comunicmobile/lib/ui/routes/login_route.dart

import 'package:comunic/helpers/account_helper.dart';
import 'package:comunic/models/authentication_details.dart';
import 'package:comunic/ui/routes/home_route.dart';
import 'package:comunic/utils/input_utils.dart';
import 'package:comunic/utils/intl_utils.dart';
import 'package:comunic/utils/ui_utils.dart';
import 'package:flutter/material.dart';

/// Login route
///
/// @author Pierre HUBERT

class LoginRoute extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _LoginRouteState();
}

class _LoginRouteState extends State<LoginRoute> {
  String _currEmail;
  String _currPassword;
  AuthResult _authResult;
  bool _loading = false;

  @override
  void initState() {
    super.initState();
    _currEmail = "";
    _currPassword = "";
  }

  void _emailChanged(String newEmail) {
    setState(() {
      _currEmail = newEmail;
    });
  }

  void _passwordChanged(String newValue) {
    setState(() {
      _currPassword = newValue;
    });
  }

  /// Call this whenever the user request to perform login
  Future<void> _submitForm(BuildContext context) async {
    setState(() {
      _loading = true;
    });

    final loginResult = await AccountHelper().signIn(
        AuthenticationDetails(email: _currEmail, password: _currPassword));

    if (loginResult == AuthResult.SUCCESS)
      Navigator.pushReplacement(
          context, MaterialPageRoute(builder: (b) => HomeRoute()));
    else
      setState(() {
        _authResult = loginResult;
        _loading = false;
      });
  }

  // Build error card
  Widget _buildErrorCard() {
    if (_authResult == null) return null;

    //Determine the right message
    final message = (_authResult == AuthResult.INVALID_CREDENTIALS
        ? tr("Invalid credentials!")
        : (_authResult == AuthResult.TOO_MANY_ATTEMPTS
            ? tr(
                "Too many unsuccessfull login attempts! Please try again later...")
            : tr("A network error occured!")));

    return buildErrorCard(message);
  }

  /// Build login form
  Widget _buildLoginForm() {
    // Whether the form can be submitted or not
    final valid = validateEmail(_currEmail) && _currPassword.length >= 3;

    return SingleChildScrollView(
      child: Padding(
        padding: const EdgeInsets.all(8.0),
        child: Column(
          children: <Widget>[
            Text(tr("Please sign into your Comunic account: ")),
            Container(
              child: _buildErrorCard(),
            ),
            //Email address
            TextField(
              keyboardType: TextInputType.emailAddress,
              decoration: InputDecoration(
                  labelText: tr("Email address"),
                  alignLabelWithHint: true,
                  errorText: _currEmail.length > 0 && !validateEmail(_currEmail)
                      ? tr("Invalid email address!")
                      : null),
              onChanged: _emailChanged,
            ),

            //Password
            TextField(
              obscureText: true,
              decoration: InputDecoration(
                labelText: tr("Password"),
                alignLabelWithHint: true,
              ),
              onChanged: _passwordChanged,
              onSubmitted: valid ? (s) => _submitForm(context) : null,
            ),

            Container(
              padding: EdgeInsets.all(8.0),
              child: _loading
                  ? CircularProgressIndicator()
                  : RaisedButton(
                      child: Text(tr("Sign in")),
                      onPressed: valid ? () => _submitForm(context) : null,
                    ),
            )
          ],
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text("Comunic"),
        ),
        body: _buildLoginForm());
  }
}