authentication.dart

import 'package:flutter/material.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:firebase_database/firebase_database.dart';
import 'package:bencana/main.dart';

class AuthenticationPage extends StatefulWidget {
  @override
  _AuthenticationPageState createState() => _AuthenticationPageState();
}

enum FormType { signIn, signUp }
enum AuthStatus { signIn, notSignIn }

final userRef = FirebaseDatabase.instance.reference().child('user');

class _AuthenticationPageState extends State<AuthenticationPage> {
  AuthStatus _authStatus = AuthStatus.notSignIn;

  final formKey = GlobalKey<FormState>();
  FormType _formType = FormType.signIn;

  String _email;
  String _password;
  String _fullName;

  bool validateAndSave() {
    final form = formKey.currentState;
    form.save();
    if (form.validate()) {
      print('Form is valid. Email: $_email, Password: $_password');
      return true;
    } else {
      print('Form is invalid. Email: $_email, Password: $_password');
      return false;
    }
  }

  void validateAndSubmit() async {
    if (validateAndSave()) {
      try {
        if (_formType == FormType.signIn) {
          formKey.currentState.reset();
          // Buat proses sign in
          FirebaseUser user = await FirebaseAuth.instance
              .signInWithEmailAndPassword(email: _email, password: _password);
          print('user: ${user.uid}');
          this.setState(() {
            _authStatus = AuthStatus.signIn;
          });
        } else {
          formKey.currentState.reset();
          // Buat proses sign up
          FirebaseUser user = await FirebaseAuth.instance
              .createUserWithEmailAndPassword(
                  email: _email, password: _password);
          print('user: ${user.uid}');
          userRef
              .child(user.uid)
              .set({'fullName': _fullName, 'email': _email}).then((_) {
            this.setState(() {
              _authStatus = AuthStatus.signIn;
            });
          });
        }
      } catch (e) {
        print('Error: $e');
      }
    }
  }

  void moveToSignIn() {
    setState(() {
      _formType = FormType.signIn;
    });
  }

  void moveToSignUp() {
    setState(() {
      _formType = FormType.signUp;
    });
  }

  List<Widget> buildInputs() {
    if (_formType == FormType.signIn) {
      return [
        SizedBox(
          height: 80.0,
        ),
        Container(
          width: 150,
          height: 150,
          decoration: BoxDecoration(
            color: Colors.teal[200],
            shape: BoxShape.circle,
            image: DecorationImage(
                fit: BoxFit.fill,
                image: AssetImage('images/bencana_logo.png'))
          ),
        ),

        SizedBox(
          height: 20.0,
        ),
        TextFormField(
          decoration: InputDecoration(labelText: 'Email'),
          keyboardType: TextInputType.emailAddress,
          validator: (value) => value.isEmpty ? 'Email can\'t be empty' : null,
          onSaved: (value) => _email = value,
        ),
        TextFormField(
          decoration: InputDecoration(
            labelText: 'Password',
          ),
          obscureText: true,
          validator: (value) => value.length < 6 ? 'Minimum 6 character' : null,
          onSaved: (value) => _password = value,
        ),
      ];
    } else {
      return [
        SizedBox(
          height: 80.0,
        ),
        Container(
          child: Image.asset('images/bencana_logo.png'),
          width: 200.0,
          height: 200.0,
          color: Colors.white,
        ),
        SizedBox(
          height: 20.0,
        ),
        TextFormField(
          decoration: InputDecoration(labelText: 'Email'),
          keyboardType: TextInputType.emailAddress,
          validator: (value) => value.isEmpty ? 'Email can\'t be empty' : null,
          onSaved: (value) => _email = value,
        ),
        TextFormField(
          decoration: InputDecoration(
            labelText: 'Password',
          ),
          obscureText: true,
          validator: (value) => value.length < 6 ? 'Minimum 6 character' : null,
          onSaved: (value) => _password = value,
        ),
        TextFormField(
          decoration: InputDecoration(labelText: 'Full Name'),
          validator: (value) =>
              value.isEmpty ? 'Full name can\'t be empty' : null,
          onSaved: (value) => _fullName = value,
        ),
      ];
    }
  }

  List<Widget> buildButtons() {
    if (_formType == FormType.signIn) {
      return [
        SizedBox(
          height: 10,
        ),
        RaisedButton(
          child: Text('Sign In'),
          color: Colors.teal,
          textColor: Colors.white,
          onPressed: validateAndSubmit,
        ),
        FlatButton(
          onPressed: moveToSignUp,
          child: Text('Create a new account'),
          textColor: Colors.teal,
        ),
      ];
    } else {
      return [
        SizedBox(
          height: 10,
        ),
        RaisedButton(
          child: Text('Sign Up'),
          color: Colors.teal,
          textColor: Colors.white,
          onPressed: validateAndSubmit,
        ),
        FlatButton(
          onPressed: moveToSignIn,
          child: Text('Already have account? Sign in!'),
          textColor: Colors.teal,
        ),
      ];
    }
  }

  @override
  Widget build(BuildContext context) {
    switch (_authStatus) {
      case AuthStatus.signIn:
        return DashboardScreen();
      case AuthStatus.notSignIn:
        return Scaffold(
          body: Container(
            child: Padding(
              padding: EdgeInsets.all(16.0),
              child: Form(
                key: formKey,
                child: ListView(
                  children: <Widget>[
                    Column(
                      children: buildInputs() + buildButtons(),
                    ),
                  ],
                ),
              ),
            ),
          ),
        );
    }
  }
}