/*****************************************************************************
 * Author:   Valient Gough <vgough@pobox.com>
 *
 *****************************************************************************
 * Copyright (c) 2004, Valient Gough
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser 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 Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef _CipherFileIO_incl_
#define _CipherFileIO_incl_

#include <inttypes.h>
#include <memory>
#include <stdint.h>
#include <sys/types.h>

#include "BlockFileIO.h"
#include "CipherKey.h"
#include "FSConfig.h"
#include "FileUtils.h"
#include "Interface.h"

namespace encfs {

class Cipher;
class FileIO;
struct IORequest;

/*
    Implement the FileIO interface encrypting data in blocks.

    Uses BlockFileIO to handle the block scatter / gather issues.
*/
class CipherFileIO : public BlockFileIO {
 public:
  CipherFileIO(std::shared_ptr<FileIO> base, const FSConfigPtr &cfg);
  virtual ~CipherFileIO();

  virtual Interface interface() const;

  virtual void setFileName(const char *fileName);
  virtual const char *getFileName() const;
  virtual bool setIV(uint64_t iv);

  virtual int open(int flags);

  virtual int getAttr(struct stat *stbuf) const;
  virtual off_t getSize() const;

  virtual int truncate(off_t size);

  virtual bool isWritable() const;

 private:
  virtual ssize_t readOneBlock(const IORequest &req) const;
  virtual bool writeOneBlock(const IORequest &req);
  virtual void generateReverseHeader(unsigned char *data);

  void initHeader();
  bool writeHeader();
  bool blockRead(unsigned char *buf, int size, uint64_t iv64) const;
  bool streamRead(unsigned char *buf, int size, uint64_t iv64) const;
  bool blockWrite(unsigned char *buf, int size, uint64_t iv64) const;
  bool streamWrite(unsigned char *buf, int size, uint64_t iv64) const;

  ssize_t read(const IORequest &req) const;

  std::shared_ptr<FileIO> base;

  FSConfigPtr fsConfig;

  // if haveHeader is true, then we have a transparent file header which
  // contains a 64 bit initialization vector.
  bool haveHeader;
  uint64_t externalIV;
  uint64_t fileIV;
  int lastFlags;

  std::shared_ptr<Cipher> cipher;
  CipherKey key;
};

}  // namespace encfs

#endif