using System;
using System.Diagnostics;

namespace BF
{
    internal class NetUtility
    {
        internal static int getNewSeed()
        {
            byte[] rndBytes = new byte[4];
            System.Security.Cryptography.RNGCryptoServiceProvider rng = new System.Security.Cryptography.RNGCryptoServiceProvider();
            rng.GetBytes(rndBytes);
            return BitConverter.ToInt32(rndBytes, 0);
        }

        internal static string GetRandomString(int len)
        {
            string s = "123456789abcdefghijklmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ";
            string reValue = string.Empty;
            Random rnd = new Random(getNewSeed());
            while (reValue.Length < len)
            {
                string s1 = s[rnd.Next(0, s.Length)].ToString();
                if (reValue.IndexOf(s1) == -1) reValue += s1;
            }
            return reValue;
        }

    }

    internal static class NetTime
    {
        private static readonly long epoch = new DateTime(1970, 1,1,0,0,0,DateTimeKind.Utc).Ticks;

        private static readonly long timeInitialized = Stopwatch.GetTimestamp();
        private static readonly double InvFreq = 1.0 / (double)Stopwatch.Frequency;

        /// <summary>
        /// get seconds since application start
        /// </summary>
        public static double Now => (Stopwatch.GetTimestamp() - timeInitialized) * InvFreq;

        /// <summary>
        /// ms
        /// </summary>
        /// <returns></returns>
        public static long ClientNow()
        {
            return (DateTime.UtcNow.Ticks - epoch) / 10000;
        }

        /// <summary>
        /// s
        /// </summary>
        /// <returns></returns>
        public static long ClientNowSeconds()
        {
            return (DateTime.UtcNow.Ticks - epoch) / 10000000;
        }
    }
}