<?php
declare(strict_types=1);

namespace Gatecraft;

use WP_User, WP_Error, WP_Session_Tokens, WP_CLI, RuntimeException, Throwable, Exception, DateTime, DateTimeImmutable, ZipArchive;

if (!defined('ABSPATH')) exit;


/** Queue an email. meta: ['qr' => [codes], 'ics_event' => id]. */
function queue_email(string $to, string $name, string $subject, string $html, string $text, array $meta = []): void
{
    q('INSERT INTO {email_queue} (to_email, to_name, subject, html, text_body, meta, send_after, created_at) VALUES (?,?,?,?,?,?,?,?)', [
        $to, mb_substr($name, 0, 120), mb_substr(str_replace(["\r", "\n"], ' ', $subject), 0, 255), $html, $text, $meta ? wp_json_encode($meta) : null, now(), now(),
    ]);
    gatecraft_kick_worker();
}

/**
 * Render a template from Settings > Email templates and queue it.
 * $order (optional) adds the event summary box, order lines and QR tickets.
 */
function queue_template_email(string $to, string $name, string $tplId, array $vars, ?string $buttonUrl, ?array $order = null, bool $withTickets = false, array $meta = []): void
{
    // Build the email in the recipient's language: the language of the booking, else their account's, else the site default.
    if (empty($meta['_in_language'])) {
        $lang = $order['language'] ?? null;
        if (!language_valid($lang)) $lang = user_language_by_email($to);
        with_language($lang, fn() => queue_template_email($to, $name, $tplId, $vars, $buttonUrl, $order, $withTickets, ['_in_language' => 1] + $meta));
        return;
    }
    unset($meta['_in_language']);
    $t = email_template($tplId);
    if (!$t['enabled']) return;
    $vars += ['brand_name' => setting('brand_name')];
    $tl = fn(string $s) => implode("\n", array_map(fn($l) => t($l), explode("\n", $s)));
    $subject = trim(fill_vars($tl($t['subject']), $vars));
    $heading = trim(fill_vars($tl($t['heading']), $vars));
    $body = trim(preg_replace("/\n{3,}/", "\n\n", fill_vars($tl($t['body']), $vars)));
    $label = trim(fill_vars($tl($t['button']), $vars));
    $button = $label !== '' && $buttonUrl ? [$label, $buttonUrl] : null;
    $paras = array_values(array_filter(array_map('trim', explode("\n", $body)), fn($l) => $l !== ''));

    $tickets = $order && $withTickets ? order_tickets((int)$order['id']) : [];
    foreach ($tickets as $tk) if ($tk['status'] === 'valid') $meta['qr'][] = $tk['code'];
    $pay = $order && $tplId === 'payment_pending' ? email_pay_block($order) : null;
    $html = i18n_html(render_partial('email/layout', [
        'pay' => $pay, 'info' => $pay ? email_event_info($order) : null,
        'heading' => $heading, 'paras' => $paras, 'button' => $button, 'order' => $order,
        'items' => $order ? order_items((int)$order['id']) : [], 'tickets' => array_filter($tickets, fn($tk) => $tk['status'] === 'valid'),
    ]));
    $text = $heading . "\n\n" . implode("\n\n", $paras);
    if ($order) {
        $text .= "\n\n" . $order['event_title'] . "\n" . fmt_dt($order['starts_at']) . ($order['venue_name'] ? "\n" . $order['venue_name'] : '') . "\n" . t('Reference') . ': ' . $order['reference'];
    }
    if ($pay) {
        $text .= "\n\nPAY " . $pay['amount'] . ' BY ' . strtoupper($pay['method']) . "\n" . t('Amount') . ': ' . $pay['amount'] . "\n" . t('Reference') . ': ' . $pay['reference']
            . ($pay['deadline'] !== '' ? "\n" . t('Pay before') . ': ' . $pay['deadline'] : '');
        foreach ($pay['steps'] as $i => $st) $text .= "\n" . ($i + 1) . '. ' . $st;
        $info = email_event_info($order);
        $text .= "\n\n" . t('Event details');
        foreach ($info['rows'] as $r) $text .= "\n" . t($r[0]) . ': ' . $r[1];
        if ($info['note'] !== '') $text .= "\n\n" . $info['note'];
    }
    if ($button) $text .= "\n\n" . $button[0] . ': ' . $button[1];
    foreach ($tickets as $tk) if ($tk['status'] === 'valid') $text .= "\n" . t('Ticket') . ' ' . $tk['category_name'] . ': ' . format_code($tk['code']);
    $text .= "\n\n" . setting('email_footer') . (powered_by_hidden() ? '' : "\n\n" . t('Powered by Gatecraft') . (GATECRAFT_HOME_URL !== '' ? ' ' . GATECRAFT_HOME_URL : '')) . "\n";
    queue_email($to, $name, $subject ?: setting('brand_name'), $html, $text, $meta);
}

/** Sends up to $limit queued emails. Rows are claimed atomically so parallel workers never double-send. */
function process_email_queue(int $limit = 20): int
{
    q("UPDATE {email_queue} SET status = 'queued' WHERE status = 'sending' AND send_after < ?", [ldate('Y-m-d H:i:s', time() - 900)]);
    $sent = 0;
    $ids = q("SELECT id FROM {email_queue} WHERE status = 'queued' AND send_after <= ? ORDER BY id LIMIT " . (int)$limit, [now()])->fetchAll(Result::COLUMN);
    foreach ($ids as $id) {
        $claim = q("UPDATE {email_queue} SET status = 'sending', attempts = attempts + 1, send_after = ? WHERE id = ? AND status = 'queued'", [now(), $id]);
        if ($claim->rowCount() !== 1) continue;
        $m = q1('SELECT * FROM {email_queue} WHERE id = ?', [$id]);
        try {
            send_mail_now($m);
            q("UPDATE {email_queue} SET status = 'sent', sent_at = ?, last_error = NULL WHERE id = ?", [now(), $id]);
            $sent++;
        } catch (Throwable $t) {
            $final = (int)$m['attempts'] >= 6;
            q('UPDATE {email_queue} SET status = ?, last_error = ?, send_after = ? WHERE id = ?', [
                $final ? 'failed' : 'queued', mb_substr($t->getMessage(), 0, 500), ldate('Y-m-d H:i:s', time() + 60 * (2 ** (int)$m['attempts'])), $id,
            ]);
            if ($final) notify_staff('mailfail', 'Email to ' . $m['to_email'] . ' failed', mb_substr($t->getMessage(), 0, 200), '/admin/emails');
        }
    }
    return $sent;
}

function send_mail_now(array $m): void
{
    $meta = $m['meta'] ? json_decode($m['meta'], true) : [];
    $fromName = setting('mail_from_name') ?: setting('brand_name');
    $headers = ['Content-Type: text/html; charset=UTF-8'];
    $fromAddr = setting('mail_from_address');
    if ($fromAddr !== '' && is_email($fromAddr)) $headers[] = 'From: ' . str_replace(['"', "\r", "\n"], '', $fromName) . ' <' . $fromAddr . '>';
    $reply = setting('reply_to') ?: setting('support_email');
    if ($reply !== '' && is_email($reply)) $headers[] = 'Reply-To: ' . $reply;
    foreach ((array)($meta['headers'] ?? []) as $h) if (preg_match('/^List-Unsubscribe(-Post)?: [^\r\n]+$/', (string)$h)) $headers[] = $h;
    $nameFilter = fn() => $fromName;

    $attach = function ($phpmailer) use ($m, $meta) {
        $phpmailer->AltBody = $m['text_body'];
        foreach ($meta['qr'] ?? [] as $code) {
            if (preg_match('/^[0-9A-Z]{16}$/', $code)) $phpmailer->addStringEmbeddedImage(qr_png($code, 8), 'qr-' . $code, 'ticket-' . $code . '.png', 'base64', 'image/png');
        }
        if (!empty($meta['ics_event'])) {
            $ics = event_ics((int)$meta['ics_event']);
            if ($ics) $phpmailer->addStringAttachment($ics, 'event.ics', 'base64', 'text/calendar');
        }
    };
    $error = null;
    $onFail = function ($wpError) use (&$error) { $error = $wpError instanceof WP_Error ? $wpError->get_error_message() : 'Mail failed'; };
    add_action('phpmailer_init', $attach);
    add_action('wp_mail_failed', $onFail);
    if ($fromAddr === '') add_filter('wp_mail_from_name', $nameFilter);
    try {
        $ok = wp_mail($m['to_name'] !== '' ? sprintf('%s <%s>', str_replace(['"', ',', '<', '>', "\r", "\n"], '', $m['to_name']), $m['to_email']) : $m['to_email'], $m['subject'], $m['html'], $headers);
    } finally {
        remove_action('phpmailer_init', $attach);
        remove_action('wp_mail_failed', $onFail);
        remove_filter('wp_mail_from_name', $nameFilter);
    }
    if (!$ok) throw new RuntimeException(esc_html($error ?: 'wp_mail returned false'));
}

/**
 * A text value escaped for iCalendar (RFC 5545, 3.3.11): backslash, semicolon and comma are escaped, line breaks become
 * \n, and every other control character is removed, so a value can never start a new property line.
 */
function ics_text(string $s): string
{
    $s = str_replace(["\r\n", "\r"], "\n", wp_check_invalid_utf8($s, true));
    $s = (string)preg_replace('/[\x00-\x09\x0B-\x1F\x7F]/u', '', $s);
    return str_replace(['\\', ';', ',', "\n"], ['\\\\', '\\;', '\\,', '\\n'], $s);
}

/** One content line, folded at 75 octets as RFC 5545 (3.1) requires, without splitting a UTF-8 character. */
function ics_line(string $line): string
{
    $out = '';
    $len = 0;
    foreach (preg_split('//u', $line, -1, PREG_SPLIT_NO_EMPTY) ?: [] as $ch) {
        $n = strlen($ch);
        if ($len + $n > 75) { $out .= "\r\n "; $len = 1; }
        $out .= $ch;
        $len += $n;
    }
    return $out . "\r\n";
}

function event_ics(int $eventId): ?string
{
    $ev = event_with_venue($eventId);
    if (!$ev) return null;
    $fmt = fn(string $dt) => gmdate('Ymd\THis\Z', lstrtotime($dt));
    $end = $ev['ends_at'] ?: ldate('Y-m-d H:i:s', lstrtotime($ev['starts_at']) + 7200);
    $loc = implode(', ', array_filter([$ev['venue_name'], $ev['venue_address'], $ev['venue_city']]));
    $host = (string)preg_replace('/[^a-z0-9.-]/i', '', (string)wp_parse_url((string)cfg('base_url'), PHP_URL_HOST));
    $url = (string)preg_replace('/[\x00-\x20\x7F]/', '', esc_url_raw(url('/e/' . $ev['slug'])));
    $lines = [
        'BEGIN:VCALENDAR', 'VERSION:2.0', 'PRODID:-//' . ics_text(setting('brand_name')) . '//Tickets//EN', 'CALSCALE:GREGORIAN', 'METHOD:PUBLISH',
        'BEGIN:VEVENT',
        'UID:event-' . (int)$ev['id'] . '@' . $host,
        'DTSTAMP:' . gmdate('Ymd\THis\Z'),
        'DTSTART:' . $fmt($ev['starts_at']),
        'DTEND:' . $fmt($end),
        'SUMMARY:' . ics_text((string)$ev['title']),
    ];
    if ($loc !== '') $lines[] = 'LOCATION:' . ics_text($loc);
    if ($url !== '') $lines[] = 'URL:' . $url;
    array_push($lines, 'END:VEVENT', 'END:VCALENDAR');
    return implode('', array_map(__NAMESPACE__ . '\\ics_line', $lines));
}

function order_vars(array $o, string $note = ''): array
{
    return [
        'buyer_name' => $o['buyer_name'], 'event_title' => $o['event_title'], 'event_date' => fmt_dt($o['starts_at']),
        'venue' => $o['venue_name'] ?: t('the venue'), 'doors_time' => $o['doors_at'] ? fmt_time($o['doors_at']) : fmt_time($o['starts_at']),
        'booking_reference' => $o['reference'], 'amount' => (int)$o['total'] > 0 ? money((int)$o['total']) : t('Free'),
        'pay_deadline' => $o['expires_at'] ? fmt_dt($o['expires_at']) : '',
        'staff_note' => $note !== '' ? $note : ($o['decision_note'] ? t('Note from the organiser:') . ' ' . $o['decision_note'] : ''),
        'payment_method' => payment_label($o), 'payment_instructions' => order_pay_instructions($o),
        'bank_instructions' => order_pay_instructions($o), // older templates used this name
        'event_note' => (string)qv('SELECT email_note FROM {events} WHERE id = ?', [$o['event_id']]),
    ];
}

/** Queue the buyer email for an order event. $kind is a template id. */
function email_order(int $orderId, string $kind, array $extra = []): void
{
    $o = get_order($orderId);
    if (!$o || !isset(email_templates()[$kind])) return;
    if (trim((string)$o['buyer_email']) === '') return; // a door sale or guest-list booking without an email address
    if ($kind === 'expired' && !setting_on('expired_email')) return;
    $link = order_link($o);
    $button = match ($kind) {
        'approved' => $link, // the booking page, where the Pay button starts the card payment
        'expired' => url('/e/' . $o['event_slug']),
        'confirm_email' => free_confirm_url($o),
        'konbini_pending' => str_starts_with((string)$o['pay_instructions'], 'https://') ? (string)$o['pay_instructions'] : $link,
        default => $link,
    };
    $meta = $kind === 'tickets' ? ['ics_event' => (int)$o['event_id']] : [];
    queue_template_email($o['buyer_email'], $o['buyer_name'], $kind, $extra + order_vars($o), $button, $o, in_array($kind, ['tickets', 'reminder'], true), $meta);
}

/** Email every confirmed buyer of an event once (deduplicated by order). */
function email_event_buyers(int $eventId, string $kind, array $vars = []): int
{
    $n = 0;
    foreach (q("SELECT id FROM {orders} WHERE event_id = ? AND status = 'paid' AND buyer_email <> ''", [$eventId])->fetchAll(Result::COLUMN) as $oid) {
        email_order((int)$oid, $kind, $vars);
        $n++;
    }
    return $n;
}

function send_daily_summary(): bool
{
    if (!setting_on('daily_summary_enabled')) return false;
    $today = ldate('Y-m-d');
    if (setting('daily_summary_last') === $today || ldate('H:i') < setting('daily_summary_time')) return false;
    setting_save(['daily_summary_last' => $today]);
    $y = ldate('Y-m-d', lstrtotime('-1 day'));
    $r = q1("SELECT COUNT(*) AS orders, COALESCE(SUM(total),0) AS revenue FROM {orders} WHERE status = 'paid' AND paid_at BETWEEN ? AND ?", [$y . ' 00:00:00', $y . ' 23:59:59']);
    $t = (int)qv("SELECT COUNT(*) FROM {tickets} tk JOIN {orders} o ON o.id = tk.order_id WHERE o.paid_at BETWEEN ? AND ?", [$y . ' 00:00:00', $y . ' 23:59:59']);
    $pending = (int)qv("SELECT COUNT(*) FROM {orders} WHERE status = 'awaiting_approval' AND expires_at > ?", [now()]);
    $body = 'Yesterday (' . fmt_date($y) . '): ' . plural((int)$r['orders'], 'paid booking') . ', ' . plural($t, 'ticket') . ', revenue ' . money((int)$r['revenue']) . '. Requests awaiting approval: ' . $pending . '.';
    foreach (alert_recipients() as $to) queue_template_email($to, '', 'staff_alert', ['alert_title' => 'Daily sales summary', 'alert_body' => $body], url('/admin'));
    return true;
}


/** What the buyer must do to pay, ready for the email: amount, reference, deadline and numbered steps. */
function email_pay_block(array $o): array
{
    $steps = array_values(array_filter(array_map('trim', preg_split('/\R/', order_pay_instructions($o))), fn($l) => $l !== ''));
    $steps[] = 'We check your payment and email your QR tickets.';
    return ['amount' => money((int)$o['total']), 'reference' => (string)$o['reference'], 'method' => payment_label($o),
        'deadline' => $o['expires_at'] ? fmt_dt($o['expires_at']) : '', 'steps' => $steps];
}

/** Event facts for the email: when, doors, where, map and page links, and the organiser's note. */
function email_event_info(array $o): array
{
    $rows = [['When', fmt_dt($o['starts_at'])]];
    if ($o['doors_at']) $rows[] = ['Doors open', fmt_time($o['doors_at'])];
    if ($o['venue_name']) $rows[] = ['Where', implode(', ', array_filter([$o['venue_name'], $o['venue_address'], $o['venue_city']]))];
    if (!empty($o['venue_map']) && preg_match('#^https?://#i', (string)$o['venue_map'])) $rows[] = ['Map', (string)$o['venue_map']];
    $rows[] = ['Event page', url('/e/' . $o['event_slug'])];
    return ['rows' => $rows, 'note' => trim((string)qv('SELECT email_note FROM {events} WHERE id = ?', [$o['event_id']]))];
}