using System;

using System.IO;

using System.Text.RegularExpressions;

​

public class Program

{

    public static void Main()

    {

        string illegal = "\"M\"\\a/ry/ h**ad:>> a\\/:*?\"| li*tt|le|| la\"mb** 10.?";

        string expected = "_M_a_ry_ h_ad_ a_ li_tt_le_ la_mb._";

        var valid = MakeValidFileName(illegal);

        // Console.WriteLine(valid);

        // Console.WriteLine(valid == expected);

        DateTime now = DateTime.Now;

        // now.Kind = DateTimeKind.Utc;

        // Console.WriteLine(now);

        DateTime past = now.AddDays(-2);

        // Console.WriteLine(past);

        // Console.WriteLine(TimeZoneInfo.ConvertTimeToUtc(past));

        // Console.WriteLine(TimeZoneInfo.Local);

        // Console.WriteLine(TimeZoneInfo.GetSystemTimeZones().Count);

        DateTime dtEpoch = new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc);

        DateTime dt = new DateTime(2020, 07, 13, 9, 00, 00);

        TimeZoneInfo pZone = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");

        DateTime dtUtc = TimeZoneInfo.ConvertTimeToUtc(dt, pZone);

        Console.WriteLine("UTC time: " + dtUtc);

        Console.WriteLine(dtUtc > dtEpoch);

        Console.WriteLine(1594815277540 - 1594656000000);

        TimeSpan span = dtUtc - dtEpoch;

        // int ms = (int)span.TotalMilliseconds;

        Console.WriteLine(span.TotalMilliseconds);

        Console.WriteLine(dtEpoch.AddMilliseconds(1594656000000).ToUniversalTime());

        /*foreach (TimeZoneInfo tz in TimeZoneInfo.GetSystemTimeZones()) {

            Console.WriteLine(tz.Id);

        }*/

    }

​

    private static string MakeValidFileName(string name)

    {

        var invalidFileNameChars = new string(Path.GetInvalidFileNameChars());

        string invalidChars = Regex.Escape(invalidFileNameChars);

        string invalidRegStr = string.Format(@"([{0}]*\.+$)|([{0}]+)", invalidChars);

​

        return Regex.Replace(name, "[^a-zA-Z0-9 ]", "");

    }

}