['ticket_closed_at']);
}

/** Where the ticket page is - inside its client when it has one. */
function ticketUrl($ticket_id, $client_id = 0) {
    $client_id = intval($client_id);
    return 'ticket.php?' . ($client_id ? "client_id=$client_id&" : '') . 'ticket_id=' . intval($ticket_id);
}

/** A ticket wherever a page mentions one: its reference, then its subject, both opening the ticket. 'subject' => false for the reference alone. */
function ticketLink($row, $options = []) {
    $url = escapeHtml(ticketUrl($row['ticket_id'], $row['ticket_client_id'] ?? 0));
    $reference = escapeHtml(ticketReference($row));
    $html = '<a class="font-monospace text-nowrap" href="' . $url . '">' . $reference . '</a>';
    if (($options['subject'] ?? true) && isset($row['ticket_subject'])) {
        $html .= ' <a class="' . (ticketIsOpen($row) ? 'text-body' : 'text-body-secondary') . '" href="' . $url . '">' . escapeHtml($row['ticket_subject']) . '</a>';
    }
    return $html;
}

/**
 * A record a ticket of this client may link to - its id when it is the
 * client's own, else 0. $kind is contact, asset, location, vendor or
 * project. A project may also be one with no client (internal work); a
 * ticket with no client may only link to our own vendors and projects.
 */
function ticketClientOwnedId($kind, $id, $client_id) {
    global $mysqli;
    $id = intval($id);
    $client_id = intval($client_id);
    if (!$id) {
        return 0;
    }
    if ($kind === 'project') {
        $row = mysqli_fetch_row(mysqli_query($mysqli, "SELECT project_id FROM projects WHERE project_id = $id AND project_client_id IN (0, $client_id) LIMIT 1"));
        return $row ? $id : 0;
    }
    if (!$client_id && $kind !== 'vendor') {
        return 0;
    }
    return assetClientOwnedId($kind, $id, $client_id);
}

/** The client's own assets out of a list of ids, without the primary one - for "other assets". */
function ticketClientOwnedAssetIds($ids, $client_id, $primary_asset_id = 0) {
    global $mysqli;
    $ids = array_values(array_diff(array_unique(array_filter(array_map('intval', (array) $ids))), [intval($primary_asset_id)]));
    $client_id = intval($client_id);
    if (!$ids || !$client_id) {
        return [];
    }
    $owned = [];
    $sql = mysqli_query($mysqli, "SELECT asset_id FROM assets WHERE asset_client_id = $client_id AND asset_id IN (" . implode(',', $ids) . ")");
    while ($row = mysqli_fetch_row($sql)) {
        $owned[] = intval($row[0]);
    }
    return $owned;
}

/** Replace a ticket's other assets with these (already checked) ids. */
function ticketSetOtherAssets($ticket_id, array $asset_ids) {
    global $mysqli;
    $ticket_id = intval($ticket_id);
    mysqli_query($mysqli, "DELETE FROM ticket_assets WHERE ticket_id = $ticket_id");
    foreach ($asset_ids as $asset_id) {
        mysqli_query($mysqli, "INSERT IGNORE INTO ticket_assets SET ticket_id = $ticket_id, asset_id = " . intval($asset_id));
    }
}

/** An active agent's id, else 0 (unassigned). */
function ticketAgentId($user_id) {
    global $mysqli;
    $user_id = intval($user_id);
    if (!$user_id) {
        return 0;
    }
    $row = mysqli_fetch_row(mysqli_query($mysqli, "SELECT user_id FROM users WHERE user_id = $user_id AND user_type = 1 AND user_status = 1 AND user_archived_at IS NULL LIMIT 1"));
    return $row ? $user_id : 0;
}

/** A ticket category's id, else 0 (not categorised). */
function ticketCategoryId($category_id) {
    global $mysqli;
    $category_id = intval($category_id);
    if (!$category_id) {
        return 0;
    }
    $row = mysqli_fetch_row(mysqli_query($mysqli, "SELECT category_id FROM categories WHERE category_id = $category_id AND category_type = 'Ticket' LIMIT 1"));
    return $row ? $category_id : 0;
}

/** A priority as posted, or Medium when it isn't one. */
function ticketPriority($priority) {
    return in_array($priority, TICKET_PRIORITIES, true) ? $priority : 'Medium';
}

/** A due date posted from a datetime-local field (with or without seconds) as SQL - quoted, or NULL. */
function ticketDueSql($input) {
    $input = trim((string) $input);
    if ($input === '') {
        return 'NULL';
    }
    foreach (['Y-m-d\TH:i', 'Y-m-d\TH:i:s', 'Y-m-d H:i:s', 'Y-m-d H:i'] as $format) {
        $date = DateTime::createFromFormat("!$format", $input);
        if ($date && $date->format($format) === $input) {
            return "'" . $date->format('Y-m-d H:i:s') . "'";
        }
    }
    return 'NULL';
}

/** The watchers posted - valid email addresses only, each once, lower-cased. */
function ticketWatcherEmails($input) {
    $list = is_array($input) ? $input : preg_split('/[\s,;]+/', (string) $input);
    $emails = [];
    foreach ($list as $email) {
        $email = strtolower(trim((string) $email));
        if ($email !== '' && filter_var($email, FILTER_VALIDATE_EMAIL)) {
            $emails[$email] = true;
        }
    }
    return array_keys($emails);
}

/** Add watchers a ticket doesn't have already - the ones added. */
function ticketAddWatchers($ticket_id, array $emails) {
    global $mysqli;
    $ticket_id = intval($ticket_id);
    $added = [];
    foreach ($emails as $email) {
        $email_sql = escapeSql($email);
        if (mysqli_num_rows(mysqli_query($mysqli, "SELECT 1 FROM ticket_watchers WHERE watcher_ticket_id = $ticket_id AND watcher_email = '$email_sql' LIMIT 1"))) {
            continue;
        }
        mysqli_query($mysqli, "INSERT INTO ticket_watchers SET watcher_email = '$email_sql', watcher_ticket_id = $ticket_id");
        $added[] = $email;
    }
    return $added;
}

/**
 * Delete a ticket and everything that is only its: replies, views, watchers,
 * attachments (and their files), tasks and their approvals, history and SLA
 * history. Its other-asset links go with it (ON DELETE CASCADE).
 */
function ticketDeleteForGood($ticket_id) {
    global $mysqli;
    $ticket_id = intval($ticket_id);
    if (!$ticket_id) {
        return;
    }
    mysqli_query($mysqli, "DELETE FROM task_approvals WHERE approval_task_id IN (SELECT task_id FROM tasks WHERE task_ticket_id = $ticket_id)");
    mysqli_query($mysqli, "DELETE FROM tasks WHERE task_ticket_id = $ticket_id");
    mysqli_query($mysqli, "DELETE FROM ticket_replies WHERE ticket_reply_ticket_id = $ticket_id");
    mysqli_query($mysqli, "DELETE FROM ticket_views WHERE view_ticket_id = $ticket_id");
    mysqli_query($mysqli, "DELETE FROM ticket_watchers WHERE watcher_ticket_id = $ticket_id");
    mysqli_query($mysqli, "DELETE FROM ticket_attachments WHERE ticket_attachment_ticket_id = $ticket_id");
    mysqli_query($mysqli, "DELETE FROM ticket_history WHERE ticket_history_ticket_id = $ticket_id");
    mysqli_query($mysqli, "DELETE FROM sla_history WHERE sla_history_ticket_id = $ticket_id");
    // The prepaid hours it drew go back to their contracts
    if (function_exists('contractHoursReady') && contractHoursReady()) {
        mysqli_query($mysqli, "DELETE FROM contract_block_uses WHERE contract_block_use_ticket_id = $ticket_id");
    }
    mysqli_query($mysqli, "DELETE FROM tickets WHERE ticket_id = $ticket_id");
    // The driving for it still happened - the trips stay, without the ticket
    mysqli_query($mysqli, "UPDATE trips SET trip_ticket_id = 0 WHERE trip_ticket_id = $ticket_id");
    removeDirectory(__DIR__ . "/../uploads/tickets/$ticket_id");
}

/* ------------------------------------------------------------ Emails about a ticket */

/** Who ticket emails come from - the ticket mailbox (Admin > Mail). */
function ticketEmailFrom() {
    return emailFrom('ticket');
}

/** Where a contact or watcher opens a ticket - its guest link, no sign-in needed, or the portal when it has none. */
function ticketEmailUrl(array $row) {
    global $config_base_url;
    $ticket_id = intval($row['ticket_id']);
    return !empty($row['ticket_url_key'])
        ? "https://$config_base_url/guest/guest_view_ticket.php?ticket_id=$ticket_id&url_key=" . rawurlencode((string) $row['ticket_url_key'])
        : "https://$config_base_url/client/ticket.php?id=$ticket_id";
}

/*
 * A ticket opened by its guest link - ticketRow() when $url_key is the
 * ticket's key exactly, else null. The key is all the guest pages have to go
 * on, so it is compared here, whole and case for case: MySQL's = would let
 * another case or trailing spaces match.
 */
function ticketByGuestKey($ticket_id, $url_key) {
    $row = ticketRow($ticket_id);
    $key = (string) ($row['ticket_url_key'] ?? '');
    return $row && $key !== '' && is_string($url_key) && hash_equals($key, $url_key) ? $row : null;
}

/** The guest ticket page's address, from a page in guest/. */
function ticketGuestPath(array $row) {
    return 'guest_view_ticket.php?ticket_id=' . intval($row['ticket_id']) . '&url_key=' . rawurlencode((string) $row['ticket_url_key']);
}

/** The foot's contact line on a ticket email - the company's phone and the support address. */
function ticketEmailContactLine() {
    $company = billingCompany();
    return implode('  ·  ', array_filter([$company['phone_display'] ?? '', ticketEmailFrom()['email'], $company['company_website'] ?? '']));
}

/*
 * What a new ticket's SLA promises the client - ['summary' => rows to add,
 * 'callout' => a paragraph]: when they will hear back, and for an Urgent or
 * High one, to phone instead of waiting. Nothing when no SLA with a response
 * target applies. Call it after applyTicketSla(), which sets the due time.
 */
function ticketEmailSla($ticket_id) {
    global $mysqli;
    $row = mysqli_fetch_assoc(mysqli_query($mysqli, "SELECT ticket_priority, ticket_response_due_at, sla_response_minutes
        FROM tickets LEFT JOIN slas ON ticket_sla_id = sla_id WHERE ticket_id = " . intval($ticket_id) . " LIMIT 1"));
    if (!$row || empty($row['ticket_response_due_at']) || intval($row['sla_response_minutes']) <= 0) {
        return ['summary' => [], 'callout' => ''];
    }
    $phone = billingCompany()['phone_display'] ?? '';
    $callout = '';
    if ($phone !== '' && $row['ticket_priority'] === 'Urgent') {
        $callout = "This ticket is marked Urgent. If it is stopping work right now, call us on $phone rather than waiting for a reply.";
    } elseif ($phone !== '' && $row['ticket_priority'] === 'High') {
        $callout = "This ticket is marked High priority. If it is holding up your business, calling us on $phone gets you the fastest answer.";
    }
    return [
        'summary' => ['We will respond' => 'within ' . formatSlaMinutes(intval($row['sla_response_minutes'])) . ', by ' . date('D j M, g:i A', strtotime($row['ticket_response_due_at']))],
        'callout' => $callout,
    ];
}

/*
 * The conversation on a ticket, for the end of an email about it
 * (emailHtml()'s history): its public replies newest first, and at the end
 * the request it was opened with - each a short plain-text excerpt
 * (ticketEmailExcerpt()), so a pasted screenshot or a long signature can't
 * swell the email. Never an internal note, nor the lines the portal writes
 * when a contact resolves, reopens or closes. $opts:
 *   label    the heading - Earlier on this ticket
 *   skip     the HTML of the reply the email itself shows - it, and anything newer, is left out
 *   replies  false for the request alone
 *   request  false leaves the request out, when the email shows it already
 *   limit    how many replies at most (4) - the rest are counted, before the request
 * [] when there is nothing earlier to show.
 */
function ticketEmailHistory(array $row, array $opts = []) {
    global $mysqli;
    $ticket_id = intval($row['ticket_id']);
    $limit = max(0, intval($opts['limit'] ?? 4));
    $company_name = (string) (billingCompany()['company_name'] ?? '');
    $items = [];
    $left_out = 0;
    if ($opts['replies'] ?? true) {
        $sql = mysqli_query($mysqli, "SELECT ticket_reply, ticket_reply_type, ticket_reply_created_at, contact_name, user_name FROM ticket_replies
            LEFT JOIN users ON ticket_reply_type != 'Client' AND user_id = ticket_reply_by
            LEFT JOIN contacts ON ticket_reply_type = 'Client' AND contact_id = ticket_reply_by
            WHERE ticket_reply_ticket_id = $ticket_id AND ticket_reply_archived_at IS NULL AND ticket_reply_type IN ('Public', 'Client')
            ORDER BY ticket_reply_id DESC");
        $replies = mysqli_fetch_all($sql, MYSQLI_ASSOC);
        // Only what came before the reply the email shows - that one is the newest, but for a preview's sample
        $skip = (string) ($opts['skip'] ?? '');
        if ($skip !== '') {
            foreach ($replies as $i => $reply) {
                if ((string) $reply['ticket_reply'] === $skip) {
                    $replies = array_slice($replies, $i + 1);
                    break;
                }
            }
        }
        foreach ($replies as $reply) {
            $text = ticketEmailExcerpt($reply['ticket_reply']);
            $client = $reply['ticket_reply_type'] === 'Client';
            if ($text === '' || ($client && preg_match('/^Ticket (resolved|reopened|closed) by .{1,200}\.$/', $text))) {
                continue;
            }
            if (count($items) >= $limit) {
                $left_out++;
                continue;
            }
            $items[] = [
                'by' => $client ? ((string) $reply['contact_name'] ?: 'Client') : ((string) $reply['user_name'] ?: $company_name),
                'org' => $client ? '' : $company_name,
                'when' => date('D j M, g:i A', strtotime($reply['ticket_reply_created_at'])),
                'text' => $text,
                'client' => $client,
            ];
        }
    }
    if (!($opts['request'] ?? true) && $left_out) {
        $items[] = ['gap' => $left_out];
    } elseif ($opts['request'] ?? true) {
        $text = ticketEmailExcerpt($row['ticket_details'] ?? '');
        if ($text !== '') {
            if ($left_out) {
                $items[] = ['gap' => $left_out];
            }
            $asked_by = trim((string) ($row['contact_name'] ?? ''));
            $items[] = [
                'by' => $asked_by !== '' ? $asked_by : 'The request',
                'action' => $asked_by !== '' ? 'the request' : '',
                'when' => date('D j M, g:i A', strtotime($row['ticket_created_at'])),
                'text' => $text,
                'client' => true,
            ];
        }
    }
    return $items ? ['label' => (string) ($opts['label'] ?? 'Earlier on this ticket'), 'items' => $items] : [];
}

/** A ticket message as a short plain-text excerpt - without the "Email from: ... :-" line the email parser puts on what it saves. */
function ticketEmailExcerpt($html, $limit = 700) {
    $html = preg_replace('#^\s*<i>\s*Email from:.*?</i>(\s*<br\s*/?>)*#is', '', (string) $html);
    return emailPlainText($html, $limit);
}

/*
 * What an email about a ticket says - emailHtml()'s fields (functions/email.php),
 * all but who it is to and why they get it, which ticketMailSend() adds for
 * each. $row is ticketRow(). $kind and its $opts:
 *   created   it was opened - how: agent (the default), email (the reply to an emailed one) or scheduled
 *   reply     an agent's reply - message (its HTML), by (who wrote it)
 *   resolved  marked resolved, pending closure - message (the agent's note, HTML, or ''), by
 *   closed    closed - asking how we did
 *   watcher   they were made a watcher - by (who added them)
 *   scheduled the work was booked - when (words), where (the site's address), or cancelled: true
 */
function ticketEmailContent(array $row, $kind, array $opts = []) {
    global $config_ticket_autoclose_hours;
    $reference = ticketReference($row);
    $subject = (string) $row['ticket_subject'];
    $url = ticketEmailUrl($row);
    $company_name = (string) (billingCompany()['company_name'] ?? '');
    $by = trim((string) ($opts['by'] ?? '')) !== '' ? trim((string) $opts['by']) : $company_name;
    $summary = ['Ticket' => $reference, 'Subject' => $subject, 'Status' => (string) ($row['ticket_status_name'] ?? '')];
    $email = [
        'marker' => true,
        'preview' => "$reference - $subject",
        'tone' => 'primary',
        'contact' => ticketEmailContactLine(),
        'button' => ['label' => 'View the ticket', 'url' => $url],
    ];

    if ($kind === 'created') {
        $how = (string) ($opts['how'] ?? 'agent');
        $sla = ticketEmailSla($row['ticket_id']);
        $email['kind'] = 'New ticket';
        if ($how === 'email') {
            $email['title'] = 'We have your email';
            $email['intro'] = ["Thank you - it is ticket $reference now, and we will reply to you here. To add anything, just reply to this email."];
            // Never their own words back: the sender of an email can be forged, and an echo would carry whatever it said to them
        } else {
            $email['title'] = $how === 'scheduled' ? 'A scheduled ticket was opened for you' : 'We have opened a ticket for you';
            $email['intro'] = [($how === 'scheduled' ? "Ticket $reference was opened for you, as scheduled." : "We have opened ticket $reference for you.")
                . " We will keep you posted here - to add anything, just reply to this email."];
            $email['message'] = ['html' => (string) $row['ticket_details'], 'label' => 'Details'];
        }
        $email['summary'] = $summary + ['Priority' => (string) $row['ticket_priority']] + $sla['summary'];
        $email['callout'] = $sla['callout'];
        $email['button']['label'] = 'View your ticket';
    } elseif ($kind === 'reply') {
        $email['kind'] = 'Ticket update';
        $email['title'] = $subject;
        $email['intro'] = ["There is a new reply on your ticket $reference."];
        $email['message'] = ['html' => (string) ($opts['message'] ?? ''), 'label' => "$by replied"];
        $email['summary'] = $summary;
        $email['after'] = ['To answer, just reply to this email.'];
        $email['history'] = ticketEmailHistory($row, ['skip' => (string) ($opts['message'] ?? '')]);
    } elseif ($kind === 'resolved') {
        $hours = intval($config_ticket_autoclose_hours);
        $closes = $hours > 0 ? ' - it closes by itself after ' . ($hours % 24 === 0 ? ($hours / 24) . ' day' . ($hours === 24 ? '' : 's') : "$hours hours") : '';
        $email['kind'] = 'Resolved';
        $email['tone'] = 'success';
        $email['title'] = 'Your ticket is resolved';
        $email['intro'] = ["We have marked ticket $reference resolved.", "If that sorts it, there is nothing more to do$closes. If not, reply to this email or reopen it and tell us what is still wrong."];
        $email['message'] = ['html' => (string) ($opts['message'] ?? ''), 'label' => "$by wrote"];
        $email['summary'] = $summary;
        $email['button']['label'] = 'View or reopen it';
        // Resolved from the button or the board there is no note - the conversation says what was done
        $email['history'] = ticketEmailHistory($row, ['skip' => (string) ($opts['message'] ?? ''),
            'label' => emailPlainText($opts['message'] ?? '') !== '' ? 'Earlier on this ticket' : 'The conversation']);
    } elseif ($kind === 'closed') {
        $email['marker'] = false;
        $email['kind'] = 'Closed';
        $email['tone'] = 'secondary';
        $email['title'] = 'Your ticket is closed';
        $email['intro'] = ["Ticket $reference is closed. We hope it was sorted the way you wanted."];
        $email['summary'] = $summary;
        $email['button']['label'] = 'Tell us how we did';
        $email['after'] = ['Need more help with this? Raise a new ticket - replies to this email do not reach us.'];
        $email['history'] = ticketEmailHistory($row, ['limit' => 3, 'label' => 'The conversation']);
    } elseif ($kind === 'scheduled') {
        $cancelled = !empty($opts['cancelled']);
        $email['kind'] = $cancelled ? 'Visit cancelled' : 'Work booked';
        $email['tone'] = $cancelled ? 'secondary' : 'primary';
        $email['title'] = $cancelled ? 'The booked work is cancelled' : 'Your ticket is booked in';
        $email['intro'] = [$cancelled
            ? "The work booked on ticket $reference is cancelled - the calendar file with this email takes it out of your calendar. We will be in touch to book it again."
            : "We have booked the work on ticket $reference for " . $opts['when'] . ". The calendar file with this email adds it to your calendar."];
        $email['summary'] = $summary + ($cancelled ? [] : ['When' => (string) $opts['when'], 'Where' => !empty($row['ticket_onsite']) ? (trim((string) ($opts['where'] ?? '')) !== '' ? (string) $opts['where'] : 'Onsite') : 'Remote']);
        $email['history'] = $cancelled ? [] : ticketEmailHistory($row, ['limit' => 2, 'label' => 'What it is about']);
    } elseif ($kind === 'watcher') {
        $email['kind'] = 'Watching';
        $email['title'] = 'You were added to a ticket';
        $email['intro'] = ["$by added you to ticket $reference" . (!empty($row['client_name']) ? ' for ' . $row['client_name'] : '') . ", so you will get its updates. To add anything, just reply to this email."];
        $email['message'] = ['html' => (string) $row['ticket_details'], 'label' => 'Details'];
        $email['summary'] = $summary;
        $email['history'] = ticketEmailHistory($row, ['request' => false, 'label' => 'Replies so far']);
    }
    return ticketEmailPreview($email);
}

/*
 * The inbox's preview line, beside the subject that already gives the number
 * and title - the start of the message the email carries, or else its first
 * line ("We have marked ticket TCK-12 resolved.").
 */
function ticketEmailPreview(array $email) {
    $said = emailPlainText($email['message']['html'] ?? '', 140);
    if ($said === '') {
        $said = (string) (((array) ($email['intro'] ?? []))[0] ?? '');
    }
    if (trim($said) !== '') {
        $email['preview'] = preg_replace('/\s+/', ' ', trim($said));
    }
    return $email;
}

/*
 * Queue an email about a ticket (ticketEmailContent()) to its contact, when
 * $to_contact and the address is good, and to every watcher, each told why
 * they get it. $subject is raw. Nothing is queued without a mail provider.
 * How many were queued. $opts:
 *   attachments  files to send with it ([['path', 'name'], ...])
 *   to_contact   false leaves the contact out
 *   to_watchers  false is the contact alone - no watchers, no colleagues
 *   to           [['email', 'name'], ...] in place of the contact - the sender of an emailed ticket
 *   kind         created, closed or update (the default): a contact who asked
 *                for replies only gets no created or closed email
 *                (ticketContactWantsEmail()), and the client's primary and
 *                technical contacts who asked for every update on their
 *                company's tickets get the rest, as a watcher does
 *                (ticketColleagueRecipients())
 *   ticket_reply_id  the agent's reply it carries - each email is kept with it
 *                (emailQueue()), for ticketReplyEmailed()
 */
function ticketMailSend($ticket_id, $subject, array $email, array $opts = []) {
    global $mysqli;
    if (!emailReady()) {
        return 0;
    }
    $ticket_id = intval($ticket_id);
    $kind = (string) ($opts['kind'] ?? 'update');
    $to_watchers = $opts['to_watchers'] ?? true;
    $row = mysqli_fetch_assoc(mysqli_query($mysqli, "SELECT ticket_prefix, ticket_number, contact_name, contact_email, contact_ticket_emails
        FROM tickets LEFT JOIN contacts ON contact_id = ticket_contact_id WHERE ticket_id = $ticket_id"));
    if (!$row) {
        return 0;
    }
    $reference = ticketReference($row);
    $company_name = (string) (billingCompany()['company_name'] ?? 'us');
    $recipients = [];
    if (isset($opts['to'])) {
        foreach ((array) $opts['to'] as $to) {
            $recipients[] = ['email' => $to['email'], 'name' => (string) ($to['name'] ?? ''), 'footnote' => "You get this because you emailed $company_name."];
        }
    } elseif (($opts['to_contact'] ?? true) && ticketContactWantsEmail($row['contact_ticket_emails'] ?? 'all', $kind)) {
        $recipients[] = ['email' => (string) $row['contact_email'], 'name' => (string) $row['contact_name'], 'footnote' => "You get this as the contact on ticket $reference with $company_name."];
    }
    if ($to_watchers) {
        $sql = mysqli_query($mysqli, "SELECT watcher_email FROM ticket_watchers WHERE watcher_ticket_id = $ticket_id");
        while ($watcher = mysqli_fetch_assoc($sql)) {
            $recipients[] = ['email' => trim((string) $watcher['watcher_email']), 'greet' => '', 'footnote' => "You get this because you are watching ticket $reference - ask $company_name if you would like to stop."];
        }
        // A new ticket reaches them by ticketMailColleaguesNew(), in an email of its own
        if ($kind !== 'created') {
            foreach (ticketColleagueRecipients($ticket_id, $kind) as $address => $colleague) {
                $recipients[] = ['email' => $address, 'name' => $colleague['name'], 'footnote' => "You get this because you asked for every update on " . $colleague['client_name'] . "'s tickets - change that under Your account in the client portal."];
            }
        }
    }
    return count(emailQueue($recipients, $subject, $email, ['from' => ticketEmailFrom(), 'attachments' => $opts['attachments'] ?? [], 'cal_str' => $opts['cal_str'] ?? '',
        'ticket_reply_id' => intval($opts['ticket_reply_id'] ?? 0)]));
}

/** Whether a ticket's contact gets an email of this $kind - no 'created' or 'closed' email for one who asked for replies only. */
function ticketContactWantsEmail($preference, $kind) {
    return !((string) $preference === 'replies' && in_array($kind, ['created', 'closed'], true));
}

/**
 * The client's other primary and technical contacts who asked to hear about
 * their company's tickets (Your account in the portal) - for a 'created'
 * email those who chose new tickets or everything, otherwise those who chose
 * everything. Never the ticket's own contact, nor an archived one.
 * [email => ['name', 'client_name', 'portal' => bool]].
 */
function ticketColleagueRecipients($ticket_id, $kind) {
    global $mysqli;
    $ticket = mysqli_fetch_assoc(mysqli_query($mysqli, "SELECT ticket_client_id, ticket_contact_id, client_name FROM tickets
        JOIN clients ON client_id = ticket_client_id WHERE ticket_id = " . intval($ticket_id) . " LIMIT 1"));
    if (!$ticket) {
        return [];
    }
    $wanted = $kind === 'created' ? "'new', 'all'" : "'all'";
    $recipients = [];
    $sql = mysqli_query($mysqli, "SELECT contact_name, contact_email, user_id FROM contacts
        LEFT JOIN users ON user_id = contact_user_id AND user_type = 2 AND user_status = 1 AND user_archived_at IS NULL AND user_auth_method IN ('local', 'azure')
        WHERE contact_client_id = " . intval($ticket['ticket_client_id']) . " AND contact_id <> " . intval($ticket['ticket_contact_id']) . "
          AND contact_archived_at IS NULL AND (contact_primary = 1 OR contact_technical = 1)
          AND contact_company_ticket_emails IN ($wanted)");
    while ($row = mysqli_fetch_assoc($sql)) {
        $email = trim((string) $row['contact_email']);
        if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
            $recipients[$email] = ['name' => (string) $row['contact_name'], 'client_name' => (string) $ticket['client_name'], 'portal' => !empty($row['user_id'])];
        }
    }
    return $recipients;
}

/**
 * Tell the colleagues who asked (ticketColleagueRecipients()) that a ticket
 * was raised at their company - who raised it, what about and how urgent,
 * with a link to it: in the portal for those who can sign in, else the
 * ticket's guest link. Raised in the portal, by email or by an agent; client
 * notifications have to be on (Admin > Ticket). How many were queued.
 */
function ticketMailColleaguesNew($ticket_id) {
    global $config_ticket_client_general_notifications, $config_base_url;
    if (!emailReady() || intval($config_ticket_client_general_notifications) !== 1) {
        return 0;
    }
    $ticket = ticketRow($ticket_id);
    if (!$ticket || !intval($ticket['ticket_client_id'])) {
        return 0;
    }
    $ticket_id = intval($ticket['ticket_id']);
    $reference = ticketReference($ticket);
    $raised_by = trim((string) $ticket['contact_name']) !== '' ? (string) $ticket['contact_name'] : 'We';
    // What was asked - not for an emailed ticket, sent on by itself: a forged sender would have us carry their words to the client
    $echo = (string) $ticket['ticket_source'] !== 'Email';
    $sent = 0;
    foreach (ticketColleagueRecipients($ticket_id, 'created') as $email => $colleague) {
        $url = $colleague['portal'] ? "https://$config_base_url/client/ticket.php?id=$ticket_id" : ticketEmailUrl($ticket);
        $sent += count(emailQueue([[
            'email' => $email, 'name' => $colleague['name'],
            'footnote' => "You get this because you asked to hear about new tickets at " . $colleague['client_name'] . ($colleague['portal'] ? ' - change that under Your account in the client portal.' : '.'),
        ]], "New ticket - [$reference] - " . $ticket['ticket_subject'], [
            'kind' => 'New ticket', 'tone' => 'primary', 'preview' => ($echo ? preg_replace('/\s+/', ' ', emailPlainText($ticket['ticket_details'], 140)) : '') ?: "$reference - " . $ticket['ticket_subject'],
            'title' => "New ticket at " . $colleague['client_name'],
            'intro' => ["$raised_by raised a ticket at " . $colleague['client_name'] . '.'],
            'message' => ['html' => $echo ? (string) $ticket['ticket_details'] : '', 'label' => 'Details'],
            'summary' => ['Ticket' => $reference, 'Subject' => (string) $ticket['ticket_subject'], 'Priority' => (string) $ticket['ticket_priority'], 'Raised by' => $raised_by === 'We' ? 'Us' : $raised_by],
            'button' => ['label' => $colleague['portal'] ? 'View it in the portal' : 'View the ticket', 'url' => $url],
            'contact' => ticketEmailContactLine(),
        ], ['from' => ticketEmailFrom()]));
    }
    return $sent;
}

/*
 * The "a ticket was created for you" email - to its contact, and its watchers
 * unless $to_watchers is false; or to $to (ticketMailSend()'s) in their
 * place. $how agent, email or scheduled (ticketEmailContent()).
 */
function ticketMailCreated($ticket_id, $subject_prefix, $attachments = [], $to_watchers = true, $how = 'agent', ?array $to = null) {
    $row = ticketRow($ticket_id);
    if (!$row) {
        return 0;
    }
    return ticketMailSend($row['ticket_id'], "$subject_prefix [" . ticketReference($row) . "] - " . $row['ticket_subject'], ticketEmailContent($row, 'created', ['how' => $how]),
        ['attachments' => $attachments, 'to_watchers' => $to_watchers, 'kind' => 'created'] + ($to !== null ? ['to' => $to] : []));
}

/*
 * A public reply on a ticket, to its contact and watchers - $reply_html as
 * saved (with the signature), $by who wrote it (raw). $resolved when the
 * reply resolved it. $reply_id, the reply in ticket_replies, has who it went
 * to kept with it (ticketReplyEmailed()). How many it went to.
 */
function ticketMailReply($ticket_id, $reply_html, $by, $resolved = false, $attachments = [], $reply_id = 0) {
    $row = ticketRow($ticket_id);
    if (!$row) {
        ticketReplyEmailed($reply_id, false);
        return 0;
    }
    $sent = ticketMailSend($row['ticket_id'], ($resolved ? 'Ticket resolved' : 'Ticket update') . " - [" . ticketReference($row) . "] - " . $row['ticket_subject'] . ($resolved ? ' | (pending closure)' : ''),
        ticketEmailContent($row, $resolved ? 'resolved' : 'reply', ['message' => (string) $reply_html, 'by' => (string) $by]), ['attachments' => $attachments, 'ticket_reply_id' => intval($reply_id)]);
    ticketReplyEmailed($reply_id, $sent > 0);
    return $sent;
}

/** Whether the 3.4.8 update has run - a reply keeps whether it was emailed and who to, and the mail queue which reply an email carried. */
function ticketReplyEmailReady() {
    global $mysqli;
    static $ready = null;
    if ($ready === null) {
        if (defined('CURRENT_DATABASE_VERSION')) {
            $version = CURRENT_DATABASE_VERSION;
        } else {
            $result = mysqli_query($mysqli, "SELECT config_current_database_version FROM settings WHERE company_id = 1");
            $version = $result && ($row = mysqli_fetch_row($result)) ? (string) $row[0] : '0';
        }
        $ready = version_compare($version, '3.4.8', '>=');
    }
    return $ready;
}

/*
 * Keep on an agent's reply whether it was emailed - and, once its emails are
 * queued with its id ('ticket_reply_id'), who they went to, read back from the
 * mail queue, so the conversation still says so after the queue has cleared
 * them. $emailed false for a public or internal note. Whether it went to anyone.
 */
function ticketReplyEmailed($reply_id, $emailed = true) {
    global $mysqli;
    $reply_id = intval($reply_id);
    if (!$reply_id || !ticketReplyEmailReady()) {
        return false;
    }
    $to = [];
    if ($emailed) {
        $sql = mysqli_query($mysqli, "SELECT email_recipient, email_recipient_name FROM email_queue WHERE email_ticket_reply_id = $reply_id ORDER BY email_id");
        while ($row = mysqli_fetch_assoc($sql)) {
            $to[strtolower($row['email_recipient'])] = ['email' => (string) $row['email_recipient'],
                'name' => (string) $row['email_recipient_name'] !== (string) $row['email_recipient'] ? (string) $row['email_recipient_name'] : ''];
        }
    }
    $json = $to ? "'" . escapeSql(json_encode(array_values($to), JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES)) . "'" : 'NULL';
    // ticket_reply_updated_at kept as it is - it says when the words were edited
    mysqli_query($mysqli, "UPDATE ticket_replies SET ticket_reply_emailed = " . ($to ? 1 : 0) . ", ticket_reply_emailed_to = $json,
        ticket_reply_updated_at = ticket_reply_updated_at WHERE ticket_reply_id = $reply_id");
    return (bool) $to;
}

/*
 * Who the agent replies in $rows were emailed to, and whether each email went -
 * for the conversation. $rows each have ticket_reply_id, ticket_reply_emailed
 * and ticket_reply_emailed_to. Reply id => ['to' => [['email', 'name', 'state'
 * => mailQueueState(), or null once the queue has cleared it]], 'key' => sent,
 * waiting (still to go, or being tried again), failed, cancelled, or gone (the
 * queue no longer has them - kept 90 days)], for each reply emailed.
 */
function ticketReplyEmailStates(array $rows) {
    global $mysqli;
    $states = [];
    foreach ($rows as $row) {
        if (intval($row['ticket_reply_emailed'] ?? 0) !== 1) {
            continue;
        }
        $to = [];
        foreach ((array) json_decode((string) ($row['ticket_reply_emailed_to'] ?? ''), true) as $recipient) {
            if (!empty($recipient['email'])) {
                $to[strtolower($recipient['email'])] = ['email' => (string) $recipient['email'], 'name' => (string) ($recipient['name'] ?? ''), 'state' => null];
            }
        }
        $states[intval($row['ticket_reply_id'])] = ['to' => $to, 'key' => 'gone'];
    }
    if (!$states || !ticketReplyEmailReady()) {
        return array_map(function ($state) { $state['to'] = array_values($state['to']); return $state; }, $states);
    }
    $sql = mysqli_query($mysqli, "SELECT email_ticket_reply_id, email_recipient, email_recipient_name, email_status, email_attempts, email_queued_at, email_failed_at, email_sent_at, email_error
        FROM email_queue WHERE email_ticket_reply_id IN (" . implode(',', array_keys($states)) . ") ORDER BY email_id");
    while ($sql && ($email = mysqli_fetch_assoc($sql))) {
        $reply_id = intval($email['email_ticket_reply_id']);
        $address = strtolower((string) $email['email_recipient']);
        $states[$reply_id]['to'][$address] = [
            'email' => (string) $email['email_recipient'],
            'name' => $states[$reply_id]['to'][$address]['name'] ?? ((string) $email['email_recipient_name'] !== (string) $email['email_recipient'] ? (string) $email['email_recipient_name'] : ''),
            'state' => mailQueueState($email),
        ];
    }
    foreach ($states as $reply_id => $state) {
        $keys = array_filter(array_map(function ($recipient) { return $recipient['state']['key'] ?? null; }, $state['to']));
        if (!$keys) {
            $key = 'gone';
        } elseif (in_array('failed', $keys, true)) {
            $key = 'failed';
        } elseif (array_intersect(['waiting', 'sending', 'retrying'], $keys)) {
            $key = 'waiting';
        } elseif (!in_array('sent', $keys, true)) {
            $key = 'cancelled';
        } else {
            $key = 'sent';
        }
        $states[$reply_id] = ['to' => array_values($state['to']), 'key' => $key];
    }
    return $states;
}

/** Tell people just made watchers of a ticket - $emails, by $by (raw). How many it went to. */
function ticketMailWatchersAdded($ticket_id, array $emails, $by) {
    $row = ticketRow($ticket_id);
    if (!$row || !$emails) {
        return 0;
    }
    $company_name = (string) (billingCompany()['company_name'] ?? 'us');
    return count(emailQueue(array_map(function ($watcher_email) use ($row, $company_name) {
        return ['email' => $watcher_email, 'greet' => '', 'footnote' => "You get this because you are watching ticket " . ticketReference($row) . " - ask $company_name if you would like to stop."];
    }, $emails), "Ticket Notification - [" . ticketReference($row) . "] - " . $row['ticket_subject'], ticketEmailContent($row, 'watcher', ['by' => (string) $by]), ['from' => ticketEmailFrom()]));
}

/* ------------------------------------------------------------ Emails about a ticket, to agents */

/** Where an agent opens a ticket - in ITFlow. */
function ticketAgentUrl(array $row) {
    global $config_base_url;
    return "https://$config_base_url/agent/" . ticketUrl($row['ticket_id'], $row['ticket_client_id'] ?? 0);
}

/** An agent to email - ['email', 'name'] of an active one, or null. */
function ticketMailAgent($user_id) {
    global $mysqli;
    $user_id = intval($user_id);
    $row = $user_id ? mysqli_fetch_assoc(mysqli_query($mysqli, "SELECT user_name, user_email FROM users
        WHERE user_id = $user_id AND user_type = 1 AND user_status = 1 AND user_archived_at IS NULL LIMIT 1")) : null;
    return $row && filter_var($row['user_email'], FILTER_VALIDATE_EMAIL) ? ['email' => $row['user_email'], 'name' => $row['user_name']] : null;
}

/*
 * What an email to an agent about a ticket says - emailHtml()'s fields
 * (functions/email.php), all but who it is to and why. $row is ticketRow().
 * $kind and its $opts:
 *   new       it was raised - how: portal, email or scheduled
 *   replied   the client replied - how: portal or email, message (the reply, HTML), by (who)
 *   assigned  it was assigned to them - by (who)
 *   mentioned an internal note mentions them - by (who), message (the note, HTML), reply_id (the note, to open)
 *   sla       an SLA alert - track: response or resolution, breached: true once missed, due (when)
 *   scheduled the work was booked - when, where, or cancelled: true
 */
function ticketAgentEmailContent(array $row, $kind, array $opts = []) {
    $reference = ticketReference($row);
    $subject = (string) $row['ticket_subject'];
    $client = !empty($row['client_name']) ? (string) $row['client_name'] : (intval($row['ticket_client_id'] ?? 0) ? 'A client' : 'No client');
    $by = trim((string) ($opts['by'] ?? ''));
    $email = [
        'kind' => 'Ticket', 'tone' => 'primary', 'title' => $subject, 'preview' => "$reference - $subject",
        'summary' => ['Client' => $client, 'Ticket' => $reference, 'Priority' => (string) $row['ticket_priority'], 'Status' => (string) ($row['ticket_status_name'] ?? '')],
        'button' => ['label' => 'Open in ITFlow', 'url' => ticketAgentUrl($row)],
    ];
    if ($kind === 'new') {
        $how = ['portal' => ' in the client portal', 'email' => ' by email', 'scheduled' => ', as scheduled'][$opts['how'] ?? ''] ?? '';
        $who = ($opts['how'] ?? '') === 'scheduled' ? 'A recurring ticket was raised' : (trim((string) ($row['contact_name'] ?? '')) !== '' ? $row['contact_name'] . ' raised a ticket' : 'A ticket was raised');
        $email['kind'] = 'New ticket';
        $email['intro'] = [($opts['how'] ?? '') === 'scheduled' ? "$who for $client, as scheduled." : "$who$how for $client."];
        $email['message'] = ['html' => (string) $row['ticket_details'], 'label' => 'Details'];
        $email['summary'] = ['Client' => $client, 'Ticket' => $reference, 'Priority' => (string) $row['ticket_priority']]
            + (trim((string) ($row['contact_name'] ?? '')) !== '' ? ['Contact' => (string) $row['contact_name']] : []);
    } elseif ($kind === 'replied') {
        $how = ['portal' => ' in the client portal', 'email' => ' by email'][$opts['how'] ?? ''] ?? '';
        $email['kind'] = 'Client replied';
        $email['intro'] = [($by !== '' ? $by : 'The client') . " replied to $reference$how."];
        $email['message'] = ['html' => (string) ($opts['message'] ?? ''), 'label' => ($by !== '' ? $by : 'They') . ' wrote'];
        $email['after'] = ['Answer it in ITFlow, so the client gets your reply.'];
        $email['history'] = ticketEmailHistory($row, ['skip' => (string) ($opts['message'] ?? '')]);
    } elseif ($kind === 'mentioned') {
        $email['kind'] = 'Mentioned you';
        $email['intro'] = [($by !== '' ? $by : 'Someone') . " mentioned you in an internal note on $reference."];
        $email['message'] = ['html' => (string) ($opts['message'] ?? ''), 'label' => ($by !== '' ? $by : 'They') . ' wrote - only your team can see this'];
        $email['history'] = ticketEmailHistory($row, ['limit' => 2, 'label' => 'The conversation']);
        if (!empty($opts['reply_id'])) {
            $email['button'] = ['label' => 'Open the note', 'url' => ticketMentionUrl($row, $opts['reply_id'], true)];
        }
    } elseif ($kind === 'assigned') {
        $email['kind'] = 'Assigned to you';
        $email['intro'] = [($by !== '' ? $by : 'Someone') . " assigned $reference to you."];
        $email['message'] = ['html' => (string) $row['ticket_details'], 'label' => 'Details'];
        $email['history'] = ticketEmailHistory($row, ['request' => false, 'label' => 'Replies so far']);
    } elseif ($kind === 'scheduled') {
        $cancelled = !empty($opts['cancelled']);
        $email['kind'] = $cancelled ? 'Visit cancelled' : 'Work booked';
        $email['tone'] = $cancelled ? 'secondary' : 'primary';
        $email['intro'] = [$cancelled ? "The work booked on $reference is cancelled - the calendar file with this email takes it out of your calendar." : "$reference is booked for " . $opts['when'] . " - the calendar file with this email adds it to your calendar."];
        if (!$cancelled) {
            $email['summary'] += ['When' => (string) $opts['when'], 'Where' => !empty($row['ticket_onsite']) ? (trim((string) ($opts['where'] ?? '')) !== '' ? (string) $opts['where'] : 'Onsite') : 'Remote'];
            $email['history'] = ticketEmailHistory($row, ['limit' => 2, 'label' => 'What it is about']);
        }
    } elseif ($kind === 'sla') {
        $track = ($opts['track'] ?? 'response') === 'resolution' ? 'resolution' : 'response';
        $due = !empty($opts['due']) ? date('D j M, g:i A', strtotime($opts['due'])) : '';
        $breached = !empty($opts['breached']);
        $email['kind'] = ucfirst($track) . ($breached ? ' SLA missed' : ' SLA at risk');
        $email['tone'] = $breached ? 'danger' : 'warning';
        $email['intro'] = [$breached
            ? "The $track due on $reference by $due was missed."
            : "$reference is close to its $track SLA - it is due by $due."];
        $email['summary'] += ['Assigned' => !empty($row['user_name']) ? (string) $row['user_name'] : 'Nobody', ucfirst($track) . ' due' => $due];
        $email['history'] = ticketEmailHistory($row, ['limit' => 3, 'label' => 'The conversation']);
    }
    return ticketEmailPreview($email);
}

/** Queue an email to agents (ticketAgentEmailContent()) from the ticket mailbox - [['email', 'name', 'footnote'], ...]. How many went. */
function ticketMailAgents(array $recipients, $subject, array $email) {
    return count(emailQueue($recipients, $subject, $email, ['from' => ticketEmailFrom()]));
}

/*
 * Tell the new-ticket address (Admin > Ticket) a ticket was raised - $how:
 * portal, email or scheduled. Nothing when it isn't set.
 */
function ticketMailNewTicketAddress($ticket_id, $how) {
    global $mysqli, $config_app_name;
    $address = (string) (mysqli_fetch_row(mysqli_query($mysqli, "SELECT config_ticket_new_ticket_notification_email FROM settings WHERE company_id = 1"))[0] ?? '');
    $row = ticketRow($ticket_id);
    if (!filter_var($address, FILTER_VALIDATE_EMAIL) || !$row) {
        return 0;
    }
    $client = !empty($row['client_name']) ? $row['client_name'] : 'Guest';
    $subject = ($config_app_name ?: 'ITFlow') . ($how === 'scheduled' ? ' - New Recurring Ticket - ' : ' - New Ticket - ') . "$client: " . $row['ticket_subject'];
    return ticketMailAgents([['email' => $address, 'greet' => '', 'footnote' => 'You get this at the new-ticket address in Admin > Ticket.']],
        $subject, ticketAgentEmailContent($row, 'new', ['how' => $how]));
}

/** Tell the agent a ticket is assigned to that the client replied - $how portal or email, $reply its HTML, $by who. */
function ticketMailAssigneeReplied($ticket_id, $how, $reply, $by) {
    global $config_app_name;
    $row = ticketRow($ticket_id);
    $agent = $row ? ticketMailAgent($row['ticket_assigned_to']) : null;
    if (!$agent) {
        return 0;
    }
    return ticketMailAgents([$agent + ['footnote' => 'You get this as the agent ' . ticketReference($row) . ' is assigned to.']],
        ($config_app_name ?: 'ITFlow') . " - Ticket updated - [" . ticketReference($row) . "] " . $row['ticket_subject'],
        ticketAgentEmailContent($row, 'replied', ['how' => $how, 'message' => (string) $reply, 'by' => (string) $by]));
}

/*
 * Tell an agent tickets are theirs now - one email for any number. Not when
 * they assigned them themselves. $ticket_ids, $by raw. How many went.
 */
function ticketMailAssigned($user_id, array $ticket_ids, $by) {
    global $session_user_id, $config_app_name, $config_base_url;
    $agent = intval($user_id) !== intval($session_user_id ?? 0) ? ticketMailAgent($user_id) : null;
    $rows = array_values(array_filter(array_map('ticketRow', array_unique(array_map('intval', $ticket_ids)))));
    if (!$agent || !$rows) {
        return 0;
    }
    $app = $config_app_name ?: 'ITFlow';
    $agent['footnote'] = 'You get this because ' . (count($rows) === 1 ? 'the ticket was' : 'they were') . ' assigned to you in ITFlow.';
    if (count($rows) === 1) {
        $row = $rows[0];
        return ticketMailAgents([$agent], "$app - Ticket " . ticketReference($row) . " assigned to you - " . $row['ticket_subject'], ticketAgentEmailContent($row, 'assigned', ['by' => $by]));
    }
    $lines = [];
    foreach ($rows as $row) {
        $lines[] = [['text' => ticketReference($row), 'url' => ticketAgentUrl($row)], (string) $row['ticket_subject'], !empty($row['client_name']) ? (string) $row['client_name'] : '-', (string) $row['ticket_priority']];
    }
    return ticketMailAgents([$agent], "$app - " . count($rows) . " tickets have been assigned to you", [
        'kind' => 'Assigned to you', 'tone' => 'primary', 'preview' => "$by assigned " . count($rows) . ' tickets to you',
        'title' => count($rows) . ' tickets are yours',
        'intro' => ["$by assigned these tickets to you."],
        'lines' => ['head' => ['Ticket', 'Subject', 'Client', 'Priority'], 'rows' => $lines],
        'button' => ['label' => 'Open your tickets', 'url' => "https://$config_base_url/agent/tickets.php?assigned=" . intval($user_id)],
    ]);
}

/*
 * Tell an agent recurring tickets are theirs now - the tickets they raise
 * will be. $subjects (raw) of the recurring tickets, $by who did it. Not when
 * they did it themselves.
 */
function recurringTicketMailAssigned($user_id, array $subjects, $by) {
    global $session_user_id, $config_app_name, $config_base_url;
    $agent = intval($user_id) !== intval($session_user_id ?? 0) ? ticketMailAgent($user_id) : null;
    if (!$agent || !$subjects) {
        return 0;
    }
    $count = count($subjects);
    $agent['footnote'] = 'You get this because ' . ($count === 1 ? 'it was' : 'they were') . ' assigned to you in ITFlow.';
    return ticketMailAgents([$agent], ($config_app_name ?: 'ITFlow') . ($count === 1 ? " - Recurring ticket " . $subjects[0] . " assigned to you" : " - $count recurring tickets assigned to you"), [
        'kind' => 'Assigned to you', 'tone' => 'primary', 'preview' => "$by assigned recurring tickets to you",
        'title' => $count === 1 ? 'A recurring ticket is yours' : "$count recurring tickets are yours",
        'intro' => ["$by assigned " . ($count === 1 ? 'this recurring ticket' : 'these recurring tickets') . " to you - the tickets " . ($count === 1 ? 'it raises' : 'they raise') . " will be yours."],
        'lines' => ['head' => ['Recurring ticket'], 'rows' => array_map(function ($subject) { return [(string) $subject]; }, array_values($subjects))],
        'button' => ['label' => 'Open Recurring Tickets', 'url' => "https://$config_base_url/agent/recurring_tickets.php?assigned_agent=" . intval($user_id)],
    ]);
}

/*
 * Ask for a task's approval by email - the agent named, or the client's: the
 * ticket's contact, or its technical or billing contacts. $by (raw) asked.
 * How many it went to.
 */
function ticketMailTaskApproval($approval_id, $by) {
    global $mysqli, $config_base_url, $session_user_id;
    $approval = mysqli_fetch_assoc(mysqli_query($mysqli, "SELECT approval_id, approval_scope, approval_type, approval_required_user_id, approval_url_key, task_name, task_ticket_id
        FROM task_approvals JOIN tasks ON task_id = approval_task_id WHERE approval_id = " . intval($approval_id)));
    $row = $approval ? ticketRow($approval['task_ticket_id']) : null;
    if (!$row) {
        return 0;
    }
    $reference = ticketReference($row);
    $client_id = intval($row['ticket_client_id']);
    $type = (string) $approval['approval_type'];
    $recipients = [];
    if ($approval['approval_scope'] === 'internal' && $type === 'specific' && intval($approval['approval_required_user_id']) !== intval($session_user_id)) {
        if ($agent = ticketMailAgent($approval['approval_required_user_id'])) {
            $recipients[] = $agent + ['footnote' => "You get this because $by asked you to approve it."];
        }
    } elseif ($approval['approval_scope'] === 'client') {
        $where = $type === 'technical' ? "contact_client_id = $client_id AND contact_technical = 1"
            : ($type === 'billing' ? "contact_client_id = $client_id AND contact_billing = 1" : "contact_id = " . intval($row['ticket_contact_id']));
        $sql_contacts = mysqli_query($mysqli, "SELECT contact_name, contact_email FROM contacts WHERE $where AND contact_archived_at IS NULL AND contact_email != ''");
        while ($contact = mysqli_fetch_assoc($sql_contacts)) {
            $recipients[] = ['email' => $contact['contact_email'], 'name' => $contact['contact_name'],
                'footnote' => $type === 'any' ? "You get this as the contact on ticket $reference." : "You get this as a $type contact for " . $row['client_name'] . "."];
        }
    }
    return count(emailQueue($recipients, "Ticket task approval required - [$reference] - " . $row['ticket_subject'], [
        'marker' => true, 'kind' => 'Approval needed', 'tone' => 'warning', 'preview' => "$by needs your approval - " . $approval['task_name'],
        'title' => 'Your approval is needed',
        'intro' => ["$by needs your approval for a task on ticket $reference before the work goes ahead."],
        'summary' => ['Task' => (string) $approval['task_name'], 'Ticket' => $reference, 'Subject' => (string) $row['ticket_subject'], 'Status' => (string) $row['ticket_status_name']],
        'button' => ['label' => 'Review and approve', 'url' => "https://$config_base_url/guest/guest_approve_ticket_task.php?task_approval_id=" . intval($approval['approval_id']) . '&url_key=' . rawurlencode((string) $approval['approval_url_key'])],
        'after' => ['Want to know more first? Just reply to this email.'],
        'contact' => ticketEmailContactLine(),
    ], ['from' => ticketEmailFrom()]));
}

/*
 * Tell someone who replied to a closed ticket by email that it is closed, so
 * their reply reached nobody - and how to raise a new one. $from_email raw.
 */
function ticketMailClosedReply($ticket_id, $from_email) {
    $closed = ticketRow($ticket_id);
    if (!$closed) {
        return 0;
    }
    $support = ticketEmailFrom()['email'];
    return count(emailQueue([['email' => (string) $from_email, 'greet' => '', 'footnote' => 'You get this because you replied to a closed ticket.']], "Action required: This ticket is already closed", [
        'kind' => 'Ticket closed', 'tone' => 'warning', 'preview' => 'Your reply did not reach us - raise a new ticket instead',
        'title' => 'That ticket is closed',
        'intro' => ["You replied to ticket " . ticketReference($closed) . " - \"" . $closed['ticket_subject'] . "\" - which is closed, so your reply won't reach us.", "To raise a new ticket, send a new email to $support."],
        'button' => ['label' => 'Email us', 'url' => "mailto:$support"],
        'contact' => ticketEmailContactLine(),
    ], ['from' => ticketEmailFrom()]));
}

/*
 * An SLA alert on a ticket - in the app, and by email to the SLA alert address
 * (Admin > SLAs, $address) and the agent it is assigned to. $track response or
 * resolution; $breached true once it was missed; $due when it is or was due.
 */
function ticketSlaAlert($ticket_id, $track, $breached, $due, $address) {
    $row = ticketRow($ticket_id);
    if (!$row) {
        return 0;
    }
    $ticket_id = intval($row['ticket_id']);
    $ticket_ref = ticketReference($row);
    $subject_line = ucfirst($track) . ' SLA ' . ($breached ? 'breached' : 'at risk');

    // appNotify inserts what it is given - escape at the boundary
    appNotify("Ticket SLA", escapeSql("$subject_line - $ticket_ref - " . $row['ticket_subject']), "/agent/ticket.php?ticket_id=$ticket_id", intval($row['ticket_client_id']), $ticket_id);

    $recipients = [];
    if (filter_var($address, FILTER_VALIDATE_EMAIL)) {
        $recipients[] = ['email' => $address, 'greet' => '', 'footnote' => 'You get this at the SLA alert address in Admin > SLAs.'];
    }
    // The assigned agent - once, if they are also the alert address
    if ($agent = ticketMailAgent($row['ticket_assigned_to'])) {
        $recipients[] = $agent + ['footnote' => "You get this as the agent $ticket_ref is assigned to."];
    }
    return ticketMailAgents($recipients, "$subject_line: $ticket_ref - " . $row['ticket_subject'],
        ticketAgentEmailContent($row, 'sla', ['track' => $track, 'breached' => $breached, 'due' => $due]));
}

/** Time worked as posted - HH:MM:SS, or H:MM - normalised to HH:MM:SS; nothing sensible is 00:00:00. */
function ticketTimeWorked($input) {
    if (preg_match('/^\s*(\d{1,3}):([0-5]?\d)(?::([0-5]?\d))?\s*$/', (string) $input, $match)) {
        return sprintf('%02d:%02d:%02d', intval($match[1]), intval($match[2]), intval($match[3] ?? 0));
    }
    return '00:00:00';
}

/** Statuses a reply may leave the ticket in: the active ones but New and Closed (the system sets those), plus the one it has. */
function ticketReplyStatuses($current_status) {
    global $mysqli;
    $ids = [intval($current_status)];
    $sql = mysqli_query($mysqli, "SELECT ticket_status_id FROM ticket_statuses WHERE ticket_status_id NOT IN (1, 5) AND ticket_status_active = 1");
    while ($row = mysqli_fetch_row($sql)) {
        $ids[] = intval($row[0]);
    }
    return array_values(array_unique($ids));
}

/** How many of a ticket's tasks are not done yet. */
function ticketOpenTaskCount($ticket_id) {
    global $mysqli;
    return intval(mysqli_fetch_row(mysqli_query($mysqli, "SELECT COUNT(*) FROM tasks WHERE task_ticket_id = " . intval($ticket_id) . " AND task_completed_at IS NULL"))[0]);
}

/**
 * Tickets for another page's list - open ones first, then newest - each with
 * its status, agent and is_open. $where is SQL on tickets; $limit 0 is all.
 */
function ticketRows($where, $limit = 0) {
    global $mysqli;
    $limit = intval($limit);
    $sql = mysqli_query($mysqli, "SELECT tickets.ticket_id, ticket_prefix, ticket_number, ticket_subject, ticket_priority, ticket_vendor_ticket_number,
            ticket_created_at, ticket_updated_at, ticket_resolved_at, ticket_closed_at, ticket_assigned_to, ticket_client_id,
            user_name, user_avatar, ticket_status_id, ticket_status_name, ticket_status_color
        FROM tickets
        LEFT JOIN users ON ticket_assigned_to = user_id
        LEFT JOIN ticket_statuses ON ticket_status_id = ticket_status
        WHERE ($where) AND ticket_archived_at IS NULL
        ORDER BY (ticket_resolved_at IS NULL AND ticket_closed_at IS NULL) DESC, ticket_number DESC" . ($limit ? " LIMIT $limit" : ''));
    $rows = [];
    while ($row = mysqli_fetch_assoc($sql)) {
        $row['is_open'] = ticketIsOpen($row);
        $rows[] = $row;
    }
    return $rows;
}

/** The SQL for "tickets about this asset" - its primary asset or one of its others. */
function ticketAssetSql($asset_id) {
    $asset_id = intval($asset_id);
    return "tickets.ticket_asset_id = $asset_id OR tickets.ticket_id IN (SELECT ticket_assets.ticket_id FROM ticket_assets WHERE ticket_assets.asset_id = $asset_id)";
}

/** How many tickets match, and how many of those are open - [all, open]. */
function ticketCounts($where) {
    global $mysqli;
    $row = mysqli_fetch_row(mysqli_query($mysqli, "SELECT COUNT(*), COALESCE(SUM(ticket_resolved_at IS NULL AND ticket_closed_at IS NULL), 0) FROM tickets WHERE ($where) AND ticket_archived_at IS NULL"));
    return [intval($row[0]), intval($row[1])];
}

/**
 * Tickets as a table - the one used by the asset, contact, site, vendor and
 * project pages and their quick looks. Options: 'compact' (a quick look's
 * table: no header, no priority), 'vendor_ref' (their reference for it, to
 * copy), 'client' (a Client column, for lists across clients).
 */
function ticketTableHtml(array $rows, $options = []) {
    $compact = !empty($options['compact']);
    $vendor_ref = !empty($options['vendor_ref']);
    $with_client = !empty($options['client']);
    $html = '<div class="table-responsive"><table class="table ' . ($compact ? 'table-sm ' : '') . 'table-hover align-middle mb-0 itflow-ticket-table">';
    if (!$compact) {
        $html .= '<thead class="text-nowrap table-light"><tr><th>Ticket</th><th>Subject</th>' . ($vendor_ref ? '<th>Their reference</th>' : '')
            . ($with_client ? '<th>Client</th>' : '') . '<th>Priority</th><th>Status</th><th>Assigned</th><th>Updated</th></tr></thead>';
    }
    $html .= '<tbody>';
    foreach ($rows as $row) {
        $is_open = $row['is_open'] ?? ticketIsOpen($row);
        $url = escapeHtml(ticketUrl($row['ticket_id'], $row['ticket_client_id'] ?? 0));
        $last = $row['ticket_updated_at'] ?: $row['ticket_created_at'];
        $their_ref = escapeHtml($row['ticket_vendor_ticket_number'] ?? '');
        $html .= '<tr class="' . ($is_open ? '' : 'text-body-secondary') . '">'
            . '<td class="text-nowrap"><a class="font-monospace" href="' . $url . '">' . escapeHtml(ticketReference($row)) . '</a></td>'
            . '<td class="' . ($compact ? 'w-100' : 'itflow-ticket-subject') . '"><a class="' . ($is_open ? 'text-body' . ($compact ? '' : ' fw-semibold') : 'text-body-secondary') . '" href="' . $url . '">' . escapeHtml($row['ticket_subject']) . '</a></td>';
        if ($vendor_ref) {
            $html .= '<td class="text-nowrap small">' . ($their_ref !== ''
                ? '<span class="font-monospace">' . $their_ref . '</span><button type="button" class="itflow-copy clipboardjs" title="Copy their reference" data-clipboard-text="' . $their_ref . '"><i class="far fa-copy"></i></button>'
                : '<span class="text-body-secondary">-</span>') . '</td>';
        }
        if ($with_client) {
            $html .= '<td class="small">' . escapeHtml($row['client_name'] ?? '') . '</td>';
        }
        if (!$compact) {
            $html .= '<td class="text-nowrap">' . ticketPriorityHtml($row['ticket_priority'], 'detail') . '</td>';
        }
        $html .= '<td class="text-nowrap">' . ticketStatusHtml($row['ticket_status_name'] ?? '', $row['ticket_status_color'] ?? '', 'detail') . '</td>'
            . '<td class="text-nowrap">' . formatAssignee($row['ticket_assigned_to'], $row['user_name'] ?? '', $row['user_avatar'] ?? '', $is_open) . '</td>'
            . '<td class="text-nowrap small text-body-secondary" title="' . escapeHtml($last) . '">' . timeAgo($last) . '</td>'
            . '</tr>';
    }
    return $html . '</tbody></table></div>';
}

/**
 * The other open tickets for the same contact or the same asset as this one
 * (or as the contact and asset given, for a ticket not yet created) - so a
 * duplicate or a related problem shows up. Each row says which it shares.
 */
function ticketAlsoOpen($contact_id, $asset_id, $exclude_ticket_id = 0, $limit = 6) {
    global $mysqli;
    $contact_id = intval($contact_id);
    $asset_id = intval($asset_id);
    $exclude_ticket_id = intval($exclude_ticket_id);
    $match = [];
    if ($contact_id) {
        $match[] = "tickets.ticket_contact_id = $contact_id";
    }
    if ($asset_id) {
        $match[] = ticketAssetSql($asset_id);
    }
    if (!$match) {
        return [];
    }
    $rows = ticketRows('(' . implode(' OR ', $match) . ") AND tickets.ticket_id <> $exclude_ticket_id AND ticket_resolved_at IS NULL AND ticket_closed_at IS NULL", $limit);
    foreach ($rows as &$row) {
        $shares = [];
        $ticket_id = intval($row['ticket_id']);
        $full = mysqli_fetch_assoc(mysqli_query($mysqli, "SELECT ticket_contact_id, ticket_asset_id FROM tickets WHERE ticket_id = $ticket_id"));
        if ($contact_id && intval($full['ticket_contact_id']) === $contact_id) {
            $shares[] = 'contact';
        }
        if ($asset_id && (intval($full['ticket_asset_id']) === $asset_id
            || mysqli_num_rows(mysqli_query($mysqli, "SELECT 1 FROM ticket_assets WHERE ticket_id = $ticket_id AND asset_id = $asset_id LIMIT 1")))) {
            $shares[] = 'asset';
        }
        $row['shares'] = $shares;
    }
    return $rows;
}

/** Mark a ticket resolved - status, SLA, history, audit and the custom action. The caller has checked it may be. */
function ticketResolve($row, $how = '') {
    global $mysqli, $session_name;
    $ticket_id = intval($row['ticket_id']);
    if (empty($row['ticket_first_response_at'])) {
        setTicketFirstResponse($ticket_id);
    }
    mysqli_query($mysqli, "UPDATE tickets SET ticket_status = " . TICKET_STATUS_RESOLVED . ", ticket_resolved_at = NOW() WHERE ticket_id = $ticket_id");
    syncTicketSlaClock($ticket_id);
    setTicketResolutionSlaMet($ticket_id);
    logTicketHistory($ticket_id, "$session_name resolved the ticket$how");
    logAudit("Ticket", "Resolve", "$session_name resolved ticket " . escapeSql(ticketReference($row)) . " - " . escapeSql($row['ticket_subject']), intval($row['ticket_client_id']), $ticket_id);
    triggerCustomAction('ticket_resolve', $ticket_id);
}

/** Bring a resolved (not closed) ticket back into a working status. The caller has checked it may be. */
function ticketReopen($row, $status_id = TICKET_STATUS_OPEN, $how = '') {
    global $mysqli, $session_name;
    $ticket_id = intval($row['ticket_id']);
    $status_id = intval($status_id);
    mysqli_query($mysqli, "UPDATE tickets SET ticket_status = $status_id, ticket_resolved_at = NULL WHERE ticket_id = $ticket_id");
    syncTicketSlaClock($ticket_id);
    resetTicketResolutionSla($ticket_id);
    $status_name = escapeSql(getTicketStatusName($status_id));
    logTicketHistory($ticket_id, "$session_name reopened the ticket" . ($status_id === TICKET_STATUS_OPEN ? '' : " to $status_name") . $how);
    logAudit("Ticket", "Reopen", "$session_name reopened ticket " . escapeSql(ticketReference($row)), intval($row['ticket_client_id']), $ticket_id);
    triggerCustomAction('ticket_update', $ticket_id);
}

/** The "your ticket is closed" email - to its contact and watchers, asking how we did. */
function ticketMailClosed($ticket_id) {
    $row = ticketRow($ticket_id);
    if (!$row) {
        return 0;
    }
    return ticketMailSend($row['ticket_id'], "Ticket closed - [" . ticketReference($row) . "] - " . $row['ticket_subject'] . " | (do not reply)",
        ticketEmailContent($row, 'closed'), ['kind' => 'closed']);
}

/*
 * The "Emailed to ..." line on an agent's reply in the conversation, and the
 * panel it opens - each recipient and whether their email went. $state is
 * the reply's from ticketReplyEmailStates(); $queue_url the Mail Queue for
 * this ticket's email, for admins, or ''. ['line' => html, 'panel' => html].
 */
function ticketReplyEmailHtml($reply_id, array $state, $queue_url = '') {
    $reply_id = intval($reply_id);
    $to = $state['to'] ?? [];
    if (!$to) {
        // Marked emailed, but who to wasn't kept
        return ['line' => '<span class="ticket-reply-emailed"><i class="fas fa-fw fa-paper-plane me-1"></i>Emailed</span>', 'panel' => ''];
    }
    $who = function ($recipient) {
        return $recipient['name'] !== '' ? $recipient['name'] : $recipient['email'];
    };
    $first = escapeHtml($who($to[0])) . (count($to) > 1 ? ' and ' . (count($to) - 1) . ' more' : '');
    $failed = count(array_filter($to, function ($recipient) {
        return ($recipient['state']['key'] ?? '') === 'failed';
    }));
    switch ($state['key'] ?? 'gone') {
        case 'sent':
            [$icon, $text, $title] = ['fa-check text-success', "Emailed to $first", 'Sent'];
            break;
        case 'waiting':
            [$icon, $text, $title] = ['fa-hourglass-half text-primary', "Sending to $first", 'Waiting in the mail queue'];
            break;
        case 'failed':
            [$icon, $text, $title] = ['fa-exclamation-circle text-danger', $failed === count($to) ? "<span class=\"text-danger\">Couldn't email $first</span>"
                : "Emailed to $first <span class=\"text-danger\">&middot; $failed not sent</span>", 'Not sent'];
            break;
        case 'cancelled':
            [$icon, $text, $title] = ['fa-ban', "Email to $first cancelled", 'Cancelled'];
            break;
        default:
            [$icon, $text, $title] = ['fa-paper-plane', "Emailed to $first", ''];
    }
    $line = '<a class="ticket-reply-emailed text-reset" data-bs-toggle="collapse" href="#replyEmailed' . $reply_id . '" role="button" aria-expanded="false" aria-controls="replyEmailed' . $reply_id . '"'
        . ' title="' . escapeHtml(($title !== '' ? "$title - " : '') . 'who it went to') . '" data-reply-emailed="' . escapeHtml($state['key'] ?? 'gone') . '">'
        . '<i class="fas fa-fw ' . $icon . ' me-1"></i>' . $text . '</a>';

    $items = '';
    foreach ($to as $recipient) {
        $item_state = $recipient['state'];
        $address = $recipient['name'] !== '' ? escapeHtml($recipient['name']) . ' <span class="text-body-secondary">&lt;' . escapeHtml($recipient['email']) . '&gt;</span>' : escapeHtml($recipient['email']);
        $items .= '<li class="d-flex flex-wrap align-items-center gap-2" data-reply-recipient="' . escapeHtml($recipient['email']) . '">'
            . ($item_state ? '<span class="badge ' . $item_state['badge'] . '" title="' . escapeHtml($item_state['title']) . '"><i class="fas fa-fw ' . $item_state['icon'] . ' me-1"></i>' . escapeHtml($item_state['label']) . '</span>' : '')
            . '<span class="text-break">' . $address . '</span>'
            . ($item_state && $item_state['detail'] !== '' ? '<span class="text-body-secondary">' . escapeHtml($item_state['detail']) . '</span>' : '')
            . ($item_state && $item_state['error'] !== '' ? '<span class="w-100 text-danger">' . escapeHtml($item_state['error']) . '</span>' : '')
            . '</li>';
    }
    $gone = !array_filter(array_column($to, 'state'));
    $panel = '<div class="collapse" id="replyEmailed' . $reply_id . '">'
        . '<div class="ticket-reply-recipients small mt-2">'
        . '<ul class="list-unstyled d-grid gap-1 mb-0">' . $items . '</ul>'
        . ($gone ? '<div class="text-body-secondary mt-1">The mail queue keeps email ' . MAIL_QUEUE_KEEP_DAYS . ' days, so whether each one went is no longer known.</div>' : '')
        . ($queue_url !== '' ? '<a class="d-inline-block mt-1" href="' . escapeHtml($queue_url) . '"><i class="fas fa-fw fa-mail-bulk me-1"></i>This ticket\'s email in the Mail Queue</a>' : '')
        . '</div></div>';
    return ['line' => $line, 'panel' => $panel];
}

/*
 * The "your ticket is resolved, pending closure" email - to its contact and
 * watchers. $note is the agent's words as HTML, raw, or ''; $reply_id the
 * reply they were saved as, which keeps who it went to (ticketReplyEmailed()).
 */
function ticketMailResolved($ticket_id, $note = '', $reply_id = 0) {
    global $session_name;
    $row = ticketRow($ticket_id);
    if (!$row) {
        ticketReplyEmailed($reply_id, false);
        return 0;
    }
    $sent = ticketMailSend($row['ticket_id'], "Ticket resolved - [" . ticketReference($row) . "] - " . $row['ticket_subject'] . " | (pending closure)",
        ticketEmailContent($row, 'resolved', ['message' => (string) $note, 'by' => stripslashes((string) ($session_name ?? ''))]), ['ticket_reply_id' => intval($reply_id)]);
    ticketReplyEmailed($reply_id, $sent > 0);
    return $sent;
}

/*
 * ---------- the ticket list and board ----------
 *
 * Whose move it is. A ticket is waiting on us until we reply where the
 * client can see it; after that it waits on them until they write back.
 * Internal notes change neither. A status that pauses the SLA clock (On
 * Hold, or one of yours like "Waiting on vendor") parks it - waiting, too.
 */

/** SQL: still being worked - neither resolved nor closed. On tickets. */
const TICKET_OPEN_SQL = "(tickets.ticket_resolved_at IS NULL AND tickets.ticket_closed_at IS NULL)";

/**
 * SQL for who spoke last where the client can see it: 'Client', 'Public'
 * (us), or NULL when nobody has replied yet. Correlated on tickets, so it
 * goes after the open-ticket test in a condition - MySQL stops at the first
 * false AND, and it then only runs for open tickets.
 */
function ticketLastSpokeSql() {
    return "(SELECT tr.ticket_reply_type FROM ticket_replies tr WHERE tr.ticket_reply_ticket_id = tickets.ticket_id
        AND tr.ticket_reply_archived_at IS NULL AND tr.ticket_reply_type IN ('Public', 'Client')
        ORDER BY tr.ticket_reply_id DESC LIMIT 1)";
}

/** SQL: open, not parked, and the client spoke last (or nobody has yet). Needs tickets joined to ticket_statuses. */
function ticketNeedsReplySql() {
    return TICKET_OPEN_SQL . " AND COALESCE(ticket_statuses.ticket_status_pauses_sla, 0) = 0 AND COALESCE(" . ticketLastSpokeSql() . ", 'Client') = 'Client'";
}

/** SQL: open, and parked or we spoke last. Needs tickets joined to ticket_statuses. */
function ticketWaitingSql() {
    return TICKET_OPEN_SQL . " AND (COALESCE(ticket_statuses.ticket_status_pauses_sla, 0) = 1 OR " . ticketLastSpokeSql() . " = 'Public')";
}

/** SQL: open and past its due date, or its SLA is breached. */
function ticketOverdueSql() {
    return TICKET_OPEN_SQL . " AND ((tickets.ticket_due_at IS NOT NULL AND tickets.ticket_due_at < NOW())
        OR (tickets.ticket_sla_id > 0 AND (tickets.ticket_response_sla_alert_stage = 2 OR tickets.ticket_resolution_sla_alert_stage = 2)))";
}

/** Whose move: 'us', 'client', 'parked', or '' for a ticket that is done. From a row with ticket_last_spoke and ticket_status_pauses_sla. */
function ticketWhoseMove($row) {
    if (!ticketIsOpen($row)) {
        return '';
    }
    if (intval($row['ticket_status_pauses_sla'] ?? 0)) {
        return 'parked';
    }
    return ($row['ticket_last_spoke'] ?? null) === 'Public' ? 'client' : 'us';
}

/**
 * Where its SLA stands: ['key' => breached | at_risk | paused | running |
 * met | missed | none, 'due' => the clock still running's deadline, 'what'].
 * A breach recorded stands even while paused - it already happened.
 */
function ticketSlaState($row) {
    if (!intval($row['ticket_sla_id'] ?? 0)) {
        return ['key' => 'none'];
    }
    $stage = max(intval($row['ticket_response_sla_alert_stage'] ?? 0), intval($row['ticket_resolution_sla_alert_stage'] ?? 0));
    if (!ticketIsOpen($row)) {
        if ($stage === 2 || ($row['ticket_response_sla_met'] ?? null) === '0' || ($row['ticket_resolution_sla_met'] ?? null) === '0') {
            return ['key' => 'missed'];
        }
        $met = intval($row['ticket_response_sla_met'] ?? 0) && (empty($row['ticket_resolution_due_at']) || intval($row['ticket_resolution_sla_met'] ?? 0));
        return ['key' => $met ? 'met' : 'none'];
    }
    $responded = !empty($row['ticket_first_response_at']);
    $state = [
        'due' => $responded ? ($row['ticket_resolution_due_at'] ?? null) : ($row['ticket_response_due_at'] ?? null),
        'what' => $responded ? 'Resolution due' : 'First response due',
    ];
    if ($stage === 2) {
        return ['key' => 'breached'] + $state;
    }
    if (intval($row['ticket_status_pauses_sla'] ?? 0)) {
        return ['key' => 'paused'] + $state;
    }
    if ($stage === 1) {
        return ['key' => 'at_risk'] + $state;
    }
    return ['key' => empty($state['due']) ? 'none' : 'running'] + $state;
}

/** The SLA as a small pill - '' when there is nothing to say. */
function ticketSlaPill($sla) {
    $due = !empty($sla['due']) ? ' title="' . escapeHtml($sla['what'] . ' ' . $sla['due']) . '"' : '';
    switch ($sla['key']) {
        case 'breached':
            return '<span class="badge rounded-pill text-bg-danger"' . $due . '><i class="fas fa-stopwatch me-1"></i>Breached</span>';
        case 'at_risk':
            return '<span class="badge rounded-pill text-bg-warning"' . $due . '><i class="fas fa-stopwatch me-1"></i>' . (!empty($sla['due']) ? timeAgo($sla['due']) : 'At risk') . '</span>';
        case 'paused':
            return '<span class="badge rounded-pill text-bg-secondary" title="The SLA clock is paused in this status"><i class="fas fa-pause me-1"></i>Paused</span>';
        case 'running':
            return '<span class="badge rounded-pill bg-body-secondary text-body-secondary fw-normal"' . $due . '><i class="fas fa-stopwatch me-1"></i>' . timeAgo($sla['due']) . '</span>';
        case 'met':
            return '<span class="badge rounded-pill bg-success-subtle text-success-emphasis fw-normal"><i class="fas fa-check me-1"></i>SLA met</span>';
        case 'missed':
            return '<span class="badge rounded-pill bg-danger-subtle text-danger-emphasis fw-normal"><i class="fas fa-stopwatch me-1"></i>SLA missed</span>';
    }
    return '';
}

/** Its own due date, for an open ticket: ['key' => overdue | soon (a day or less) | later, 'at'], or null. */
function ticketDueState($row) {
    if (empty($row['ticket_due_at']) || !ticketIsOpen($row)) {
        return null;
    }
    $left = strtotime($row['ticket_due_at']) - time();
    return ['key' => $left < 0 ? 'overdue' : ($left <= 86400 ? 'soon' : 'later'), 'at' => $row['ticket_due_at']];
}

function ticketDuePill($due) {
    if (!$due) {
        return '';
    }
    $title = ' title="Due ' . escapeHtml(date('M j, Y g:i A', strtotime($due['at']))) . '"';
    if ($due['key'] === 'overdue') {
        return '<span class="badge rounded-pill text-bg-danger"' . $title . '><i class="far fa-calendar-times me-1"></i>Due ' . timeAgo($due['at']) . '</span>';
    }
    return '<span class="badge rounded-pill ' . ($due['key'] === 'soon' ? 'text-bg-warning' : 'bg-body-secondary text-body-secondary fw-normal') . '"' . $title . '><i class="far fa-calendar me-1"></i>Due ' . timeAgo($due['at']) . '</span>';
}

/** The edge a row or card gets: danger (late), warning (close to it) or ''. */
function ticketAttention($sla, $due) {
    if ($sla['key'] === 'breached' || ($due['key'] ?? '') === 'overdue') {
        return 'danger';
    }
    if ($sla['key'] === 'at_risk' || ($due['key'] ?? '') === 'soon') {
        return 'warning';
    }
    return '';
}

/** The last reply on each of these tickets, any kind, with who wrote it - [ticket id => row]. */
function ticketLastReplies(array $ticket_ids) {
    global $mysqli;
    $ids = implode(',', array_filter(array_map('intval', $ticket_ids)));
    if ($ids === '') {
        return [];
    }
    $sql = mysqli_query($mysqli, "SELECT ticket_reply_ticket_id, ticket_reply_type, ticket_reply_created_at, ticket_reply_by,
            contact_name, contact_photo, contact_client_id, user_name, user_avatar
        FROM ticket_replies
        LEFT JOIN users ON ticket_reply_type <> 'Client' AND ticket_reply_by = user_id
        LEFT JOIN contacts ON ticket_reply_type = 'Client' AND ticket_reply_by = contact_id
        WHERE ticket_reply_id IN (SELECT MAX(ticket_reply_id) FROM ticket_replies
            WHERE ticket_reply_ticket_id IN ($ids) AND ticket_reply_archived_at IS NULL GROUP BY ticket_reply_ticket_id)");
    $rows = [];
    while ($row = mysqli_fetch_assoc($sql)) {
        $rows[intval($row['ticket_reply_ticket_id'])] = $row;
    }
    return $rows;
}

/** Tasks on each of these tickets - [ticket id => [done, all]]. */
function ticketTaskCounts(array $ticket_ids) {
    global $mysqli;
    $ids = implode(',', array_filter(array_map('intval', $ticket_ids)));
    if ($ids === '') {
        return [];
    }
    $sql = mysqli_query($mysqli, "SELECT task_ticket_id, COUNT(task_id) AS task_count, SUM(task_completed_at IS NOT NULL) AS done_count
        FROM tasks WHERE task_ticket_id IN ($ids) GROUP BY task_ticket_id");
    $counts = [];
    while ($row = mysqli_fetch_assoc($sql)) {
        $counts[intval($row['task_ticket_id'])] = [intval($row['done_count']), intval($row['task_count'])];
    }
    return $counts;
}

/** A small bar and "2/5" for a ticket's tasks - '' when it has none. */
function ticketTasksHtml($counts) {
    if (!$counts || !$counts[1]) {
        return '';
    }
    [$done, $all] = $counts;
    $percent = round($done / $all * 100);
    return '<span class="itflow-ticket-tasks" title="' . "$done of $all tasks done" . '">'
        . '<span class="progress" role="progressbar" aria-valuenow="' . $percent . '" aria-valuemin="0" aria-valuemax="100"><span class="progress-bar ' . ($done === $all ? 'bg-success' : 'bg-secondary') . '" style="width: ' . $percent . '%"></span></span>'
        . "$done/$all</span>";
}

/**
 * The last reply as one line - when, and who - with an icon for which way it
 * went. The whole thing is what the list's Activity column and the board's
 * cards show.
 */
function ticketActivityHtml($reply, $row) {
    if (!$reply) {
        $created = $row['ticket_created_at'];
        return '<span class="text-body-secondary" title="Opened ' . escapeHtml($created) . '"><i class="far fa-fw fa-clock me-1"></i>No replies</span>';
    }
    $type = $reply['ticket_reply_type'];
    $who = $type === 'Client' ? ($reply['contact_name'] ?? '') : ($reply['user_name'] ?? '');
    $icons = [
        'Client' => ['fa-reply text-warning', 'The client replied'],
        'Public' => ['fa-paper-plane text-body-secondary', 'We replied'],
        'Internal' => ['fa-sticky-note text-body-secondary', 'Internal note'],
    ];
    [$icon, $label] = $icons[$type] ?? $icons['Internal'];
    return '<span title="' . escapeHtml($label . ($who !== '' ? " - $who" : '') . ', ' . $reply['ticket_reply_created_at']) . '">'
        . '<i class="fas fa-fw ' . $icon . ' me-1"></i>' . timeAgo($reply['ticket_reply_created_at']) . '</span>'
        . ($who !== '' ? '<div class="small text-body-secondary text-truncate itflow-ticket-who">' . escapeHtml($who) . '</div>' : '');
}

/** Where it came in from, as an icon - '' for one an agent raised. */
function ticketSourceIcon($source) {
    $icons = ['Email' => ['fa-envelope', 'Came in by email'], 'Portal' => ['fa-globe', 'Raised in the client portal'],
        'Recurring' => ['fa-redo-alt', 'Raised by a recurring ticket'], 'API' => ['fa-plug', 'Raised through the API'],
        'Project' => ['fa-project-diagram', 'From a project template']];
    foreach ($icons as $match => [$icon, $title]) {
        if (stripos((string) $source, $match) !== false) {
            return '<i class="fas fa-fw ' . $icon . '" title="' . $title . '"></i>';
        }
    }
    return '';
}

/*
 * ---------- recurring tickets ----------
 */

/** One recurring ticket by id, with its client - raw, or null. */
function recurringTicketRow($recurring_ticket_id) {
    global $mysqli;
    $recurring_ticket_id = intval($recurring_ticket_id);
    if (!$recurring_ticket_id) {
        return null;
    }
    $row = mysqli_fetch_assoc(mysqli_query($mysqli, "SELECT recurring_tickets.*, client_name FROM recurring_tickets
        LEFT JOIN clients ON client_id = recurring_ticket_client_id
        WHERE recurring_ticket_id = $recurring_ticket_id LIMIT 1"));
    return $row ?: null;
}

/** A frequency as posted, or '' when it isn't one. */
function recurringTicketFrequency($frequency) {
    foreach (array_keys(RECURRING_TICKET_FREQUENCIES) as $known) {
        if (strcasecmp(trim((string) $frequency), $known) === 0) {
            return $known;
        }
    }
    return '';
}

/**
 * The next run after $after (today by default), stepping from the run that
 * was due. Month-based schedules keep to the day of the month the run that
 * was due fell on - except when that was a shorter month's last day standing
 * in for a later one: one that started ($anchor) on the 31st runs on the last
 * day of shorter months and back on the 31st after, rather than drifting.
 * Missed runs are stepped over, not raised one by one.
 */
function recurringTicketNextRun($due, $frequency, $anchor = '', $after = '') {
    $frequency = recurringTicketFrequency($frequency) ?: 'Monthly';
    $step = RECURRING_TICKET_FREQUENCIES[$frequency];
    $after = $after !== '' ? $after : date('Y-m-d');
    $date = DateTime::createFromFormat('!Y-m-d', substr((string) $due, 0, 10)) ?: new DateTime('today');
    $anchor_date = DateTime::createFromFormat('!Y-m-d', substr((string) $anchor, 0, 10));
    $anchor_day = intval($date->format('j'));
    if ($anchor_date && intval($anchor_date->format('j')) > $anchor_day && $anchor_day === intval($date->format('t'))) {
        $anchor_day = intval($anchor_date->format('j'));
    }
    $guard = 0;
    do {
        if (isset($step['days'])) {
            $date->modify('+' . $step['days'] . ' days');
        } else {
            $year = intval($date->format('Y'));
            $month = intval($date->format('n')) + $step['months'];
            $year += intdiv($month - 1, 12);
            $month = ($month - 1) % 12 + 1;
            $days_in_month = intval(date('t', mktime(0, 0, 0, $month, 1, $year)));
            $date->setDate($year, $month, min($anchor_day, $days_in_month));
        }
    } while ($date->format('Y-m-d') <= $after && ++$guard < 5000);
    return $date->format('Y-m-d');
}

/** When in the week or month it comes round, in words - "on Mondays", "on the 15th", "on the last day of the month". */
function recurringTicketCadenceText($row) {
    $frequency = recurringTicketFrequency($row['recurring_ticket_frequency'] ?? '') ?: 'Monthly';
    $next = DateTime::createFromFormat('!Y-m-d', substr((string) ($row['recurring_ticket_next_run'] ?? ''), 0, 10));
    if (!$next) {
        return '';
    }
    $step = RECURRING_TICKET_FREQUENCIES[$frequency];
    if (isset($step['days'])) {
        return $step['days'] === 7 ? 'on ' . $next->format('l') . 's' : ($step['days'] === 14 ? 'every other ' . $next->format('l') : 'every three days');
    }
    $day = intval($next->format('j'));
    $start = DateTime::createFromFormat('!Y-m-d', substr((string) ($row['recurring_ticket_start_date'] ?? ''), 0, 10));
    if ($start && intval($start->format('j')) > $day && $day === intval($next->format('t'))) {
        $day = intval($start->format('j'));
    }
    if ($day >= 31 || ($day >= 29 && $day === intval($next->format('t')) && (!$start || intval($start->format('j')) >= 31))) {
        return 'on the last day of the month';
    }
    $suffix = ($day % 100 >= 11 && $day % 100 <= 13) ? 'th' : (['th', 'st', 'nd', 'rd'][$day % 10] ?? 'th');
    return "on the $day$suffix";
}

/** Is a recurring ticket paused? */
function recurringTicketPaused($row) {
    return !empty($row['recurring_ticket_paused_at']);
}

/** When it runs next, in words - "Today", "Tomorrow", "In 3 days", "Missed - was due 2 days ago", or "Paused". */
function recurringTicketNextRunText($row) {
    if (recurringTicketPaused($row)) {
        return ['text' => 'Paused', 'tone' => 'secondary', 'icon' => 'fa-pause'];
    }
    $next = DateTime::createFromFormat('!Y-m-d', substr((string) $row['recurring_ticket_next_run'], 0, 10));
    if (!$next) {
        return ['text' => 'Not scheduled', 'tone' => 'secondary', 'icon' => 'fa-question'];
    }
    $days = intval((new DateTime('today'))->diff($next)->format('%r%a'));
    if ($days < 0) {
        return ['text' => 'Missed - was due ' . ($days === -1 ? 'yesterday' : abs($days) . ' days ago'), 'tone' => 'danger', 'icon' => 'fa-exclamation-triangle'];
    }
    if ($days === 0) {
        return ['text' => 'Today', 'tone' => 'warning', 'icon' => 'fa-clock'];
    }
    if ($days === 1) {
        return ['text' => 'Tomorrow', 'tone' => 'info', 'icon' => 'fa-clock'];
    }
    return ['text' => $days <= 14 ? "In $days days" : timeAgo($next->format('Y-m-d')), 'tone' => $days <= 7 ? 'info' : 'success', 'icon' => 'fa-calendar-alt'];
}

/** The next run as a soft pill. */
function recurringTicketNextRunPill($row) {
    $state = recurringTicketNextRunText($row);
    $tone = $state['tone'];
    return '<span class="badge rounded-pill bg-' . $tone . '-subtle text-' . $tone . '-emphasis border border-' . $tone . '-subtle fw-normal" title="' . escapeHtml((string) $row['recurring_ticket_next_run']) . '">'
        . '<i class="fas ' . $state['icon'] . ' me-1"></i>' . escapeHtml($state['text']) . '</span>';
}

/**
 * Raise the ticket a recurring ticket describes, now: its subject, details,
 * priority, category, agent, contact, asset and other assets, billing and
 * tasks, with the SLA applied, the client told (when general notifications
 * are on) and the new-ticket address told. $by is who did it, for the audit
 * log. Does not move the next run - the caller does. The new ticket's id, or 0.
 */
function recurringTicketRaise($recurring_ticket_id, $by = 'Cron') {
    global $mysqli, $config_ticket_client_general_notifications;

    $row = recurringTicketRow($recurring_ticket_id);
    if (!$row) {
        return 0;
    }

    // The settings, read here: the cron keeps its own copies SQL-escaped, the pages don't
    $settings = mysqli_fetch_assoc(mysqli_query($mysqli, "SELECT config_ticket_prefix, config_ticket_from_email, config_ticket_from_name,
        config_ticket_new_ticket_notification_email, config_ticket_client_general_notifications, config_smtp_provider FROM settings WHERE company_id = 1"));
    $config_ticket_prefix = $settings['config_ticket_prefix'] ?? '';
    $config_ticket_from_email = $settings['config_ticket_from_email'] ?? '';
    $config_ticket_from_name = $settings['config_ticket_from_name'] ?? '';
    $config_ticket_new_ticket_notification_email = $settings['config_ticket_new_ticket_notification_email'] ?? '';
    $config_ticket_client_general_notifications = intval($settings['config_ticket_client_general_notifications'] ?? 0);
    $config_smtp_provider = $settings['config_smtp_provider'] ?? '';
    $recurring_ticket_id = intval($row['recurring_ticket_id']);
    $client_id = intval($row['recurring_ticket_client_id']);
    $subject = escapeSql($row['recurring_ticket_subject']);
    $details = mysqli_real_escape_string($mysqli, (string) $row['recurring_ticket_details']);
    $priority = escapeSql(ticketPriority($row['recurring_ticket_priority']));
    $frequency = strtolower((string) $row['recurring_ticket_frequency']);
    $billable = intval($row['recurring_ticket_billable']);
    $created_by = intval($row['recurring_ticket_created_by']);
    $assigned_to = ticketAgentId($row['recurring_ticket_assigned_to']);
    // What it links to has to still be the client's
    $contact_id = ticketClientOwnedId('contact', $row['recurring_ticket_contact_id'], $client_id);
    $asset_id = ticketClientOwnedId('asset', $row['recurring_ticket_asset_id'], $client_id);
    $category_id = ticketCategoryId($row['recurring_ticket_category']);
    $ticket_status = $assigned_to ? TICKET_STATUS_OPEN : TICKET_STATUS_NEW;
    $url_key = randomString(32);
    $prefix = escapeSql($config_ticket_prefix);

    // Atomically increment and get the new ticket number
    mysqli_query($mysqli, "UPDATE settings SET config_ticket_next_number = LAST_INSERT_ID(config_ticket_next_number), config_ticket_next_number = config_ticket_next_number + 1 WHERE company_id = 1");
    $ticket_number = mysqli_insert_id($mysqli);

    mysqli_query($mysqli, "INSERT INTO tickets SET ticket_prefix = '$prefix', ticket_number = $ticket_number, ticket_source = 'Recurring', ticket_subject = '$subject',
        ticket_details = '$details', ticket_priority = '$priority', ticket_status = $ticket_status, ticket_billable = $billable, ticket_url_key = '$url_key',
        ticket_created_by = $created_by, ticket_assigned_to = $assigned_to, ticket_contact_id = $contact_id, ticket_client_id = $client_id,
        ticket_asset_id = $asset_id, ticket_category = $category_id, ticket_recurring_ticket_id = $recurring_ticket_id");
    $ticket_id = mysqli_insert_id($mysqli);
    if (!$ticket_id) {
        return 0;
    }
    applyTicketSla($ticket_id);

    // Its other assets that are still the client's, and its tasks
    mysqli_query($mysqli, "INSERT IGNORE INTO ticket_assets (ticket_id, asset_id)
        SELECT $ticket_id, recurring_ticket_assets.asset_id FROM recurring_ticket_assets
        JOIN assets ON assets.asset_id = recurring_ticket_assets.asset_id AND asset_client_id = $client_id
        WHERE recurring_ticket_id = $recurring_ticket_id AND recurring_ticket_assets.asset_id <> $asset_id");
    addTasksFromRecurringTicket($ticket_id, $recurring_ticket_id);

    // The template it was made from, kept for the template's use, the answers it was given for
    // what the template asks, and its [Client], [Month] and the like filled in - every time
    // it is raised (functions/ticket_template.php)
    $template_id = intval($row['recurring_ticket_ticket_template_id'] ?? 0);
    if ($template_id && ticketTemplateRow($template_id)) {
        mysqli_query($mysqli, "UPDATE tickets SET ticket_template_id = $template_id WHERE ticket_id = $ticket_id");
    }
    $fill_ins = ticketFillInsStored('recurring_ticket', $recurring_ticket_id);
    if ($fill_ins) {
        ticketFillInsStore('ticket', $ticket_id, $fill_ins);
    }
    ticketPlaceholdersFill($ticket_id);

    logAudit("Ticket", "Create", escapeSql($by) . " created recurring $frequency ticket $prefix$ticket_number - $subject", $client_id, $ticket_id);
    triggerCustomAction('ticket_create', $ticket_id);

    // The client is told (when general notifications are on) - the contact alone
    $new = ticketRow($ticket_id);
    if (intval($config_ticket_client_general_notifications) === 1 && $new) {
        ticketMailSend($ticket_id, "Ticket created - [" . ticketReference($new) . "] - " . $new['ticket_subject'] . " (scheduled)",
            ticketEmailContent($new, 'created', ['how' => 'scheduled']), ['kind' => 'created', 'to_watchers' => false]);
    }

    // The new-ticket address (Admin > Ticket), when there is one
    ticketMailNewTicketAddress($ticket_id, 'scheduled');

    return $ticket_id;
}

/**
 * Raise a recurring ticket's ticket now and move its next run on: one step
 * past the run that was due, or past today when that was missed - so forcing
 * an early run takes the place of the next one, and nothing is raised twice.
 * The new ticket's id, or 0.
 */
function recurringTicketRunNow($row, $by) {
    global $mysqli;
    $recurring_ticket_id = intval($row['recurring_ticket_id']);
    $ticket_id = recurringTicketRaise($recurring_ticket_id, $by);
    if ($ticket_id) {
        $due = (string) $row['recurring_ticket_next_run'];
        $next_run = recurringTicketNextRun($due, $row['recurring_ticket_frequency'], $row['recurring_ticket_start_date'], max(date('Y-m-d'), substr($due, 0, 10)));
        mysqli_query($mysqli, "UPDATE recurring_tickets SET recurring_ticket_next_run = '$next_run' WHERE recurring_ticket_id = $recurring_ticket_id");
    }
    return $ticket_id;
}

/**
 * For post handlers: the recurring ticket a request names, after the module
 * and client checks - or back with an error if it is gone. Sets the global
 * $client_id.
 */
function recurringTicketForRequest($recurring_ticket_id, $level) {
    global $client_id;
    enforceUserPermission('module_support', $level);
    $row = recurringTicketRow($recurring_ticket_id);
    if (!$row) {
        flashAlert('That recurring ticket no longer exists.', 'error');
        redirect();
    }
    $client_id = intval($row['recurring_ticket_client_id']);
    if ($client_id) {
        enforceClientAccess();
    }
    return $row;
}

/** For post handlers: the recurring tickets a bulk action names (recurring_ticket_ids[]) - [id => row]. */
function recurringTicketsForBulk($level) {
    global $client_id;
    enforceUserPermission('module_support', $level);
    $rows = [];
    foreach (array_unique(array_map('intval', (array) ($_POST['recurring_ticket_ids'] ?? []))) as $recurring_ticket_id) {
        $row = recurringTicketRow($recurring_ticket_id);
        if (!$row) {
            continue;
        }
        $client_id = intval($row['recurring_ticket_client_id']);
        if ($client_id) {
            enforceClientAccess();
        }
        $rows[$recurring_ticket_id] = $row;
    }
    return $rows;
}

/** A date posted from a date field as Y-m-d, or '' when it isn't one. */
function recurringTicketDate($input) {
    $input = trim((string) $input);
    $date = DateTime::createFromFormat('!Y-m-d', $input);
    return $date && $date->format('Y-m-d') === $input && $input <= '2999-12-31' ? $input : '';
}

/** The next few runs from the next one - for showing what a schedule means. */
function recurringTicketUpcoming($row, $count = 3) {
    $runs = [];
    $date = substr((string) $row['recurring_ticket_next_run'], 0, 10);
    if (!recurringTicketDate($date)) {
        return $runs;
    }
    $runs[] = $date;
    while (count($runs) < $count) {
        $date = recurringTicketNextRun($date, $row['recurring_ticket_frequency'], $row['recurring_ticket_start_date'], $date);
        $runs[] = $date;
    }
    return $runs;
}

/** The last ticket each of these recurring tickets raised, with its status - [recurring id => row]. */
function recurringTicketLastTickets(array $recurring_ticket_ids) {
    global $mysqli;
    $ids = array_values(array_unique(array_filter(array_map('intval', $recurring_ticket_ids))));
    if (!$ids) {
        return [];
    }
    $last = [];
    $sql = mysqli_query($mysqli, "SELECT ticket_recurring_ticket_id, MAX(ticket_id) FROM tickets WHERE ticket_recurring_ticket_id IN (" . implode(',', $ids) . ") GROUP BY ticket_recurring_ticket_id");
    while ($row = mysqli_fetch_row($sql)) {
        $last[intval($row[1])] = intval($row[0]);
    }
    if (!$last) {
        return [];
    }
    $rows = [];
    foreach (ticketRows('tickets.ticket_id IN (' . implode(',', array_keys($last)) . ')') as $row) {
        $rows[$last[intval($row['ticket_id'])]] = $row;
    }
    return $rows;
}

/*
 * ---------- scheduled work ----------
 * Booked from the ticket, or by dragging it on the calendar - both come here.
 */

/** Work out when a datetime-local value is - 'Y-m-d H:i:s', or '' when it isn't a date and time. */
function ticketScheduleValue($input) {
    $sql = ticketDueSql($input);
    return $sql === 'NULL' ? '' : trim($sql, "'");
}

/*
 * The scheduled-work emails, each with the calendar file - the invite, or its
 * cancellation: to the agent doing the work, and when client notifications
 * are on (Admin > Ticket) to the contact and the watchers. $row has the
 * ticket's id and, for a booking, location_address.
 */
function ticketMailSchedule($row, $cal_str, $cancelled, $when_text) {
    global $config_ticket_client_general_notifications;
    $ticket = ticketRow($row['ticket_id']);
    if (!$ticket || !emailReady()) {
        return;
    }
    $reference = ticketReference($ticket);
    $opts = ['cancelled' => $cancelled, 'when' => $when_text, 'where' => (string) ($row['location_address'] ?? '')];
    $subject = ($cancelled ? 'Ticket Schedule Cancelled' : 'Ticket Scheduled') . " - [$reference] - " . $ticket['ticket_subject'];
    if ($agent = ticketMailAgent($ticket['ticket_assigned_to'])) {
        emailQueue([$agent + ['footnote' => "You get this as the agent $reference is assigned to."]], $subject,
            ticketAgentEmailContent($ticket, 'scheduled', $opts), ['from' => ticketEmailFrom(), 'cal_str' => $cal_str]);
    }
    if (intval($config_ticket_client_general_notifications) === 1) {
        ticketMailSend($ticket['ticket_id'], $subject, ticketEmailContent($ticket, 'scheduled', $opts), ['cal_str' => $cal_str]);
    }
}

/** What the booking emails and the calendar file need of a ticket - the site is the ticket's location, else its contact's. */
function ticketScheduleRow($ticket_id) {
    global $mysqli;
    return mysqli_fetch_assoc(mysqli_query($mysqli, "SELECT tickets.ticket_id, ticket_prefix, ticket_number, ticket_subject, ticket_details, ticket_client_id, client_name,
            contact_name, contact_email, user_name, user_email, location_address
        FROM tickets
        LEFT JOIN clients ON ticket_client_id = client_id
        LEFT JOIN contacts ON ticket_contact_id = contact_id
        LEFT JOIN locations ON location_id = IF(ticket_location_id > 0, ticket_location_id, contact_location_id)
        LEFT JOIN users ON ticket_assigned_to = user_id
        WHERE tickets.ticket_id = " . intval($ticket_id))) ?: [];
}

/*
 * The calendar file for the work booked on a ticket (ticketScheduleRow()) at
 * $schedule - the one the booking emails carry, and Add to calendar on the
 * guest ticket page. The UID is the ticket's, so either one updates the same
 * event in the calendar.
 */
function ticketScheduleIcs(array $row, $schedule) {
    global $config_base_url;
    $ticket_id = intval($row['ticket_id'] ?? 0);
    $subject = intval($row['ticket_number'] ?? 0) . ": " . ($row['client_name'] ?? '') . " - " . ($row['ticket_subject'] ?? '');
    $description = mb_substr(strip_tags((string) ($row['ticket_details'] ?? '')), 0, 100) . " - https://$config_base_url/client/ticket.php?id=$ticket_id";
    return createiCalStr($schedule, $subject, $description, (string) ($row['location_address'] ?? ''), getTicketCalendarUid($ticket_id));
}

/**
 * Book the work on a ticket for $schedule ('Y-m-d H:i:s'), onsite or remote:
 * the agent, the contact and the watchers are emailed with the calendar file,
 * and it is noted on the ticket. Returns ['when_text' => ..., 'conflicts' =>
 * the same agent's other open work within two hours, as plain text].
 */
function ticketSetSchedule(array $row, $schedule, $onsite) {
    global $mysqli, $session_user_id, $session_name;
    $ticket_id = intval($row['ticket_id']);
    $client_id = intval($row['ticket_client_id']);
    $onsite = $onsite ? 1 : 0;
    $schedule = escapeSql($schedule);

    mysqli_query($mysqli, "UPDATE tickets SET ticket_schedule = '$schedule', ticket_onsite = $onsite WHERE ticket_id = $ticket_id");

    // The same agent's other open tickets within two hours of it
    $conflicts = [];
    $assigned_to = intval($row['ticket_assigned_to']);
    if ($assigned_to) {
        $start = date('Y-m-d H:i:s', strtotime($schedule) - 7200);
        $end = date('Y-m-d H:i:s', strtotime($schedule) + 7200);
        $sql = mysqli_query($mysqli, "SELECT ticket_prefix, ticket_number, ticket_schedule, ticket_subject FROM tickets
            WHERE ticket_schedule BETWEEN '$start' AND '$end' AND ticket_id <> $ticket_id AND ticket_assigned_to = $assigned_to
            AND ticket_resolved_at IS NULL AND ticket_closed_at IS NULL ORDER BY ticket_schedule");
        while ($conflict = mysqli_fetch_assoc($sql)) {
            $conflicts[] = ticketReference($conflict) . ' - ' . $conflict['ticket_subject'] . ' @ ' . date('g:ia', strtotime($conflict['ticket_schedule']));
        }
    }

    // Who to tell, with the calendar file
    $mail_row = ticketScheduleRow($ticket_id);
    $cal_str = ticketScheduleIcs($mail_row, $schedule);
    $when_text = date('l, F j, Y \a\t g:ia', strtotime($schedule));
    ticketMailSchedule($mail_row, $cal_str, false, $when_text);

    // Note it on the ticket
    $note = escapeSql("Ticket scheduled for $when_text " . ($onsite ? '(onsite).' : '(remote).'));
    mysqli_query($mysqli, "INSERT INTO ticket_replies SET ticket_reply = '$note', ticket_reply_type = 'Internal', ticket_reply_time_worked = '00:00:00', ticket_reply_by = " . intval($session_user_id) . ", ticket_reply_ticket_id = $ticket_id");

    logTicketHistory($ticket_id, "$session_name scheduled the work for " . escapeSql($when_text) . ($onsite ? ' (onsite)' : ' (remote)'));
    logAudit("Ticket", "Edit", "$session_name scheduled ticket " . escapeSql(ticketReference($row)) . " for " . escapeSql($when_text), $client_id, $ticket_id);
    triggerCustomAction('ticket_schedule', $ticket_id);

    return ['when_text' => $when_text, 'conflicts' => $conflicts];
}

/** Take the scheduled work off a ticket, cancelling the calendar file everyone was sent. */
function ticketCancelSchedule(array $row) {
    global $mysqli, $session_user_id, $session_name;
    $ticket_id = intval($row['ticket_id']);
    $client_id = intval($row['ticket_client_id']);
    $old_schedule = $row['ticket_schedule'];

    mysqli_query($mysqli, "UPDATE tickets SET ticket_schedule = NULL WHERE ticket_id = $ticket_id");

    $mail_row = mysqli_fetch_assoc(mysqli_query($mysqli, "SELECT tickets.ticket_id, ticket_prefix, ticket_number, ticket_subject, ticket_client_id, client_name,
            contact_name, contact_email, user_name, user_email
        FROM tickets
        LEFT JOIN clients ON ticket_client_id = client_id
        LEFT JOIN contacts ON ticket_contact_id = contact_id
        LEFT JOIN users ON ticket_assigned_to = user_id
        WHERE tickets.ticket_id = $ticket_id"));
    $cal_subject = intval($mail_row['ticket_number']) . ": " . $mail_row['client_name'] . " - " . $mail_row['ticket_subject'];
    $cal_str = createiCalStrCancel($old_schedule, $cal_subject, getTicketCalendarUid($ticket_id));
    ticketMailSchedule($mail_row, $cal_str, true, '');

    mysqli_query($mysqli, "INSERT INTO ticket_replies SET ticket_reply = 'Ticket schedule cancelled.', ticket_reply_type = 'Internal', ticket_reply_time_worked = '00:00:00', ticket_reply_by = " . intval($session_user_id) . ", ticket_reply_ticket_id = $ticket_id");

    logTicketHistory($ticket_id, "$session_name cancelled the scheduled work");
    logAudit("Ticket", "Edit", "$session_name cancelled the schedule of ticket " . escapeSql(ticketReference($row)), $client_id, $ticket_id);
    triggerCustomAction('ticket_unschedule', $ticket_id);
}