#include "coding/file_container.hpp"
#include "coding/read_write_utils.hpp"
#include "coding/write_to_sink.hpp"
#include "coding/internal/file_data.hpp"

#include "std/cstring.hpp"

#ifndef OMIM_OS_WINDOWS
  #include <stdio.h>
  #include <unistd.h>
  #include <sys/mman.h>
  #include <sys/stat.h>
  #ifdef OMIM_OS_ANDROID
    #include <fcntl.h>
  #else
    #include <sys/fcntl.h>
  #endif
#else
  #include <windows.h>
#endif

#include <errno.h>

template <class TSource, class InfoT> void Read(TSource & src, InfoT & i)
{
  rw::Read(src, i.m_tag);

  i.m_offset = ReadVarUint<uint64_t>(src);
  i.m_size = ReadVarUint<uint64_t>(src);
}

template <class TSink, class InfoT> void Write(TSink & sink, InfoT const & i)
{
  rw::Write(sink, i.m_tag);

  WriteVarUint(sink, i.m_offset);
  WriteVarUint(sink, i.m_size);
}

string DebugPrint(FilesContainerBase::Info const & info)
{
  ostringstream ss;
  ss << "{ " << info.m_tag << ", " << info.m_offset << ", " << info.m_size << " }";
  return ss.str();
}

/////////////////////////////////////////////////////////////////////////////
// FilesContainerBase
/////////////////////////////////////////////////////////////////////////////

template <class ReaderT>
void FilesContainerBase::ReadInfo(ReaderT & reader)
{
  uint64_t offset = ReadPrimitiveFromPos<uint64_t>(reader, 0);

  ReaderSource<ReaderT> src(reader);
  src.Skip(offset);

  rw::Read(src, m_info);
}

/////////////////////////////////////////////////////////////////////////////
// FilesContainerR
/////////////////////////////////////////////////////////////////////////////

FilesContainerR::FilesContainerR(string const & filePath,
                                 uint32_t logPageSize,
                                 uint32_t logPageCount)
  : m_source(make_unique<FileReader>(filePath, logPageSize, logPageCount))
{
  ReadInfo(m_source);
}

FilesContainerR::FilesContainerR(TReader const & file)
  : m_source(file)
{
  ReadInfo(m_source);
}

FilesContainerR::TReader FilesContainerR::GetReader(Tag const & tag) const
{
  Info const * p = GetInfo(tag);
  if (!p)
    MYTHROW(Reader::OpenException, ("Can't find section:", GetFileName(), tag));
  return m_source.SubReader(p->m_offset, p->m_size);
}

pair<uint64_t, uint64_t> FilesContainerR::GetAbsoluteOffsetAndSize(Tag const & tag) const
{
  Info const * p = GetInfo(tag);
  if (!p)
    MYTHROW(Reader::OpenException, ("Can't find section:", GetFileName(), tag));

  auto reader = dynamic_cast<FileReader const *>(m_source.GetPtr());
  uint64_t const offset = reader ? reader->GetOffset() : 0;
  return make_pair(offset + p->m_offset, p->m_size);
}

FilesContainerBase::Info const * FilesContainerBase::GetInfo(Tag const & tag) const
{
  auto i = lower_bound(m_info.begin(), m_info.end(), tag, LessInfo());
  if (i != m_info.end() && i->m_tag == tag)
    return &(*i);
  else
    return 0;
}

namespace detail
{
/////////////////////////////////////////////////////////////////////////////
// MappedFile
/////////////////////////////////////////////////////////////////////////////
void MappedFile::Open(string const & fName)
{
  Close();

#ifdef OMIM_OS_WINDOWS
  m_hFile = CreateFileA(fName.c_str(), GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL);
  if (m_hFile == INVALID_HANDLE_VALUE)
    MYTHROW(Reader::OpenException, ("Can't open file:", fName, "win last error:", GetLastError()));
  m_hMapping = CreateFileMappingA(m_hFile, NULL, PAGE_READONLY, 0, 0, NULL);
  if (m_hMapping == NULL)
    MYTHROW(Reader::OpenException, ("Can't create file's Windows mapping:", fName, "win last error:", GetLastError()));
#else
  m_fd = open(fName.c_str(), O_RDONLY | O_NONBLOCK);
  if (m_fd == -1)
  {
    if (errno == EMFILE || errno == ENFILE)
    {
      MYTHROW(Reader::TooManyFilesException,
              ("Can't open file:", fName, ", reason:", strerror(errno)));
    }
    else
    {
      MYTHROW(Reader::OpenException, ("Can't open file:", fName, ", reason:", strerror(errno)));
    }
  }
#endif
}

void MappedFile::Close()
{
#ifdef OMIM_OS_WINDOWS
  if (m_hMapping != INVALID_HANDLE_VALUE)
  {
    CloseHandle(m_hMapping);
    m_hMapping = INVALID_HANDLE_VALUE;
  }
  if (m_hFile != INVALID_HANDLE_VALUE)
  {
    CloseHandle(m_hFile);
    m_hFile = INVALID_HANDLE_VALUE;
  }
#else
  if (m_fd != -1)
  {
    close(m_fd);
    m_fd = -1;
  }
#endif
}

MappedFile::Handle MappedFile::Map(uint64_t offset, uint64_t size, string const & tag) const
{
#ifdef OMIM_OS_WINDOWS
  SYSTEM_INFO sysInfo;
  memset(&sysInfo, 0, sizeof(sysInfo));
  GetSystemInfo(&sysInfo);
  long const align = sysInfo.dwAllocationGranularity;
#else
  long const align = sysconf(_SC_PAGE_SIZE);
#endif

  uint64_t const alignedOffset = (offset / align) * align;
  ASSERT_LESS_OR_EQUAL(alignedOffset, offset, ());
  uint64_t const length = size + (offset - alignedOffset);
  ASSERT_GREATER_OR_EQUAL(length, size, ());

#ifdef OMIM_OS_WINDOWS
  void * pMap = MapViewOfFile(m_hMapping, FILE_MAP_READ, alignedOffset >> (sizeof(DWORD) * 8), DWORD(alignedOffset), length);
  if (pMap == NULL)
    MYTHROW(Reader::OpenException, ("Can't map section:", tag, "with [offset, size]:", offset, size, "win last error:", GetLastError()));
#else
  void * pMap = mmap(0, length, PROT_READ, MAP_SHARED, m_fd, alignedOffset);
  if (pMap == MAP_FAILED)
    MYTHROW(Reader::OpenException, ("Can't map section:", tag, "with [offset, size]:", offset, size, "errno:", strerror(errno)));
#endif

  char const * data = reinterpret_cast<char const *>(pMap);
  char const * d = data + (offset - alignedOffset);
  return Handle(d, data, size, length);
}

} // namespace detail

/////////////////////////////////////////////////////////////////////////////
// FilesMappingContainer
/////////////////////////////////////////////////////////////////////////////

FilesMappingContainer::FilesMappingContainer(string const & fName)
{
  Open(fName);
}

FilesMappingContainer::~FilesMappingContainer()
{
  Close();
}

void FilesMappingContainer::Open(string const & fName)
{
  {
    FileReader reader(fName);
    ReadInfo(reader);
  }

  m_file.Open(fName);

  m_name = fName;
}

void FilesMappingContainer::Close()
{
  m_file.Close();

  m_name.clear();
}

FilesMappingContainer::Handle FilesMappingContainer::Map(Tag const & tag) const
{
  Info const * p = GetInfo(tag);
  if (!p)
    MYTHROW(Reader::OpenException, ("Can't find section:", m_name, tag));

  ASSERT_EQUAL(tag, p->m_tag, ());
  return m_file.Map(p->m_offset, p->m_size, tag);
}

FileReader FilesMappingContainer::GetReader(Tag const & tag) const
{
  Info const * p = GetInfo(tag);
  if (!p)
    MYTHROW(Reader::OpenException, ("Can't find section:", m_name, tag));
  return FileReader(m_name).SubReader(p->m_offset, p->m_size);
}

/////////////////////////////////////////////////////////////////////////////
// FilesMappingContainer::Handle
/////////////////////////////////////////////////////////////////////////////

FilesMappingContainer::Handle::~Handle()
{
  Unmap();
}

void FilesMappingContainer::Handle::Assign(Handle && h)
{
  Unmap();

  m_base = h.m_base;
  m_origBase = h.m_origBase;
  m_size = h.m_size;
  m_origSize = h.m_origSize;

  h.Reset();
}

void FilesMappingContainer::Handle::Unmap()
{
  if (IsValid())
  {
    #ifdef OMIM_OS_WINDOWS
      VERIFY(UnmapViewOfFile(m_origBase), ());
    #else
      VERIFY(0 == munmap((void*)m_origBase, m_origSize), ());
    #endif
    Reset();
  }
}

void FilesMappingContainer::Handle::Reset()
{
  m_base = m_origBase = 0;
  m_size = m_origSize = 0;
}

/////////////////////////////////////////////////////////////////////////////
// FilesContainerW
/////////////////////////////////////////////////////////////////////////////

FilesContainerW::FilesContainerW(string const & fName, FileWriter::Op op)
: m_name(fName), m_bFinished(false)
{
  Open(op);
}

void FilesContainerW::Open(FileWriter::Op op)
{
  m_bNeedRewrite = true;

  switch (op)
  {
  case FileWriter::OP_WRITE_TRUNCATE:
    break;

  case FileWriter::OP_WRITE_EXISTING:
    {
      // read an existing service info
      FileReader reader(m_name);
      ReadInfo(reader);
    }

    // Important: in append mode we should sort info-vector by offsets
    sort(m_info.begin(), m_info.end(), LessOffset());

    // Check that all offsets are unique
#ifdef DEBUG
    for (size_t i = 1; i < m_info.size(); ++i)
      ASSERT(m_info[i-1].m_offset < m_info[i].m_offset ||
             m_info[i-1].m_size == 0 ||
             m_info[i].m_size == 0, ());
#endif
    break;

  default:
    ASSERT ( false, ("Unsupported options") );
    break;
  }

  if (m_info.empty())
    StartNew();
}

void FilesContainerW::StartNew()
{
  // leave space for offset to service info
  FileWriter writer(m_name);
  uint64_t skip = 0;
  writer.Write(&skip, sizeof(skip));
  m_bNeedRewrite = false;
}

FilesContainerW::~FilesContainerW()
{
  if (!m_bFinished)
    Finish();
}

uint64_t FilesContainerW::SaveCurrentSize()
{
  ASSERT(!m_bFinished, ());
  uint64_t const curr = FileReader(m_name).Size();
  if (!m_info.empty())
    m_info.back().m_size = curr - m_info.back().m_offset;
  return curr;
}

void FilesContainerW::DeleteSection(Tag const & tag)
{
  {
    // rewrite files on disk
    FilesContainerR contR(m_name);
    FilesContainerW contW(m_name + ".tmp");

    for (size_t i = 0; i < m_info.size(); ++i)
    {
      if (m_info[i].m_tag != tag)
        contW.Write(contR.GetReader(m_info[i].m_tag), m_info[i].m_tag);
    }
  }

  // swap files
  if (!my::DeleteFileX(m_name) || !my::RenameFileX(m_name + ".tmp", m_name))
    MYTHROW(RootException, ("Can't rename file", m_name, "Sharing violation or disk error!"));

  // do open to update m_info
  Open(FileWriter::OP_WRITE_EXISTING);
}

FileWriter FilesContainerW::GetWriter(Tag const & tag)
{
  ASSERT(!m_bFinished, ());

  InfoContainer::const_iterator it = find_if(m_info.begin(), m_info.end(), EqualTag(tag));
  if (it != m_info.end())
  {
    if (it+1 == m_info.end())
    {
      m_info.pop_back();

      if (m_info.empty())
        StartNew();
      else
        m_bNeedRewrite = true;
    }
    else
    {
      DeleteSection(it->m_tag);
    }
  }

  if (m_bNeedRewrite)
  {
    m_bNeedRewrite = false;
    ASSERT(!m_info.empty(), ());

    uint64_t const curr = m_info.back().m_offset + m_info.back().m_size;
    FileWriter writer(m_name, FileWriter::OP_WRITE_EXISTING, true);
    writer.Seek(curr);
    writer.WritePaddingByPos(kSectionAlignment);
    m_info.push_back(Info(tag, writer.Pos()));
    ASSERT(m_info.back().m_offset % kSectionAlignment == 0, ());
    return writer;
  }
  else
  {
    SaveCurrentSize();
    FileWriter writer(m_name, FileWriter::OP_APPEND);
    writer.WritePaddingByPos(kSectionAlignment);
    m_info.push_back(Info(tag, writer.Pos()));
    ASSERT(m_info.back().m_offset % kSectionAlignment == 0, ());
    return writer;
  }
}

void FilesContainerW::Write(string const & fPath, Tag const & tag)
{
  Write(ModelReaderPtr(make_unique<FileReader>(fPath)), tag);
}

void FilesContainerW::Write(ModelReaderPtr reader, Tag const & tag)
{
  ReaderSource<ModelReaderPtr> src(reader);
  FileWriter writer = GetWriter(tag);

  rw::ReadAndWrite(src, writer);
}

void FilesContainerW::Write(vector<char> const & buffer, Tag const & tag)
{
  if (!buffer.empty())
    GetWriter(tag).Write(&buffer[0], buffer.size());
}

void FilesContainerW::Finish()
{
  ASSERT(!m_bFinished, ());

  uint64_t const curr = SaveCurrentSize();

  FileWriter writer(m_name, FileWriter::OP_WRITE_EXISTING);
  writer.Seek(0);
  WriteToSink(writer, curr);
  writer.Seek(curr);

  sort(m_info.begin(), m_info.end(), LessInfo());

  rw::Write(writer, m_info);

  m_bFinished = true;
}