cinny/src/app/pages/auth/login/Login.tsx

import React, { useMemo } from 'react';
import { Box, Text, color } from 'folds';
import { Link, useSearchParams } from 'react-router-dom';
import { SSOAction } from 'matrix-js-sdk';
import { useAuthFlows } from '../../../hooks/useAuthFlows';
import { useAuthServer } from '../../../hooks/useAuthServer';
import { useParsedLoginFlows } from '../../../hooks/useParsedLoginFlows';
import { PasswordLoginForm } from './PasswordLoginForm';
import { SSOLogin } from '../SSOLogin';
import { TokenLogin } from './TokenLogin';
import { OidcLogin } from './OidcLogin';
import { useAutoDiscoveryInfo } from '../../../hooks/useAutoDiscoveryInfo';
import { OrDivider } from '../OrDivider';
import { getLoginPath, getRegisterPath, withSearchParam } from '../../pathUtils';
import { usePathWithOrigin } from '../../../hooks/usePathWithOrigin';
import { LoginPathSearchParams } from '../../paths';
import { useClientConfig } from '../../../hooks/useClientConfig';

const getLoginTokenSearchParam = () => {
  // when using hasRouter query params in existing route
  // gets ignored by react-router, so we need to read it ourself
  // we only need to read loginToken as it's the only param that
  // is provided by external entity. example: SSO login
  const parmas = new URLSearchParams(window.location.search);
  const loginToken = parmas.get('loginToken');
  return loginToken ?? undefined;
};

const useLoginSearchParams = (searchParams: URLSearchParams): LoginPathSearchParams =>
  useMemo(
    () => ({
      username: searchParams.get('username') ?? undefined,
      email: searchParams.get('email') ?? undefined,
      loginToken: searchParams.get('loginToken') ?? undefined,
    }),
    [searchParams],
  );

export function Login() {
  const server = useAuthServer();
  const discovery = useAutoDiscoveryInfo();
  const { hashRouter } = useClientConfig();
  const { loginFlows, authMetadata } = useAuthFlows();
  const [searchParams] = useSearchParams();
  const loginSearchParams = useLoginSearchParams(searchParams);
  const ssoRedirectUrl = usePathWithOrigin(getLoginPath(server));
  const loginTokenForHashRouter = getLoginTokenSearchParam();
  const absoluteLoginPath = usePathWithOrigin(getLoginPath(server));

  if (hashRouter?.enabled && loginTokenForHashRouter) {
    window.location.replace(
      withSearchParam(absoluteLoginPath, {
        loginToken: loginTokenForHashRouter,
      }),
    );
  }

  const parsedFlows = useParsedLoginFlows(loginFlows.flows);

  // Next-gen auth (MSC3861): when the homeserver serves OAuth metadata
  // (`/auth_metadata`, e.g. matrix.org via MAS), use the native OAuth flow and
  // suppress the password / legacy-SSO forms, as Element does. Detected the way
  // the SDK finds the auth server for refresh; the old `.well-known`
  // `m.authentication` key is gone from matrix.org. A legacy SSO `loginToken`
  // coming back from a redirect still completes below.
  if (authMetadata && !loginSearchParams.loginToken) {
    return (
      <Box direction="Column" gap="500">
        <Text as="h1" size="H2" priority="400">
          Login
        </Text>
        <OidcLogin homeserverBaseUrl={discovery['m.homeserver'].base_url} serverName={server} />
        <span data-spacing-node />
        <Text align="Center">
          Do not have an account? <Link to={getRegisterPath(server)}>Register</Link>
        </Text>
      </Box>
    );
  }

  return (
    <Box direction="Column" gap="500">
      <Text as="h1" size="H2" priority="400">
        Login
      </Text>
      {parsedFlows.token && loginSearchParams.loginToken && (
        <TokenLogin token={loginSearchParams.loginToken} />
      )}
      {parsedFlows.password && (
        <>
          <PasswordLoginForm
            defaultUsername={loginSearchParams.username}
            defaultEmail={loginSearchParams.email}
          />
          <span data-spacing-node />
          {parsedFlows.sso && <OrDivider />}
        </>
      )}
      {parsedFlows.sso && (
        <>
          <SSOLogin
            providers={parsedFlows.sso.identity_providers}
            redirectUrl={ssoRedirectUrl}
            action={SSOAction.LOGIN}
            saveScreenSpace={parsedFlows.password !== undefined}
          />
          <span data-spacing-node />
        </>
      )}
      {!parsedFlows.password && !parsedFlows.sso && (
        <>
          <Text style={{ color: color.Critical.Main }}>
            {`This client does not support login on "${server}" homeserver. Password and SSO based login method not found.`}
          </Text>
          <span data-spacing-node />
        </>
      )}
      <Text align="Center">
        Do not have an account? <Link to={getRegisterPath(server)}>Register</Link>
      </Text>
    </Box>
  );
}