const YANDEX_AUTHORIZE = "https://oauth.yandex.ru/authorize";

export function yandexCodeFromQuery(search: string): string | null {
  const params = new URLSearchParams(search.startsWith("?") ? search : `?${search}`);
  const code = params.get("code")?.trim();
  if (!code) return null;
  // Telegram login also lands on /login with id/hash — never treat that as Yandex.
  if (params.has("hash") && params.has("id")) return null;
  return code;
}

export function yandexErrorFromQuery(search: string): string | null {
  const params = new URLSearchParams(search.startsWith("?") ? search : `?${search}`);
  if (params.has("hash") && params.has("id")) return null;
  return params.get("error_description")?.trim() || params.get("error")?.trim() || null;
}

export function yandexAuthorizeUrl(
  clientId: string,
  redirectUri: string,
  state?: string | null,
): string {
  const params = new URLSearchParams({
    response_type: "code",
    client_id: clientId,
    redirect_uri: redirectUri,
    force_confirm: "yes",
  });
  if (state) params.set("state", state);
  return `${YANDEX_AUTHORIZE}?${params.toString()}`;
}

/** Must match the Callback URL registered in the Yandex app (trailing slash). */
export function yandexRedirectUri(
  configured?: string | null,
  origin = window.location.origin,
): string {
  const local = `${origin.replace(/\/$/, "")}/`;
  if (!configured) return local;
  try {
    if (new URL(configured).origin === new URL(local).origin) return configured;
  } catch {
    // Fall through to the current origin.
  }
  return local;
}

/** @deprecated use yandexRedirectUri */
export function cabinetLoginRedirectUri(origin = window.location.origin): string {
  return yandexRedirectUri(null, origin);
}