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

import 'dart:convert';
import 'dart:typed_data';

import 'package:flutter/material.dart';
import 'package:flutter_dotenv/flutter_dotenv.dart';
import 'package:http/http.dart' as http;

import '/utils/encryption/aes_helper.dart';
import '/utils/encryption/crypto_utils.dart';

Future<SignupResponse> signUp(context, String username, String password, String confirmPassword) async {
  var keyPair = CryptoUtils.generateRSAKeyPair();

  var rsaPubPem = CryptoUtils.encodeRSAPublicKeyToPem(keyPair.publicKey);
  var rsaPrivPem = CryptoUtils.encodeRSAPrivateKeyToPem(keyPair.privateKey);

  String encRsaPriv = AesHelper.aesEncrypt(password, Uint8List.fromList(rsaPrivPem.codeUnits));

  // TODO: Check for timeout here
  final resp = await http.post(
      Uri.parse('${dotenv.env["SERVER_URL"]}api/v1/signup'),
      headers: <String, String>{
        'Content-Type': 'application/json; charset=UTF-8',
      },
      body: jsonEncode(<String, String>{
        'username': username,
        'password': password,
        'confirm_password': confirmPassword,
        'asymmetric_public_key': rsaPubPem,
        'asymmetric_private_key': encRsaPriv,
      }),
  );

  SignupResponse response = SignupResponse.fromJson(jsonDecode(resp.body));

  if (resp.statusCode != 201) {
    throw Exception(response.message);
  }

  return response;
}

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        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)
                }
            ),
            backgroundColor: Colors.transparent,
            shadowColor: Colors.transparent,
        ),
        body: const SafeArea(
            child: SignupWidget(),
        )
    );
  }
}

class SignupResponse {
  final String status;
  final String message;

  const SignupResponse({
    required this.status,
    required this.message,
  });

  factory SignupResponse.fromJson(Map<String, dynamic> json) {
    return SignupResponse(
        status: json['status'],
        message: json['message'],
    );
  }
}

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

  @override
  State<SignupWidget> createState() => _SignupWidgetState();
}

class _SignupWidgetState extends State<SignupWidget> {
  final _formKey = GlobalKey<FormState>();

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

  @override
  Widget build(BuildContext context) {
    const TextStyle inputTextStyle = TextStyle(
        fontSize: 18,
    );

    final OutlineInputBorder inputBorderStyle = OutlineInputBorder(
        borderRadius: BorderRadius.circular(5),
        borderSide: const BorderSide(
            color: Colors.transparent,
        )
    );

    final ButtonStyle buttonStyle = ElevatedButton.styleFrom(
        primary: Theme.of(context).colorScheme.surface,
        onPrimary: Theme.of(context).colorScheme.onSurface,
        minimumSize: const Size.fromHeight(50),
        padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 10),
        textStyle: TextStyle(
            fontSize: 20,
            fontWeight: FontWeight.bold,
            color: Theme.of(context).colorScheme.error,
        ),
    );

    return Center(
        child: Form(
            key: _formKey,
            child: Center(
                child: Padding(
                    padding: const EdgeInsets.only(
                        left: 20,
                        right: 20,
                        top: 0,
                        bottom: 100,
                    ),
                    child: Column(
                        mainAxisAlignment: MainAxisAlignment.center,
                        crossAxisAlignment: CrossAxisAlignment.center,
                        children: [
                          Text(
                              'Sign Up',
                              style: TextStyle(
                                  fontSize: 35,
                                  color: Theme.of(context).colorScheme.onBackground,
                              ),
                          ),
                          const SizedBox(height: 30),
                          TextFormField(
                              controller: usernameController,
                              decoration: InputDecoration(
                                  hintText: 'Username',
                                  enabledBorder: inputBorderStyle,
                                  focusedBorder: inputBorderStyle,
                              ),
                              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: 10),
                          TextFormField(
                              controller: passwordController,
                              obscureText: true,
                              enableSuggestions: false,
                              autocorrect: false,
                              decoration: InputDecoration(
                                  hintText: 'Password',
                                  enabledBorder: inputBorderStyle,
                                  focusedBorder: inputBorderStyle,
                              ),
                              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: 10),
                          TextFormField(
                              controller: passwordConfirmController,
                              obscureText: true,
                              enableSuggestions: false,
                              autocorrect: false,
                              decoration: InputDecoration(
                                  hintText: 'Password',
                                  enabledBorder: inputBorderStyle,
                                  focusedBorder: inputBorderStyle,
                              ),
                              style: inputTextStyle,
                              // The validator receives the text that the user has entered.
                              validator: (value) {
                                if (value == null || value.isEmpty) {
                                  return 'Confirm your password';
                                }
                                if (value != passwordController.text) {
                                  return 'Passwords do not match';
                                }
                                return null;
                              },
                          ),
                          const SizedBox(height: 15),
                          ElevatedButton(
                              style: buttonStyle,
                              onPressed: () {
                                if (_formKey.currentState!.validate()) {
                                  ScaffoldMessenger.of(context).showSnackBar(
                                      const SnackBar(content: Text('Processing Data')),
                                  );

                                  signUp(
                                      context,
                                      usernameController.text,
                                      passwordController.text,
                                      passwordConfirmController.text
                                  ).then((value) {
                                    Navigator.of(context).popUntil((route) => route.isFirst);
                                  }).catchError((error) {
                                    print(error); // TODO: Show error on interface
                                  });
                                }
                              },
                              child: const Text('Submit'),
                          ),
                      ],
                  )
              )
          )
      )
    );
  }
}