Login Screen

import 'package:flutter/material.dart';

class LoginHero extends StatefulWidget {
  /// Called with the trimmed email and the password once both validate.
  final void Function(String email, String password)? onSignIn;

  /// Called by 'Forgot password?'.
  final VoidCallback? onForgotPassword;

  /// Called by 'Sign up'.
  final VoidCallback? onSignUp;

  /// Each callback is optional. Without one, the demo shows a SnackBar.
  const LoginHero({
    super.key,
    this.onSignIn,
    this.onForgotPassword,
    this.onSignUp,
  });

  @override
  State<LoginHero> createState() => _LoginHeroState();
}

class _LoginHeroState extends State<LoginHero> {
  final _formKey = GlobalKey<FormState>();
  final _emailController = TextEditingController();
  final _passwordController = TextEditingController();
  bool _remember = true;
  bool _obscure = true;

  @override
  void dispose() {
    _emailController.dispose();
    _passwordController.dispose();
    super.dispose();
  }

  void _showMessage(String message) {
    ScaffoldMessenger.of(context)
      ..hideCurrentSnackBar()
      ..showSnackBar(SnackBar(content: Text(message)));
  }

  String? _validateEmail(String? value) {
    final email = value?.trim() ?? '';
    if (email.isEmpty) return 'Enter your email';
    final valid = RegExp(r'^[^@\s]+@[^@\s]+\.[^@\s]+$').hasMatch(email);
    return valid ? null : 'Enter a valid email';
  }

  String? _validatePassword(String? value) =>
      (value ?? '').isEmpty ? 'Enter your password' : null;

  void _signIn() {
    if (!_formKey.currentState!.validate()) return;
    final email = _emailController.text.trim();
    final onSignIn = widget.onSignIn;
    if (onSignIn != null) {
      onSignIn(email, _passwordController.text);
    } else {
      _showMessage('Signing in as $email (demo)');
    }
  }

  void _forgotPassword() {
    final onForgotPassword = widget.onForgotPassword;
    if (onForgotPassword != null) {
      onForgotPassword();
    } else {
      _showMessage('Password reset goes here (demo)');
    }
  }

  void _signUp() {
    final onSignUp = widget.onSignUp;
    if (onSignUp != null) {
      onSignUp();
    } else {
      _showMessage('Sign up goes here (demo)');
    }
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final scheme = theme.colorScheme;

    return Scaffold(
      body: SafeArea(
        child: Form(
          key: _formKey,
          child: ListView(
            padding: const EdgeInsets.symmetric(horizontal: 24),
            children: [
              const SizedBox(height: 24),
              Center(
                child: Container(
                  height: 160,
                  width: double.infinity,
                  decoration: BoxDecoration(
                    color: scheme.primaryContainer,
                    borderRadius: BorderRadius.circular(24),
                  ),
                  child: Icon(
                    Icons.lock_person_rounded,
                    size: 72,
                    color: scheme.onPrimaryContainer,
                  ),
                ),
              ),
              const SizedBox(height: 28),
              Text(
                'Welcome back',
                style: theme.textTheme.headlineSmall?.copyWith(
                  fontWeight: FontWeight.bold,
                ),
              ),
              const SizedBox(height: 4),
              Text(
                'Sign in to continue to your account',
                style: theme.textTheme.bodyMedium?.copyWith(
                  color: scheme.onSurfaceVariant,
                ),
              ),
              const SizedBox(height: 24),
              TextFormField(
                controller: _emailController,
                validator: _validateEmail,
                keyboardType: TextInputType.emailAddress,
                autofillHints: const [AutofillHints.email],
                textInputAction: TextInputAction.next,
                decoration: const InputDecoration(
                  labelText: 'Email',
                  prefixIcon: Icon(Icons.mail_outline),
                  border: OutlineInputBorder(),
                ),
              ),
              const SizedBox(height: 16),
              TextFormField(
                controller: _passwordController,
                validator: _validatePassword,
                obscureText: _obscure,
                autofillHints: const [AutofillHints.password],
                onFieldSubmitted: (_) => _signIn(),
                decoration: InputDecoration(
                  labelText: 'Password',
                  prefixIcon: const Icon(Icons.lock_outline),
                  border: const OutlineInputBorder(),
                  suffixIcon: IconButton(
                    tooltip: _obscure ? 'Show password' : 'Hide password',
                    icon: Icon(
                      _obscure ? Icons.visibility_off : Icons.visibility,
                    ),
                    onPressed: () => setState(() => _obscure = !_obscure),
                  ),
                ),
              ),
              // Wrap, so the two drop onto separate lines at large text sizes.
              Wrap(
                alignment: WrapAlignment.spaceBetween,
                crossAxisAlignment: WrapCrossAlignment.center,
                children: [
                  Row(
                    mainAxisSize: MainAxisSize.min,
                    children: [
                      Checkbox(
                        value: _remember,
                        onChanged: (v) =>
                            setState(() => _remember = v ?? false),
                      ),
                      const Text('Remember me'),
                    ],
                  ),
                  TextButton(
                    onPressed: _forgotPassword,
                    child: const Text('Forgot password?'),
                  ),
                ],
              ),
              const SizedBox(height: 8),
              SizedBox(
                height: 52,
                child: FilledButton(
                  onPressed: _signIn,
                  child: const Text('Sign in'),
                ),
              ),
              const SizedBox(height: 16),
              Wrap(
                alignment: WrapAlignment.center,
                crossAxisAlignment: WrapCrossAlignment.center,
                children: [
                  Text(
                    "Don't have an account?",
                    style: TextStyle(color: scheme.onSurfaceVariant),
                  ),
                  TextButton(onPressed: _signUp, child: const Text('Sign up')),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }
}