/*===========================================================================*\
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/*===========================================================================*\
 *                                                                           *             
 *   $Revision: 460 $                                                         *
 *   $Date: 2011-11-16 10:45:08 +0100 (Mi, 16 Nov 2011) $                   *
 *                                                                           *
 \*===========================================================================*/

/** \file McDecimaterT.cc
 */

//=============================================================================
//
//  CLASS McDecimaterT - IMPLEMENTATION
//
//=============================================================================
#define OPENMESH_MULTIPLE_CHOICE_DECIMATER_DECIMATERT_CC

//== INCLUDES =================================================================

#include <OpenMesh/Tools/Decimater/McDecimaterT.hh>

#include <vector>
#if defined(OM_CC_MIPS)
#  include <float.h>
#else
#  include <cfloat>
#endif

//== NAMESPACE ===============================================================

namespace OpenMesh {
namespace Decimater {

//== IMPLEMENTATION ==========================================================

template<class Mesh>
McDecimaterT<Mesh>::McDecimaterT(Mesh& _mesh) :
    mesh_(_mesh), cmodule_(NULL), initialized_(false),randomSamples_(10) {

  // default properties
  mesh_.request_vertex_status();
  mesh_.request_halfedge_status();
  mesh_.request_edge_status();
  mesh_.request_face_status();
  mesh_.request_face_normals();

}

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

template<class Mesh>
McDecimaterT<Mesh>::~McDecimaterT() {
  // default properties
  mesh_.release_vertex_status();
  mesh_.release_edge_status();
  mesh_.release_halfedge_status();
  mesh_.release_face_status();
  mesh_.release_face_normals();

  // dispose of modules
  {
    set_uninitialized();
    typename ModuleList::iterator m_it, m_end = all_modules_.end();
    for (m_it = all_modules_.begin(); m_it != m_end; ++m_it)
      delete *m_it;
    all_modules_.clear();
  }
}

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

template<class Mesh>
void McDecimaterT<Mesh>::info(std::ostream& _os) {
  if (initialized_) {
    _os << "initialized : yes" << std::endl;
    _os << "binary modules: " << bmodules_.size() << std::endl;
    for (ModuleListIterator m_it = bmodules_.begin(); m_it != bmodules_.end();
        ++m_it) {
      _os << "  " << (*m_it)->name() << std::endl;
    }
    _os << "priority module: " << cmodule_->name().c_str() << std::endl;
  } else {
    _os << "initialized : no" << std::endl;
    _os << "available modules: " << all_modules_.size() << std::endl;
    for (ModuleListIterator m_it = all_modules_.begin();
        m_it != all_modules_.end(); ++m_it) {
      _os << "  " << (*m_it)->name() << " : ";
      if ((*m_it)->is_binary()) {
        _os << "binary";
        if ((*m_it)->name() == "Quadric") {
          _os << " and priority (special treatment)";
        }
      } else {
        _os << "priority";
      }
      _os << std::endl;
    }
  }
}

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

template<class Mesh>
bool McDecimaterT<Mesh>::initialize() {
  if (initialized_) {
    return true;
  }

  // FIXME: quadric module shouldn't be treated specially.
  // Q: Why?
  // A: It isn't generic and breaks encapsulation. Also, using string
  // name comparison is not reliable, since you can't guarantee that
  // no one else will name their custom module "Quadric".
  // Q: What should be done instead?
  // A: ModBaseT API should support modules that can be both binary
  // and priority, or BETTER YET, let the McDecimaterT API specify the
  // priority module explicitly.

  // find the priority module: either the only non-binary module in the list, or "Quadric"
  Module *quadric = NULL;
  Module *pmodule = NULL;
  for (ModuleListIterator m_it = all_modules_.begin(), m_end =
      all_modules_.end(); m_it != m_end; ++m_it) {
    if ((*m_it)->name() == "Quadric")
      quadric = *m_it;

    if (!(*m_it)->is_binary()) {
      if (pmodule) {
        // only one priority module allowed!
        set_uninitialized();
        return false;
      }
      pmodule = *m_it;
    }
  }

  // Quadric is used as default priority module (even if it is set to be binary)
  if (!pmodule && quadric) {
    pmodule = quadric;
  }

  if (!pmodule) {
    // At least one priority module required
    set_uninitialized();
    return false;
  }

  // set pmodule as the current priority module
  cmodule_ = pmodule;

  for (ModuleListIterator m_it = all_modules_.begin(), m_end =
      all_modules_.end(); m_it != m_end; ++m_it) {
    // every module gets initialized
    (*m_it)->initialize();

    if (*m_it != pmodule) {
      // all other modules are binary, and go into bmodules_ list
      bmodules_.push_back(*m_it);
    }
  }

  return initialized_ = true;
}

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

template<class Mesh>
bool McDecimaterT<Mesh>::is_collapse_legal(const CollapseInfo& _ci) {
  //   std::clog << "McDecimaterT<>::is_collapse_legal()\n";

  // locked ? deleted ?
  if (mesh_.status(_ci.v0).locked() || mesh_.status(_ci.v0).deleted())
    return false;

  if (!mesh_.is_collapse_ok(_ci.v0v1))
    return false;

  if (_ci.vl.is_valid() && _ci.vr.is_valid()
      && mesh_.find_halfedge(_ci.vl, _ci.vr).is_valid()
      && mesh_.valence(_ci.vl) == 3 && mesh_.valence(_ci.vr) == 3) {
    return false;
  }
  //--- feature test ---

  if (mesh_.status(_ci.v0).feature()
      && !mesh_.status(mesh_.edge_handle(_ci.v0v1)).feature())
    return false;

  //--- test one ring intersection ---

  typename Mesh::VertexVertexIter vv_it;

  for (vv_it = mesh_.vv_iter(_ci.v0); vv_it; ++vv_it)
    mesh_.status(vv_it).set_tagged(false);

  for (vv_it = mesh_.vv_iter(_ci.v1); vv_it; ++vv_it)
    mesh_.status(vv_it).set_tagged(true);

  for (vv_it = mesh_.vv_iter(_ci.v0); vv_it; ++vv_it)
    if (mesh_.status(vv_it).tagged() && vv_it.handle() != _ci.vl
        && vv_it.handle() != _ci.vr)
      return false;

  // if both are invalid OR equal -> fail
  if (_ci.vl == _ci.vr)
    return false;

  //--- test boundary cases ---
  if (mesh_.is_boundary(_ci.v0)) {
    if (!mesh_.is_boundary(_ci.v1)) { // don't collapse a boundary vertex to an inner one
      return false;
    } else { // edge between two boundary vertices has to be a boundary edge
      if (!(mesh_.is_boundary(_ci.v0v1) || mesh_.is_boundary(_ci.v1v0)))
        return false;
    }
    // only one one ring intersection
    if (_ci.vl.is_valid() && _ci.vr.is_valid())
      return false;
  }

  // v0vl and v1vl must not both be boundary edges
  if (_ci.vl.is_valid() && mesh_.is_boundary(_ci.vlv1)
      && mesh_.is_boundary(_ci.v0vl))
    return false;

  // v0vr and v1vr must not be both boundary edges
  if (_ci.vr.is_valid() && mesh_.is_boundary(_ci.vrv0)
      && mesh_.is_boundary(_ci.v1vr))
    return false;

  // there have to be at least 2 incident faces at v0
  if (mesh_.cw_rotated_halfedge_handle(
      mesh_.cw_rotated_halfedge_handle(_ci.v0v1)) == _ci.v0v1)
    return false;

  // collapse passed all tests -> ok
  return true;
}

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

template<class Mesh>
float McDecimaterT<Mesh>::collapse_priority(const CollapseInfo& _ci) {
  typename ModuleList::iterator m_it, m_end = bmodules_.end();

  for (m_it = bmodules_.begin(); m_it != m_end; ++m_it) {
    if ((*m_it)->collapse_priority(_ci) < 0.0)
      return ModBaseT<McDecimaterT<Mesh> >::ILLEGAL_COLLAPSE;
  }
  return cmodule_->collapse_priority(_ci);
}

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

template<class Mesh>
void McDecimaterT<Mesh>::postprocess_collapse(CollapseInfo& _ci) {
  typename ModuleList::iterator m_it, m_end = bmodules_.end();

  for (m_it = bmodules_.begin(); m_it != m_end; ++m_it)
    (*m_it)->postprocess_collapse(_ci);

  cmodule_->postprocess_collapse(_ci);
}

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

template<class Mesh>
void McDecimaterT<Mesh>::preprocess_collapse(CollapseInfo& _ci) {
  typename ModuleList::iterator m_it, m_end = bmodules_.end();

  for (m_it = bmodules_.begin(); m_it != m_end; ++m_it)
    (*m_it)->preprocess_collapse(_ci);

  cmodule_->preprocess_collapse(_ci);
}

//-----------------------------------------------------------------------------
template<class Mesh>
size_t McDecimaterT<Mesh>::decimate(size_t _n_collapses) {

  if (!is_initialized())
    return 0;

  unsigned int n_collapses(0);

  while ( n_collapses <  _n_collapses) {

    // Optimal id and value will be collected during the random sampling
    typename Mesh::HalfedgeHandle bestHandle(-1);
    double bestEnergy = FLT_MAX;

    // Generate random samples for collapses
    for ( unsigned int i = 0; i < randomSamples_; ++i) {

      // Random halfedge handle
      typename Mesh::HalfedgeHandle tmpHandle = typename Mesh::HalfedgeHandle(double(rand()) / RAND_MAX * mesh_.n_halfedges() );

      // if it is not deleted, we analyse it
      if ( ! mesh_.status(tmpHandle).deleted()  ) {

        CollapseInfo ci(mesh_, tmpHandle);

        // Check if legal we analyze the priority of this collapse operation
        if (is_collapse_legal(ci)) {
          double energy = collapse_priority(ci);

          // Check if the current samples energy is better than any energy before
          if ( energy < bestEnergy ) {
            bestEnergy = energy;
            bestHandle = tmpHandle;
          }
        } else {
          continue;
        }
      }

    }

    // Found the best energy?
    if ( bestEnergy != FLT_MAX ) {

      // setup collapse info
      CollapseInfo ci(mesh_, bestHandle);

      // check topological correctness AGAIN !
      if (!is_collapse_legal(ci))
        continue;

      // pre-processing
      preprocess_collapse(ci);

      // perform collapse
      mesh_.collapse(bestHandle);
      ++n_collapses;

      // update triangle normals
      typename Mesh::VertexFaceIter vf_it = mesh_.vf_iter(ci.v1);
      for (; vf_it; ++vf_it)
        if (!mesh_.status(vf_it).deleted())
          mesh_.set_normal(vf_it, mesh_.calc_face_normal(vf_it.handle()));

      // post-process collapse
      postprocess_collapse(ci);

    }

  }

  // DON'T do garbage collection here! It's up to the application.
  return n_collapses;
}

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

template<class Mesh>
size_t McDecimaterT<Mesh>::decimate_to_faces(size_t _nv, size_t _nf) {
  if (!is_initialized())
    return 0;

  unsigned int nv = mesh_.n_vertices();
  unsigned int nf = mesh_.n_faces();
  unsigned int n_collapses(0);

  while ( (_nv < nv) && (_nf < nf) ) {

    // Optimal id and value will be collected during the random sampling
    typename Mesh::HalfedgeHandle bestHandle(-1);
    double bestEnergy = FLT_MAX;

    // Generate random samples for collapses
    for ( unsigned int i = 0; i < randomSamples_; ++i) {

      // Random halfedge handle
      typename Mesh::HalfedgeHandle tmpHandle = typename Mesh::HalfedgeHandle(double(rand()) / RAND_MAX * mesh_.n_halfedges() );

      // if it is not deleted, we analyse it
      if ( ! mesh_.status(tmpHandle).deleted()  ) {

        CollapseInfo ci(mesh_, tmpHandle);

        // Check if legal we analyze the priority of this collapse operation
        if (is_collapse_legal(ci)) {
          double energy = collapse_priority(ci);

          // Check if the current samples energy is better than any energy before
          if ( energy < bestEnergy ) {
            bestEnergy = energy;
            bestHandle = tmpHandle;
          }
        } else {
          continue;
        }
      }

    }

    // Found the best energy?
    if ( bestEnergy != FLT_MAX ) {

      // setup collapse info
      CollapseInfo ci(mesh_, bestHandle);

      // check topological correctness AGAIN !
      if (!is_collapse_legal(ci))
        continue;

      // adjust complexity in advance (need boundary status)
      ++n_collapses;

      // One vertex is killed by the collapse
      --nv;

      // If we are at a boundary, one face is lost,
      // otherwise two
      if (mesh_.is_boundary(ci.v0v1) || mesh_.is_boundary(ci.v1v0))
        --nf;
      else
        nf -= 2;

      // pre-processing
      preprocess_collapse(ci);

      // perform collapse
      mesh_.collapse(bestHandle);
      ++n_collapses;

      // update triangle normals
      typename Mesh::VertexFaceIter vf_it = mesh_.vf_iter(ci.v1);
      for (; vf_it; ++vf_it)
        if (!mesh_.status(vf_it).deleted())
          mesh_.set_normal(vf_it, mesh_.calc_face_normal(vf_it.handle()));

      // post-process collapse
      postprocess_collapse(ci);

    }

  }

  // DON'T do garbage collection here! It's up to the application.
  return n_collapses;
}

//=============================================================================
}// END_NS_MC_DECIMATER
} // END_NS_OPENMESH
//=============================================================================