import { TokenOptions, LoginUrlOptions } from "../types/auth";

/**
 * Default storage key for the access token
 */
const DEFAULT_STORAGE_KEY = "b44_access_token";

/**
 * Default parameter name for the access token in URL
 */
const DEFAULT_PARAM_NAME = "access_token";

/**
 * Get the access token from URL parameters or localStorage
 * @param options Token options
 * @returns Access token or null if not found
 */
export function getAccessToken(options: TokenOptions = {}): string | null {
  const {
    storageKey = DEFAULT_STORAGE_KEY,
    paramName = DEFAULT_PARAM_NAME,
    saveToStorage = true,
    removeFromUrl = true,
  } = options;

  let token: string | null = null;

  // Try to get token from URL parameters
  if (typeof window !== "undefined" && window.location) {
    try {
      const urlParams = new URLSearchParams(window.location.search);
      token = urlParams.get(paramName);

      if (token) {
        // Save token to localStorage if requested
        if (saveToStorage) {
          saveAccessToken(token, { storageKey });
        }

        // Remove token from URL if requested
        if (removeFromUrl) {
          urlParams.delete(paramName);
          const newUrl = `${window.location.pathname}${urlParams.toString() ? `?${urlParams.toString()}` : ""}${window.location.hash}`;
          window.history.replaceState({}, document.title, newUrl);
        }

        return token;
      }
    } catch (error) {
      console.error("Error retrieving token from URL:", error);
    }
  }

  // Try to get token from localStorage
  if (typeof window !== "undefined" && window.localStorage) {
    try {
      token = window.localStorage.getItem(storageKey);
      return token;
    } catch (error) {
      console.error("Error retrieving token from localStorage:", error);
    }
  }

  return null;
}

/**
 * Save the access token to localStorage
 * @param token Access token
 * @param options Token options
 * @returns Whether the token was successfully saved
 */
export function saveAccessToken(
  token: string,
  options: TokenOptions = {}
): boolean {
  const { storageKey = DEFAULT_STORAGE_KEY } = options;

  if (typeof window === "undefined" || !window.localStorage || !token) {
    return false;
  }

  try {
    window.localStorage.setItem(storageKey, token);
    return true;
  } catch (error) {
    console.error("Error saving token to localStorage:", error);
    return false;
  }
}

/**
 * Remove the access token from localStorage
 * @param options Token options
 * @returns Whether the token was successfully removed
 */
export function removeAccessToken(options: TokenOptions = {}): boolean {
  const { storageKey = DEFAULT_STORAGE_KEY } = options;

  if (typeof window === "undefined" || !window.localStorage) {
    return false;
  }

  try {
    window.localStorage.removeItem(storageKey);
    return true;
  } catch (error) {
    console.error("Error removing token from localStorage:", error);
    return false;
  }
}

/**
 * Get the login URL for the specified return URL and configuration
 * @param returnUrl URL to return to after login
 * @param options Login URL options
 * @returns Login URL
 */
export function getLoginUrl(
  returnUrl: string | undefined,
  options: LoginUrlOptions
): string {
  const { serverUrl, appId, loginPath = "/login" } = options;

  if (!serverUrl || !appId) {
    throw new Error("serverUrl and appId are required to construct login URL");
  }

  const actualReturnUrl =
    returnUrl || (typeof window !== "undefined" ? window.location.href : "");

  return `${serverUrl}${loginPath}?from_url=${encodeURIComponent(actualReturnUrl)}&app_id=${appId}`;
}