/*==LICENSE==*

CyanWorlds.com Engine - MMOG client, server and tools
Copyright (C) 2011  Cyan Worlds, Inc.

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/>.

You can contact Cyan Worlds, Inc. by email legal@cyan.com
 or by snail mail at:
      Cyan Worlds, Inc.
      14617 N Newport Hwy
      Mead, WA   99021

*==LICENSE==*/
#ifndef plSecureStream_h_inc
#define plSecureStream_h_inc

#include "hsStream.h"
#include <windows.h>

// A slightly more secure stream then plEncryptedStream in that it uses windows file functions
// to prevent other processes from accessing the file it is working with. It also can be set
// to download the file from a server into a temporary directory (with a mangled name) and
// delete that file on close, thereby minimizing the chance of having that file examined or
// edited.
class plSecureStream: public hsStream
{
protected:
	HANDLE fRef;
	UInt32 fKey[4];

	UInt32 fActualFileSize;

	bool fBufferedStream;

	hsStream* fRAMStream;
	
	wchar* fWriteFileName;

	enum OpenMode {kOpenRead, kOpenWrite, kOpenFail};
	OpenMode fOpenMode;

	hsBool fDeleteOnExit;

	void IBufferFile();

	UInt32 IRead(UInt32 bytes, void* buffer);

	void IEncipher(UInt32* const v, UInt32 n);
	void IDecipher(UInt32* const v, UInt32 n);

	bool IWriteEncrypted(hsStream* sourceStream, const wchar* outputFile);

	static bool ICheckMagicString(HANDLE fp);

public:
	plSecureStream(hsBool deleteOnExit = false, UInt32* key = nil); // uses default key if you don't pass one in
	~plSecureStream();

	virtual hsBool Open(const char* name, const char* mode = "rb");
	virtual hsBool Open(const wchar* name, const wchar* mode = L"rb");
	virtual hsBool Close();

	virtual UInt32 Read(UInt32 byteCount, void* buffer);
	virtual UInt32 Write(UInt32 byteCount, const void* buffer);
	virtual hsBool AtEnd();
	virtual void Skip(UInt32 deltaByteCount);
	virtual void Rewind();
	virtual void FastFwd();
	virtual UInt32 GetEOF();

	UInt32 GetActualFileSize() const {return fActualFileSize;}

	static bool FileEncrypt(const char* fileName, UInt32* key = nil);
	static bool FileEncrypt(const wchar* fileName, UInt32* key = nil);
	static bool FileDecrypt(const char* fileName, UInt32* key = nil);
	static bool FileDecrypt(const wchar* fileName, UInt32* key = nil);

	enum OpenSecureFileFlags
	{
		kRequireEncryption = 0x01,
		kDeleteOnExit = 0x02,
	};

	static bool IsSecureFile(const char* fileName);
	static bool IsSecureFile(const wchar* fileName);

	// Attempts to create a read-binary stream for the requested file (delete the stream
	// when you are done with it!)
	static hsStream* OpenSecureFile(const char* fileName, const UInt32 flags = kRequireEncryption, UInt32* key = nil);
	static hsStream* OpenSecureFile(const wchar* fileName, const UInt32 flags = kRequireEncryption, UInt32* key = nil);
	// Attempts to create a write-binary stream for the requested file (delete the stream
	// when you are done with it!)
	static hsStream* OpenSecureFileWrite(const char* fileName, UInt32* key = nil);
	static hsStream* OpenSecureFileWrite(const wchar* fileName, UInt32* key = nil);

	static const UInt32 kDefaultKey[4]; // our default encryption key
};

#endif // plSecureStream_h_inc