import { redirect, type Cookies } from '@sveltejs/kit';

export interface ClientOptions {
  id: string;
  secret: string;
  redirectURI: string;
}

export interface CallbackOptions {
  url: URL;
  cookies: Cookies;
  cookie: string;
  authorise: string;
  redirect?: string;
  client: ClientOptions;
  verifier?: string;
}

export const callback = async (options: CallbackOptions) => {
  const { url, cookies, cookie, authorise, client } = options;
  const formData = new FormData();

  formData.append('grant_type', 'authorization_code');
  formData.append('client_id', client.id);
  formData.append('client_secret', client.secret);
  formData.append('redirect_uri', client.redirectURI);
  formData.append('code', url.searchParams.get('code') || 'null');

  if (options.verifier) formData.append('code_verifier', options.verifier);

  cookies.set(
    cookie,
    JSON.stringify(
      await (
        await fetch(authorise, {
          method: 'POST',
          body: formData
        })
      ).json()
    ),
    {
      path: '/',
      maxAge: 31536000 / 2,
      httpOnly: false,
      sameSite: 'lax',
      secure: false
    }
  );

  redirect(303, options.redirect ?? '/');
};