Envelope/mobile/lib/models/messages.dart

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

import 'package:pointycastle/export.dart';

import '/models/conversation_users.dart';
import '/models/conversations.dart';
import '/models/my_profile.dart';
import '/models/friends.dart';
import '/utils/encryption/aes_helper.dart';
import '/utils/encryption/crypto_utils.dart';
import '/utils/storage/database.dart';
import '/utils/strings.dart';

const messageTypeReceiver = 'receiver';
const messageTypeSender = 'sender';

Future<List<Message>> getMessagesForThread(Conversation conversation) async {
  final db = await getDatabaseConnection();

  final List<Map<String, dynamic>> maps = await db.rawQuery(
    '''
    SELECT * FROM messages WHERE association_key IN (
      SELECT association_key FROM conversation_users WHERE conversation_id = ?
    )
    ORDER BY created_at DESC;
    ''',
    [conversation.id]
  );

  return List.generate(maps.length, (i) {
    return Message(
      id: maps[i]['id'],
      symmetricKey: maps[i]['symmetric_key'],
      userSymmetricKey: maps[i]['user_symmetric_key'],
      data: maps[i]['data'],
      senderId: maps[i]['sender_id'],
      senderUsername: maps[i]['sender_username'],
      associationKey: maps[i]['association_key'],
      createdAt: maps[i]['created_at'],
      failedToSend: maps[i]['failed_to_send'] == 1,
    );
  });

}

class Message {
  String id;
  String symmetricKey;
  String userSymmetricKey;
  String data;
  String senderId;
  String senderUsername;
  String associationKey;
  String createdAt;
  bool failedToSend;
  Message({
    required this.id,
    required this.symmetricKey,
    required this.userSymmetricKey,
    required this.data,
    required this.senderId,
    required this.senderUsername,
    required this.associationKey,
    required this.createdAt,
    required this.failedToSend,
  });


  factory Message.fromJson(Map<String, dynamic> json, RSAPrivateKey privKey) {
    var userSymmetricKey = CryptoUtils.rsaDecrypt(
      base64.decode(json['symmetric_key']),
      privKey,
    );

    var symmetricKey = AesHelper.aesDecrypt(
      userSymmetricKey,
      base64.decode(json['message_data']['symmetric_key']),
    );

    var senderId = AesHelper.aesDecrypt(
      base64.decode(symmetricKey),
      base64.decode(json['message_data']['sender_id']),
    );

    var data = AesHelper.aesDecrypt(
      base64.decode(symmetricKey),
      base64.decode(json['message_data']['data']),
    );

    return Message(
      id: json['id'],
      symmetricKey: symmetricKey,
      userSymmetricKey: base64.encode(userSymmetricKey),
      data: data,
      senderId: senderId,
      senderUsername: 'Unknown',
      associationKey: json['association_key'],
      createdAt: json['created_at'],
      failedToSend: false,
    );
  }

  Future<String> toJson(Conversation conversation, String messageDataId) async {
    MyProfile profile = await MyProfile.getProfile();
    if (profile.publicKey == null) {
      throw Exception('Could not get profile.publicKey');
    }
    RSAPublicKey publicKey = profile.publicKey!;

    final userSymmetricKey = AesHelper.deriveKey(generateRandomString(32));
    final symmetricKey = AesHelper.deriveKey(generateRandomString(32));

    List<Map<String, String>> messages = [];

    String id = '';

    List<ConversationUser> conversationUsers = await getConversationUsers(conversation);

    for (var i = 0; i < conversationUsers.length; i++) {
      ConversationUser user = conversationUsers[i];

      if (profile.id == user.userId) {
        id = user.id;

        messages.add({
          'message_data_id': messageDataId,
          'symmetric_key': base64.encode(CryptoUtils.rsaEncrypt(
            userSymmetricKey,
            publicKey,
          )),
          'association_key': user.associationKey,
        });

        continue;
      }

      Friend friend = await getFriendByFriendId(user.userId);
      RSAPublicKey friendPublicKey = CryptoUtils.rsaPublicKeyFromPem(friend.asymmetricPublicKey);

      messages.add({
        'message_data_id': messageDataId,
        'symmetric_key': base64.encode(CryptoUtils.rsaEncrypt(
          userSymmetricKey,
          friendPublicKey,
        )),
        'association_key': user.associationKey,
      });
    }

    Map<String, String> messageData = {
      'id': messageDataId,
      'data': AesHelper.aesEncrypt(symmetricKey, Uint8List.fromList(data.codeUnits)),
      'sender_id': AesHelper.aesEncrypt(symmetricKey, Uint8List.fromList(senderId.codeUnits)),
      'symmetric_key': AesHelper.aesEncrypt(
        userSymmetricKey,
        Uint8List.fromList(base64.encode(symmetricKey).codeUnits),
      ),
    };

    return jsonEncode(<String, dynamic>{
      'message_data': messageData,
      'message': messages,
    });
  }

  Map<String, dynamic> toMap() {
    return {
      'id': id,
      'symmetric_key': symmetricKey,
      'user_symmetric_key': userSymmetricKey,
      'data': data,
      'sender_id': senderId,
      'sender_username': senderUsername,
      'association_key': associationKey,
      'created_at': createdAt,
      'failed_to_send': failedToSend ? 1 : 0,
    };
  }

  @override
  String toString() {
    return '''


      id: $id
      data: $data
      senderId: $senderId
      senderUsername: $senderUsername
      associationKey: $associationKey
      createdAt: $createdAt
      ''';
  }

}