using Microsoft.AspNetCore.Cryptography.KeyDerivation;
using System;
using System.Collections.Generic;
using System.Security.Cryptography;
using System.Text;

namespace ReallifeGamemode.Server.Common
{
  public class PasswordHasher
  {
    public static byte[] GetNewSalt(int length = 256)
    {
      if ((length % 8) != 0)
      {
        throw new ArgumentException("Length mus be completely divisble through 8");
      }

      var salt = new byte[length / 8];

      using (var rng = RandomNumberGenerator.Create())
      {
        rng.GetBytes(salt);
      }

      return salt;
    }

    public static string HashPassword(string password, byte[] salt, int length = 512)
    {
      if ((length % 8) != 0)
      {
        throw new ArgumentException("Length mus be completely divisble through 8");
      }

      var hashedPassword = KeyDerivation.Pbkdf2(password, salt, KeyDerivationPrf.HMACSHA512, 50000, length / 8);

      return Convert.ToBase64String(hashedPassword);
    }
  }
}