// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-FileCopyrightText: Copyright (c) Sandia Corporation
// SPDX-License-Identifier: BSD-3-Clause

#include "LSDynaFamily.h"
#include <vtksys/SystemTools.hxx>

#include <cassert>
#include <cctype>
#include <cerrno>

#include <algorithm>
#include <map>
#include <set>
#include <string>
#include <vector>

VTK_ABI_NAMESPACE_BEGIN
namespace
{
// Decide which of 3 stat varieties to use: stat, stat64, __stat64
// Usually stat uses 32 bit fields, and stat64 (with underscores in Windows) uses 64 bit fields.
// But on the BSDs, stat uses 64 bit fields these days.
#if (VTK_SIZEOF_ID_TYPE == 8) && !defined(_DARWIN_FEATURE_64_BIT_INODE) &&                         \
  !defined(__FreeBSD__) && !defined(__NetBSD__) && !defined(__OpenBSD__)
#ifndef _WIN32
#if defined __EMSCRIPTEN__
#if defined _LARGEFILE64_SOURCE
#define USE_STAT_64
#else
#define USE_STAT
#endif
#else
#define USE_STAT_64
#endif
#else
#define USE_WIN_STAT_64
#endif
#else
#define USE_STAT
#endif

#if defined(USE_STAT_64)
int LS_DYNA_STAT(const char* fname, struct stat64& s)
{
  return stat64(fname, &s);
}
#elif defined(USE_WIN_STAT_64)
int LS_DYNA_STAT(const char* fname, struct __stat64& s)
{
  return __stat64(fname, &s);
}
#elif defined(USE_STAT)
int LS_DYNA_STAT(const char* fname, struct stat& s)
{
  return stat(fname, &s);
}
#endif

vtkLSDynaFile_t VTK_LSDYNA_OPENFILE(const char* fname)
{
#ifndef _WIN32
  vtkLSDynaFile_t f = open(fname, O_RDONLY);
  return f;
#else
  vtkLSDynaFile_t f = vtksys::SystemTools::Fopen(fname, "rb");
  setvbuf(f, nullptr, _IONBF, 0); // disable buffer
  return f;
#endif
}

std::string vtkLSGetFamilyFileName(
  const char* basedir, const std::string& dbname, int adaptationLvl, int number)
{
  std::string blorb;

  blorb = basedir + dbname;

  if (adaptationLvl > 0)
  {
    // convert adaptationLvl from an integer to "aa", "ab", "ac", ...
    // and tack it onto the end of our blorb.
    std::string slvl;
    int a = adaptationLvl - 1;
    while (a)
    {
      slvl += char(97 + (a % 26));
      a = a / 26;
    }
    while (slvl.size() < 2)
    {
      slvl += 'a';
    }
    std::reverse(slvl.begin(), slvl.end());
    blorb += slvl;
  }

  if (number > 0)
  {
    char n[12];
    snprintf(n, sizeof(n), "%02d", number);
    blorb += n;
  }

  return blorb;
}
}

const char* LSDynaFamily::SectionTypeNames[] = { "ControlSection", "StaticSection",
  "TimeStepSection", "MaterialTypeData", "FluidMaterialIdData", "SPHElementData", "GeometryData",
  "UserIdData", "AdaptedParentData", "SPHNodeData", "RigidSurfaceData", "EndOfStaticSection",
  "ElementDeletionState", "SPHNodeState", "RigidSurfaceState" };

const float LSDynaFamily::EOFMarker = -999999.0f;

struct LSDynaFamily::BufferingInfo
{
  BufferingInfo()
    : numWordsToRead(0)
    , loopTimes(0)
    , leftOver(0)
    , size(1048576)
  {
  }
  vtkIdType numWordsToRead;
  vtkIdType loopTimes;
  vtkIdType leftOver;
  const vtkIdType size; // default buffer size
private:
  LSDynaFamily::BufferingInfo& operator=(const LSDynaFamily::BufferingInfo&) = delete;
};

//------------------------------------------------------------------------------
LSDynaFamily::LSDynaFamily()
{
  this->FD = VTK_LSDYNA_BADFILE; // No file open
  this->FAdapt = -1;             // Invalid adaptation
  this->FNum = -1;               // No files in filelist
  this->FWord = 0;               // At start of file

  this->SwapEndian = -1; // No endian-ness determined
  this->WordSize = 0;    // No word size determined

  this->TimeStep = 0;  // Initial time step
  this->StateSize = 0; // Time steps take up no room on disk

  this->AdaptationsMarkers.emplace_back();
  this->Chunk = nullptr;
  this->ChunkWord = 0;
  this->ChunkAlloc = 0;

  this->FileHandlesClosed = false;

  this->BufferInfo = new LSDynaFamily::BufferingInfo();
}

//------------------------------------------------------------------------------
LSDynaFamily::~LSDynaFamily()
{
  if (!VTK_LSDYNA_ISBADFILE(this->FD))
  {
    VTK_LSDYNA_CLOSEFILE(this->FD);
  }

  delete[] this->Chunk;

  delete this->BufferInfo;
}

//------------------------------------------------------------------------------
void LSDynaFamily::SetDatabaseDirectory(const std::string& dd)
{
  this->DatabaseDirectory = dd;
}
std::string LSDynaFamily::GetDatabaseDirectory()
{
  return this->DatabaseDirectory;
}

//------------------------------------------------------------------------------
void LSDynaFamily::SetDatabaseBaseName(const std::string& bn)
{
  this->DatabaseBaseName = bn;
}
std::string LSDynaFamily::GetDatabaseBaseName()
{
  return this->DatabaseBaseName;
}

//------------------------------------------------------------------------------
int LSDynaFamily::ScanDatabaseDirectory()
{
  // FIXME: None of this need be cleared if we are trying to track a
  // simulation in progress.  But it won't hurt to redo the scan from the
  // beginning... it will just take longer.
  this->Files.clear();
  this->FileSizes.clear();
  this->FileAdaptLevels.clear();
  this->TimeAdaptLevels.clear();
  this->Adaptations.clear();
  this->TimeStepMarks.clear();

  std::string tmpFile;
  int filenum = 0;
  int adaptLevel = 0;
  int tryAdapt = 0; // don't try an adaptive step unless we have one good file at the current level.
  bool adapted = true; // true when advancing over a mesh adaptation.
#if defined(USE_WIN_STAT_64)
  struct __stat64 st;
#elif defined(USE_STAT_64)
  struct stat64 st;
#elif defined(USE_STAT)
  struct stat st;
#endif
  while (tryAdapt >= 0)
  {
    tmpFile = vtkLSGetFamilyFileName(
      this->DatabaseDirectory.c_str(), this->DatabaseBaseName, adaptLevel, filenum);
    if (LS_DYNA_STAT(tmpFile.c_str(), st) == 0)
    {
      if (adapted)
      {
        this->Adaptations.push_back((int)this->Files.size());
        adapted = false;
      }
      this->Files.push_back(tmpFile);
      this->FileSizes.push_back(st.st_size);
      this->FileAdaptLevels.push_back(adaptLevel);
      tryAdapt = 1;
      ++filenum;
    }
    else
    {
      --tryAdapt;
      ++adaptLevel;
      filenum = 0;
      adapted = true;
    }
  }
  return this->Files.empty();
}

//------------------------------------------------------------------------------
const char* LSDynaFamily::SectionTypeToString(SectionType s)
{
  return SectionTypeNames[s];
}

//------------------------------------------------------------------------------
int LSDynaFamily::SkipToWord(SectionType sType, vtkIdType sId, vtkIdType wordNumber)
{
  LSDynaFamilySectionMark mark;
  if (sType != TimeStepSection && sType < ElementDeletionState)
  {
    assert(sId < (int)this->Adaptations.size());
    if (sId < 0)
      sId = 0;
    mark = this->AdaptationsMarkers[sId].Marks[sType];
    mark.Offset += wordNumber;
  }
  else
  {
    // NOTE: SkipToWord cannot jump outside of the current adaptation level!
    // You must use SetTimeStep() to do that -- it will call ReadHeaderInformation().
    mark = this->AdaptationsMarkers[this->FAdapt].Marks[sType];
    mark.Offset += wordNumber;
    if (sId >= (vtkIdType)this->TimeStepMarks.size())
    {
      return 1;
    }
    mark.FileNumber = this->TimeStepMarks[sId].FileNumber;
    mark.Offset = this->TimeStepMarks[sId].Offset +
      (this->AdaptationsMarkers[this->FAdapt].Marks[sType].Offset -
        this->AdaptationsMarkers[this->FAdapt].Marks[TimeStepSection].Offset) +
      wordNumber;
  }

  // if the skip is too big for one file, advance to the correct file
  while ((mark.FileNumber < (vtkIdType)this->Files.size()) &&
    (mark.Offset > this->FileSizes[mark.FileNumber]))
  {
    mark.Offset -= this->FileSizes[mark.FileNumber];
    mark.FileNumber++;
  }

  if (mark.FileNumber > (vtkIdType)this->Files.size())
  {
    // when stepping past the end of the entire database (as opposed
    // to a single file), return a different value
    return 2;
  }

  if (this->FNum < 0 || (this->FNum != mark.FileNumber))
  {
    if (this->FNum >= 0)
    {
      if (!VTK_LSDYNA_ISBADFILE(this->FD))
      {
        VTK_LSDYNA_CLOSEFILE(this->FD);
      }
    }
    this->FD = VTK_LSDYNA_OPENFILE(this->Files[mark.FileNumber].c_str());
    if (VTK_LSDYNA_ISBADFILE(this->FD))
    {
      return errno;
    }
    this->FNum = mark.FileNumber;
    this->FAdapt = this->FileAdaptLevels[this->FNum];
  }
  vtkLSDynaOff_t offset = static_cast<vtkLSDynaOff_t>(mark.Offset * this->WordSize);
  // FIXME: Handle case where wordNumber + mark.Offset > (7=factor)*512*512
  if (VTK_LSDYNA_SEEKTELL(this->FD, offset, SEEK_SET) != offset)
  {
    return errno;
  }
  this->FWord = mark.Offset;
  return 0;
}

// FIXME: Assumes there is a valid file open and that
// lseek will return the byte just past the time value word.
// the BufferChunks buffer).
//------------------------------------------------------------------------------
int LSDynaFamily::MarkTimeStep()
{
  LSDynaFamilySectionMark mark;
  mark.FileNumber = this->FNum;
  mark.Offset = VTK_LSDYNA_TELL(this->FD) / this->GetWordSize() - 1;
  this->TimeStepMarks.push_back(mark);
  this->TimeAdaptLevels.push_back(this->FAdapt);
  return 0;
}

//------------------------------------------------------------------------------
int LSDynaFamily::SkipWords(vtkIdType numWords)
{
  if (numWords <= 0)
  {
    return 0;
  }

  if (this->FNum < 0 || VTK_LSDYNA_ISBADFILE(this->FD))
  {
    return -1;
  }
  vtkIdType offset = numWords * this->WordSize;

  // determine where we are currently in the file
  vtkIdType currentPos = VTK_LSDYNA_TELL(this->FD);

  VTK_LSDYNA_SEEK(this->FD, static_cast<vtkLSDynaOff_t>(offset), SEEK_CUR);
  vtkIdType amountMoved = VTK_LSDYNA_TELL(this->FD) - currentPos;

  offset -= amountMoved;
  if (offset > 0)
  {
    // try advancing to next file
    VTK_LSDYNA_CLOSEFILE(this->FD);

    // if the skip is too big for one file, advance to the correct file
    ++this->FNum;
    while ((this->FNum < (vtkIdType)this->Files.size()) && (offset > this->FileSizes[this->FNum]))
    {
      offset -= this->FileSizes[this->FNum];
      ++this->FNum;
    }

    this->FD = VTK_LSDYNA_OPENFILE(this->Files[this->FNum].c_str());
    this->FWord = 0;
    if (VTK_LSDYNA_ISBADFILE(this->FD))
    { // bad file (permissions, deleted) or request (too big)
      this->FNum = -1;
      this->FAdapt = -1;
      return errno;
    }

    // seek into the file the current offset amount
    VTK_LSDYNA_SEEK(this->FD, static_cast<vtkLSDynaOff_t>(offset), SEEK_CUR);
    amountMoved = VTK_LSDYNA_TELL(this->FD);
    offset -= amountMoved;
  }

  this->FWord = VTK_LSDYNA_TELL(this->FD);
  return 0;
}

//------------------------------------------------------------------------------
int LSDynaFamily::BufferChunk(WordType wType, vtkIdType chunkSizeInWords)
{
  if (chunkSizeInWords == 0)
    return 0;

  if (this->ChunkAlloc < chunkSizeInWords)
  {
    delete[] this->Chunk;
    this->ChunkAlloc = chunkSizeInWords;
    this->Chunk = new unsigned char[this->ChunkAlloc * this->WordSize];
  }

  this->FWord = VTK_LSDYNA_TELL(this->FD);

  // Eventually, we must check the return value and see if the read
  // came up short (EOF). If it did, then we must advance to the next
  // file.
  vtkIdType bytesLeft = chunkSizeInWords * this->WordSize;
  vtkIdType bytesRead;
  unsigned char* buf = this->Chunk;
  this->ChunkValid = 0;
  this->ChunkWord = 0;
  while (bytesLeft)
  {
    bytesRead = static_cast<vtkIdType>(VTK_LSDYNA_READ(this->FD, (void*)buf, bytesLeft));
    this->ChunkValid += bytesRead;
    if (bytesRead < bytesLeft)
    {
      if (bytesRead <= 0)
      { // try advancing to next file
        VTK_LSDYNA_CLOSEFILE(this->FD);
        if (++this->FNum == (vtkIdType)this->Files.size())
        { // no more files to read. Oops.
          this->FNum = -1;
          this->FAdapt = -1;
          return 1;
        }
        this->FD = VTK_LSDYNA_OPENFILE(this->Files[this->FNum].c_str());
        this->FWord = 0;
        if (VTK_LSDYNA_ISBADFILE(this->FD))
        { // bad file (permissions, deleted) or request (too big)
          this->FNum = -1;
          this->FAdapt = -1;
          return errno;
        }
      }
    }
    bytesLeft -= bytesRead;
    buf += bytesRead;
  }
  this->FWord = VTK_LSDYNA_TELL(this->FD);

  if (this->SwapEndian && wType != LSDynaFamily::Char)
  {
    unsigned char tmp[4];
    vtkIdType i;
    unsigned char* cur = this->Chunk;

    // Currently, wType is unused, but if I ever have to support cray
    // floating point types, this will need to be different
    switch (this->WordSize)
    {
      case 4:
        for (i = 0; i < chunkSizeInWords; ++i)
        {
          tmp[0] = cur[0];
          tmp[1] = cur[1];
          cur[0] = cur[3];
          cur[1] = cur[2];
          cur[2] = tmp[1];
          cur[3] = tmp[0];
          cur += this->WordSize;
        }
        break;
      case 8:
      default:
        for (i = 0; i < chunkSizeInWords; ++i)
        {
          tmp[0] = cur[0];
          tmp[1] = cur[1];
          tmp[2] = cur[2];
          tmp[3] = cur[3];
          cur[0] = cur[7];
          cur[1] = cur[6];
          cur[2] = cur[5];
          cur[3] = cur[4];
          cur[4] = tmp[3];
          cur[5] = tmp[2];
          cur[6] = tmp[1];
          cur[7] = tmp[0];
          cur += this->WordSize;
        }
        break;
    }
  }

  return 0;
}

//------------------------------------------------------------------------------
int LSDynaFamily::ClearBuffer()
{
  if (this->Chunk)
  {
    this->ChunkAlloc = 0;
    this->ChunkWord = 0;
    this->ChunkValid = 0;
    delete[] this->Chunk;
    this->Chunk = nullptr;
  }

  return 0;
}

//------------------------------------------------------------------------------
vtkIdType LSDynaFamily::InitPartialChunkBuffering(
  const vtkIdType& numTuples, const vtkIdType& numComps)
{
  if (numTuples == 0)
  {
    this->BufferInfo->numWordsToRead = 0;
    this->BufferInfo->leftOver = 0;
    this->BufferInfo->loopTimes = 0;
  }
  else
  {
    const vtkIdType size(this->BufferInfo->size);
    this->BufferInfo->numWordsToRead = (size * numComps);
    this->BufferInfo->leftOver = (numTuples % size) * numComps;
    this->BufferInfo->loopTimes = (numTuples / size);
  }
  vtkIdType numChunks = this->BufferInfo->loopTimes;
  if (this->BufferInfo->leftOver > 0)
  {
    ++numChunks;
  }
  return numChunks;
}

//------------------------------------------------------------------------------
vtkIdType LSDynaFamily::GetNextChunk(const WordType& wType)
{
  vtkIdType size;
  if (this->BufferInfo->loopTimes > 0)
  {
    size = this->BufferInfo->numWordsToRead;
  }
  else if (this->BufferInfo->loopTimes == 0)
  {
    size = this->BufferInfo->leftOver;
  }
  else
  {
    size = 0;
  }

  this->BufferChunk(wType, size);
  --this->BufferInfo->loopTimes;
  return size;
}

//------------------------------------------------------------------------------
int LSDynaFamily::AdvanceFile()
{
  if (this->FNum < 0 && VTK_LSDYNA_ISBADFILE(this->FD))
  {
    if (!this->Files.empty())
    {
      this->FNum = 0;
      this->FAdapt = 0;
      return 0;
    }
    else
    {
      return 1;
    }
  }
  if (!VTK_LSDYNA_ISBADFILE(this->FD))
  {
    VTK_LSDYNA_CLOSEFILE(this->FD);
    // this->FD = VTK_LSDYNA_BADFILE;
  }
  this->FWord = 0;
  this->ChunkValid = 0;
  if (this->FNum + 1 < (vtkIdType)this->Files.size())
  {
    this->FNum++;
    this->FAdapt = this->FileAdaptLevels[this->FNum];
  }
  else
  {
    this->FD = VTK_LSDYNA_BADFILE;
    return 1;
  }
  this->FD = VTK_LSDYNA_OPENFILE(this->Files[this->FNum].c_str());
  if (VTK_LSDYNA_ISBADFILE(this->FD))
  {
    return errno;
  }
  return 0;
}

void LSDynaFamily::MarkSectionStart(int adaptLevel, SectionType m)
{
  vtkIdType myWord;

  if (!VTK_LSDYNA_ISBADFILE(this->FD))
  {
    myWord = VTK_LSDYNA_TELL(this->FD) / this->WordSize;
  }
  else
  {
    myWord = 0;
  }

  // OK, mark it.
  LSDynaFamilySectionMark mark;

  mark.FileNumber = this->FNum;
  mark.Offset = myWord;
  while (adaptLevel >= (int)this->AdaptationsMarkers.size())
  {
    this->AdaptationsMarkers.emplace_back();
  }
  this->AdaptationsMarkers[adaptLevel].Marks[m] = mark;

  // fprintf( stderr, "Mark \"%s\" is (%d,%d)\n", SectionTypeToString(m), mark.FileNumber,
  // mark.Offset );
}

//------------------------------------------------------------------------------
int LSDynaFamily::JumpToMark(SectionType m)
{
  return this->SkipToWord(m, this->TimeStep, 0);
}

//------------------------------------------------------------------------------
int LSDynaFamily::DetermineStorageModel()
{
  double test;
  this->WordSize = 4;
  this->SwapEndian = 0;
  this->JumpToMark(ControlSection); // opens file 0, since marks are all zeroed
  this->BufferChunk(Float, 128);    // does no swapping, buffers enough for 64 8-byte words
  this->ChunkWord = 14;
  test = this->GetNextWordAsFloat();
  if (test > 900. && test < 1000.)
  {
    this->JumpToMark(ControlSection); // seek to start of file
    return 0;
  }
  this->ChunkWord = 14;
  this->WordSize = 8;
  test = this->GetNextWordAsFloat();
  if (test > 900. && test < 1000.)
  {
    this->JumpToMark(ControlSection); // seek to start of file
    return 0;
  }
  // OK, try swapping endianness
  this->SwapEndian = 1;
  this->WordSize = 4;
  this->JumpToMark(ControlSection); // seek to start of file
  this->BufferChunk(Float, 128);
  this->ChunkWord = 14;
  test = this->GetNextWordAsFloat();
  if (test > 900. && test < 1000.)
  {
    this->JumpToMark(ControlSection); // seek to start of file
    return 0;
  }
  this->ChunkWord = 14;
  this->WordSize = 8;
  test = this->GetNextWordAsFloat();
  if (test > 900. && test < 1000.)
  {
    this->JumpToMark(ControlSection); // seek to start of file
    return 0;
  }

  // Oops, couldn't identify storage model
  VTK_LSDYNA_CLOSEFILE(this->FD);
  this->FNum = -1;
  this->FAdapt = -1;
  return 1;
}

//------------------------------------------------------------------------------
void LSDynaFamily::SetStateSize(vtkIdType sz)
{
  this->StateSize = sz;
}

//------------------------------------------------------------------------------
vtkIdType LSDynaFamily::GetStateSize() const
{
  return this->StateSize;
}

//------------------------------------------------------------------------------
vtkIdType LSDynaFamily::GetNumberOfFiles()
{
  return static_cast<vtkIdType>(this->Files.size());
}

//------------------------------------------------------------------------------
std::string LSDynaFamily::GetFileName(int i)
{
  return this->Files[i];
}

//------------------------------------------------------------------------------
vtkIdType LSDynaFamily::GetFileSize(int i)
{
  return this->FileSizes[i];
}

//------------------------------------------------------------------------------
int LSDynaFamily::GetWordSize() const
{
  return this->WordSize;
}

// Reset erases all information about the current database.
// It does not free memory allocated for the current chunk.
//------------------------------------------------------------------------------
void LSDynaFamily::Reset()
{
  if (!VTK_LSDYNA_ISBADFILE(this->FD))
  {
    VTK_LSDYNA_CLOSEFILE(this->FD);
    this->FD = VTK_LSDYNA_BADFILE;
  }

  this->DatabaseDirectory = "";
  this->DatabaseBaseName = "";
  this->Files.clear();
  this->FileSizes.clear();
  this->Adaptations.clear();
  this->FileAdaptLevels.clear();
  this->TimeStepMarks.clear();
  this->TimeAdaptLevels.clear();
  this->FNum = -1;
  this->FAdapt = -1;
  this->FWord = 0;
  this->TimeStep = -1;
  this->ChunkValid = 0;
  this->FileHandlesClosed = false;

  delete this->BufferInfo;
  this->BufferInfo = new LSDynaFamily::BufferingInfo();
}

//------------------------------------------------------------------------------
void LSDynaFamily::DumpMarks(std::ostream& os)
{
  int i, j;
  os << "Files: " << std::endl;
  for (i = 0; i < (int)this->Files.size(); ++i)
  {
    os << i << ": " << this->Files[i] << " [" << this->FileAdaptLevels[i] << "] "
       << this->FileSizes[i] << std::endl;
  }
  os << std::endl;

  os << "Adaptation levels:" << std::endl;
  for (i = 0; i < (int)this->Adaptations.size(); ++i)
  {
    os << this->Adaptations[i] << ":" << std::endl;
    for (j = 0; j < LSDynaFamily::NumberOfSectionTypes; ++j)
    {
      os << "  " << LSDynaFamily::SectionTypeToString((LSDynaFamily::SectionType)j) << " = "
         << this->AdaptationsMarkers[i].Marks[j].FileNumber << "/"
         << this->AdaptationsMarkers[i].Marks[j].Offset << std::endl;
    }
  }
  os << std::endl;

  os << "State section marks:" << std::endl;
  for (i = 0; i < (int)this->TimeStepMarks.size(); ++i)
  {
    os << i << ": " << this->TimeStepMarks[i].FileNumber << "/" << this->TimeStepMarks[i].Offset
       << std::endl;
  }
}

//------------------------------------------------------------------------------
void LSDynaFamily::CloseFileHandles()
{
  if (!VTK_LSDYNA_ISBADFILE(this->FD) && !this->FileHandlesClosed)
  {
    VTK_LSDYNA_CLOSEFILE(this->FD);
    this->FD = VTK_LSDYNA_BADFILE;
    this->ClearBuffer();
    this->FileHandlesClosed = true;
  }
}

//------------------------------------------------------------------------------
void LSDynaFamily::OpenFileHandles()
{
  if (VTK_LSDYNA_ISBADFILE(this->FD) && this->FileHandlesClosed)
  {
    this->FD = VTK_LSDYNA_OPENFILE(this->Files[this->FNum].c_str());
    VTK_LSDYNA_SEEK(this->FD, static_cast<vtkLSDynaOff_t>(this->FWord), SEEK_SET);
    this->FileHandlesClosed = false;
  }
}
VTK_ABI_NAMESPACE_END
