LibAC-dart/lib/utils/uuid/UUID.dart

import 'dart:convert';
import 'dart:math';

import 'package:crypto/crypto.dart';
import 'package:libac_flutter/nbt/Stream.dart';

class UUID {
  late final int LSB;
  late final int MSB;
  late final List<int> _bytes;

  UUID(int msb, int lsb) {
    MSB = msb;
    LSB = lsb;

    ByteLayer layer = ByteLayer();
    layer.writeLong(MSB);
    layer.writeLong(LSB);
    layer.resetPosition();

    _bytes = layer.readBytes(16);
  }

  static final UUID ZERO = UUID.generate(0);

  /// Validates whether the given [uuid] is a valid UUID.
  static bool validate(String uuid) {
    if (uuid.length == ((16 * 2) + 4)) {
      return true; // Likely is true. This is just a surface level check
    } else
      return false;
  }

  /// Parses the given [uuid] string and returns a UUID object.
  static UUID parse(String uuid) {
    if (validate(uuid)) {
      final segments = uuid.split('-');
      if (segments.length != 5) {
        throw const FormatException('Invalid UUID format');
      }

      final msbString = segments.sublist(0, 3).join('');
      final lsbString = segments.sublist(3, 5).join('');

      int msb = 0;
      int lsb = 0;

      int i = 0;
      ByteLayer layer = ByteLayer();
      for (i = 0; i < msbString.length; i += 2) {
        int byte = int.parse(msbString.substring(i, i + 1), radix: 16);
        layer.writeByte(byte);
      }

      for (i = 0; i < lsbString.length; i += 2) {
        int byte = int.parse(lsbString.substring(i, i + 1), radix: 16);
        layer.writeByte(byte);
      }

      layer.resetPosition();
      msb = layer.readLong();
      lsb = layer.readLong();

      return UUID(msb, lsb);
    } else
      return UUID.ZERO;
  }

  @override
  String toString() {
    String hexBuilder = "";
    for (int byte in _bytes) {
      hexBuilder += byte.toRadixString(16).padLeft(2, '0');
    }
    return '${hexBuilder.substring(0, 8)}-${hexBuilder.substring(8, 12)}-${hexBuilder.substring(12, 16)}-${hexBuilder.substring(16, 20)}-${hexBuilder.substring(20, 32)}';
  }

  /// Returns the Most Significant Bits (MSB) long value of the UUID.
  int getMostSignificantBits() => MSB;

  /// Returns the Least Significant Bits (LSB) long value of the UUID.
  int getLeastSignificantBits() => LSB;

  /// Factory method to generate UUID of the specific version.
  factory UUID.generate(int version, {List<Object>? parameters}) {
    List<Object> params = [];
    if (parameters == null) {
      if (version != 4) {
        return UUID.generate(4);
      }
    } else
      params = parameters!;
    switch (version) {
      case 0:
        return UUID(0, 0);
      case 3:
        {
          if (params.length != 2)
            throw Exception(
                "UUID v3 requires two parameters, [namespace,name]");
          String namespace = params[0] as String;
          String name = params[1] as String;

          ByteLayer layer = ByteLayer();

          final namespaceBytes = utf8.encode(namespace);
          layer.writeBytes(namespaceBytes);
          final nameBytes = utf8.encode(name);
          layer.writeBytes(nameBytes);

          var bytes = md5.convert(List.from(layer.bytes)).bytes;
          layer.clear();
          layer.writeBytes(bytes);

          layer.unsetSetBit(6, 0x0F, 0x30);
          layer.unsetSetBit(8, 0x3F, 0x80);

          layer.resetPosition();

          var msb = layer.readUnsignedLong();
          var lsb = layer.readUnsignedLong();

          layer.resetPosition();
          return UUID(msb, lsb);
        }
      case 4:
        {
          ByteLayer layer = ByteLayer();
          final random = Random.secure();

          layer.writeLong(
              (random.nextInt(0xFFFFFFFF) << 32) | random.nextInt(0xFFFFFFFF));
          layer.writeLong(
              (random.nextInt(0xFFFFFFFF) << 32) | random.nextInt(0xFFFFFFFF));

          layer.unsetSetBit(6, 0x0F, 0x40);
          layer.unsetSetBit(8, 0x3F, 0x80);

          layer.resetPosition();

          return UUID(layer.readUnsignedLong(), layer.readUnsignedLong());
        }
      case 5:
        {
          ByteLayer layer = ByteLayer();
          if (params.length != 2)
            throw Exception(
                "UUID v5 requires two parameters, [namespace,name]");
          String namespace = params[0] as String;
          String name = params[1] as String;

          if (!namespace.isEmpty) {
            final namespaceBytes = utf8.encode(namespace);
            layer.writeBytes(namespaceBytes);
          }

          if (!name.isEmpty) {
            final nameBytes = utf8.encode(name);
            layer.writeBytes(nameBytes);
          }

          final hashBytes = sha1.convert(List.from(layer.bytes)).bytes;
          layer.clear();
          layer.writeBytes(hashBytes);

          layer.unsetSetBit(6, 0x0F, 0x50);
          layer.unsetSetBit(8, 0x3F, 0x80);

          layer.resetPosition();

          return UUID(layer.readUnsignedLong(), layer.readUnsignedLong());
        }
      default:
        throw ArgumentError('Unsupported UUID version: $version');
    }
  }
}