const METHOD_PREFIX = /^(?:GET|POST|PUT|PATCH|DELETE|OPTIONS|HEAD)\s+/i;

function normalizeLink(link, baseUrl = "", verifiedRoutes = [], options = {}) {
  if (!link || typeof link.href !== "string") return null;
  const routeSet = verifiedRoutes instanceof Set ? verifiedRoutes : new Set(verifiedRoutes);
  const href = decodeHtmlEntities(link.href).trim().replace(METHOD_PREFIX, "");
  const label = stripTags(String(link.label || routeLabel(href))).trim();
  if (!href || !label) return null;

  if (href.startsWith("/")) {
    const pathname = routePath(href);
    if (!routeSet.has(pathname)) return null;
    return { href: absoluteInternalUrl(href, baseUrl), label, internal: true };
  }

  let parsed;
  try {
    parsed = new URL(href);
  } catch {
    return null;
  }
  if (!["http:", "https:"].includes(parsed.protocol)) return null;

  const base = safeBaseUrl(baseUrl);
  if (base && parsed.origin === base.origin) {
    if (!routeSet.has(parsed.pathname)) return null;
    return { href: parsed.href, label, internal: true };
  }
  if (options.allowExternal === false || link.external === false) return null;
  return { href: parsed.href, label, internal: false };
}

function absoluteInternalUrl(route, baseUrl) {
  const base = safeBaseUrl(baseUrl);
  return base ? new URL(route, base).href : route;
}

function safeBaseUrl(value) {
  if (!value) return null;
  try {
    const parsed = new URL(value);
    return ["http:", "https:"].includes(parsed.protocol) ? parsed : null;
  } catch {
    return null;
  }
}

function routePath(value) {
  return String(value || "").split(/[?#]/, 1)[0];
}

function routeLabel(route) {
  const pathname = routePath(String(route || "").replace(METHOD_PREFIX, ""));
  const segment = pathname.split("/").filter(Boolean).pop() || "Lumi page";
  return segment.replace(/[-_]/g, " ").replace(/\b\w/g, (letter) => letter.toUpperCase());
}

function stripTags(value) {
  return String(value || "").replace(/<[^>]*>/g, "");
}

function decodeHtmlEntities(value) {
  return String(value || "")
    .replace(/&amp;/gi, "&")
    .replace(/&quot;/gi, "\"")
    .replace(/&#39;|&apos;/gi, "'")
    .replace(/&lt;/gi, "<")
    .replace(/&gt;/gi, ">");
}

module.exports = {
  METHOD_PREFIX,
  normalizeLink,
  absoluteInternalUrl,
  safeBaseUrl,
  routeLabel,
  stripTags
};