using System;
using System.Diagnostics;
using System.Security.Cryptography;
using System.Text;
using System.Threading;

namespace ThreadTest
{
    class Program
    {
        const int Count = 1_000_000;
        const int Cores = 4;

        static Thread[] Threads;

        static void Main(string[] args)
        {
            Threads = new Thread[Cores];
            var countPerThread = Count / Cores;

            for (var i = 0; i < Cores; i++)
            {
                Threads[i] = new Thread(() => { ThreadFunction(i, countPerThread); });
                Threads[i].Start();
                Console.WriteLine($"Thread {i} dispatched.");
            }
        }

        static void ThreadFunction(int id, int count)
        {
            var sw = new Stopwatch();
            sw.Start();

            var rand = new Random();
            for (int i = 0; i < count; i++) ComputeSha256Hash(rand.Next().ToString());

            sw.Stop();
            Console.WriteLine($"Finished: {sw.ElapsedMilliseconds}ms.");
        }

        // Heavy task copied from https://www.c-sharpcorner.com/article/compute-sha256-hash-in-c-sharp/
        static string ComputeSha256Hash(string rawData)
        {
            // Create a SHA256
            using (SHA256 sha256Hash = SHA256.Create())
            {
                // ComputeHash - returns byte array
                byte[] bytes = sha256Hash.ComputeHash(Encoding.UTF8.GetBytes(rawData));

                // Convert byte array to a string
                StringBuilder builder = new StringBuilder();
                for (int i = 0; i < bytes.Length; i++)
                {
                    builder.Append(bytes[i].ToString("x2"));
                }
                return builder.ToString();
            }
        }
    }
}