' Classes/System/DateTime.ab

#ifndef __SYSTEM_DATETIME_AB__
#define __SYSTEM_DATETIME_AB__

Class DateTime
	m_Date As Int64
Public
	Static MaxValue = 3162240000000000000 As Int64 'Const
	Static MinValue = 316224000000000 As Int64 'Const

	Sub DateTime()
		DateTime(316224000000000)
	End Sub

	Sub DateTime(ticks As Int64)
		Ticks = ticks
		Kind = DateTimeKind.Unspecified
	End Sub

	Sub DateTime(ticks As Int64, kind As DateTimeKind)
		DateTime(ticks)
		Kind = kind
	End Sub

	Sub DateTime(year As Long, month As Long, day As Long)
		If year < 1 Or year > 9999 Or month < 1 Or month > 12 Or day < 1 Or day > DaysInMonth(year, month) Then
			'ArgumentOutOfRangeException
			debug
		End If
		DateTime(316224000000000)
		DateTime( AddYears(year - 1) )

		Dim days As Long
		Dim i As Long
		For i = 1 To month - 1
			days += DaysInMonth(Year, i)
		Next
		days += day
		DateTime( AddDays(days - 1) )
	End Sub

	Sub DateTime(year As Long, month As Long, day As Long, kind As DateTimeKind)
		DateTime(year, month, day)
		Kind = kind
	End Sub

	Sub DateTime(year As Long, month As Long, day As Long, hour As Long, minute As Long, second As Long)
		If hour < 0 Or hour > 23 Or minute < 0 Or minute > 59 Or second < 0 Or second > 59 Then
			'ArgumentOutOfRangeException
			debug
		End If

		DateTime(year, month, day)
		DateTime( AddHours(hour) )
		DateTime( AddMinutes(minute) )
		DateTime( AddSeconds(second) )
	End Sub

	Sub DateTime(year As Long, month As Long, day As Long, hour As Long, minute As Long, second As Long, kind As DateTimeKind)
		DateTime(year, month, day, hour, minute, second)
		Kind = kind
	End Sub

	Sub DateTime(year As Long, month As Long, day As Long, hour As Long, minute As Long, second As Long, millisecond As Long)
		DateTime(year, month, day, hour, minute, second)
		DateTime( AddMilliseconds(millisecond) )
	End Sub

	Sub DateTime(year As Long, month As Long, day As Long, hour As Long, minute As Long, second As Long, millisecond As Long, kind As DateTimeKind)
		DateTime(year, month, day, hour, minute, second, millisecond)
		Kind = kind
	End Sub

	Sub DateTime(ByRef time As SYSTEMTIME)
		DateTime(time.wYear, time.wMonth, time.wDay, time.wHour, time.wMinute, time.wSecond, time.wMilliseconds)
	End Sub

	Sub DateTime(ByRef time As SYSTEMTIME, kind As DateTimeKind)
		DateTime(time.wYear, time.wMonth, time.wDay, time.wHour, time.wMinute, time.wSecond, time.wMilliseconds, kind)
	End Sub

	'Copy Constructor
	Sub DateTime(ByRef datetime As DateTime)
		This.m_Date = datetime.m_Date
	End Sub

	Sub ~DateTime()
	End Sub

	Function Operator + (ByRef value As TimeSpan) As DateTime
		Dim date As DateTime(Ticks + value.Ticks)
		Return date
	End Function

	Function Operator - (ByRef value As DateTime) As TimeSpan
		Return TimeSpan.FromTicks(Ticks - value.Ticks)
	End Function

	Function Operator - (ByRef value As TimeSpan) As DateTime
		Dim date As DateTime(Ticks - value.Ticks)
		Return date
	End Function

	Function Operator == (ByRef value As DateTime) As Boolean
		Return Equals(value)
	End Function

	Function Operator <> (ByRef value As DateTime) As Boolean
		Return Not Equals(value)
	End Function

	Function Operator > (ByRef value As DateTime) As Boolean
		If DateTime.Compare(This, value) > 0 Then
			Return True
		Else
			Return False
		End If
	End Function

	Function Operator < (ByRef value As DateTime) As Boolean
		If DateTime.Compare(This, value) < 0 Then
			Return True
		Else
			Return False
		End If
	End Function

	Function Operator >= (ByRef value As DateTime) As Boolean
		If DateTime.Compare(This, value) => 0 Then
			Return True
		Else
			Return False
		End If
	End Function

	Function Operator <= (ByRef value As DateTime) As Boolean
		If DateTime.Compare(This, value) <= 0 Then
			Return True
		Else
			Return False
		End If
	End Function
	
	'Property
	Function Ticks() As Int64
		Return (m_Date And &H3FFFFFFFFFFFFFFF)
	End Function

	Function Millisecond() As Long
		Return (Ticks \ TimeSpan.TicksPerMillisecond Mod 1000) As Long
	End Function

	Function Second() As Long
		Return (Ticks \ TimeSpan.TicksPerSecond Mod 60) As Long
	End Function

	Function Minute() As Long
		Return (Ticks \ TimeSpan.TicksPerMinute Mod 60) As Long
	End Function

	Function Hour() As Long
		Return (Ticks \ TimeSpan.TicksPerHour Mod 24) As Long
	End Function

	Function Day() As Long
		Dim day As Long
		day = DayOfYear

		Dim i As Long
		For i = 1 To Month - 1
			day -= DaysInMonth(Year, i)
		Next
		Return day
	End Function

	Function Month() As Long
		Dim year As Long
		Dim day As Long
		year = Year
		day = DayOfYear

		Dim i As Long
		For i = 1 To 12
			day -= DaysInMonth(year, i)
			If day <= 0 Then Return i
		Next
		Return 12
	End Function

	Function Year() As Long
		Dim day As Long
		day = totalDays()
		Return Int((day + day \ 36523 - day \ 146097) / 365.25)
	End Function

	Function DayOfWeek() As Long
		Return totalDays() Mod 7 - 1
	End Function

	Function Kind() As DateTimeKind
		Return kindFromBinary(m_Date)
	End Function

	Function DayOfYear() As Long
		Dim day As Long
		day = totalDays()
		Return day - Int(Year * 365.25 - day \ 36523 + day \ 146097)
	End Function

	Function Date() As DateTime
		Dim date As DateTime(Year, Month, Day, Kind)
		Return date
	End Function

	Static Function Now() As DateTime
		Dim time As SYSTEMTIME
		GetLocalTime(time)
		Dim date As DateTime(time, DateTimeKind.Local)
		Return date
	End Function

	Static Function ToDay() As DateTime
		Dim time As SYSTEMTIME
		GetLocalTime(time)
		Dim date As DateTime(time.wYear, time.wMonth, time.wDay, DateTimeKind.Local)
		Return date
	End Function

	Static Function UtcNow() As DateTime
		Dim time As SYSTEMTIME
		GetSystemTime(time)
		Dim date As DateTime(time, DateTimeKind.Utc)
		Return date
	End Function
		
	'method
	Static Function Compare(ByRef t1 As DateTime, ByRef t2 As DateTime) As Int64
		Return t1.Ticks - t2.Ticks
	End Function

	Function Equals(ByRef value As DateTime) As Boolean
		If value.m_Date = m_Date Then
			Return True
		Else
			Return False
		End If
	End Function

	Static Function Equals(ByRef t1 As DateTime, ByRef t2 As DateTime) As Boolean
		If t1.m_Date = t2.m_Date Then
			Return True
		Else
			Return False
		End If
	End Function

	Override Function GetHashCode() As Long
		Return HIDWORD(m_Date) Xor LODWORD(m_Date)
	End Function

	Function Add(ByRef value As TimeSpan) As DateTime
		Return This + value
	End Function

	Function AddTicks(value As Int64) As DateTime
		Dim ticks As Int64
		ticks = Ticks
		If (ticks > MaxValue - value) Or (ticks < MinValue - value) Then
			'ArgumentOutOfRangeException
			debug
		End If

		AddTicks.Ticks = ticks + value
		AddTicks.Kind = Kind
	End Function

	Function AddMilliseconds(value As Double) As DateTime
		Return AddTicks((value * TimeSpan.TicksPerMillisecond) As Int64)
	End Function

	Function AddSeconds(value As Double) As DateTime
		Return AddTicks((value * TimeSpan.TicksPerSecond) As Int64)
	End Function

	Function AddMinutes(value As Double) As DateTime
		Return AddTicks((value * TimeSpan.TicksPerMinute) As Int64)
	End Function

	Function AddHours(value As Double) As DateTime
		Return AddTicks((value * TimeSpan.TicksPerHour) As Int64)
	End Function

	Function AddDays(value As Double) As DateTime
		Return AddTicks((value * TimeSpan.TicksPerDay) As Int64)
	End Function

	Function AddYears(value As Double) As DateTime
		Dim year As Long
		Dim intValue As Long
		Dim ticks As Int64
		year = Year
		intValue = Int(value)
		ticks = Ticks + intValue * 315360000000000 + 864000000000 * ((year Mod 4 + intValue) \ 4 - (year Mod 100 + intValue) \ 100 + (year Mod 400 + intValue) \ 400)

		If value < 0 Then
			If (year Mod 4 + intValue <= 0 And year Mod 100 > 4) Or (year Mod 400 <= 4) Then
				ticks -= 864000000000
			End If
		End If
		If IsLeapYear(year) = TRUE Then
			ticks += (value - intValue) * 316224000000000
		Else
			ticks += (value - intValue) * 315360000000000
		End If
		
		AddYears.Ticks = ticks
		AddYears.Kind = Kind
	End Function

	Function Subtract(ByRef value As DateTime) As TimeSpan
		Return This - value
	End Function

	Function Subtract(ByRef value As TimeSpan) As DateTime
		Return This - value
	End Function

	Static Function DaysInMonth(year As Long, month As Long) As Long
		If year < 1 Or year > 9999 Or month < 1 Or month > 12 Then
			'ArgumentOutOfRangeException
			debug
		End If
		If IsLeapYear(year) And month = 2 Then
			Return 29
		Else
			Dim daysInMonth[11] = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31] As Byte
			Return daysInMonth[month - 1]
		End If
	End Function

	Static Function IsLeapYear(year As Long) As Boolean
		If (year Mod 400) = 0 Then Return True
		If (year Mod 100) = 0 Then Return False
		If (year Mod 4) = 0 Then Return True
		Return False
	End Function

	Function GetDateTimeFormats() As String
		Return GetDateTimeFormats(NULL)
	End Function

	Function GetDateTimeFormats(format As *Byte) As String
		Dim time As SYSTEMTIME
		With time
			.wYear = Year As Word
			.wMonth = Month As Word
			.wDay = Day As Word
			.wHour = Hour As Word
			.wMinute = Minute As Word
			.wSecond = Second As Word
			.wMilliseconds = Millisecond As Word
			.wDayOfWeek = DayOfWeek() As Word
		End With

		Dim size As Long
		size = GetDateFormat(LOCALE_USER_DEFAULT, 0, time, format, NULL, 0)
		GetDateTimeFormats.ReSize(size - 1)
		GetDateFormat(LOCALE_USER_DEFAULT, 0, time, format, GetDateTimeFormats, size)

		Dim temp As String		
		If format = NULL Then
			size = GetTimeFormat(LOCALE_USER_DEFAULT, 0, time, format, NULL, 0)
			temp.ReSize(size - 1)
			GetTimeFormat(LOCALE_USER_DEFAULT, 0, time, format, temp, size)
			GetDateTimeFormats = GetDateTimeFormats + " " + temp
		Else
			size = GetTimeFormat(LOCALE_USER_DEFAULT, 0, time, GetDateTimeFormats, NULL, 0)
			temp.ReSize(size - 1)
			GetTimeFormat(LOCALE_USER_DEFAULT, 0, time, GetDateTimeFormats, temp, size)
			GetDateTimeFormats = temp
		End If
	End Function

	Static Function FromBinary(dateData As Int64) As DateTime
		Dim date As DateTime((dateData And &H3FFFFFFFFFFFFFFF), kindFromBinary(dateData))
		Return date
	End Function

	Function ToBinary() As Int64
		Return m_Date
	End Function

	Static Function FromFileTime(fileTime As FILETIME) As DateTime
		Dim localTime As FILETIME
		Dim time As SYSTEMTIME
		FileTimeToLocalFileTime(fileTime, localTime)
		FileTimeToSystemTime(localTime, time)

		Dim date As DateTime(time, DateTimeKind.Local)
		Return date
	End Function

	Function ToFileTime() As FILETIME
		Dim time As SYSTEMTIME
		With time
			.wYear = Year As Word
			.wMonth = Month As Word
			.wDayOfWeek = DayOfWeek As Word
			.wDay = Day As Word
			.wHour = Hour As Word
			.wMinute = Minute As Word
			.wSecond = Second As Word
			.wMilliseconds = Millisecond As Word
		End With
		Dim fileTime As FILETIME
		SystemTimeToFileTime(time, fileTime)
		Return fileTime
	End Function

	Static Function FromFileTimeUtc(fileTime As FILETIME) As DateTime
		Dim time As SYSTEMTIME
		FileTimeToSystemTime(fileTime, time)

		Dim date As DateTime(time, DateTimeKind.Utc)
		Return date
	End Function

	Function ToFileTimeUtc() As FILETIME
		Dim fileTime As FILETIME
		fileTime = ToFileTime()
		If Kind = DateTimeKind.Utc Then
			ToFileTimeUtc = fileTime
		Else
			LocalFileTimeToFileTime(fileTime, ToFileTimeUtc) 'Return
		End If
	End Function

	Function ToLocalTime() As DateTime
		If Kind = DateTimeKind.Local Then
			ToLocalTime = This
		Else
			ToLocalTime = DateTime.FromFileTime(ToFileTime())
			ToLocalTime.Kind = DateTimeKind.Local
		End If
	End Function

	Function ToUniversalTime() As DateTime
		If Kind = DateTimeKind.Utc Then
			ToUniversalTime = This
		Else
			ToUniversalTime = DateTime.FromFileTimeUtc(ToFileTimeUtc())
			ToUniversalTime.Kind = DateTimeKind.Utc
		End If
	End Function
Private
	Sub Ticks(value As Int64)
		Dim kind As DateTimeKind
		kind = Kind
		m_Date = value
		Kind = kind
	End Sub

	Sub Kind(kind As DateTimeKind)
		Dim temp As Int64
		temp = kind
		temp = (temp << 62) And &HC000000000000000
		m_Date = (m_Date And &H3FFFFFFFFFFFFFFF) Or temp
	End Sub

	Function totalDays() As Long
		Return (Ticks \ TimeSpan.TicksPerDay) As Long
	End Function

	Function kindFromBinary(dateData As Int64) As DateTimeKind
		dateData = (dateData >> 62) And &H03
		If dateData = &H01 Then
			Return DateTimeKind.Local
		ElseIf dateData = &H02 Then
			Return DateTimeKind.Unspecified
		ElseIf dateData = &H03 Then
			Return DateTimeKind.Utc
		End If
	End Function
End Class

Enum DateTimeKind
	Local
	Unspecified
	Utc
End Enum

Enum DayOfWeek
	Sunday = 0
	Monday
	Tuesday
	Wednesday
	Thursday
	Friday
	Saturday
End Enum

#endif '__SYSTEM_DATETIME_AB__