<?php
date_default_timezone_set('Europe/Berlin');

define('SITE_ICON',  '📑');
define('SITE_TITLE', 'Lütte Planer');
define('MAIL_FROM',  'jason@illg.de');
define('MAIL_FROM_NAME', 'Lütte Planer');
define('DATA_DIR',   __DIR__ . '/data/');
define('UPLOAD_DIR', DATA_DIR . 'uploads/');
define('UPLOAD_MAX_MB', 10);
define('UPLOAD_ACCEPT', '.pdf,.jpg,.jpeg,.png,.gif,.webp,.doc,.docx');

// Google OAuth — wird später befüllt
define('GOOGLE_CLIENT_ID',     '');
define('GOOGLE_CLIENT_SECRET', '');
define('GOOGLE_REDIRECT_URI',  (isset($_SERVER['HTTPS']) ? 'https' : 'http') . '://' . ($_SERVER['HTTP_HOST'] ?? 'localhost') . '/Develop/PlanerGoogel/auth/callback.php');

require_once __DIR__ . '/db.php';

// ── Session ───────────────────────────────────────────────────────────────────

function startSession(): void {
    if (session_status() === PHP_SESSION_NONE) session_start();
}

function requireLogin(): void {
    startSession();
    if (empty($_SESSION['user_id'])) {
        header('Location: /Develop/PlanerGoogel/login.php'); exit;
    }
}

function currentUser(): ?array {
    startSession();
    if (empty($_SESSION['user_id'])) return null;
    return dbOne('SELECT * FROM users WHERE id = ?', [$_SESSION['user_id']]);
}

function loginUser(array $user): void {
    startSession();
    $_SESSION['user_id'] = $user['id'];
}

// ── Reisen-Helfer ─────────────────────────────────────────────────────────────

function getTrip(string $id): ?array {
    return dbOne('SELECT * FROM reisen WHERE id = ?', [$id]);
}

function getTripMembers(string $tripId): array {
    return dbAll(
        'SELECT u.*, rz.access FROM users u
         JOIN reise_zugriff rz ON rz.user_id = u.id
         WHERE rz.trip_id = ?
         ORDER BY rz.access DESC, u.name ASC',
        [$tripId]
    );
}

function userCanSee(string $tripId, int $userId): bool {
    return dbOne('SELECT 1 FROM reise_zugriff WHERE trip_id = ? AND user_id = ?', [$tripId, $userId]) !== null;
}

function userCanEdit(string $tripId, int $userId): bool {
    $row = dbOne('SELECT access FROM reise_zugriff WHERE trip_id = ? AND user_id = ?', [$tripId, $userId]);
    return $row && in_array($row['access'], ['edit', 'admin']);
}

function userIsAdmin(string $tripId, int $userId): bool {
    $row = dbOne('SELECT access FROM reise_zugriff WHERE trip_id = ? AND user_id = ?', [$tripId, $userId]);
    return $row && $row['access'] === 'admin';
}

function requireTripAccess(string $tripId, bool $editRequired = false): array {
    requireLogin();
    $user = currentUser();
    $trip = getTrip($tripId);
    if (!$trip) { http_response_code(404); die('Reise nicht gefunden.'); }
    if (!userCanSee($tripId, $user['id'])) { http_response_code(403); die('Kein Zugriff.'); }
    if ($editRequired && !userCanEdit($tripId, $user['id'])) { http_response_code(403); die('Keine Berechtigung zum Bearbeiten.'); }
    return [$trip, $user];
}

function newUuid(): string {
    return sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
        mt_rand(0,0xffff), mt_rand(0,0xffff), mt_rand(0,0xffff),
        mt_rand(0,0x0fff)|0x4000, mt_rand(0,0x3fff)|0x8000,
        mt_rand(0,0xffff), mt_rand(0,0xffff), mt_rand(0,0xffff)
    );
}

// ── Datum-Helfer ──────────────────────────────────────────────────────────────

function germanDate(string $date): string {
    if (!$date) return '';
    $ts = strtotime($date);
    $monate = ['Januar','Februar','März','April','Mai','Juni',
               'Juli','August','September','Oktober','November','Dezember'];
    return date('j', $ts) . '. ' . $monate[date('n', $ts) - 1] . ' ' . date('Y', $ts);
}

function daysUntil(string $date): int {
    return (int) ceil((strtotime($date) - time()) / 86400);
}

// ── Avatar-Helfer ─────────────────────────────────────────────────────────────

function userInitials(string $name): string {
    $parts = explode(' ', trim($name));
    if (count($parts) >= 2) return strtoupper(mb_substr($parts[0], 0, 1) . mb_substr($parts[1], 0, 1));
    return strtoupper(mb_substr($name, 0, 2));
}

function avatarHtml(array $user, string $size = '32px'): string {
    $initials = userInitials($user['name']);
    $farbe    = htmlspecialchars($user['farbe'] ?? '#2563eb');
    $name     = htmlspecialchars($user['name']);
    if (!empty($user['avatar_url'])) {
        return "<img src=\"{$user['avatar_url']}\" alt=\"{$name}\" style=\"width:{$size};height:{$size};border-radius:50%;object-fit:cover;\" title=\"{$name}\">";
    }
    return "<span style=\"display:inline-flex;align-items:center;justify-content:center;width:{$size};height:{$size};border-radius:50%;background:{$farbe};color:#fff;font-size:calc({$size} * 0.38);font-weight:600;\" title=\"{$name}\">{$initials}</span>";
}

// ── XSS-Schutz ────────────────────────────────────────────────────────────────

function h(string $s): string {
    return htmlspecialchars($s, ENT_QUOTES, 'UTF-8');
}

// ── Packliste-Kategorien ──────────────────────────────────────────────────────
$PACKEN_KATEGORIEN = [
    'kleidung'   => ['label' => 'Kleidung',       'icon' => '👕'],
    'dokumente'  => ['label' => 'Dokumente',       'icon' => '📄'],
    'elektronik' => ['label' => 'Elektronik',      'icon' => '🔌'],
    'medizin'    => ['label' => 'Medizin',         'icon' => '💊'],
    'toilette'   => ['label' => 'Toilette',        'icon' => '🧴'],
    'essen'      => ['label' => 'Essen & Trinken', 'icon' => '🍿'],
    'strand'     => ['label' => 'Strand',          'icon' => '🏖'],
    'sport'      => ['label' => 'Sport',           'icon' => '⚽'],
    'sonstiges'  => ['label' => 'Sonstiges',       'icon' => '📦'],
];

$UPLOAD_TYPEN = [
    'application/pdf'  => 'PDF',
    'image/jpeg'       => 'JPG',
    'image/png'        => 'PNG',
    'image/gif'        => 'GIF',
    'image/webp'       => 'WEBP',
    'application/msword' => 'Word',
    'application/vnd.openxmlformats-officedocument.wordprocessingml.document' => 'Word',
];

// ── E-Mail-Versand ────────────────────────────────────────────────────────────

function sendMail(string $to, string $subject, string $htmlBody): bool {
    $fromName = '=?UTF-8?B?' . base64_encode(MAIL_FROM_NAME) . '?=';
    $subjectEncoded = '=?UTF-8?B?' . base64_encode($subject) . '?=';
    $boundary = md5(uniqid());

    $headers  = "From: {$fromName} <" . MAIL_FROM . ">\r\n";
    $headers .= "Reply-To: " . MAIL_FROM . "\r\n";
    $headers .= "MIME-Version: 1.0\r\n";
    $headers .= "Content-Type: multipart/alternative; boundary=\"{$boundary}\"\r\n";
    $headers .= "X-Mailer: PHP/" . phpversion();

    $plain = strip_tags(str_replace(['<br>', '<br/>', '<br />', '</p>', '</div>'], "\n", $htmlBody));
    $plain = preg_replace('/\n{3,}/', "\n\n", trim($plain));

    $body  = "--{$boundary}\r\n";
    $body .= "Content-Type: text/plain; charset=UTF-8\r\n";
    $body .= "Content-Transfer-Encoding: base64\r\n\r\n";
    $body .= chunk_split(base64_encode($plain)) . "\r\n";
    $body .= "--{$boundary}\r\n";
    $body .= "Content-Type: text/html; charset=UTF-8\r\n";
    $body .= "Content-Transfer-Encoding: base64\r\n\r\n";
    $body .= chunk_split(base64_encode($htmlBody)) . "\r\n";
    $body .= "--{$boundary}--";

    return mail($to, $subjectEncoded, $body, $headers);
}

function sendInviteMail(string $toEmail, string $tripName, string $inviteLink, string $inviterName): bool {
    $subject = $inviterName . ' laedt dich zu "' . $tripName . '" ein';
    $html = '<!DOCTYPE html><html><head><meta charset="UTF-8"></head><body style="font-family:Inter,sans-serif;background:#f0f6ff;padding:30px;">
    <div style="max-width:480px;margin:0 auto;background:#fff;border-radius:12px;padding:32px;box-shadow:0 4px 20px rgba(37,99,235,.1);">
      <div style="text-align:center;margin-bottom:24px;">
        <div style="font-size:2.5rem;">📑</div>
        <h1 style="font-family:Georgia,serif;font-size:1.4rem;color:#1d4ed8;margin:8px 0 4px;">Lütte Planer</h1>
      </div>
      <p style="color:#1e293b;font-size:.95rem;margin-bottom:12px;">Hallo!</p>
      <p style="color:#1e293b;font-size:.95rem;margin-bottom:20px;">
        <strong>' . htmlspecialchars($inviterName) . '</strong> hat dich zur Reise
        <strong>„' . htmlspecialchars($tripName) . '"</strong> eingeladen.
      </p>
      <div style="text-align:center;margin:28px 0;">
        <a href="' . htmlspecialchars($inviteLink) . '" style="background:#2563eb;color:#fff;padding:13px 28px;border-radius:8px;text-decoration:none;font-weight:600;font-size:.95rem;">
          Einladung annehmen
        </a>
      </div>
      <p style="color:#64748b;font-size:.78rem;margin-top:24px;">
        Oder kopiere diesen Link in deinen Browser:<br>
        <span style="color:#2563eb;word-break:break-all;">' . htmlspecialchars($inviteLink) . '</span>
      </p>
      <hr style="border:none;border-top:1px solid #e2e8f0;margin:20px 0;">
      <p style="color:#94a3b8;font-size:.72rem;text-align:center;">Lütte Planer · Reisen planen &amp; teilen</p>
    </div>
    </body></html>';

    return sendMail($toEmail, $subject, $html);
}

function sendAddedToTripMail(string $toEmail, string $toName, string $tripName, string $tripUrl, string $inviterName): bool {
    $subject = 'Du wurdest zu "' . $tripName . '" hinzugefuegt';
    $html = '<!DOCTYPE html><html><head><meta charset="UTF-8"></head><body style="font-family:Inter,sans-serif;background:#f0f6ff;padding:30px;">
    <div style="max-width:480px;margin:0 auto;background:#fff;border-radius:12px;padding:32px;box-shadow:0 4px 20px rgba(37,99,235,.1);">
      <div style="text-align:center;margin-bottom:24px;">
        <div style="font-size:2.5rem;">📑</div>
        <h1 style="font-family:Georgia,serif;font-size:1.4rem;color:#1d4ed8;margin:8px 0 4px;">Lütte Planer</h1>
      </div>
      <p style="color:#1e293b;font-size:.95rem;margin-bottom:12px;">Hallo ' . htmlspecialchars($toName) . '!</p>
      <p style="color:#1e293b;font-size:.95rem;margin-bottom:20px;">
        <strong>' . htmlspecialchars($inviterName) . '</strong> hat dich zur Reise
        <strong>„' . htmlspecialchars($tripName) . '"</strong> hinzugefügt.
      </p>
      <div style="text-align:center;margin:28px 0;">
        <a href="' . htmlspecialchars($tripUrl) . '" style="background:#2563eb;color:#fff;padding:13px 28px;border-radius:8px;text-decoration:none;font-weight:600;font-size:.95rem;">
          Zur Reise
        </a>
      </div>
      <hr style="border:none;border-top:1px solid #e2e8f0;margin:20px 0;">
      <p style="color:#94a3b8;font-size:.72rem;text-align:center;">Lütte Planer · Reisen planen &amp; teilen</p>
    </div>
    </body></html>';

    return sendMail($toEmail, $subject, $html);
}