/**
 * Telegram init data and access checks.
 */

/**
 * Get tgWebAppData value from hash when it contains unencoded & and =.
 * Value runs from tgWebAppData= until next &tgWebApp or end.
 * @param {string} hash - location.hash without #
 * @returns {string}
 */
export function getTgWebAppDataFromHash(hash) {
  const idx = hash.indexOf("tgWebAppData=");
  if (idx === -1) return "";
  const start = idx + "tgWebAppData=".length;
  let end = hash.indexOf("&tgWebApp", start);
  if (end === -1) end = hash.length;
  const raw = hash.substring(start, end);
  try {
    return decodeURIComponent(raw);
  } catch (e) {
    return raw;
  }
}

/**
 * Get Telegram init data string (from SDK, hash or query).
 * @returns {string}
 */
export function getInitData() {
  const fromSdk =
    (window.Telegram && window.Telegram.WebApp && window.Telegram.WebApp.initData) || "";
  if (fromSdk) return fromSdk;
  const hash = window.location.hash ? window.location.hash.slice(1) : "";
  if (hash) {
    const fromHash = getTgWebAppDataFromHash(hash);
    if (fromHash) return fromHash;
    try {
      const hashParams = new URLSearchParams(hash);
      const tgFromHash = hashParams.get("tgWebAppData");
      if (tgFromHash) return decodeURIComponent(tgFromHash);
    } catch (e) {
      /* ignore */
    }
  }
  const q = window.location.search
    ? new URLSearchParams(window.location.search).get("tgWebAppData")
    : null;
  if (q) {
    try {
      return decodeURIComponent(q);
    } catch (e) {
      return q;
    }
  }
  return "";
}

/**
 * @returns {boolean} True if host is localhost or 127.0.0.1
 */
export function isLocalhost() {
  const h = window.location.hostname;
  return h === "localhost" || h === "127.0.0.1" || h === "";
}

/**
 * True when hash has tg WebApp params but no init data (e.g. version without data).
 * @returns {boolean}
 */
export function hasTelegramHashButNoInitData() {
  const hash = window.location.hash ? window.location.hash.slice(1) : "";
  if (!hash) return false;
  try {
    const keys = Array.from(new URLSearchParams(hash).keys());
    const hasVersion = keys.indexOf("tgWebAppVersion") !== -1;
    const hasData = keys.indexOf("tgWebAppData") !== -1 || !!getTgWebAppDataFromHash(hash);
    return hasVersion && !hasData;
  } catch (e) {
    return false;
  }
}