<?php
die();
header('Content-Type: text/calendar; charset=utf-8');
header('Content-Disposition: attachment; filename="kreuzfahrten_2026.ics"');

$pdo = new PDO(
    'mysql:host=localhost;dbname=seaside_pas;charset=utf8mb4',
    'seaside_pas',
    'Kmyuk9sYP9EeXqAywJ4V',
    [
        PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
        PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
    ]
);

/*
 * Doppelte aussortieren:
 * gleiche �berschrift + gleiches Datum => nur 1 Termin
 * Wir nehmen pro Gruppe den kleinsten event_calendar_id und den fr�hesten Begin
 */
$sql = "
    SELECT
        MIN(event_calendar_id) AS source_id,
        event_calendar_title AS title,
        DATE(event_calendar_begin) AS event_date,
        MIN(event_calendar_begin) AS start_datetime
    FROM pacim_events
    WHERE
        YEAR(event_calendar_begin) = 2026
        AND event_calendar_active = 1
    GROUP BY
        DATE(event_calendar_begin),
        event_calendar_title
    ORDER BY
        event_date ASC,
        title ASC
";

$stmt = $pdo->query($sql);

$timezoneLocal = new DateTimeZone('Europe/Berlin');
$timezoneUtc   = new DateTimeZone('UTC');

/*
 * ICS-sichere Ausgabe
 */
function icsEscape(string $value): string
{
    $value = str_replace("\\", "\\\\", $value);
    $value = str_replace(";", "\;", $value);
    $value = str_replace(",", "\,", $value);
    $value = preg_replace("/\r\n|\r|\n/", "\\n", $value);
    return $value;
}

/*
 * Lange Zeilen f�r ICS falten
 */
function icsLine(string $key, string $value): string
{
    $line = $key . ':' . $value;
    $max  = 73;

    if (strlen($line) <= $max) {
        return $line . "\r\n";
    }

    $out = '';
    while (strlen($line) > $max) {
        $out .= substr($line, 0, $max) . "\r\n" . ' ';
        $line = substr($line, $max);
        $max  = 72;
    }
    $out .= $line . "\r\n";

    return $out;
}

echo "BEGIN:VCALENDAR\r\n";
echo "VERSION:2.0\r\n";
echo "PRODID:-//Kreuzfahrten 2026 Rostock//DE\r\n";
echo "CALSCALE:GREGORIAN\r\n";
echo "METHOD:PUBLISH\r\n";
echo icsLine('X-WR-CALNAME', icsEscape('Kreuzfahrten 2026 Rostock'));
echo icsLine('X-WR-TIMEZONE', 'Europe/Berlin');

while ($row = $stmt->fetch()) {
    $date = new DateTime($row['event_date'], $timezoneLocal);

    $start = clone $date;
    $start->setTime(7, 0, 0);

    $end = clone $date;
    $end->setTime(16, 0, 0);

    $startUtc = clone $start;
    $startUtc->setTimezone($timezoneUtc);

    $endUtc = clone $end;
    $endUtc->setTimezone($timezoneUtc);

    $eventDateForUrl = $date->format('Y-m-d');
    $eventUrl = 'https://seaside.pacim.de/mobile/calendar.php?token=nico&date=' . $eventDateForUrl;

    /*
     * Stabile UID:
     * gleiches Datum + gleicher Titel => immer gleiche UID
     * so werden Re-Imports und Feed-Updates beherrschbar
     */
    $uidSource = $row['title'] . '|' . $row['event_date'];
    $uid = md5($uidSource) . '@pacim-calendar';

    /*
     * LAST-MODIFIED / DTSTAMP
     */
    $dtStamp = gmdate('Ymd\THis\Z');

    echo "BEGIN:VEVENT\r\n";
    echo icsLine('UID', $uid);
    echo icsLine('DTSTAMP', $dtStamp);
    echo icsLine('DTSTART', $startUtc->format('Ymd\THis\Z'));
    echo icsLine('DTEND', $endUtc->format('Ymd\THis\Z'));
    echo icsLine('SUMMARY', icsEscape($row['title']));
    echo icsLine('DESCRIPTION', icsEscape("Details zum Termin:\n" . $eventUrl));
    echo icsLine('URL', $eventUrl);

    /*
     * Praktisch zum Wiederfinden
     */
    echo icsLine('CATEGORIES', icsEscape('PACIM,Kreuzfahrten 2026'));

    /*
     * Eigene Kennung aus DB, falls du sp�ter doch API-seitig matchen willst
     */
    echo icsLine('X-PACIM-ID', (string)$row['source_id']);
    echo "END:VEVENT\r\n";
}

echo "END:VCALENDAR\r\n";