stack/apps/web/src/app/(auth)/login/page.tsx

'use client';

import { useEffect, useState } from 'react';
import { useRouter } from 'next/navigation';
import Link from 'next/link';
import { api } from '@/lib/api';
import { authClient, signIn } from '@/lib/auth-client';
import type { SsoProviderDiscovery } from '@/lib/sso';
import { SsoProviderButtons } from '@/components/auth/sso-provider-buttons';

export default function LoginPage(): React.ReactElement {
  const router = useRouter();
  const [error, setError] = useState<string | null>(null);
  const [loading, setLoading] = useState(false);
  const [ssoProviders, setSsoProviders] = useState<SsoProviderDiscovery[]>([]);
  const [ssoLoadingProviderId, setSsoLoadingProviderId] = useState<
    SsoProviderDiscovery['id'] | null
  >(null);

  useEffect(() => {
    api<SsoProviderDiscovery[]>('/api/sso/providers')
      .catch(() => [] as SsoProviderDiscovery[])
      .then((providers) => setSsoProviders(providers.filter((provider) => provider.configured)));
  }, []);

  async function handleSubmit(e: React.FormEvent<HTMLFormElement>): Promise<void> {
    e.preventDefault();
    setError(null);
    setLoading(true);

    const form = new FormData(e.currentTarget);
    const email = form.get('email') as string;
    const password = form.get('password') as string;

    const result = await signIn.email({ email, password });

    if (result.error) {
      setError(result.error.message ?? 'Sign in failed');
      setLoading(false);
      return;
    }

    router.push('/chat');
  }

  async function handleSsoSignIn(providerId: SsoProviderDiscovery['id']): Promise<void> {
    setError(null);
    setSsoLoadingProviderId(providerId);

    try {
      const result = await authClient.signIn.oauth2({
        providerId,
        callbackURL: '/chat',
        newUserCallbackURL: '/chat',
      });

      if (result.error) {
        setError(result.error.message ?? `Sign in with ${providerId} failed`);
        setSsoLoadingProviderId(null);
      }
    } catch (err: unknown) {
      setError(err instanceof Error ? err.message : `Sign in with ${providerId} failed`);
      setSsoLoadingProviderId(null);
    }
  }

  return (
    <div>
      <h1 className="text-2xl font-semibold">Sign in</h1>
      <p className="mt-1 text-sm text-text-secondary">Sign in to your Mosaic account</p>

      {error && (
        <div
          role="alert"
          className="mt-4 rounded-lg border border-error/30 bg-error/10 px-4 py-3 text-sm text-error"
        >
          {error}
        </div>
      )}

      <form className="mt-6 space-y-4" onSubmit={handleSubmit}>
        <div>
          <label htmlFor="email" className="block text-sm font-medium text-text-secondary">
            Email
          </label>
          <input
            id="email"
            name="email"
            type="email"
            autoComplete="email"
            required
            disabled={loading}
            className="mt-1 block w-full rounded-lg border border-surface-border bg-surface-elevated px-3 py-2 text-sm text-text-primary placeholder:text-text-muted focus:border-blue-500 focus:outline-none focus:ring-1 focus:ring-blue-500 disabled:opacity-50"
            placeholder="you@example.com"
          />
        </div>

        <div>
          <label htmlFor="password" className="block text-sm font-medium text-text-secondary">
            Password
          </label>
          <input
            id="password"
            name="password"
            type="password"
            autoComplete="current-password"
            required
            disabled={loading}
            className="mt-1 block w-full rounded-lg border border-surface-border bg-surface-elevated px-3 py-2 text-sm text-text-primary placeholder:text-text-muted focus:border-blue-500 focus:outline-none focus:ring-1 focus:ring-blue-500 disabled:opacity-50"
            placeholder="••••••••"
          />
        </div>

        <button
          type="submit"
          disabled={loading}
          className="w-full rounded-lg bg-blue-600 px-4 py-2.5 text-sm font-medium text-white transition-colors hover:bg-blue-700 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:ring-offset-2 focus:ring-offset-surface-card disabled:opacity-50"
        >
          {loading ? 'Signing in...' : 'Sign in'}
        </button>
      </form>

      <SsoProviderButtons
        providers={ssoProviders}
        loadingProviderId={ssoLoadingProviderId}
        onOidcSignIn={(providerId) => {
          void handleSsoSignIn(providerId);
        }}
      />

      <p className="mt-4 text-center text-sm text-text-muted">
        Don&apos;t have an account?{' '}
        <Link href="/register" className="text-blue-400 hover:text-blue-300">
          Sign up
        </Link>
      </p>
    </div>
  );
}