/***************************************************************************
FileSystem identifier and checker
----------------------------------------------------------------------------
 
Filename       : DateHandlers.cs
Version        : 1.0
Author(s)      : Natalia Portillo
 
Component      : Program tools

Revision       : $Revision$
Last change by : $Author$
Date           : $Date$
 
--[ Description ] ----------------------------------------------------------
 
Convert several timestamp formats to C# DateTime.
 
--[ License ] --------------------------------------------------------------
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as
    published by the Free Software Foundation, either version 3 of the
    License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

----------------------------------------------------------------------------
Copyright (C) 2011-2014 Claunia.com
****************************************************************************/
//$Id$

using System;

namespace FileSystemIDandChk
{
    public static class DateHandlers
    {
        static readonly DateTime LisaEpoch = new DateTime(1901, 1, 1, 0, 0, 0);
        static readonly DateTime MacEpoch = new DateTime(1904, 1, 1, 0, 0, 0);
        static readonly DateTime UNIXEpoch = new DateTime(1970, 1, 1, 0, 0, 0);
        // Day 0 of Julian Date system
        static readonly DateTime JulianEpoch = new DateTime(1858, 11, 17, 0, 0, 0);

        public static DateTime MacToDateTime(ulong MacTimeStamp)
        {
            return MacEpoch.AddTicks((long)(MacTimeStamp * 10000000));
        }

        public static DateTime LisaToDateTime(UInt32 LisaTimeStamp)
        {
            return LisaEpoch.AddSeconds(LisaTimeStamp);
        }

        public static DateTime UNIXToDateTime(Int32 UNIXTimeStamp)
        {
            return UNIXEpoch.AddSeconds(UNIXTimeStamp);
        }

        public static DateTime UNIXUnsignedToDateTime(UInt32 UNIXTimeStamp)
        {
            return UNIXEpoch.AddSeconds(UNIXTimeStamp);
        }

        public static DateTime ISO9660ToDateTime(byte[] VDDateTime)
        {
            int year, month, day, hour, minute, second, hundredths;
            byte[] twocharvalue = new byte[2];
            byte[] fourcharvalue = new byte[4];
			
            fourcharvalue[0] = VDDateTime[0];
            fourcharvalue[1] = VDDateTime[1];
            fourcharvalue[2] = VDDateTime[2];
            fourcharvalue[3] = VDDateTime[3];
            if (MainClass.isDebug)
                Console.WriteLine("ISO9600ToDateTime: year = \"{0}\"", StringHandlers.CToString(fourcharvalue));
            if (!Int32.TryParse(StringHandlers.CToString(fourcharvalue), out year))
                year = 0;
//			year = Convert.ToInt32(StringHandlers.CToString(fourcharvalue));
			
            twocharvalue[0] = VDDateTime[4];
            twocharvalue[1] = VDDateTime[5];
            if (MainClass.isDebug)
                Console.WriteLine("ISO9600ToDateTime: month = \"{0}\"", StringHandlers.CToString(twocharvalue));
            if (!Int32.TryParse(StringHandlers.CToString(twocharvalue), out month))
                month = 0;
//			month = Convert.ToInt32(StringHandlers.CToString(twocharvalue));
			
            twocharvalue[0] = VDDateTime[6];
            twocharvalue[1] = VDDateTime[7];
            if (MainClass.isDebug)
                Console.WriteLine("ISO9600ToDateTime: day = \"{0}\"", StringHandlers.CToString(twocharvalue));
            if (!Int32.TryParse(StringHandlers.CToString(twocharvalue), out day))
                day = 0;
//			day = Convert.ToInt32(StringHandlers.CToString(twocharvalue));
			
            twocharvalue[0] = VDDateTime[8];
            twocharvalue[1] = VDDateTime[9];
            if (MainClass.isDebug)
                Console.WriteLine("ISO9600ToDateTime: hour = \"{0}\"", StringHandlers.CToString(twocharvalue));
            if (!Int32.TryParse(StringHandlers.CToString(twocharvalue), out hour))
                hour = 0;
//			hour = Convert.ToInt32(StringHandlers.CToString(twocharvalue));
			
            twocharvalue[0] = VDDateTime[10];
            twocharvalue[1] = VDDateTime[11];
            if (MainClass.isDebug)
                Console.WriteLine("ISO9600ToDateTime: minute = \"{0}\"", StringHandlers.CToString(twocharvalue));
            if (!Int32.TryParse(StringHandlers.CToString(twocharvalue), out minute))
                minute = 0;
//			minute = Convert.ToInt32(StringHandlers.CToString(twocharvalue));
			
            twocharvalue[0] = VDDateTime[12];
            twocharvalue[1] = VDDateTime[13];
            if (MainClass.isDebug)
                Console.WriteLine("ISO9600ToDateTime: second = \"{0}\"", StringHandlers.CToString(twocharvalue));
            if (!Int32.TryParse(StringHandlers.CToString(twocharvalue), out second))
                second = 0;
//			second = Convert.ToInt32(StringHandlers.CToString(twocharvalue));
			
            twocharvalue[0] = VDDateTime[14];
            twocharvalue[1] = VDDateTime[15];
            if (MainClass.isDebug)
                Console.WriteLine("ISO9600ToDateTime: hundredths = \"{0}\"", StringHandlers.CToString(twocharvalue));
            if (!Int32.TryParse(StringHandlers.CToString(twocharvalue), out hundredths))
                hundredths = 0;
//			hundredths = Convert.ToInt32(StringHandlers.CToString(twocharvalue));

            if (MainClass.isDebug)
                Console.WriteLine("ISO9600ToDateTime: decodedDT = new DateTime({0}, {1}, {2}, {3}, {4}, {5}, {6}, DateTimeKind.Unspecified);", year, month, day, hour, minute, second, hundredths * 10);
            DateTime decodedDT = new DateTime(year, month, day, hour, minute, second, hundredths * 10, DateTimeKind.Unspecified);
			
            return decodedDT;
        }

        // C# works in UTC, VMS on Julian Date, some displacement may occur on disks created outside UTC
        public static DateTime VMSToDateTime(UInt64 vmsDate)
        {
            double delta = vmsDate * 0.0001; // Tenths of microseconds to milliseconds, will lose some detail
            return JulianEpoch.AddMilliseconds(delta);
        }
    }
}