using System;
using System.Security.Cryptography;
using System.Text;

namespace MarketData.Security
{
  public class Encryption
  {
    public static string HashPassword(string password)
    {
      using (SHA256 sha256 = SHA256.Create())
      {
        byte[] bytes = Encoding.UTF8.GetBytes(password);
        byte[] hashBytes = sha256.ComputeHash(bytes);
        return Convert.ToBase64String(hashBytes);
      }
    }

    // public static (string Salt, string Hash) HashPasswordWithSalt(string password)
    // {
    //   using (RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider())
    //   {
    //     byte[] salt = new byte[16];
    //     rng.GetBytes(salt);
    //     using (SHA256 sha256 = SHA256.Create())
    //     {
    //       byte[] passwordBytes = Encoding.UTF8.GetBytes(password);
    //       byte[] saltedPassword = new byte[passwordBytes.Length + salt.Length];
    //       Buffer.BlockCopy(passwordBytes, 0, saltedPassword, 0, passwordBytes.Length);
    //       Buffer.BlockCopy(salt, 0, saltedPassword, passwordBytes.Length, salt.Length);
    //       byte[] hashBytes = sha256.ComputeHash(saltedPassword);
    //       return (Convert.ToBase64String(salt), Convert.ToBase64String(hashBytes));
    //     }
    //   }
    // }

    public static (string Salt, string Hash) HashPasswordWithSalt(string password)
    {
      byte[] salt = new byte[16];
      RandomNumberGenerator.Fill(salt);
      using (SHA256 sha256 = SHA256.Create())
      {
        byte[] passwordBytes = Encoding.UTF8.GetBytes(password);
        byte[] saltedPassword = new byte[passwordBytes.Length + salt.Length];
        Buffer.BlockCopy(passwordBytes, 0, saltedPassword, 0, passwordBytes.Length);
        Buffer.BlockCopy(salt, 0, saltedPassword, passwordBytes.Length, salt.Length);
        byte[] hashBytes = sha256.ComputeHash(saltedPassword);
        return (Convert.ToBase64String(salt), Convert.ToBase64String(hashBytes));
      }
    }

    public static bool VerifyPassword(string inputPassword, string storedSalt, string storedHash)
    {
      byte[] salt = Convert.FromBase64String(storedSalt);
      byte[] passwordBytes = Encoding.UTF8.GetBytes(inputPassword);
      byte[] saltedPassword = new byte[passwordBytes.Length + salt.Length];
      Buffer.BlockCopy(passwordBytes, 0, saltedPassword, 0, passwordBytes.Length);
      Buffer.BlockCopy(salt, 0, saltedPassword, passwordBytes.Length, salt.Length);
      using (SHA256 sha256 = SHA256.Create())
      {
        byte[] hashBytes = sha256.ComputeHash(saltedPassword);
        string inputHash = Convert.ToBase64String(hashBytes);
        return inputHash == storedHash;
      }
    }
  }
}