using Microsoft.AspNetCore.Identity;
using Microsoft.Extensions.Options;
using System;
using System.Diagnostics;

namespace ConsoleApp2
{
    public static class Program
    {
        private const int IterationCount = 100000;

        public static void Main(string[] args)
        {
            Console.WriteLine("Start.");

            if(!int.TryParse(args[0], out var iterations))
                iterations = IterationCount;

            const string password = "test";

            var sw = new Stopwatch();
            sw.Start();

            var hasher = new PasswordHasher(PasswordHasherCompatibilityMode.IdentityV3, iterations);

            var user = new User { Id = 1, Name = "Dvorak" };

            var hash = hasher.HashPassword(
                user,
                password);

            Console.WriteLine("time: {0}", DateTime.Now);

            Console.WriteLine("hash: {0}", hash);

            var verificationResult = hasher.VerifyHashedPassword(null, hash, password);

            Console.WriteLine("success: {0}", verificationResult == PasswordVerificationResult.Success);

            sw.Stop();
            Console.WriteLine("Took {0} milliseconds..", sw.ElapsedMilliseconds);

            //Console.ReadLine();
        }
    }

    internal sealed class PasswordHasher : PasswordHasher<object>
    {
        public PasswordHasher(PasswordHasherCompatibilityMode? compatMode = null, int? iterCount = null)
            : base(BuildOptions(compatMode, iterCount))
        {
        }

        private static IOptions<PasswordHasherOptions> BuildOptions(PasswordHasherCompatibilityMode? compatMode, int? iterCount)
        {
            var options = new PasswordHasherOptionsAccessor();
            if (compatMode != null)
            {
                options.Value.CompatibilityMode = (PasswordHasherCompatibilityMode)compatMode;
            }
            if (iterCount != null)
            {
                options.Value.IterationCount = (int)iterCount;
            }
            //Assert.NotNull(options.Value.Rng); // should have a default value
            //options.Value.Rng = new SequentialRandomNumberGenerator();
            return options;
        }

        private class PasswordHasherOptionsAccessor : IOptions<PasswordHasherOptions>
        {
            public PasswordHasherOptions Value { get; } = new PasswordHasherOptions();
        }
    }
}