/*
 * Project: MoleCuilder
 * Description: creates and alters molecular systems
 * Copyright (C)  2010-2012 University of Bonn. All rights reserved.
 * Copyright (C)  2013 Frederik Heber. All rights reserved.
 * 
 *
 *   This file is part of MoleCuilder.
 *
 *    MoleCuilder is free software: you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation, either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    MoleCuilder is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with MoleCuilder.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * GLMoleculeObject_bond.cpp
 *
 *  Created on: Aug 17, 2011
 *      Author: heber
 */

// include config.h
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "GLMoleculeObject_bond.hpp"

#include <Qt3D/qglmaterial.h>
#include <Qt3D/qglscenenode.h>

#include "UIElements/Qt4/InstanceBoard/QtObservedInstanceBoard.hpp"

//#include "CodePatterns/MemDebug.hpp"

#include <cmath>

#include "CodePatterns/Assert.hpp"
#include "CodePatterns/Log.hpp"

#include "Atom/atom.hpp"
#include "Bond/bond.hpp"
#include "Element/element.hpp"
#include "Helpers/defs.hpp"
#include "LinearAlgebra/Line.hpp"
#include "LinearAlgebra/Vector.hpp"
#include "World.hpp"

GLMoleculeObject_bond::GLMoleculeObject_bond(
    QGLSceneNode *mesh[],
    QObject *parent,
    QtObservedBond::ptr &_ObservedBond,
    const enum SideOfBond side) :
  GLMoleculeObject(mesh, parent),
  BondSide(side),
  ObservedBond(_ObservedBond)
{
  resetElement();
  resetPosition();
  resetWidth();

  // connect to observed bond's signals
  connect(_ObservedBond.get(), SIGNAL(degreeChanged()), this, SLOT(resetWidth()));
  if (side == left)
    connect(_ObservedBond.get(), SIGNAL(leftAtomElementChanged()), this, SLOT(resetElement()));
  else
    connect(_ObservedBond.get(), SIGNAL(rightAtomElementChanged()), this, SLOT(resetElement()));
  connect(_ObservedBond.get(), SIGNAL(leftAtomPositionChanged()), this, SLOT(resetPosition()));
  connect(_ObservedBond.get(), SIGNAL(rightAtomPositionChanged()), this, SLOT(resetPosition()));
}

static const atomicNumber_t& getElement(
    const QtObservedBond::ptr &_ObservedBond,
    const enum GLMoleculeObject_bond::SideOfBond _side)
{
  if (_side == GLMoleculeObject_bond::left)
    return _ObservedBond->getLeftAtomElement();
  else
    return _ObservedBond->getRightAtomElement();
}

static const Vector& getPosition(
    const QtObservedBond::ptr &_ObservedBond,
    const enum GLMoleculeObject_bond::SideOfBond _side)
{
  if (_side == GLMoleculeObject_bond::left)
    return _ObservedBond->getLeftAtomPosition();
  else
    return _ObservedBond->getRightAtomPosition();
}

static const Vector& getOtherPosition(
    const QtObservedBond::ptr &_ObservedBond,
    const enum GLMoleculeObject_bond::SideOfBond _side)
{
  if (_side == GLMoleculeObject_bond::left)
    return _ObservedBond->getRightAtomPosition();
  else
    return _ObservedBond->getLeftAtomPosition();
}

GLMoleculeObject_bond::~GLMoleculeObject_bond()
{
  LOG(4, "DEBUG: Destroying  GLMoleculeObject_bond to bond [" <<
      ObservedBond->getBondIndex() << "] and side " << BondSide << ".");
  // signOff() if not already done
}

void GLMoleculeObject_bond::resetElement()
{
  const atomicNumber_t& elementno = getElement(ObservedBond, BondSide);
  QGLMaterial *elementmaterial = getMaterial(elementno);
  setMaterial(elementmaterial);
}

void GLMoleculeObject_bond::resetWidth()
{
  const double factor = 1.0f+.5f*(ObservedBond->getBondDegree()-1);
  LOG(4, "DEBUG: GLMoleculeObject_bond::resetWidth() - setting bond's width to " << factor << ".");
  setScaleX(factor);
  setScaleY(factor);

  emit changed();
}

void GLMoleculeObject_bond::resetPosition()
{
  const Vector& Position = getPosition(ObservedBond, BondSide);
  const Vector& OtherPosition = getOtherPosition(ObservedBond, BondSide);
  const double distance =
      Position.distance(OtherPosition)/2.;
  setScaleZ(distance);

  // calculate position
  Vector Z(unitVec[2]); // cylinder are initially aligned along the Z axis
  Vector zeroVec(0.,0.,0.);
  Vector a,b;
  Vector OtherAxis;
  double alpha;
  a = OtherPosition - Position;
  // construct rotation axis
  b = a;
  b.VectorProduct(Z);
  Line axis(zeroVec, b);
  // calculate rotation angle
  alpha = a.Angle(Z);
  // construct other axis to check right-hand rule
  OtherAxis = b;
  OtherAxis.VectorProduct(Z);
  // assure right-hand rule for the rotation
  if (a.ScalarProduct(OtherAxis) < MYEPSILON)
    alpha = M_PI-alpha;
  // check
  Vector a_rotated = axis.rotateVector(a, alpha);
  LOG(4, "DEBUG: Created cylinder from "// << Position << " to " << OtherPosition
      << a << " to " << a_rotated << " around " << b << " by " << alpha/M_PI*180. << ", respectively.");

  // set position (cylinder offset is in its barymetric center)
  Vector OneFourth(OtherPosition - 0.75 * a);
  setPosition(QVector3D(OneFourth[0], OneFourth[1], OneFourth[2]));
  setRotationVector(QVector3D(b[0], b[1], b[2]));
  setRotationAngle(alpha/M_PI*180.);

  emit changed();
}