import 'dart:typed_data';
import 'dart:math';

class AES {
  final Uint8List _aesKey;

  AES._(this._aesKey);

  static Future<AES> generate({int aesKeySize = 256}) async {
    final random = Random.secure();

    // Generate AES Key
    final aesKey = Uint8List(aesKeySize ~/ 8);
    for (int i = 0; i < aesKey.length; i++) {
      aesKey[i] = random.nextInt(256);
    }

    return AES._(aesKey);
  }

  static AES useKey(Uint8List key) {
    AES aes = AES._(key);

    return aes;
  }

  Uint8List getKey() {
    return Uint8List.fromList(_aesKey);
  }

  Uint8List encrypt(Uint8List data) {
    return _aesEncrypt(data, _aesKey);
  }

  Uint8List decrypt(Uint8List encryptedData) {
    return _aesDecrypt(encryptedData, _aesKey);
  }

  static Uint8List _aesEncrypt(Uint8List data, Uint8List key) {
    final blockSize = 16;
    final paddedData = _pad(data, blockSize);
    final encrypted = Uint8List(paddedData.length);

    for (int i = 0; i < paddedData.length; i += blockSize) {
      for (int j = 0; j < blockSize; j++) {
        encrypted[i + j] = paddedData[i + j] ^ key[j % key.length];
      }
    }

    return encrypted;
  }

  static Uint8List _aesDecrypt(Uint8List data, Uint8List key) {
    final blockSize = 16;
    final decrypted = Uint8List(data.length);

    for (int i = 0; i < data.length; i += blockSize) {
      for (int j = 0; j < blockSize; j++) {
        decrypted[i + j] = data[i + j] ^ key[j % key.length];
      }
    }

    return _unpad(decrypted);
  }

  static Uint8List _pad(Uint8List data, int blockSize) {
    final padLength = blockSize - (data.length % blockSize);
    final paddedData = Uint8List(data.length + padLength);
    paddedData.setAll(0, data);
    for (int i = data.length; i < paddedData.length; i++) {
      paddedData[i] = padLength;
    }
    return paddedData;
  }

  static Uint8List _unpad(Uint8List data) {
    final padLength = data[data.length - 1];
    return Uint8List.sublistView(data, 0, data.length - padLength);
  }
}