Envelope/mobile/lib/views/authentication/login.dart

import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'package:shared_preferences/shared_preferences.dart';
import '/utils/encryption/rsa_key_helper.dart';
import '/utils/encryption/aes_helper.dart';
import '/utils/storage/encryption_keys.dart';

class LoginResponse {
    final String status;
    final String message;
    final String asymmetricPublicKey;
    final String asymmetricPrivateKey;

    const LoginResponse({
        required this.status,
        required this.message,
        required this.asymmetricPublicKey,
        required this.asymmetricPrivateKey,
    });

    factory LoginResponse.fromJson(Map<String, dynamic> json) {
        return LoginResponse(
                status: json['status'],
                message: json['message'],
                asymmetricPublicKey: json['asymmetric_public_key'],
                asymmetricPrivateKey: json['asymmetric_private_key'],
        );
    }
}

Future<LoginResponse> login(context, String username, String password) async {
    final resp = await http.post(
            Uri.parse('http://192.168.1.5:8080/api/v1/login'),
            headers: <String, String>{
                'Content-Type': 'application/json; charset=UTF-8',
            },
            body: jsonEncode(<String, String>{
                'username': username,
                'password': password,
            }),
    );
    
    LoginResponse response = LoginResponse.fromJson(jsonDecode(resp.body));

    if (resp.statusCode != 200) {
        throw Exception(response.message);
    }

    var rsaPrivPem = AesHelper.aesDecrypt(password, base64.decode(response.asymmetricPrivateKey));
    var rsaPriv = RsaKeyHelper.parsePrivateKeyFromPem(rsaPrivPem);
    setPrivateKey(rsaPriv);

    final preferences = await SharedPreferences.getInstance();
    preferences.setBool('islogin', true);

    return response;
}

class Login extends StatelessWidget {
    const Login({Key? key}) : super(key: key);

    static const String _title = 'Envelope';

    @override
    Widget build(BuildContext context) {
        return Scaffold(
                backgroundColor: Colors.cyan,
                appBar: AppBar(
                        title: null,
                        automaticallyImplyLeading: true,
                        //`true` if you want Flutter to automatically add Back Button when needed,
                        //or `false` if you want to force your own back button every where
                        leading: IconButton(icon: const Icon(Icons.arrow_back),
                                onPressed:() => {
                                    Navigator.pop(context)
                                }
                        )
                ),
                body: const SafeArea(
                        child: LoginWidget(),
                ),
        );
    }
}

class LoginWidget extends StatefulWidget {
    const LoginWidget({Key? key}) : super(key: key);

    @override
    State<LoginWidget> createState() => _LoginWidgetState();
}

class _LoginWidgetState extends State<LoginWidget> {
    final _formKey = GlobalKey<FormState>();

    TextEditingController usernameController = TextEditingController();
    TextEditingController passwordController = TextEditingController();

    @override
    Widget build(BuildContext context) {
        const TextStyle _inputTextStyle = TextStyle(fontSize: 18, color: Colors.black);

        final ButtonStyle _buttonStyle = ElevatedButton.styleFrom(
                primary: Colors.white,
                onPrimary: Colors.cyan,
                minimumSize: const Size.fromHeight(50),
                padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 10),
                textStyle: const TextStyle(
                        fontSize: 20, 
                        fontWeight: FontWeight.bold,
                        color: Colors.red,
                        ),
        );

        return Center(
                child: Form(
                        key: _formKey,
                        child: Center(
                                child: Padding(
                                        padding: const EdgeInsets.all(15),
                                        child: Column(
                                                mainAxisAlignment: MainAxisAlignment.center,
                                                crossAxisAlignment: CrossAxisAlignment.center,
                                                children: [
                                                    const Text('Login', style: TextStyle(fontSize: 35, color: Colors.white),),
                                                    const SizedBox(height: 30),
                                                    TextFormField(
                                                            controller: usernameController,
                                                            decoration: const InputDecoration(
                                                                    hintText: 'Username',
                                                            ),
                                                            style: _inputTextStyle,
                                                            // The validator receives the text that the user has entered.
                                                            validator: (value) {
                                                                if (value == null || value.isEmpty) {
                                                                    return 'Create a username';
                                                                }
                                                                return null;
                                                            },
                                                    ),
                                                    const SizedBox(height: 5),
                                                    TextFormField(
                                                            controller: passwordController,
                                                            obscureText: true,
                                                            enableSuggestions: false,
                                                            autocorrect: false,
                                                            decoration: const InputDecoration(
                                                                    hintText: 'Password',
                                                            ),
                                                            style: _inputTextStyle,
                                                            // The validator receives the text that the user has entered.
                                                            validator: (value) {
                                                                if (value == null || value.isEmpty) {
                                                                    return 'Enter a password';
                                                                }
                                                                return null;
                                                            },
                                                    ),
                                                    const SizedBox(height: 5),
                                                    ElevatedButton(
                                                            style: _buttonStyle,
                                                            onPressed: () {
                                                                if (_formKey.currentState!.validate()) {
                                                                    ScaffoldMessenger.of(context).showSnackBar(
                                                                            const SnackBar(content: Text('Processing Data')),
                                                                    );

                                                                    login(
                                                                            context,
                                                                            usernameController.text,
                                                                            passwordController.text,
                                                                    ).then((value) {
                                                                        /*
                                                                        Navigator.of(context).popUntil((route) {
                                                                            print(route.isFirst);
                                                                            return route.isFirst;
                                                                        });
                                                                        */

                                                                        Navigator.pushNamedAndRemoveUntil(context, '/home', ModalRoute.withName('/home'));
                                                                    }).catchError((error) {
                                                                        print(error); // TODO: Show error on interface
                                                                    });
                                                                }
                                                            },
                                                            child: const Text('Submit'),
                                                    ),
                                                ],
                                        )
                                )
                        )

                )
        );
    }
}