export const VISITOR_COOKIE_NAME = "arena_visitor_id";
export const VISITOR_COOKIE_MAX_AGE_SECONDS = 60 * 60 * 24 * 365 * 2;

export function readVisitorCookie(request) {
  return readCookie(request, VISITOR_COOKIE_NAME);
}

export function writeVisitorCookie(reply, visitorId, { secure = false } = {}) {
  const secureFlag = secure ? "; Secure" : "";

  reply.header(
    "Set-Cookie",
    `${VISITOR_COOKIE_NAME}=${encodeURIComponent(visitorId)}; Path=/; Max-Age=${VISITOR_COOKIE_MAX_AGE_SECONDS}; SameSite=Lax; HttpOnly${secureFlag}`,
  );
}

export function isValidVisitorId(value) {
  return /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i.test(
    value,
  );
}

function readCookie(request, name) {
  const cookieHeader = request.headers.cookie;

  if (!cookieHeader) {
    return "";
  }

  const cookies = cookieHeader.split(";").map((cookie) => cookie.trim());
  const matchedCookie = cookies.find((cookie) => cookie.startsWith(`${name}=`));

  if (!matchedCookie) {
    return "";
  }

  try {
    return decodeURIComponent(matchedCookie.slice(name.length + 1));
  } catch {
    return "";
  }
}