/**
 * MOAB, a Mesh-Oriented datABase, is a software component for creating,
 * storing and accessing finite element mesh data.
 * 
 * Copyright 2004 Sandia Corporation.  Under the terms of Contract
 * DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government
 * retains certain rights in this software.
 * 
 * This library 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 2.1 of the License, or (at your option) any later version.
 * 
 */

#ifdef _MSC_VER
#ifdef _DEBUG
// turn off warnings that say they debugging identifier has been truncated
// this warning comes up when using some STL containers
#pragma warning(disable : 4786)
#endif
#endif

#include "WriteVtk.hpp"
#include "VtkUtil.hpp"
#include "SysUtil.hpp"

#include <fstream>
#include <iostream>
#include <stdio.h>
#include <assert.h>
#include <vector>
#include <set>
#include <iterator>

#include "moab/Interface.hpp"
#include "moab/Range.hpp"
#include "moab/CN.hpp"
#include "MBTagConventions.hpp"
#include "moab/WriteUtilIface.hpp"
#include "Internals.hpp"
#include "moab/FileOptions.hpp"
#include "moab/Version.h"

#define INS_ID(stringvar, prefix, id) \
  sprintf(stringvar, prefix, id)

namespace moab {

const int DEFAULT_PRECISION = 10;
const bool DEFAULT_STRICT = true;

WriterIface *WriteVtk::factory(Interface* iface)
{
  return new WriteVtk(iface);
}

WriteVtk::WriteVtk(Interface* impl)
  : mbImpl(impl), writeTool(0), mStrict(DEFAULT_STRICT)
{
  assert(impl != NULL);
  impl->query_interface(writeTool);
}

WriteVtk::~WriteVtk()
{
  mbImpl->release_interface(writeTool);
}

ErrorCode WriteVtk::write_file(const char *file_name,
                               const bool overwrite,
                               const FileOptions& opts,
                               const EntityHandle *output_list,
                               const int num_sets,
                               const std::vector<std::string>& /* qa_list */,
                               const Tag* tag_list,
                               int num_tags,
                               int /* export_dimension */)
{
  ErrorCode rval;

  // Get precision for node coordinates
  int precision;
  if (MB_SUCCESS != opts.get_int_option("PRECISION", precision))
    precision = DEFAULT_PRECISION;

  if (MB_SUCCESS == opts.get_null_option("STRICT"))
    mStrict = true;
  else if (MB_SUCCESS == opts.get_null_option("RELAXED"))
    mStrict = false;
  else
    mStrict = DEFAULT_STRICT;

  // Get entities to write
  Range nodes, elems;
  rval = gather_mesh(output_list, num_sets, nodes, elems);
  if (MB_SUCCESS != rval)
    return rval;

  // Honor overwrite flag
  if (!overwrite) {
    rval = writeTool->check_doesnt_exist(file_name);
    if (MB_SUCCESS != rval)
      return rval;
  }

  // Create file
  std::ofstream file(file_name);
  if (!file) {
    MB_SET_ERR(MB_FILE_WRITE_ERROR, "Could not open file: " << file_name);
  }
  file.precision(precision);

  // Write file
  if ((rval = write_header(file              )) != MB_SUCCESS ||
      (rval = write_nodes( file, nodes       )) != MB_SUCCESS ||
      (rval = write_elems( file, nodes, elems)) != MB_SUCCESS ||
      (rval = write_tags ( file, true,  nodes, tag_list, num_tags)) != MB_SUCCESS ||
      (rval = write_tags ( file, false, elems, tag_list, num_tags)) != MB_SUCCESS) {
    file.close();
    remove(file_name);
    return rval;
  }

  return MB_SUCCESS;
}

ErrorCode WriteVtk::gather_mesh(const EntityHandle* set_list,
                                int num_sets,
                                Range& nodes,
                                Range& elems)
{
  ErrorCode rval;
  int e;

  if (!set_list || !num_sets) {
    Range a;
    rval = mbImpl->get_entities_by_handle(0, a);
    if (MB_SUCCESS != rval)
      return rval;

    Range::const_iterator node_i, elem_i, set_i;
    node_i = a.lower_bound(a.begin(), a.end(), CREATE_HANDLE(   MBVERTEX, 0, e));
    elem_i = a.lower_bound(   node_i, a.end(), CREATE_HANDLE(     MBEDGE, 0, e));
    set_i  = a.lower_bound(   elem_i, a.end(), CREATE_HANDLE(MBENTITYSET, 0, e));
    nodes.merge(node_i, elem_i);
    elems.merge(elem_i, set_i);

    // Filter out unsupported element types
    EntityType et = MBEDGE;
    for (et++; et < MBENTITYSET; et++) {
      if (VtkUtil::get_vtk_type(et, CN::VerticesPerEntity(et)))
        continue;
      Range::iterator
        eit = elems.lower_bound(elems.begin(), elems.end(), CREATE_HANDLE(et, 0, e)),
        ep1it = elems.lower_bound(elems.begin(), elems.end(), CREATE_HANDLE(et + 1, 0, e));
      elems.erase(eit, ep1it);
    }
  }
  else {
    std::set<EntityHandle> visited;
    std::vector<EntityHandle> sets;
    sets.reserve(num_sets);
    std::copy(set_list, set_list + num_sets, std::back_inserter(sets));
    while (!sets.empty()) {
      // Get next set
      EntityHandle set = sets.back();
      sets.pop_back();
      // Skip sets we've already done
      if (!visited.insert(set).second)
        continue;

      Range a;
      rval = mbImpl->get_entities_by_handle(set, a);
      if (MB_SUCCESS != rval)
        return rval;

      Range::const_iterator node_i, elem_i, set_i;
      node_i = a.lower_bound(a.begin(), a.end(), CREATE_HANDLE(   MBVERTEX, 0, e));
      elem_i = a.lower_bound(   node_i, a.end(), CREATE_HANDLE(     MBEDGE, 0, e));
      set_i  = a.lower_bound(   elem_i, a.end(), CREATE_HANDLE(MBENTITYSET, 0, e));
      nodes.merge(node_i, elem_i);
      elems.merge(elem_i, set_i);
      std::copy(set_i, a.end(), std::back_inserter(sets));

      a.clear();
      rval = mbImpl->get_child_meshsets(set, a);
      std::copy(a.begin(), a.end(), std::back_inserter(sets));
    }

    for (Range::const_iterator ei = elems.begin(); ei != elems.end(); ++ei) {
      std::vector<EntityHandle> connect;
      rval = mbImpl->get_connectivity(&(*ei), 1, connect);
      if (MB_SUCCESS != rval)
        return rval;

      for (unsigned int i = 0; i < connect.size(); ++i)
        nodes.insert(connect[i]);
    }
  }

  if (nodes.empty()) {
    MB_SET_ERR(MB_ENTITY_NOT_FOUND, "Nothing to write");
  }

  return MB_SUCCESS;
}

ErrorCode WriteVtk::write_header(std::ostream& stream)
{
  stream << "# vtk DataFile Version 3.0" << std::endl;
  stream << MOAB_VERSION_STRING << std::endl;
  stream << "ASCII" << std::endl;
  stream << "DATASET UNSTRUCTURED_GRID" << std::endl;
  return MB_SUCCESS;
}

ErrorCode WriteVtk::write_nodes(std::ostream& stream, const Range& nodes)
{
  ErrorCode rval;

  stream << "POINTS " << nodes.size() << " double" << std::endl;

  double coords[3];
  for (Range::const_iterator i = nodes.begin(); i != nodes.end(); ++i) {
    coords[1] = coords[2] = 0.0;
    rval = mbImpl->get_coords(&(*i), 1, coords);
    if (MB_SUCCESS != rval)
      return rval;
    stream << coords[0] << ' ' << coords[1] << ' ' << coords[2] << std::endl;
  }

  return MB_SUCCESS;
}

ErrorCode WriteVtk::write_elems(std::ostream& stream,
                                const Range& nodes,
                                const Range& elems)
{
  ErrorCode rval;

  Range connected_nodes;
  rval = mbImpl->get_connectivity(elems, connected_nodes);
  if (MB_SUCCESS != rval)
    return rval;
  Range free_nodes = subtract(nodes, connected_nodes);

  // Get and write counts
  unsigned long num_elems, num_uses;
  num_elems = num_uses = elems.size();
  for (Range::const_iterator i = elems.begin(); i != elems.end(); ++i) {
    EntityType type = mbImpl->type_from_handle(*i);
    if (!VtkUtil::get_vtk_type(type, CN::VerticesPerEntity(type)))
      continue;

    std::vector<EntityHandle> connect;
    rval = mbImpl->get_connectivity(&(*i), 1, connect);

    if (MB_SUCCESS != rval)
      return rval;

    num_uses += connect.size();
  }
  stream << "CELLS " << num_elems + free_nodes.size()<< ' ' << num_uses + 2*free_nodes.size() << std::endl;

  // Write element connectivity
  std::vector<int> conn_data;
  std::vector<unsigned> vtk_types(elems.size() + free_nodes.size() );
  std::vector<unsigned>::iterator t = vtk_types.begin();
  for (Range::const_iterator i = elems.begin(); i != elems.end(); ++i) {
    // Get type information for element
    EntityType type = TYPE_FROM_HANDLE(*i);

    // Get element connectivity
    std::vector<EntityHandle> connect;
    rval = mbImpl->get_connectivity(&(*i), 1, connect);
    int conn_len = connect.size();

    if (MB_SUCCESS != rval)
      return rval;

    // Get VTK type
    const VtkElemType* vtk_type = VtkUtil::get_vtk_type(type, conn_len);
    if (!vtk_type) {
      // Try connectivity with 1 fewer node
      vtk_type = VtkUtil::get_vtk_type(type, conn_len - 1);
      if (vtk_type)
        conn_len--;
      else {
        MB_SET_ERR(MB_FAILURE, "Vtk file format does not support elements of type " << CN::EntityTypeName(type) << " (" << (int)type << ") with " << conn_len << " nodes");
      }
    }

    // Get IDs from vertex handles
    assert(conn_len > 0);
    conn_data.resize(conn_len);
    for (int j = 0; j < conn_len; ++j)
      conn_data[j] = nodes.index(connect[j]);

    // Save VTK type index for later
    *t = vtk_type->vtk_type;
    ++t;

    // Write connectivity list
    stream << conn_len;
    if (vtk_type->node_order)
      for (int k = 0; k < conn_len; ++k)
        stream << ' ' << conn_data[vtk_type->node_order[k]];
    else
      for (int k = 0; k < conn_len; ++k)
        stream << ' ' << conn_data[k];
    stream << std::endl;
  }
  for (Range::const_iterator v=free_nodes.begin(); v!= free_nodes.end(); ++v, t++)
  {
    EntityHandle node=*v;
    stream << "1 " << nodes.index(node) << std::endl;
    *t = 1;
  }

  // Write element types
  stream << "CELL_TYPES " << vtk_types.size() << std::endl;
  for (std::vector<unsigned>::const_iterator i = vtk_types.begin(); i != vtk_types.end(); ++i)
    stream << *i << std::endl;

  return MB_SUCCESS;
}

ErrorCode WriteVtk::write_tags(std::ostream& stream,
                               bool nodes,
                               const Range& entities,
                               const Tag* tag_list,
                               int num_tags)
{
  ErrorCode rval;

  // The #$%@#$% MOAB interface does not have a function to retrieve
  // all entities with a tag, only all entities with a specified type
  // and tag. Define types to loop over depending on the if vertex
  // or element tag data is being written. It seems horribly inefficient
  // to have the implementation subdivide the results by type and have
  // to call that function once for each type just to recombine the results.
  // Unfortunately, there doesn't seem to be any other way.
  EntityType low_type, high_type;
  if (nodes) {
    low_type = MBVERTEX;
    high_type = MBEDGE;
  }
  else {
    low_type = MBEDGE;
    high_type = MBENTITYSET;
  }

  // Get all defined tags
  std::vector<Tag> tags;
  std::vector<Tag>::iterator i;
  rval = writeTool->get_tag_list(tags, tag_list, num_tags, false);
  if (MB_SUCCESS != rval)
    return rval;

  // For each tag...
  bool entities_have_tags = false;
  for (i = tags.begin(); i != tags.end(); ++i) {
    // Skip tags holding entity handles -- no way to save them
    DataType dtype;
    rval = mbImpl->tag_get_data_type(*i, dtype);
    if (MB_SUCCESS != rval)
      return rval;
    if (dtype == MB_TYPE_HANDLE)
      continue;

    // If in strict mode, don't write tags that do not fit in any
    // attribute type (SCALAR : 1 to 4 values, VECTOR : 3 values, TENSOR : 9 values)
    if (mStrict) {
      int count;
      rval = mbImpl->tag_get_length(*i, count);
      if (MB_SUCCESS != rval)
        return rval;
      if (count < 1 || (count > 4 && count != 9))
        continue;
    }

    // Get subset of input entities that have the tag set
    Range tagged;
    for (EntityType type = low_type; type < high_type; ++type) {
      Range tmp_tagged;
      rval = mbImpl->get_entities_by_type_and_tag(0, type, &(*i), 0, 1, tmp_tagged);
      if (MB_SUCCESS != rval)
        return rval;
      tmp_tagged = intersect(tmp_tagged, entities);
      tagged.merge(tmp_tagged);
    }

    // If any entities were tagged
    if (!tagged.empty()) {
      // If this is the first tag being written for the
      // entity type, write the label marking the beginning
      // of the tag data.
      if (!entities_have_tags) {
        entities_have_tags = true;
        stream << (nodes ? "POINT_DATA " : "CELL_DATA ") << entities.size() << std::endl;
      }

      // Write the tag
      rval = write_tag(stream, *i, entities, tagged);
      if (MB_SUCCESS != rval)
        return rval;
    }
  }

  return MB_SUCCESS;
}

template <typename T>
void WriteVtk::write_data(std::ostream& stream,
                          const std::vector<T>& data,
                          unsigned vals_per_tag)
{
  typename std::vector<T>::const_iterator d = data.begin();
  const unsigned long n = data.size() / vals_per_tag;

  for (unsigned long i = 0; i < n; ++i) {
    for (unsigned j = 0; j < vals_per_tag; ++j, ++d) {
      if (sizeof(T) == 1)
        stream << (unsigned int)*d << ' ';
      else
        stream << *d << ' ';
    }
    stream << std::endl;
  }
}

//template <>
//void WriteVtk::write_data<unsigned char>(std::ostream& stream,
//                                         const std::vector<unsigned char>& data,
//                                         unsigned vals_per_tag)
//{
//  std::vector<unsigned char>::const_iterator d = data.begin();
//  const unsigned long n = data.size() / vals_per_tag;
//  
//  for (unsigned long i = 0; i < n; ++i) {
//    for (unsigned j = 0; j < vals_per_tag; ++j, ++d)
//      stream << (unsigned int)*d << ' ';
//    stream << std::endl;
//  }
//}

template <typename T>
ErrorCode WriteVtk::write_tag(std::ostream& stream,
                              Tag tag,
                              const Range& entities,
                              const Range& tagged,
                              const int)
{
  ErrorCode rval;
  const unsigned long n = entities.size();

  // Get tag properties

  std::string name;
  int vals_per_tag;
  if (MB_SUCCESS != mbImpl->tag_get_name(tag, name) ||
      MB_SUCCESS != mbImpl->tag_get_length(tag, vals_per_tag))
    return MB_FAILURE;

  // Get a tag value for each entity. Do this by initializing the
  // "data" vector with zero, and then filling in the values for
  // the entities that actually have the tag set.
  std::vector<T> data;
  data.resize(n * vals_per_tag, 0);
  // If there is a default value for the tag, set the actual default value
  std::vector<T> def_value(vals_per_tag);
  rval = mbImpl->tag_get_default_value(tag, &(def_value[0]));
  if (MB_SUCCESS == rval)
     SysUtil::setmem(&(data[0]), &(def_value[0]), vals_per_tag * sizeof(T), n);

  Range::const_iterator t = tagged.begin();
  typename std::vector<T>::iterator d = data.begin();
  for (Range::const_iterator i = entities.begin();
       i != entities.end() && t != tagged.end(); ++i, d += vals_per_tag) {
    if (*i == *t) {
      ++t;
      rval = mbImpl->tag_get_data(tag, &(*i), 1, &(*d));
      if (MB_SUCCESS != rval)
        return rval;
    }
  }

  // Write the tag values, one entity per line.
  write_data(stream, data, vals_per_tag);

  return MB_SUCCESS;
}

ErrorCode WriteVtk::write_bit_tag(std::ostream& stream,
                                  Tag tag,
                                  const Range& entities,
                                  const Range& tagged)
{
  ErrorCode rval;
  const unsigned long n = entities.size();

  // Get tag properties

  std::string name;
  int vals_per_tag;
  if (MB_SUCCESS != mbImpl->tag_get_name(tag, name) ||
      MB_SUCCESS != mbImpl->tag_get_length(tag, vals_per_tag))
    return MB_FAILURE;

  if (vals_per_tag > 8) {
    MB_SET_ERR(MB_FAILURE, "Invalid tag size for bit tag \"" << name << "\"");
  }

  // Get a tag value for each entity.
  // Get bits for each entity and unpack into
  // one integer in the 'data' array for each bit.
  // Initialize 'data' to zero because we will skip
  // those entities for which the tag is not set.
  std::vector<unsigned short> data;
  data.resize(n * vals_per_tag, 0);
  Range::const_iterator t = tagged.begin();
  std::vector<unsigned short>::iterator d = data.begin();
  for (Range::const_iterator i = entities.begin();
       i != entities.end() && t != tagged.end(); ++i) {
    if (*i == *t) {
      ++t;
      unsigned char value;
      rval = mbImpl->tag_get_data(tag, &(*i), 1, &value);
      for (int j = 0; j < vals_per_tag; ++j, ++d)
        *d = (unsigned short)(value & (1 << j) ? 1 : 0);
      if (MB_SUCCESS != rval)
        return rval;
    }
    else {
      // If tag is not set for entity, skip values in array
      d += vals_per_tag;
    }
  }

  // Write the tag values, one entity per line.
  write_data(stream, data, vals_per_tag);

  return MB_SUCCESS;
}

ErrorCode WriteVtk::write_tag(std::ostream& s, Tag tag,
                              const Range& entities,
                              const Range& tagged)
{
  // Get tag properties
  std::string name;
  DataType type;
  int vals_per_tag;
  if (MB_SUCCESS != mbImpl->tag_get_name(tag, name) ||
      MB_SUCCESS != mbImpl->tag_get_length(tag, vals_per_tag) ||
      MB_SUCCESS != mbImpl->tag_get_data_type(tag, type))
    return MB_FAILURE;

  // Skip tags of type ENTITY_HANDLE
  if (MB_TYPE_HANDLE == type)
    return MB_FAILURE;

  // Now that we're past the point where the name would be used in
  // an error message, remove any spaces to conform to VTK file.
  for (std::string::iterator i = name.begin(); i != name.end(); ++i) {
    if (isspace(*i) || iscntrl(*i))
      *i = '_';
  }

  // Write the tag description
  if (3 == vals_per_tag && MB_TYPE_DOUBLE == type)
    s << "VECTORS " << name << ' ' << VtkUtil::vtkTypeNames[type] << std::endl;
  else if (9 == vals_per_tag)
    s << "TENSORS " << name << ' ' << VtkUtil::vtkTypeNames[type] << std::endl;
  else
    s << "SCALARS " << name << ' ' << VtkUtil::vtkTypeNames[type] << ' '
      << vals_per_tag << std::endl << "LOOKUP_TABLE default" << std::endl;

  // Write the tag data
  switch (type) {
    case MB_TYPE_OPAQUE:
      return write_tag<unsigned char>(s, tag, entities, tagged, 0);
    case MB_TYPE_INTEGER:
      return write_tag<int>(s, tag, entities, tagged, 0);
    case MB_TYPE_DOUBLE:
      return write_tag<double>(s, tag, entities, tagged, 0);
    case MB_TYPE_BIT:
      return write_bit_tag(s, tag, entities, tagged);
    default:
      return MB_FAILURE;
  }
}

} // namespace moab
