using System;
using System.Collections.Generic;
using System.Data.SqlTypes;
using System.Linq;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Threading.Tasks;

namespace WorkFlowCheck.Common.Security
{
    public static class PasswordHasher
    {
        // Jelszó hashelése
        private const string _saltstring = "xc45DDfrt!!ED210:";
        public static string HashPassword(string password)
        {
            // Generate a random salt
            byte[] salt = Encoding.UTF8.GetBytes(_saltstring);
            

            // Hash the password with the salt
            using (var rfc2898 = new Rfc2898DeriveBytes(password, salt, 10000, HashAlgorithmName.SHA256))
            {
                byte[] hash = rfc2898.GetBytes(32); // 256-bit hash
                byte[] hashBytes = new byte[48]; // Salt (16 bytes) + Hash (32 bytes)
                Array.Copy(salt, 0, hashBytes, 0, 16);
                Array.Copy(hash, 0, hashBytes, 16, 32);

                return Convert.ToBase64String(hashBytes);
            }
        }

        // Jelszó ellenőrzése
        public static bool VerifyPassword(string storedPasswordHash, string inputPassword)
        {
            var inputPasswordHash = HashPassword(inputPassword);

            byte[] hashBytes = Convert.FromBase64String(storedPasswordHash);

            // Extract salt (first 16 bytes) and stored hash (next 32 bytes)
            byte[] salt = Encoding.UTF8.GetBytes(_saltstring);
            byte[] storedHash = new byte[32];
            Array.Copy(hashBytes, 0, salt, 0, 16);
            Array.Copy(hashBytes, 16, storedHash, 0, 32);

            // Hash the input password with the same salt
            using (var rfc2898 = new Rfc2898DeriveBytes(inputPassword, salt, 10000, HashAlgorithmName.SHA256))
            {
                byte[] inputHash = rfc2898.GetBytes(32);

                // Compare the stored hash and the calculated hash
                return CryptographicOperations.FixedTimeEquals(storedHash, inputHash);
            }
        }
    }
}