e_receipt_mobile/lib/presentation/login/login_page.dart

import 'package:e_receipt_mobile/presentation/components/rounded_input.dart';
import 'package:e_receipt_mobile/presentation/home/home_screen.dart';
import 'package:e_receipt_mobile/presentation/login/login_view_model.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

class LoginPage extends ConsumerStatefulWidget {
  const LoginPage({super.key});

  @override
  ConsumerState<LoginPage> createState() => _LoginPageState();
}

class _LoginPageState extends ConsumerState<LoginPage> {
  final _formKey = GlobalKey<FormState>();
  final _usernameController = TextEditingController();
  final _passwordController = TextEditingController();

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

  @override
  Widget build(BuildContext context) {
    final state = ref.watch(loginViewModelProvider);

    ref.listen(loginViewModelProvider, (previous, next) {
      if (!mounted) {
        return;
      }

      if (next.errorMessage != null &&
          previous?.errorMessage != next.errorMessage) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text(next.errorMessage!),
            backgroundColor: Colors.red,
          ),
        );
      }

      if (next.successMessage != null &&
          previous?.successMessage != next.successMessage) {
        Navigator.of(context).pushReplacement(
          MaterialPageRoute<void>(
            builder: (_) => const HomeScreen(),
          ),
        );
      }
    });

    return Scaffold(
      backgroundColor: Colors.blue,
      body: Center(
        child: SingleChildScrollView(
          padding: const EdgeInsets.all(32),
          child: ConstrainedBox(
            constraints: const BoxConstraints(maxWidth: 420),
            child: Card(
              elevation: 8,
              shape: RoundedRectangleBorder(
                borderRadius: BorderRadius.circular(24),
              ),
              child: Padding(
                padding: const EdgeInsets.all(20),
                child: Form(
                  key: _formKey,
                  child: Column(
                    mainAxisSize: MainAxisSize.min,
                    crossAxisAlignment: CrossAxisAlignment.stretch,
                    children: [
                      Text(
                        'E-Receipt',
                        textAlign: TextAlign.center,
                        style: Theme.of(context).textTheme.headlineSmall,
                      ),
                      const SizedBox(height: 20),
                      //Username
                      roundedInput(controller: _usernameController, hint: "Username", icon: Icons.person),
                      const SizedBox(height: 12),
                      //Password
                      roundedInput(controller: _passwordController, hint: "Password", icon: Icons.lock, isPassword: true),
                      const SizedBox(height: 20),
                      FilledButton(
                        onPressed: state.isLoading
                            ? null
                            : () {
                                ref
                                    .read(loginViewModelProvider.notifier)
                                    .clearMessages();
                                if (_formKey.currentState?.validate() ??
                                    false) {
                                  ref
                                      .read(loginViewModelProvider.notifier)
                                      .login(
                                        username: _usernameController.text,
                                        password: _passwordController.text,
                                      );
                                }
                              },
                        child: state.isLoading
                            ? const SizedBox(
                                height: 20,
                                width: 20,
                                child: CircularProgressIndicator(
                                  strokeWidth: 2,
                                ),
                              )
                            : const Text('Login'),
                      ),
                    ],
                  ),
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }
}