/* Copyright (C) 2014 InfiniDB, 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; version 2 of
   the License.

   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, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
   MA 02110-1301, USA. */

/******************************************************************************************
 * $Id: idbcompress.cpp 3907 2013-06-18 13:32:46Z dcathey $
 *
 ******************************************************************************************/
#include <cstring>
#include <iostream>
#include <stdexcept>
#include <unordered_map>
using namespace std;

#include "blocksize.h"
#include "logger.h"
#include "snappy.h"
#include "hasher.h"
#include "mcsconfig.h"
#ifdef HAVE_LZ4
#include "lz4.h"
#else
// Taken from lz4.h.
#define LZ4_MAX_INPUT_SIZE 0x7E000000 /* 2 113 929 216 bytes */
#define LZ4_COMPRESSBOUND(isize) \
  ((unsigned)(isize) > (unsigned)LZ4_MAX_INPUT_SIZE ? 0 : (isize) + ((isize) / 255) + 16)
#endif

#define IDBCOMP_DLLEXPORT
#include "idbcompress.h"
#undef IDBCOMP_DLLEXPORT

namespace
{
const uint64_t MAGIC_NUMBER = 0xfdc119a384d0778eULL;
const uint64_t VERSION_NUM3 = 3;

// version 1.1 of the chunk data has a short header
// QuickLZ compressed data never has the high bit set on the first byte
const int SIG_OFFSET = 0;
const int CHECKSUM_OFFSET = 1;
const int LEN_OFFSET = 5;
const unsigned HEADER_SIZE = 9;

// The max number of lbids to be stored in segment file.
const uint32_t LBID_MAX_SIZE = 48;

struct CompressedDBFileHeader
{
  uint64_t fMagicNumber;
  uint64_t fVersionNum;
  uint64_t fCompressionType;
  uint64_t fHeaderSize;
  uint64_t fBlockCount;
  uint64_t fColumnWidth;
  execplan::CalpontSystemCatalog::ColDataType fColDataType;
  uint64_t fLBIDCount;
  uint64_t fLBIDS[LBID_MAX_SIZE];
};

// Make the header to be 4K, regardless number of fields being defined/used in header.
union CompressedDBFileHeaderBlock
{
  CompressedDBFileHeader fHeader;
  char fDummy[compress::CompressInterface::HDR_BUF_LEN];
};

void initCompressedDBFileHeader(void* hdrBuf, uint32_t columnWidth,
                                execplan::CalpontSystemCatalog::ColDataType colDataType, int compressionType,
                                int hdrSize)
{
  CompressedDBFileHeaderBlock* hdr = reinterpret_cast<CompressedDBFileHeaderBlock*>(hdrBuf);
  hdr->fHeader.fMagicNumber = MAGIC_NUMBER;
  hdr->fHeader.fVersionNum = VERSION_NUM3;
  hdr->fHeader.fCompressionType = compressionType;
  hdr->fHeader.fBlockCount = 0;
  hdr->fHeader.fHeaderSize = hdrSize;
  hdr->fHeader.fColumnWidth = columnWidth;
  hdr->fHeader.fColDataType = colDataType;
  hdr->fHeader.fLBIDCount = 0;
  std::memset(hdr->fHeader.fLBIDS, 0, sizeof(hdr->fHeader.fLBIDS));
}

}  // namespace

namespace compress
{
#ifndef SKIP_IDB_COMPRESSION

CompressInterface::CompressInterface(unsigned int numUserPaddingBytes)
 : fNumUserPaddingBytes(numUserPaddingBytes)
{
}

/* V1 is really only available for decompression, we kill any DDL using V1 by hand.
 * Maybe should have a new api, isDecompressionAvail() ? Any request to compress
 * using V1 will silently be changed to V2.
 */
/*static*/
bool CompressInterface::isCompressionAvail(int compressionType)
{
  return ((compressionType == 0) || (compressionType == 1) || (compressionType == 2) ||
          (compressionType == 3));
}

size_t CompressInterface::getMaxCompressedSizeGeneric(size_t inLen)
{
  return std::max(snappy::MaxCompressedLength(inLen), LZ4_COMPRESSBOUND(inLen)) + HEADER_SIZE;
}

//------------------------------------------------------------------------------
// Compress a block of data
//------------------------------------------------------------------------------
int CompressInterface::compressBlock(const char* in, const size_t inLen, unsigned char* out,
                                     size_t& outLen) const
{
  size_t snaplen = 0;
  utils::Hasher128 hasher;

  // loose input checking.
  if (outLen < maxCompressedSize(inLen))
  {
    cerr << "got outLen = " << outLen << " for inLen = " << inLen << ", needed " << (maxCompressedSize(inLen))
         << endl;
    return ERR_BADOUTSIZE;
  }

  auto rc = compress(in, inLen, reinterpret_cast<char*>(&out[HEADER_SIZE]), &outLen);
  if (rc != ERR_OK)
  {
    return rc;
  }

  snaplen = outLen;
  uint8_t* signature = (uint8_t*)&out[SIG_OFFSET];
  uint32_t* checksum = (uint32_t*)&out[CHECKSUM_OFFSET];
  uint32_t* len = (uint32_t*)&out[LEN_OFFSET];
  *signature = getChunkMagicNumber();
  *checksum = hasher((char*)&out[HEADER_SIZE], snaplen);
  *len = snaplen;

  // cerr << "cb: " << inLen << '/' << outLen << '/' << (snappy::MaxCompressedLength(inLen) + HEADER_SIZE) <<
  //	" : " << (snaplen + HEADER_SIZE) << endl;

  outLen = snaplen + HEADER_SIZE;

  return ERR_OK;
}

//------------------------------------------------------------------------------
// Decompress a block of data
//------------------------------------------------------------------------------
int CompressInterface::uncompressBlock(const char* in, const size_t inLen, unsigned char* out,
                                       size_t& outLen) const
{
  uint32_t realChecksum;
  uint32_t storedChecksum;
  uint32_t storedLen;
  uint8_t storedMagic;
  utils::Hasher128 hasher;
  auto tmpOutLen = outLen;
  outLen = 0;

  if (inLen < 1)
    return ERR_BADINPUT;

  storedMagic = *((uint8_t*)&in[SIG_OFFSET]);

  if (storedMagic == getChunkMagicNumber())
  {
    if (inLen < HEADER_SIZE)
      return ERR_BADINPUT;

    storedChecksum = *((uint32_t*)&in[CHECKSUM_OFFSET]);
    storedLen = *((uint32_t*)(&in[LEN_OFFSET]));

    if (inLen < storedLen + HEADER_SIZE)
      return ERR_BADINPUT;

    realChecksum = hasher(&in[HEADER_SIZE], storedLen);

    if (storedChecksum != realChecksum)
      return ERR_CHECKSUM;

    auto rc = uncompress(&in[HEADER_SIZE], storedLen, reinterpret_cast<char*>(out), &tmpOutLen);
    if (rc != ERR_OK)
    {
      cerr << "uncompressBlock failed!" << endl;
      return ERR_DECOMPRESS;
    }

    outLen = tmpOutLen;
  }
  else
  {
    // v1 compression or bad header
    return ERR_BADINPUT;
  }

  // cerr << "ub: " << inLen << " : " << outLen << endl;

  return ERR_OK;
}

//------------------------------------------------------------------------------
// Verify the passed in buffer contains a valid compression file header.
//------------------------------------------------------------------------------
int CompressInterface::verifyHdr(const void* hdrBuf)
{
  const CompressedDBFileHeader* hdr = reinterpret_cast<const CompressedDBFileHeader*>(hdrBuf);

  if (hdr->fMagicNumber != MAGIC_NUMBER)
    return -1;

  if (!isCompressionAvail(hdr->fCompressionType))
    return -2;

  return 0;
}

//------------------------------------------------------------------------------
// Extract compression pointer information out of the pointer buffer that is
// passed in.  ptrBuf points to the pointer section of the compression hdr.
//------------------------------------------------------------------------------
int CompressInterface::getPtrList(const char* ptrBuf, const int ptrBufSize, CompChunkPtrList& chunkPtrs)
{
  int rc = 0;
  chunkPtrs.clear();

  const uint64_t* ptrs = reinterpret_cast<const uint64_t*>(ptrBuf);
  const unsigned int NUM_PTRS = ptrBufSize / sizeof(uint64_t);

  for (unsigned int i = 0; (i < NUM_PTRS) && (rc == 0); i++)
  {
    if (ptrs[i + 1] == 0)  // 0 offset means end of data
      break;

    if (ptrs[i + 1] > ptrs[i])
      chunkPtrs.push_back(make_pair(ptrs[i], (ptrs[i + 1] - ptrs[i])));
    else
      rc = -1;
  }

  return rc;
}

//------------------------------------------------------------------------------
// Extract compression pointer information out of the file compression hdr.
// Function assume that the file is a column file that has just two 4096-hdrs,
// one for the file header, and one for the list of pointers.
// Wrapper of above method for backward compatibility.
//------------------------------------------------------------------------------
int CompressInterface::getPtrList(const char* hdrBuf, CompChunkPtrList& chunkPtrs)
{
  return getPtrList(hdrBuf + HDR_BUF_LEN, HDR_BUF_LEN, chunkPtrs);
}

//------------------------------------------------------------------------------
// Count the number of chunk pointers in the pointer header(s)
//------------------------------------------------------------------------------
unsigned int CompressInterface::getPtrCount(const char* ptrBuf, const int ptrBufSize)
{
  unsigned int chunkCount = 0;

  const uint64_t* ptrs = reinterpret_cast<const uint64_t*>(ptrBuf);
  const unsigned int NUM_PTRS = ptrBufSize / sizeof(uint64_t);

  for (unsigned int i = 0; i < NUM_PTRS; i++)
  {
    if (ptrs[i + 1] == 0)  // 0 offset means end of data
      break;

    chunkCount++;
  }

  return chunkCount;
}

//------------------------------------------------------------------------------
// Count the number of chunk pointers in the specified 8192 byte compression
// file header, which carries a single 4096 byte compression chunk header.
// This should not be used for compressed dictionary files which could have
// more compression chunk headers.
//------------------------------------------------------------------------------
unsigned int CompressInterface::getPtrCount(const char* hdrBuf)
{
  return getPtrCount(hdrBuf + HDR_BUF_LEN, HDR_BUF_LEN);
}

//------------------------------------------------------------------------------
// Store list of compression pointers into the specified header.
//------------------------------------------------------------------------------
void CompressInterface::storePtrs(const std::vector<uint64_t>& ptrs, void* ptrBuf, int ptrSectionSize)
{
  memset((ptrBuf), 0, ptrSectionSize);  // reset the pointer section to 0
  uint64_t* hdrPtrs = reinterpret_cast<uint64_t*>(ptrBuf);

  for (unsigned i = 0; i < ptrs.size(); i++)
  {
    hdrPtrs[i] = ptrs[i];
  }
}

//------------------------------------------------------------------------------
// Wrapper of above method for backward compatibility
//------------------------------------------------------------------------------
void CompressInterface::storePtrs(const std::vector<uint64_t>& ptrs, void* ptrBuf)
{
  storePtrs(ptrs, reinterpret_cast<char*>(ptrBuf) + HDR_BUF_LEN, HDR_BUF_LEN);
}

//------------------------------------------------------------------------------
// Initialize the header blocks to be written at the start of a dictionary file.
//------------------------------------------------------------------------------
void CompressInterface::initHdr(void* hdrBuf, void* ptrBuf, uint32_t colWidth,
                                execplan::CalpontSystemCatalog::ColDataType columnType, int compressionType,
                                int hdrSize)
{
  memset(hdrBuf, 0, HDR_BUF_LEN);
  memset(ptrBuf, 0, hdrSize - HDR_BUF_LEN);
  initCompressedDBFileHeader(hdrBuf, colWidth, columnType, compressionType, hdrSize);
}

//------------------------------------------------------------------------------
// Initialize the header blocks to be written at the start of a column file.
//------------------------------------------------------------------------------
void CompressInterface::initHdr(void* hdrBuf, uint32_t columnWidth,
                                execplan::CalpontSystemCatalog::ColDataType columnType, int compressionType)
{
  memset(hdrBuf, 0, HDR_BUF_LEN * 2);
  initCompressedDBFileHeader(hdrBuf, columnWidth, columnType, compressionType, HDR_BUF_LEN * 2);
}

//------------------------------------------------------------------------------
// Get the header's version number
//------------------------------------------------------------------------------
uint64_t CompressInterface::getVersionNumber(const void* hdrBuf)
{
  return (reinterpret_cast<const CompressedDBFileHeader*>(hdrBuf)->fVersionNum);
}

//------------------------------------------------------------------------------
// Set the file's block count
//------------------------------------------------------------------------------
void CompressInterface::setBlockCount(void* hdrBuf, uint64_t count)
{
  reinterpret_cast<CompressedDBFileHeader*>(hdrBuf)->fBlockCount = count;
}

//------------------------------------------------------------------------------
// Get the file's block count
//------------------------------------------------------------------------------
uint64_t CompressInterface::getBlockCount(const void* hdrBuf)
{
  return (reinterpret_cast<const CompressedDBFileHeader*>(hdrBuf)->fBlockCount);
}

//------------------------------------------------------------------------------
// Get the file's compression type
//------------------------------------------------------------------------------
uint64_t CompressInterface::getCompressionType(const void* hdrBuf)
{
  return (reinterpret_cast<const CompressedDBFileHeader*>(hdrBuf)->fCompressionType);
}

//------------------------------------------------------------------------------
// Set the overall header size
//------------------------------------------------------------------------------
void CompressInterface::setHdrSize(void* hdrBuf, uint64_t size)
{
  reinterpret_cast<CompressedDBFileHeader*>(hdrBuf)->fHeaderSize = size;
}

//------------------------------------------------------------------------------
// Get the overall header size
//------------------------------------------------------------------------------
uint64_t CompressInterface::getHdrSize(const void* hdrBuf)
{
  return (reinterpret_cast<const CompressedDBFileHeader*>(hdrBuf)->fHeaderSize);
}

//------------------------------------------------------------------------------
// Get column type
//-----------------------------------------------------------------------------
execplan::CalpontSystemCatalog::ColDataType CompressInterface::getColDataType(const void* hdrBuf)
{
  return (reinterpret_cast<const CompressedDBFileHeader*>(hdrBuf)->fColDataType);
}

//------------------------------------------------------------------------------
// Get column width
//------------------------------------------------------------------------------
uint64_t CompressInterface::getColumnWidth(const void* hdrBuf)
{
  return (reinterpret_cast<const CompressedDBFileHeader*>(hdrBuf)->fColumnWidth);
}

//------------------------------------------------------------------------------
// Get LBID by index
//------------------------------------------------------------------------------
uint64_t CompressInterface::getLBIDByIndex(const void* hdrBuf, uint64_t index)
{
  if (index < LBID_MAX_SIZE)
    return (reinterpret_cast<const CompressedDBFileHeader*>(hdrBuf)->fLBIDS[index]);
  return 0;
}

//------------------------------------------------------------------------------
// Set LBID by index
//------------------------------------------------------------------------------
void CompressInterface::setLBIDByIndex(void* hdrBuf, uint64_t lbid, uint64_t index)
{
  if (lbid && index < LBID_MAX_SIZE)
  {
    reinterpret_cast<CompressedDBFileHeader*>(hdrBuf)->fLBIDS[index] = lbid;
    reinterpret_cast<CompressedDBFileHeader*>(hdrBuf)->fLBIDCount =
        std::max(index + 1, reinterpret_cast<CompressedDBFileHeader*>(hdrBuf)->fLBIDCount);
  }
}

//------------------------------------------------------------------------------
// Get LBID count
//------------------------------------------------------------------------------
uint64_t CompressInterface::getLBIDCount(void* hdrBuf)
{
  return reinterpret_cast<const CompressedDBFileHeader*>(hdrBuf)->fLBIDCount;
}

//------------------------------------------------------------------------------
// Calculates the chunk and block offset within the chunk for the specified
// block number.
//------------------------------------------------------------------------------
void CompressInterface::locateBlock(unsigned int block, unsigned int& chunkIndex,
                                    unsigned int& blockOffsetWithinChunk) const
{
  const uint64_t BUFLEN = UNCOMPRESSED_INBUF_LEN;

  uint64_t byteOffset = (uint64_t)block * BLOCK_SIZE;
  uint64_t chunk = byteOffset / BUFLEN;
  uint64_t blockInChunk = (byteOffset % BUFLEN) / BLOCK_SIZE;

  chunkIndex = chunk;
  blockOffsetWithinChunk = blockInChunk;
}

//------------------------------------------------------------------------------
// Round up the size of the buffer to the applicable compressed size increment,
// also expand to allow for user requested padding.  Lastly, initialize padding
// bytes to 0.
//------------------------------------------------------------------------------
int CompressInterface::padCompressedChunks(unsigned char* buf, size_t& len, unsigned int maxLen) const
{
  int nPaddingBytes = 0;
  int nRem = len % COMPRESSED_CHUNK_INCREMENT_SIZE;

  if (nRem != 0)
  {
    nPaddingBytes = COMPRESSED_CHUNK_INCREMENT_SIZE - nRem;
  }

  nPaddingBytes = nPaddingBytes + fNumUserPaddingBytes;

  if (nPaddingBytes > 0)
  {
    if ((len + nPaddingBytes) > maxLen)
      return -1;

    memset(buf + len, 0, nPaddingBytes);
    len = len + nPaddingBytes;
  }

  return 0;
}

// Snappy
CompressInterfaceSnappy::CompressInterfaceSnappy(uint32_t numUserPaddingBytes)
 : CompressInterface(numUserPaddingBytes)
{
}

int32_t CompressInterfaceSnappy::compress(const char* in, size_t inLen, char* out, size_t* outLen) const
{
  snappy::RawCompress(in, inLen, out, outLen);

#ifdef DEBUG_COMPRESSION
  std::cout << "Snappy::compress: inLen " << inLen << ", outLen " << *outLen << std::endl;
#endif

  return ERR_OK;
}

int32_t CompressInterfaceSnappy::uncompress(const char* in, size_t inLen, char* out, size_t* outLen) const
{
  size_t realOutLen = 0;
  auto rc = snappy::GetUncompressedLength(in, inLen, &realOutLen);

  if (!rc || realOutLen > *outLen)
  {
    cerr << "snappy::GetUncompressedLength failed. InLen: " << inLen << ", outLen: " << *outLen
         << ", realOutLen: " << realOutLen << endl;
    return ERR_DECOMPRESS;
  }

  rc = snappy::RawUncompress(in, inLen, out);

  if (!rc)
  {
    cerr << "snappy::RawUnompress failed. InLen: " << inLen << ", outLen: " << *outLen << endl;
    return ERR_DECOMPRESS;
  }

#ifdef DEBUG_COMPRESSION
  std::cout << "Snappy::uncompress: inLen " << inLen << ", outLen " << *outLen << std::endl;
#endif
  *outLen = realOutLen;

  return ERR_OK;
}

size_t CompressInterfaceSnappy::maxCompressedSize(size_t uncompSize) const
{
  return (snappy::MaxCompressedLength(uncompSize) + HEADER_SIZE);
}

bool CompressInterfaceSnappy::getUncompressedSize(char* in, size_t inLen, size_t* outLen) const
{
  return snappy::GetUncompressedLength(in, inLen, outLen);
}

uint8_t CompressInterfaceSnappy::getChunkMagicNumber() const
{
  return CHUNK_MAGIC_SNAPPY;
}

// LZ4
CompressInterfaceLZ4::CompressInterfaceLZ4(uint32_t numUserPaddingBytes)
 : CompressInterface(numUserPaddingBytes)
{
}

int32_t CompressInterfaceLZ4::compress(const char* in, size_t inLen, char* out, size_t* outLen) const
{
#ifdef HAVE_LZ4
  auto compressedLen = LZ4_compress_default(in, out, inLen, *outLen);

  if (!compressedLen)
  {
    cerr << "LZ_compress_default failed. InLen: " << inLen << ", compressedLen: " << compressedLen << endl;
    return ERR_COMPRESS;
  }

#ifdef DEBUG_COMPRESSION
  std::cout << "LZ4::compress: inLen " << inLen << ", comressedLen " << compressedLen << std::endl;
#endif

  *outLen = compressedLen;
  return ERR_OK;
#else
  return ERR_COMPRESS;
#endif
}

int32_t CompressInterfaceLZ4::uncompress(const char* in, size_t inLen, char* out, size_t* outLen) const
{
#ifdef HAVE_LZ4
  auto decompressedLen = LZ4_decompress_safe(in, out, inLen, *outLen);

  if (decompressedLen < 0)
  {
    cerr << "LZ_decompress_safe failed with error code " << decompressedLen << endl;
    cerr << "InLen: " << inLen << ", outLen: " << *outLen << endl;
    return ERR_DECOMPRESS;
  }

  *outLen = decompressedLen;

#ifdef DEBUG_COMPRESSION
  std::cout << "LZ4::uncompress: inLen " << inLen << ", outLen " << *outLen << std::endl;
#endif

  return ERR_OK;
#else
  return ERR_DECOMPRESS;
#endif
}

size_t CompressInterfaceLZ4::maxCompressedSize(size_t uncompSize) const
{
  return (LZ4_COMPRESSBOUND(uncompSize) + HEADER_SIZE);
}

bool CompressInterfaceLZ4::getUncompressedSize(char* in, size_t inLen, size_t* outLen) const
{
  // LZ4 does not have such function.
  idbassert(false);
  return false;
}

uint8_t CompressInterfaceLZ4::getChunkMagicNumber() const
{
  return CHUNK_MAGIC_LZ4;
}

CompressInterface* getCompressInterfaceByType(uint32_t compressionType, uint32_t numUserPaddingBytes)
{
  switch (compressionType)
  {
    case 1:
    case 2: return new CompressInterfaceSnappy(numUserPaddingBytes);
    case 3: return new CompressInterfaceLZ4(numUserPaddingBytes);
  }

  return nullptr;
}

CompressInterface* getCompressInterfaceByName(const std::string& compressionName,
                                              uint32_t numUserPaddingBytes)
{
  if (compressionName == "SNAPPY")
    return new CompressInterfaceSnappy(numUserPaddingBytes);
  else if (compressionName == "LZ4")
    return new CompressInterfaceLZ4(numUserPaddingBytes);
  return nullptr;
}

void initializeCompressorPool(
    std::unordered_map<uint32_t, std::shared_ptr<CompressInterface>>& compressorPool,
    uint32_t numUserPaddingBytes)
{
  compressorPool = {
      make_pair(2, std::shared_ptr<CompressInterface>(new CompressInterfaceSnappy(numUserPaddingBytes))),
      make_pair(3, std::shared_ptr<CompressInterface>(new CompressInterfaceLZ4(numUserPaddingBytes)))};
}

std::shared_ptr<CompressInterface> getCompressorByType(
    std::unordered_map<uint32_t, std::shared_ptr<CompressInterface>>& compressorPool,
    uint32_t compressionType)
{
  switch (compressionType)
  {
    case 1:
    case 2:
      if (!compressorPool.count(2))
      {
        return nullptr;
      }
      return compressorPool[2];
    case 3:
      if (!compressorPool.count(3))
      {
        return nullptr;
      }
      return compressorPool[3];
  }

  return nullptr;
}

#endif

}  // namespace compress
