<?php
declare(strict_types=1);

/* ========= Session & Bootstrap ========= */
$secure = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off');
session_set_cookie_params([
  'lifetime' => 0,
  'path' => '/',
  'secure' => $secure,
  'httponly' => true,
  'samesite' => 'Lax',
]);
session_name('WLISTSESSID');
session_start();
umask(0022); // sorgt für 0644/0755 als Default für neu erstellte Dateien/Ordner

require_once __DIR__ . '/config/config.php';

// ===== Debug Toggle =====
if (!empty($app_debug)) {
  ini_set('display_errors', '1');
  ini_set('display_startup_errors', '1');
  ini_set('log_errors', '1');
  if (!is_dir(__DIR__ . '/logs')) {
    @mkdir(__DIR__ . '/logs', 0750, true);
  }
  ini_set('error_log', __DIR__ . '/logs/php-error.log');
  error_reporting(E_ALL);
} else {
  ini_set('display_errors', '0');
  ini_set('display_startup_errors', '0');
  ini_set('log_errors', '1');
  if (!is_dir(__DIR__ . '/logs')) {
    @mkdir(__DIR__ . '/logs', 0750, true);
  }
  ini_set('error_log', __DIR__ . '/logs/php-error.log');
  error_reporting(E_ALL);
}


/* ============= Helpers ============= */

function fail(string $msg = 'Unerwarteter Fehler', int $code = 400): void
{
  http_response_code($code);
  exit($msg);
}
function require_csrf(): void
{
  $t = (string) ($_POST['csrf'] ?? '');
  if (empty($_SESSION['csrf']) || !hash_equals($_SESSION['csrf'], $t))
    fail('Ungültiges CSRF-Token', 403);
}
function require_logged_in(): int
{
  if (!isset($_SESSION['listid']))
    fail('Nicht eingeloggt', 403);
  return (int) $_SESSION['listid'];
}
function db(): mysqli
{
  global $servername, $username, $password, $db;
  $conn = new mysqli($servername, $username, $password, $db);
  if ($conn->connect_error)
    fail('Interner Fehler (DB)', 500);
  $conn->set_charset('utf8mb4');
  return $conn;
}
function parse_price_to_cents(string $in): int
{
  $clean = preg_replace('/[^\d,\.]/', '', $in ?? '');
  $norm = str_replace('.', '', $clean);
  $norm = str_replace(',', '.', $norm);
  if ($norm === '' || !is_numeric($norm))
    return 0;
  $cents = (int) round((float) $norm * 100);
  if ($cents < 0)
    $cents = 0;
  if ($cents > 100000000)
    $cents = 100000000; // 1 Mio €
  return $cents;
}
function is_valid_http_url(string $url): bool
{
  if (!filter_var($url, FILTER_VALIDATE_URL))
    return false;
  $p = parse_url($url);
  if (!$p || empty($p['scheme']) || empty($p['host']))
    return false;
  $s = strtolower($p['scheme']);
  return $s === 'http' || $s === 'https';
}
function ip_in_cidr(string $ip, string $cidr): bool
{
  if (strpos($cidr, ':') !== false) {
    [$subnet, $mask] = array_pad(explode('/', $cidr, 2), 2, null);
    $mask = (int) $mask;
    $binIp = inet_pton($ip);
    $binSubnet = inet_pton($subnet);
    if ($binIp === false || $binSubnet === false)
      return false;
    $bytes = intdiv($mask, 8);
    $bits = $mask % 8;
    if ($bytes && substr($binIp, 0, $bytes) !== substr($binSubnet, 0, $bytes))
      return false;
    if ($bits) {
      $b1 = ord($binIp[$bytes]) & (0xFF << (8 - $bits));
      $b2 = ord($binSubnet[$bytes]) & (0xFF << (8 - $bits));
      return $b1 === $b2;
    }
    return true;
  } else {
    [$subnet, $mask] = array_pad(explode('/', $cidr, 2), 2, null);
    $mask = (int) $mask;
    $ipL = ip2long($ip);
    $subL = ip2long($subnet);
    if ($ipL === false || $subL === false)
      return false;
    $maskL = -1 << (32 - $mask);
    return (($ipL & $maskL) === ($subL & $maskL));
  }
}
function is_private_ip(string $ip): bool
{
  if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)) {
    foreach (['10.0.0.0/8', '172.16.0.0/12', '192.168.0.0/16', '127.0.0.0/8', '169.254.0.0/16'] as $c)
      if (ip_in_cidr($ip, $c))
        return true;
  } elseif (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6)) {
    foreach (['::1/128', 'fc00::/7', 'fe80::/10'] as $c)
      if (ip_in_cidr($ip, $c))
        return true;
  }
  return false;
}
function validate_remote_host_not_private(string $url): void
{
  $p = parse_url($url);
  if (!$p || empty($p['host']))
    fail('Ungültige URL', 400);
  $host = $p['host'];
  global $image_host_whitelist;
  if (isset($image_host_whitelist) && is_array($image_host_whitelist) && count($image_host_whitelist) > 0) {
    $ok = false;
    foreach ($image_host_whitelist as $allowed) {
      if (strcasecmp($host, $allowed) === 0) {
        $ok = true;
        break;
      }
      if (preg_match('/\.' . preg_quote($allowed, '/') . '$/i', $host)) {
        $ok = true;
        break;
      }
    }
    if (!$ok)
      fail('Host nicht erlaubt', 400);
  }
  $recs = dns_get_record($host, DNS_A + DNS_AAAA);
  if (!$recs || !count($recs))
    fail('Host nicht auflösbar', 400);
  foreach ($recs as $r) {
    $ip = $r['type'] === 'A' ? ($r['ip'] ?? null) : ($r['ipv6'] ?? null);
    if (!$ip)
      continue;
    if (is_private_ip($ip))
      fail('Zieladresse unzulässig', 400);
  }
}
function download_remote_image_limited(string $url, int $maxBytes = 5_000_000, int $timeout = 8): string
{
  $tmp = tempnam(sys_get_temp_dir(), 'wlimg_');
  if ($tmp === false)
    fail('Temp-Datei Fehler', 500);
  $fh = fopen($tmp, 'wb');
  if ($fh === false) {
    @unlink($tmp);
    fail('Temp-Datei Fehler', 500);
  }
  $ch = curl_init($url);
  if ($ch === false) {
    fclose($fh);
    @unlink($tmp);
    fail('Download Fehler', 500);
  }
  $received = 0;
  curl_setopt_array($ch, [
    CURLOPT_FOLLOWLOCATION => true,
    CURLOPT_MAXREDIRS => 3,
    CURLOPT_CONNECTTIMEOUT => 3,
    CURLOPT_TIMEOUT => $timeout,
    CURLOPT_USERAGENT => 'wishlist/1.0',
    CURLOPT_SSL_VERIFYPEER => true,
    CURLOPT_SSL_VERIFYHOST => 2,
    CURLOPT_WRITEFUNCTION => function ($ch, $data) use (&$received, $maxBytes, $fh) {
      $len = strlen($data);
      $received += $len;
      if ($received > $maxBytes)
        return 0;
      return fwrite($fh, $data);
    }
  ]);
  $ok = curl_exec($ch);
  $code = (int) curl_getinfo($ch, CURLINFO_HTTP_CODE);
  curl_close($ch);
  fclose($fh);
  if (!$ok || $code < 200 || $code >= 300) {
    @unlink($tmp);
    fail('Bild-Download fehlgeschlagen', 400);
  }
  return $tmp;
}
function safe_image_filename_from_url(string $url): string
{
  $stripped = strtok($url, '?#');
  $ext = strtolower(pathinfo((string) $stripped, PATHINFO_EXTENSION));
  if (!preg_match('/^[a-z0-9]{1,5}$/i', $ext))
    $ext = 'jpg';
  return bin2hex(random_bytes(10)) . '.' . $ext;
}

/* ============= Controller ============= */

require_csrf();
$sessionListId = require_logged_in();

$action = strtolower(trim((string) ($_POST['action'] ?? '')));
$ItemTitle = trim((string) ($_POST['ItemTitle'] ?? ''));
$ItemDescription = trim((string) ($_POST['ItemDescription'] ?? ''));
$ItemPrice = parse_price_to_cents((string) ($_POST['ItemPrice'] ?? ''));
$ItemQty = isset($_POST['ItemQty']) ? max(1, (int) $_POST['ItemQty']) : 1;
$ItemLink = trim((string) ($_POST['ItemLink'] ?? ''));
$ItemImageUrl = trim((string) ($_POST['ItemImage'] ?? ''));   // optional URL zum Pull
$ListUUID = trim((string) ($_POST['ItemListUUID'] ?? ''));
$sortbyTransfer = (string) ($_POST['sortby_transfer'] ?? 'priority');

$removeImage = isset($_POST['RemoveImage']) && ($_POST['RemoveImage'] === '1');
$WhishID = isset($_POST['WhishID']) ? (int) $_POST['WhishID'] : 0; // bei edit

if (!preg_match('/^[0-9a-fA-F-]{32,36}$/', $ListUUID))
  fail('Liste nicht autorisiert', 403);

$conn = db();

/* UUID -> int ID */
$stmt = $conn->prepare('SELECT ID FROM lists WHERE uuid = ?');
$stmt->bind_param('s', $ListUUID);
$stmt->execute();
$res = $stmt->get_result();
if (!$res || !($row = $res->fetch_assoc())) {
  $stmt->close();
  $conn->close();
  fail('Liste nicht autorisiert', 403);
}
$ListID = (int) $row['ID'];
$stmt->close();

/* Session muss zu dieser Liste gehören */
if ($ListID !== $sessionListId) {
  $conn->close();
  fail('Liste nicht autorisiert', 403);
}

/* Validierungen (add & edit) */
if ($ItemTitle === '')
  fail('Titel fehlt', 400);
if ($ItemLink !== '' && !is_valid_http_url($ItemLink))
  fail('Ungültiger Angebotslink', 400);

/* Optional: Bild von externer URL holen */
$imageLocalLink = null;
if (!$removeImage && $ItemImageUrl !== '') {
  if (!is_valid_http_url($ItemImageUrl)) {
    $conn->close();
    fail('Ungültiger Bildlink', 400);
  }
  validate_remote_host_not_private($ItemImageUrl);
  $tmp = download_remote_image_limited($ItemImageUrl, 5_000_000, 8);
  $info = @getimagesize($tmp);
  if ($info === false || empty($info['mime']) || stripos($info['mime'], 'image/') !== 0) {
    @unlink($tmp);
    $conn->close();
    fail('Link ist kein gültiges Bild', 400);
  }
  global $imagedir;
  if (!is_dir($imagedir)) {
    @mkdir($imagedir, 0755, true);
  }
  $filename = safe_image_filename_from_url($ItemImageUrl);
  $target = rtrim($imagedir, '/') . '/' . $filename;

  if (!@rename($tmp, $target)) {
    // Fallback falls rename scheitert
    if (!@copy($tmp, $target)) {
      @unlink($tmp);
      $conn->close();
      fail('Bildspeicherung fehlgeschlagen', 500);
    }
    @unlink($tmp);
  }

  // HIER: Permissions fixen
  @chmod($target, 0644);

  $imageLocalLink = $filename;
}

/* ====== ADD ====== */
if ($action === 'add') {
  // nächste Priority ermitteln
  $next = 1;
  $s = $conn->prepare('SELECT COALESCE(MAX(priority),0) AS maxp FROM wishes WHERE wishlist = ?');
  $s->bind_param('i', $ListID);
  $s->execute();
  $r = $s->get_result();
  if ($r && $m = $r->fetch_assoc())
    $next = ((int) $m['maxp']) + 1;
  $s->close();

  $stmt = $conn->prepare('
  INSERT INTO wishes (title, description, link, image, price, wishlist, priority, qty)
  VALUES (?, ?, ?, ?, ?, ?, ?, ?)
');
  $link = $ItemLink !== '' ? $ItemLink : null;
  $image = $imageLocalLink !== null ? $imageLocalLink : null;
  $stmt->bind_param(
    'ssssiiii',
    $ItemTitle,
    $ItemDescription,
    $link,
    $image,
    $ItemPrice,
    $ListID,
    $next,
    $ItemQty
  );

  if (!$stmt->execute()) {
    $stmt->close();
    $conn->close();
    fail('Speichern fehlgeschlagen', 500);
  }
  $stmt->close();
}
/* ====== EDIT ====== */ elseif ($action === 'edit') {
  if ($WhishID <= 0) {
    $conn->close();
    fail('Ungültige Item-ID', 400);
  }

  // Besitz prüfen & altes Bild holen
  $stmt = $conn->prepare('SELECT image FROM wishes WHERE ID = ? AND wishlist = ?');
  $stmt->bind_param('ii', $WhishID, $ListID);
  $stmt->execute();
  $res = $stmt->get_result();
  if (!$res || !($row = $res->fetch_assoc())) {
    $stmt->close();
    $conn->close();
    fail('Item nicht gefunden/autorisiert', 404);
  }
  $oldImage = (string) $row['image'];
  $stmt->close();

  // Bild-Entscheidung: entfernen, ersetzen oder behalten
  $newImage = $oldImage;
  if ($removeImage) {
    if (!empty($oldImage)) {
      global $imagedir;
      $full = rtrim($imagedir, '/') . '/' . $oldImage;
      if (is_file($full))
        @unlink($full);
    }
    $newImage = '';
  } elseif ($imageLocalLink !== null) {
    if (!empty($oldImage)) {
      global $imagedir;
      $full = rtrim($imagedir, '/') . '/' . $oldImage;
      if (is_file($full))
        @unlink($full);
    }
    $newImage = $imageLocalLink;
  }

  $link = $ItemLink !== '' ? $ItemLink : null;
  $imgNullable = ($newImage !== '') ? $newImage : null;

  $stmt = $conn->prepare(
    'UPDATE wishes SET title=?, description=?, link=?, image=?, price=?, qty=? WHERE ID=? AND wishlist=?'
  );
  $stmt->bind_param(
    'sssssiii',
    $ItemTitle,
    $ItemDescription,
    $link,
    $imgNullable,
    $ItemPrice,
    $ItemQty,
    $WhishID,
    $ListID
  );

  if (!$stmt->execute()) {
    $stmt->close();
    $conn->close();
    fail('Update fehlgeschlagen', 500);
  }
  $stmt->close();
}
/* ====== Unbekannt ====== */ else {
  $conn->close();
  fail('Unbekannte Aktion', 400);
}

$conn->close();

/* Redirect zurück (sicher, mit UUID) */
$redirect = (string) ($_SERVER['HTTP_REFERER'] ?? '');
if ($redirect === '' || stripos($redirect, 'http') !== 0) {
  $host = $_SERVER['HTTP_HOST'] ?? '';
  $scheme = $secure ? 'https' : 'http';
  $qs = '?list=' . urlencode($ListUUID);
  if ($sortbyTransfer !== '')
    $qs .= '&sort=' . urlencode($sortbyTransfer);
  $redirect = $scheme . '://' . $host . '/' . $qs;
}
header('Location: ' . $redirect, true, 303);
exit;