Namespace System
Namespace IO

/* ほんとはmiscに入れるかかファイルを分けたほうがいいかもしれないが一先ず実装 */
Enum FileOptions
	None = 0
	Asynchronous = FILE_FLAG_OVERLAPPED
	DeleteOnClose = FILE_FLAG_DELETE_ON_CLOSE
	Encrypted = FILE_ATTRIBUTE_ENCRYPTED
	RandomAccess = FILE_FLAG_RANDOM_ACCESS
	SequentialScan = FILE_FLAG_SEQUENTIAL_SCAN
	WriteThrough = FILE_FLAG_WRITE_THROUGH
End Enum

Class FileStream
	Inherits Stream

	handle As HANDLE

	/*
	ファイルハンドルからこれらを取得できれば、これらは入らないが
	今のところは不明なので自前で実装するしかない
	*/
	filePath As String
	fileMode As DWord
	fileAccess As DWord
	fileShare As DWord
	fileOptions As DWord
	
	offset As QWord 'オーバーラップドIO用

Public
	/* コンストラクタ.NETと同じように実装は難しい、一先ず動くものを実装したが変更が必要だと思う */
	Sub FileStream(path As String, mode As FileMode, access As FileAccess, share As FileShare, options As FileOptions)
		Dim ac As DWord
		Dim mo As DWord
		Dim sh As DWord
		Dim op As DWord

		Select Case access
			Case FileAccess.Read
				ac=GENERIC_READ
			Case FileAccess.ReadWrite
				ac=GENERIC_READ or GENERIC_WRITE
			Case FileAccess.Write
				ac=GENERIC_WRITE
		End Select

		Select Case share
			Case FileShare.DeleteFile
				sh=FILE_SHARE_DELETE
			Case FileShare.None
				sh=0
			Case FileShare.Read
				sh=FILE_SHARE_READ
			Case FileShare.ReadWrite
				sh=FILE_SHARE_READ or FILE_SHARE_WRITE
			Case FileShare.Write
				sh=FILE_SHARE_WRITE
		End Select

		Select Case mode
			Case FileMode.Append
				mo=OPEN_ALWAYS
			Case FileMode.Create
				mo=CREATE_ALWAYS
			Case FileMode.CreateNew
				mo=CREATE_NEW
			Case FileMode.Open
				mo=OPEN_EXISTING
			Case FileMode.OpenOrCreate
				mo=OPEN_ALWAYS
			Case FileMode.Truncate
				mo=TRUNCATE_EXISTING
		End Select

		op = options As DWord
		If Not Environment.OSVersion.Platform = PlatformID.Win32NT Then
			op And= Not FILE_FLAG_OVERLAPPED
		End If

		This.handle=CreateFile(ToTCStr(path),ac,sh,ByVal NULL,mo,op,0)
		If This.handle=INVALID_HANDLE_VALUE Then
		'エラー処理
		'Throw ArgumentException
		'Throw IOException
		'Throw System.IO.FileNotFoundException 
			This.handle=0
			Beep(220,500)
			Exit Sub
		End If

		This.filePath = path
		This.fileMode = mo
		This.fileAccess = ac
		This.fileShare = sh
		This.fileOptions = op
		This.offset = 0
	End Sub
	Sub FileStream(path As String, mode As FileMode, access As FileAccess, share As FileShare)
		This.FileStream(path,mode,access,share,FileOptions.None)
	End Sub
	Sub FileStream(path As String, mode As FileMode, access As FileAccess)
		This.FileStream(path,mode,access,FileShare.None,FileOptions.None)
	End Sub
	Sub FileStream(path As String, mode As FileMode)
		Dim access As FileAccess
		Select Case mode
			Case FileMode.Append
				access=FileAccess.Write
			Case FileMode.Create
				access=FileAccess.ReadWrite
			Case FileMode.CreateNew
				access=FileAccess.ReadWrite
			Case FileMode.Open
				access=FileAccess.ReadWrite
			Case FileMode.OpenOrCreate
				access=FileAccess.ReadWrite
			Case FileMode.Truncate
				access=FileAccess.Write
		End Select
		This.FileStream(path,mode,access,FileShare.None,FileOptions.None)
	End Sub
Public
	/*!
	@brief	ファイルが読み込みに対応しているかを返す
	*/
	Override Function CanRead() As Boolean
		If This.fileAccess And GENERIC_READ Then
			Return True
		Else
			Return False
		End If
	End Function

	/*!
	@brief	ファイルがシークに対応しているかを返す
	*/
	Override Function CanSeek() As Boolean
		If GetFileType(This.handle)=FILE_TYPE_DISK Then
			Return True
		Else
			Return False
		End If
	End Function

'	Override Function CanTimeout() As Boolean
'		/* ファイルがタイムアウトに対応しているかを返す */
'		Return False /*今のところ対応していないのでFalse*/
'	End Function*/

	/*!
	@brief	ファイルが書き込みに対応しているかを返す
	*/
	Override Function CanWrite() As Boolean
		If This.fileAccess And GENERIC_WRITE Then
			Return True
		Else
			Return False
		End If
	End Function

	/*Handle*/

	/*!
	@brief	ファイルが非同期操作に対応しているかを返す
	*/
	Function IsAsync() As Boolean
		If This.fileOptions And FILE_FLAG_OVERLAPPED /*FileOptions.Asynchronous*/ Then
			Return True
		Else
			Return False
		End If
	End Function

	Override Function Length() As Int64
		disposedCheck()
		If This.CanSeek() Then
			Dim length = VarPtr(Length) As *ULARGE_INTEGER
			length->LowPart = GetFileSize(This.handle, VarPtr(length->HighPart))
			If LODWORD(Length) = INVALID_FILE_SIZE Then
				Dim error = GetLastError()
				If error <> NO_ERROR Then
'					Detail.ThrowWinIOException("FileStream.Read: Failed to read.", error)
				End If
			End If
			
			If Length < 0 Then
				Debug 'Throw OverflowException
			End If
		End If
	End Function

	Function Name() As String
		Return This.filePath
	End Function
	
	Override Sub Position(value As Int64)
		disposedCheck()
		If This.CanSeek() Then
			If This.IsAsync() Then
				offset = value As QWord
			Else
				Dim position As LARGE_INTEGER
				position.LowPart=LODWORD(value)
				position.HighPart=HIDWORD(value)
				SetFilePointer(This.handle,position.LowPart,VarPtr(position.HighPart) As *DWord,FILE_BEGIN)
			End If
		End If
	End Sub
	Override Function Position() As Int64
		disposedCheck()
		If This.CanSeek() Then
			If This.IsAsync() Then
				Return offset As Int64
			Else
				Dim position As LARGE_INTEGER
				ZeroMemory(VarPtr(position),SizeOf(LARGE_INTEGER))
				position.LowPart=SetFilePointer(This.handle,position.LowPart,VarPtr(position.HighPart) As *DWord,FILE_CURRENT)
				Return MAKEQWORD(position.LowPart,position.HighPart) As Int64
			End If
		End If
	End Function

/*	Override Sub ReadTimeout(value As Long)
		'TODO
	End Sub
	Override Function ReadTimeout() As Long
		'TODO
	End Function*/

	/* Safe〜Handle系の実装は要相談！！ */
/*	Function SafeFileHandle() As SafeFileHandle
	End Function*/

	Override Sub WriteTimeout(value As Long)
		'TODO
	End Sub
	Override Function WriteTimeout() As Long
		'TODO
	End Function
	

Public
	Override Function BeginRead(buffer As *Byte, offset As Long, count As Long, callback As AsyncCallback, state As Object) As System.IAsyncResult
		If This.IsAsync() Then
		Else
			Read(buffer,offset,count)
		End If
	End Function

	Override Function BeginWrite(buffer As *Byte, offset As Long, count As Long, callback As AsyncCallback, state As Object) As System.IAsyncResult
		If This.IsAsync() Then
		Else
			Write(buffer,offset,count)
		End If
	End Function

/*	CreateObjRef*/
	
	Override Sub Dispose(disposing As Boolean)
		Flush()
		CloseHandle(InterlockedExchangePointer(VarPtr(This.handle),NULL))
	End Sub

	Override Function EndRead(asyncResult As System.IAsyncResult) As Long
		'TODO
	End Function

	Override Sub EndWrite(asyncResult As System.IAsyncResult)
		'TODO
	End Sub

/*	Equals*/

	Override Sub Flush()
		disposedCheck()
		Dim ret = FlushFileBuffers(This.handle)
		If ret = FALSE Then
'			Detail.ThrowWinLastErrorIOException("FileStream.Read: Failed to read.")
		End If
	End Sub

/*	Function GetAccessControl() As FileSecurity
	FileSecurityの実装がまだできてない。
	End Function*/

/*	GetLifetimeService*/

/*	Override Function GetType() As TypeInfo
		Return Super.GetType()
	End Function*/

/*	InitializeLifetimeService*/

	Sub Lock(position As Int64, length As Int64)
		disposedCheck()
		If position < 0 Then
			Throw New ArgumentOutOfRangeException("FileStream.Lock: An argument is negative value.", New System.Int64(position), "position")
		ElseIf length < 0 Then
			Throw New ArgumentOutOfRangeException("FileStream.Lock: An argument is negative value.", New System.Int64(length), "length")
		End If
		LockFile(handle, LODWORD(position As QWord), HIDWORD(position As QWord),
			LODWORD(length As QWord), HIDWORD(length As QWord))
	End Sub

	Override Function Read( buffer As *Byte, offset As Long, count As Long) As Long
		disposedCheck()
		If buffer = 0 Then
'			Throw ArgumentNullException("FileStream.Read: An argument is null value.", "buffer")
		ElseIf Not This.CanRead() Then
'			Throw NotSupportedException("FileStream.Read: This stream is not readable.")
		End If

		Dim ret As BOOL
		Dim readBytes As DWord
		If This.IsAsync() Then
			Dim overlapped As OVERLAPPED
			SetQWord(VarPtr(overlapped.Offset), offset)
			overlapped.hEvent = CreateEvent(0, TRUE, FALSE, 0)
			If overlapped.hEvent = 0 Then
'				Throw OutOfMemoryException("FileStream.Read: Failed to create an event object.")
			End If
			Try
				ret = ReadFile(This.handle, VarPtr(buffer[offset]), count, 0, overlapped)
				If ret = FALSE Then
					Dim error = GetLastError()
					If error <> ERROR_IO_PENDING Then
'						Detail.ThrowWinIOException("FileStream.Read: Failed to read.", error)
					End If
				End If
				ret = GetOverlappedResult(This.handle, overlapped, readBytes, TRUE)
				If ret = FALSE Then
'					Detail.ThrowWinLastErrorIOException("FileStream.Read: Failed to read.")
				End If
				offset += Read
			Finally
				CloseHandle(overlapped.hEvent)
			End Try
		Else
			ret = ReadFile(This.handle,VarPtr(buffer[offset]),count,VarPtr(readBytes),ByVal NULL)
			If ret = FALSE Then
'				Detail.ThrowWinLastErrorIOException("FileStream.Read: Failed to read.")
			End If
		End If
		Read = readBytes As Long
	End Function

	/*!
	@brief	ストリームの現在位置を移動させる。
	@param[in] offset	originからの移動量
	@param[in] origin	移動の基準位置
	@return	移動後の新しい現在位置
	@exception DisposedException	既にストリームが閉じられている場合
	@exception ArgumentException	移動後の位置が負の位置（ファイル先頭より手前）になる場合
	@exception IOException	その他エラーが発生した場合
	*/
	Override Function Seek(offset As Int64, origin As SeekOrigin) As Int64
		disposedCheck()
		If This.CanSeek() Then
			If This.IsAsync() Then
				Select Case origin
					Case SeekOrigin.Begin
						This.offset = offset
					Case SeekOrigin.Current
						This.offset += offset
					Case SeekOrigin.End
						This.offset = This.Length + offset
				End Select
				Seek = This.offset As Int64
				If Seek < 0 Then
'					Throw ArgumentException("FileStream.Seek: Cannot seek to negative offset.")
				End If
			Else
				Dim seek = VarPtr(offset) As *ULARGE_INTEGER
				Dim ret = SetFilePointer(This.handle, seek->LowPart, VarPtr(seek->HighPart), origin As DWord)
				If ret = INVALID_SET_FILE_POINTER Then
					Dim error = GetLastError()
					If error = ERROR_NEGATIVE_SEEK Then
'						Throw ArgumentException("FileStream.Seek: Cannot seek to negative offset.")
					ElseIf error <> NO_ERROR Then
'						Throw Detail.ThrowWinIOException("FileStream.Seek: Failed to seek.", error)
					End If
				End If
				seek->LowPart = ret
				Seek = offset
			End If
		End If
	End Function

/*	Sub SetAccessControl(fileSecurity As FileSecurity)
	FileSecurityの実装がまだできてない。
	End Sub*/

	Override Sub SetLength(value As Int64)
		disposedCheck()
		If This.CanWrite() and This.CanSeek() Then
			If This.IsAsync() Then
			Else
				Dim current = This.Position()
				This.Position(value)
				Dim ret = SetEndOfFile(This.handle)
				If ret = FALSE Then
					Detail.ThrowWinLastErrorIOException("FileStream.Read: Failed to read.")
				End If
				Position = current
			End If
		End If
	End Sub

/*	Synchronized*/

	Override Function ToString() As String
		Return This.Name()
	End Function

	Sub Unlock(position As Int64, length As Int64)
		disposedCheck()
		If position < 0 Then
			Throw New ArgumentOutOfRangeException("FileStream.Lock: An argument is negative value.", New System.Int64(position), "position")
		ElseIf length < 0 Then
			Throw New ArgumentOutOfRangeException("FileStream.Lock: An argument is negative value.", New System.Int64(length), "length")
		End If
		Dim ret = UnlockFile(handle, LODWORD(position As QWord), HIDWORD(position As QWord),
			LODWORD(length As QWord), HIDWORD(length As QWord))
		If ret = FALSE Then
			Detail.ThrowWinLastErrorIOException("FileStream.Read: Failed to read.")
		End If
	End Sub

	Override Sub Write(buffer As *Byte, offset As Long, count As Long)
		disposedCheck()
		If This.CanWrite() Then
			Dim writeBytes As DWord
			If This.IsAsync() Then
				Dim overlapped As OVERLAPPED
				SetQWord(VarPtr(overlapped.Offset), offset)
				overlapped.hEvent = CreateEvent(0, TRUE, FALSE, 0)
				Dim ret = WriteFile(This.handle, VarPtr(buffer[offset]), count, 0, overlapped)
				If ret <> FALSE Or GetLastError() = ERROR_IO_PENDING Then
					GetOverlappedResult(This.handle, overlapped, writeBytes, TRUE)
				End If
				offset += writeBytes
				CloseHandle(overlapped.hEvent)
			Else
				WriteFile(This.handle, VarPtr(buffer[offset]), count, VarPtr(writeBytes), ByVal NULL)
			End If
		End If
	End Sub

Protected
	Override Function CreateWaitHandle() As System.Threading.WaitHandle
		'調査した限りでは、System.Threading.EventWaitHandleクラスをNewする模様。
		'現状ではSystem.Threading.WaitHandleクラスをNewしてからHandleにて設定
		Dim wh As System.Threading.WaitHandle
		wh.Handle=CreateEvent(NULL,TRUE,FALSE,NULL)
		Return wh
	End Function

Private
	Sub disposedCheck()
		If handle = 0 Then
'			Throw ObjectDisposedException("FileStream: This stream has closed.")
		End If
	End Sub

End Class


End Namespace
End Namespace