export const API_KEY_PREFIX = 'create_';

type Client = {
  clientId: string;
  clientSecret: string;
};

/**
 * This function will decode the api key supplied by the user.
 * If the key is invalid, then it will return undefined, otherwise
 * it will return the clientId and clientSecret.
 */
export const decodeApiKey = (apiKey: string): Client | undefined => {
  if (!apiKey.startsWith(API_KEY_PREFIX)) {
    return;
  }

  const nonPrefixedKey = Buffer.from(
    apiKey.slice(API_KEY_PREFIX.length),
    'base64url'
  ).toString('utf-8');

  const clientId = nonPrefixedKey.slice(0, nonPrefixedKey.indexOf('.'));
  const clientSecret = nonPrefixedKey.slice(nonPrefixedKey.indexOf('.') + 1);

  if (clientId === '' || clientSecret === '') {
    return;
  }

  return {
    clientId,
    clientSecret,
  };
};

/**
 * This function will encode the api key in a url safe way.
 */
export const encodeApiKey = ({ clientId, clientSecret }: Client): string => {
  const key = Buffer.from(`${clientId}.${clientSecret}`).toString('base64url');

  return `${API_KEY_PREFIX}${key}`;
};