import "dart:typed_data";
import 'dart:convert';
import 'package:convert/convert.dart' as convert;

Uint8List createUint8ListFromString(String s) {
  var ret = new Uint8List(s.length);
  for (var i = 0; i < s.length; i++) {
    ret[i] = s.codeUnitAt(i);
  }
  return ret;
}

Uint8List createUint8ListFromHexString(String hex) {
  var result = new Uint8List(hex.length ~/ 2);
  for (var i = 0; i < hex.length; i += 2) {
    var num = hex.substring(i, i + 2);
    var byte = int.parse(num, radix: 16);
    result[i ~/ 2] = byte;
  }
  return result;
}

Uint8List createUint8ListFromSequentialNumbers(int len) {
  var ret = new Uint8List(len);
  for (var i = 0; i < len; i++) {
    ret[i] = i;
  }
  return ret;
}

String formatBytesAsHexString(Uint8List bytes) {
  var result = new StringBuffer();
  for (var i = 0; i < bytes.lengthInBytes; i++) {
    var part = bytes[i];
    result.write('${part < 16 ? '0' : ''}${part.toRadixString(16)}');
  }
  return result.toString();
}

List<int> decodePEM(String pem) {
  var startsWith = [
    "-----BEGIN PUBLIC KEY-----",
    "-----BEGIN PRIVATE KEY-----",
    "-----BEGIN ENCRYPTED MESSAGE-----",
    "-----BEGIN PGP PUBLIC KEY BLOCK-----\r\nVersion: React-Native-OpenPGP.js 0.1\r\nComment: http://openpgpjs.org\r\n\r\n",
    "-----BEGIN PGP PRIVATE KEY BLOCK-----\r\nVersion: React-Native-OpenPGP.js 0.1\r\nComment: http://openpgpjs.org\r\n\r\n",
  ];
  var endsWith = [
    "-----END PUBLIC KEY-----",
    "-----END PRIVATE KEY-----",
    "-----END ENCRYPTED MESSAGE-----",
    "-----END PGP PUBLIC KEY BLOCK-----",
    "-----END PGP PRIVATE KEY BLOCK-----",
  ];
  bool isOpenPgp = pem.indexOf('BEGIN PGP') != -1;

  for (var s in startsWith) {
    if (pem.startsWith(s)) {
      pem = pem.substring(s.length);
    }
  }

  for (var s in endsWith) {
    if (pem.endsWith(s)) {
      pem = pem.substring(0, pem.length - s.length);
    }
  }

  if (isOpenPgp) {
    var index = pem.indexOf('\r\n');
    pem = pem.substring(0, index);
  }

  pem = pem.replaceAll('\n', '');
  pem = pem.replaceAll('\r', '');

  return base64.decode(pem);
}

List<int> decodeHex(String hex) {
  hex = hex
      .replaceAll(':', '')
      .replaceAll('\n', '')
      .replaceAll('\r', '')
      .replaceAll('\t', '');

  return convert.hex.decode(hex);
}