Envelope/mobile/lib/database/models/friends.dart

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

import 'package:pointycastle/export.dart';

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

// TODO: Find good place for this to live
Friend findFriendByFriendId(List<Friend> friends, String id) {
  for (var friend in friends) {
    if (friend.friendId == id) {
      return friend;
    }
  }
  // Or return `null`.
  throw ArgumentError.value(id, 'id', 'No element with that id');
}


class Friend {
  String id;
  String userId;
  String username;
  String friendId;
  String friendSymmetricKey;
  RSAPublicKey publicKey;
  DateTime? acceptedAt;
  bool? selected;
  Friend({
    required this.id,
    required this.userId,
    required this.username,
    required this.friendId,
    required this.friendSymmetricKey,
    required this.publicKey,
    required this.acceptedAt,
    this.selected,
  });

  factory Friend.fromJson(Map<String, dynamic> json, RSAPrivateKey privKey) {
    Uint8List idDecrypted = CryptoUtils.rsaDecrypt(
        base64.decode(json['friend_id']),
        privKey,
    );

    Uint8List username = CryptoUtils.rsaDecrypt(
        base64.decode(json['friend_username']),
        privKey,
    );

    Uint8List symmetricKeyDecrypted = CryptoUtils.rsaDecrypt(
        base64.decode(json['symmetric_key']),
        privKey,
    );

    String publicKeyString = AesHelper.aesDecrypt(
      symmetricKeyDecrypted,
      base64.decode(json['asymmetric_public_key'])
    );

    RSAPublicKey publicKey = CryptoUtils.rsaPublicKeyFromPem(publicKeyString);

    return Friend(
        id: json['id'],
        userId: json['user_id'],
        username: String.fromCharCodes(username),
        friendId: String.fromCharCodes(idDecrypted),
        friendSymmetricKey: base64.encode(symmetricKeyDecrypted),
        publicKey: publicKey,
        acceptedAt: json['accepted_at']['Valid'] ?
          DateTime.parse(json['accepted_at']['Time']) :
          null,
    );
  }

  Map<String, dynamic> payloadJson() {

    Uint8List friendIdEncrypted = CryptoUtils.rsaEncrypt(
      Uint8List.fromList(friendId.codeUnits),
      publicKey,
    );

    Uint8List usernameEncrypted = CryptoUtils.rsaEncrypt(
      Uint8List.fromList(username.codeUnits),
      publicKey,
    );

    Uint8List symmetricKeyEncrypted = CryptoUtils.rsaEncrypt(
      Uint8List.fromList(
        base64.decode(friendSymmetricKey),
      ),
      publicKey,
    );

    var publicKeyEncrypted = AesHelper.aesEncrypt(
      base64.decode(friendSymmetricKey),
      Uint8List.fromList(CryptoUtils.encodeRSAPublicKeyToPem(publicKey).codeUnits),
    );

    return {
      'id': id,
      'user_id': userId,
      'friend_id': base64.encode(friendIdEncrypted),
      'friend_username': base64.encode(usernameEncrypted),
      'symmetric_key': base64.encode(symmetricKeyEncrypted),
      'asymmetric_public_key': publicKeyEncrypted,
      'accepted_at': null,
    };
  }

  String publicKeyPem() {
    return CryptoUtils.encodeRSAPublicKeyToPem(publicKey);
  }

  Map<String, dynamic> toMap() {
    return {
      'id': id,
      'user_id': userId,
      'username': username,
      'friend_id': friendId,
      'symmetric_key': base64.encode(friendSymmetricKey.codeUnits),
      'asymmetric_public_key': publicKeyPem(),
      'accepted_at': acceptedAt?.toIso8601String(),
    };
  }

  @override
  String toString() {
    return '''


        id: $id
        userId: $userId
        username: $username
        friendId: $friendId
        accepted_at: $acceptedAt''';
  }
}