/*==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/>.

Additional permissions under GNU GPL version 3 section 7

If you modify this Program, or any covered work, by linking or
combining it with any of RAD Game Tools Bink SDK, Autodesk 3ds Max SDK,
NVIDIA PhysX SDK, Microsoft DirectX SDK, OpenSSL library, Independent
JPEG Group JPEG library, Microsoft Windows Media SDK, or Apple QuickTime SDK
(or a modified version of those libraries),
containing parts covered by the terms of the Bink SDK EULA, 3ds Max EULA,
PhysX SDK EULA, DirectX SDK EULA, OpenSSL and SSLeay licenses, IJG
JPEG Library README, Windows Media SDK EULA, or QuickTime SDK EULA, the
licensors of this Program grant you additional
permission to convey the resulting work. Corresponding Source for a
non-source form of such a combination shall include the source code for
the parts of OpenSSL and IJG JPEG Library used as well as that of the covered
work.

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 "HeadSpin.h"
#include "hsStream.h"

#if HS_BUILD_FOR_WIN32
#    define hsFD HANDLE
#else
#    define hsFD FILE*
#endif

// 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:
    hsFD fRef;
    uint32_t fKey[4];

    uint32_t fActualFileSize;

    bool fBufferedStream;

    hsStream* fRAMStream;
    
    wchar_t* fWriteFileName;

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

    bool fDeleteOnExit;

    void IBufferFile();

    uint32_t IRead(uint32_t bytes, void* buffer);

    void IEncipher(uint32_t* const v, uint32_t n);
    void IDecipher(uint32_t* const v, uint32_t n);

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

    static bool ICheckMagicString(hsFD fp);
    static bool ICheckMagicString(hsStream* s);

public:
    plSecureStream(bool deleteOnExit = false, uint32_t* key = nil); // uses default key if you don't pass one in
    plSecureStream(hsStream* base, uint32_t* key = nil);
    ~plSecureStream();

    virtual bool Open(const char* name, const char* mode = "rb");
    virtual bool Open(const wchar_t* name, const wchar_t* mode = L"rb");
    bool           Open(hsStream* stream);
    virtual bool Close();

    virtual uint32_t Read(uint32_t byteCount, void* buffer);
    virtual uint32_t Write(uint32_t byteCount, const void* buffer);
    virtual bool AtEnd();
    virtual void Skip(uint32_t deltaByteCount);
    virtual void Rewind();
    virtual void FastFwd();
    virtual uint32_t GetEOF();

    uint32_t GetActualFileSize() const {return fActualFileSize;}

    static bool FileEncrypt(const char* fileName, uint32_t* key = nil);
    static bool FileEncrypt(const wchar_t* fileName, uint32_t* key = nil);
    static bool FileDecrypt(const char* fileName, uint32_t* key = nil);
    static bool FileDecrypt(const wchar_t* fileName, uint32_t* key = nil);

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

    static bool IsSecureFile(const char* fileName);
    static bool IsSecureFile(const wchar_t* 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_t flags = kRequireEncryption, uint32_t* key = nil);
    static hsStream* OpenSecureFile(const wchar_t* fileName, const uint32_t flags = kRequireEncryption, uint32_t* 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_t* key = nil);
    static hsStream* OpenSecureFileWrite(const wchar_t* fileName, uint32_t* key = nil);

    static const uint32_t kDefaultKey[4]; // our default encryption key

    // searches the parent directory of filename for the encryption key file, and reads it
    // into the key passed in. Returns false if the key file didn't exist (and sets key to
    // the default key)
    static bool GetSecureEncryptionKey(const char* filename, uint32_t* key, unsigned length);
    static bool GetSecureEncryptionKey(const wchar_t* filename, uint32_t* key, unsigned length);

    static const char kKeyFilename[];
    static const wchar_t kWKeyFilename[];
};

#endif // plSecureStream_h_inc