#include <iostream>
#include <iterator>
// -------------------- OpenMesh
#include <OpenMesh/Core/IO/MeshIO.hh>
#include <OpenMesh/Core/Mesh/TriMesh_ArrayKernelT.hh>
#include <OpenMesh/Tools/Utils/getopt.h>

// ----------------------------------------------------------------------------

using namespace OpenMesh;

// ----------------------------------------------------------------------------

typedef TriMesh_ArrayKernelT<>  MyMesh;

// ----------------------------------------------------------------------------

#define CHKROPT( Option ) \
  std::cout << "  provides " << #Option \
            << (ropt.check(IO::Options:: Option)?": yes\n":": no\n")

#define CHKWOPT( Option ) \
  std::cout << "  write " << #Option \
            << (wopt.check(IO::Options:: Option)?": yes\n":": no\n")

#define MESHOPT( msg, tf ) \
  std::cout << "  " << msg << ": " << ((tf)?"yes\n":"no\n")

// ----------------------------------------------------------------------------

void parse_commandline( int _argc, char **_argv, MyMesh& _mesh,
                        IO::Options &ropt, IO::Options &wopt );

void usage_and_exit(int xcode);

// ----------------------------------------------------------------------------

int main(int argc, char **argv)
{
  MyMesh  mesh;
  IO::Options ropt, wopt;

  // -------------------- evaluate commandline

  parse_commandline( argc, argv, mesh, ropt, wopt );

  // -------------------- read mesh

  if ( ! IO::read_mesh(mesh,argv[optind], ropt))
  {
    std::cerr << "Error loading mesh from file " << argv[optind] << std::endl;
    return 1;
  }

  // -------------------- show options

  std::cout << "File " << argv[optind] << std::endl;

  std::cout << "  is binary: " 
            << (ropt.check(IO::Options::Binary) ? " yes\n" : " no\n");

  std::cout << "  byte order: ";
  if (ropt.check(IO::Options::Swap))
    std::cout << "swapped\n";
  else if (ropt.check(IO::Options::LSB))
    std::cout << "little endian\n";
  else if (ropt.check(IO::Options::MSB))
    std::cout << "big endian\n";
  else
    std::cout << "don't care\n";
  
  std::cout << "  provides VertexNormal"
            << ( // strange layout for doxygen
                ropt.check(IO::Options::VertexNormal) 
                ? ": yes\n":": no\n");
  CHKROPT( VertexColor    );
  CHKROPT( VertexTexCoord );
  CHKROPT( FaceNormal     );
  CHKROPT( FaceColor      );


  // -------------------- mesh stats

  std::cout << "# Vertices: " << mesh.n_vertices() << std::endl;
  std::cout << "# Edges   : " << mesh.n_faces() << std::endl;
  std::cout << "# Faces   : " << mesh.n_faces() << std::endl;


  // -------------------- show write options

  std::cout << "Selected write options:\n";
  std::cout << "  use binary: " 
            << (wopt.check(IO::Options::Binary) ? " yes\n" : " no\n");

  std::cout << "  byte order: ";
  if (wopt.check(IO::Options::Swap))
    std::cout << "swapped\n";
  else if (wopt.check(IO::Options::LSB))
    std::cout << "little endian\n";
  else if (wopt.check(IO::Options::MSB))
    std::cout << "big endian\n";
  else
    std::cout << "don't care\n";
  
  std::cout << "  write VertexNormal"
            << (wopt.check(IO::Options::VertexNormal) ? ": yes\n":": no\n");
  CHKWOPT( VertexColor    );
  CHKWOPT( VertexTexCoord );
  CHKWOPT( FaceNormal     );
  CHKWOPT( FaceColor      );

  // -------------------- show mesh capabilities

  std::cout << "Mesh supports\n";
  MESHOPT("vertex normals", mesh.has_vertex_normals());
  MESHOPT("vertex colors", mesh.has_vertex_colors());
  MESHOPT("texcoords", mesh.has_vertex_texcoords2D());
  MESHOPT("face normals", mesh.has_face_normals());
  MESHOPT("face colors", mesh.has_face_colors());

  // -------------------- write mesh

  std::cout << "Write mesh to " << argv[optind+1] << "..";
  if ( !IO::write_mesh( mesh, argv[optind+1], wopt ) )
  {
    std::cerr << "Error" << std::endl;
    std::cerr << "Possible reasons:\n";
    std::cerr << "1. Chosen format cannot handle an option!\n";
    std::cerr << "2. Mesh does not provide necessary information!\n";
    std::cerr << "3. Or simply cannot open file for writing!\n";
    return 1;
  }
  else
    std::cout << "Ok.\n";

  return 0;
}

// ----------------------------------------------------------------------------

void parse_commandline( int _argc, char **_argv, MyMesh& _mesh,
                        IO::Options &ropt, IO::Options &wopt )
{
  int c;
  while ((c=getopt(_argc, _argv, "bhsBF:LMSV:X:"))!=-1)
  {
    switch(c) 
    {
      // -------------------- read options

      // force binary input
      case 'b': 
        ropt += IO::Options::Binary; 
        break;

      // force swapping the byte order, when reading a binary file
      case 's': 
        ropt += IO::Options::Swap; 
        break;

      // -------------------- write options

      // Write binary variant of format if possible
      case 'B': 
        wopt += IO::Options::Binary; 
        break;

      // 
      case 'F':
        for(size_t i=0; optarg[i]; ++i)
          switch(optarg[i]) {
            case 'n' : wopt += IO::Options::FaceNormal; break;
            case 'c' : wopt += IO::Options::FaceColor; break;
          }
        break;

      // Use little endian when writing binary data
      case 'L': 
        wopt += IO::Options::LSB; 
        break;

      // Use big endian when writing binary data
      case 'M': 
        wopt += IO::Options::MSB; 
        break;

      // Swap byte order when writing binary data
      case 'S': 
        wopt += IO::Options::Swap; 
        break;

      //
      case 'V':
      {
        for(size_t i=0; optarg[i]; ++i)
          switch(optarg[i]) {
            case 'n' : // dont't change layout!!
              wopt += IO::Options::VertexNormal; 
              break;
            case 't' : wopt += IO::Options::VertexTexCoord; break;
            case 'c' : wopt += IO::Options::VertexColor; break;
          }
        break;
      }

      // -------------------- request mesh' standard properties
      case 'X':
      {        
        char entity='\0';
        for(size_t i=0; optarg[i]; ++i)
          switch(optarg[i]) {
            case 'v': 
            case 'f': entity = optarg[i]; break;
            case 'n':
              switch(entity) {
                case 'v': _mesh.request_vertex_normals(); break;
                case 'f': _mesh.request_face_normals(); break;
              }
              break;
            case 'c':
              switch(entity) {
                case 'v': _mesh.request_vertex_colors(); break;
                case 'f': _mesh.request_face_colors(); break;
              }
              break;
            case 't':
              switch(entity) {
                case 'v': _mesh.request_vertex_texcoords2D(); break;
              }
              break;
          }
        break;
      }
      
      // -------------------- help
      case 'h':
        usage_and_exit(0);
      default:
        usage_and_exit(1);
    }
  }

  if ( _argc-optind != 2)
    usage_and_exit(1);
}


// ----------------------------------------------------------------------------

void usage_and_exit(int xcode)
{
  std::ostream &os = xcode ? std::cerr : std::cout;

  os << "Usage: io_options [Options] <input> <output>\n" 
     << std::endl;
  os << "  Read and write a mesh, using OpenMesh::IO::Options\n"
     << std::endl;
  os << "Options:\n"
     << std::endl;
  os << "a) read options\n"
     << std::endl
     << "  -b\n"
     << "\tAssume input file is a binary file\n"
     << std::endl
     << "  -s\n"
     << "\tSwap byte order when reading a binary file!\n"
     << std::endl;
  os << "b) write options\n"
     << std::endl
     << "  -B\n"
     << "\tWrite binary data\n"
     << std::endl
     << "  -S\n"
     << "\tSwap byte order, when writing binary data\n"
     << std::endl
     << "  -M/-L\n"
     << "\tUse MSB/LSB byte ordering, when writing binary data\n"
     << std::endl
     << "  -V{n|t|c}\n"
     << "\tWrite vertex normals, texcoords, and/or colors\n"
     << std::endl
     << "  -F{n|c}\n"
     << "\tWrite face normals, and/or colors\n"
     << std::endl;
  os << "c) Mesh properties\n"
     << std::endl
     << "  -Xv{n|c|t}\n"
     << "\tRequest vertex property normals|colors|texcoords\n"
     << std::endl
     << "  -Xf{n|c}\n"
     << "\tRequest face property normals|colors\n"
     << std::endl;
  exit(xcode);
}

// end of file
// ============================================================================