import { buildAuthenticatedFetch, createDpopHeader, generateDpopKeyPair } from '@inrupt/solid-client-authn-core';
import fetch from 'cross-fetch';

async function wrapper(): Promise<void> {
// This assumes your server is started under http://localhost:3000/.
  // This URL can also be found by checking the controls in JSON responses when interacting with the IDP API,
  // as described in the Identity Provider section.
  let response = await fetch('http://localhost:3000/idp/credentials/', {
    method: 'POST',
    headers: { 'content-type': 'application/json' },
    // The email/password fields are those of your account.
    // The name field will be used when generating the ID of your token.
    body: JSON.stringify({ email: '[e-mail]', password: 'p', name: 'my-token' }),
  });

  // These are the identifier and secret of your token.
  // Store the secret somewhere safe as there is no way to request it again from the server!
  const { id, secret } = await response.json();

  // A key pair is needed for encryption.
  // This function from `solid-client-authn` generates such a pair for you.
  const dpopKey = await generateDpopKeyPair();

  // These are the ID and secret generated in the previous step.
  // Both the ID and the secret need to be form-encoded.
  const authString = `${encodeURIComponent(id)}:${encodeURIComponent(secret)}`;
  // This URL can be found by looking at the "token_endpoint" field at
  // http://localhost:3000/.well-known/openid-configuration
  // if your server is hosted at http://localhost:3000/.
  const tokenUrl = 'http://localhost:3000/.oidc/token';
  response = await fetch(tokenUrl, {
    method: 'POST',
    headers: {
      // The header needs to be in base64 encoding.
      authorization: `Basic ${Buffer.from(authString).toString('base64')}`,
      'content-type': 'application/x-www-form-urlencoded',
      dpop: await createDpopHeader(tokenUrl, 'POST', dpopKey),
    },
    body: 'grant_type=client_credentials&scope=webid',
  });

  // This is the Access token that will be used to do an authenticated request to the server.
  // The JSON also contains an "expires_in" field in seconds,
  // which you can use to know when you need request a new Access token.
  const { access_token: accessToken } = await response.json();

  // The DPoP key needs to be the same key as the one used in the previous step.
  // The Access token is the one generated in the previous step.
  const authFetch = await buildAuthenticatedFetch(fetch, accessToken, { dpopKey });
  // AuthFetch can now be used as a standard fetch function that will authenticate as your WebID.
  // This request will do a simple GET for example.
  response = await authFetch('http://localhost:3000/profile/');
  console.log(response.status);
  console.log(await response.json());
}
wrapper();