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

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

#include "GLMoleculeObject_atom.hpp"

#include <Qt3D/qglscenenode.h>

//#include "CodePatterns/MemDebug.hpp"

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

#include <algorithm>

#include "Atom/atom.hpp"
#include "Bond/bond.hpp"
#include "Element/element.hpp"
#include "Element/periodentafel.hpp"
#include "LinearAlgebra/Line.hpp"
#include "LinearAlgebra/Vector.hpp"
#include "UIElements/Views/Qt4/Qt3D/GLMoleculeObject_bond.hpp"
#include "UIElements/Qt4/InstanceBoard/QtObservedInstanceBoard.hpp"
#include "World.hpp"

GLMoleculeObject_atom::GLMoleculeObject_atom(
    QGLSceneNode *mesh[],
    QGLSceneNode *mesharrow[],
    QObject *parent,
    QtObservedAtom::ptr &_ObservedAtom) :
  GLMoleculeObject(mesh, parent),
  GLMoleculeObjectVelocity(mesharrow, this),
  GLMoleculeObjectForce(mesharrow, this),
  ObservedAtom(_ObservedAtom)
{
  init(ObservedAtom->getAtomIndex());
}

void GLMoleculeObject_atom::init(const atomId_t _id)
{
  setObjectId(_id);
  resetPosition();
  resetVelocity();
  resetForce();
  resetElement();

  GLMoleculeObjectVelocity.setMaterial(GLMoleculeObject::m_velocityMaterial);
  GLMoleculeObjectForce.setMaterial(GLMoleculeObject::m_forceMaterial);

  m_selected = ObservedAtom->getAtomSelected();

  connect( this, SIGNAL(clicked()), this, SLOT(wasClicked()));
  connect( ObservedAtom.get(), SIGNAL(indexChanged()), this, SLOT(resetIndex()));
  connect( ObservedAtom.get(), SIGNAL(elementChanged()), this, SLOT(resetElement()));
  connect( ObservedAtom.get(), SIGNAL(positionChanged()), this, SLOT(resetPosition()));
  connect( ObservedAtom.get(), SIGNAL(velocityChanged()), this, SLOT(resetVelocity()));
  connect( ObservedAtom.get(), SIGNAL(forceChanged()), this, SLOT(resetForce()));
  connect( ObservedAtom.get(), SIGNAL(selectedChanged()), this, SLOT(resetSelected()));
}

GLMoleculeObject_atom::~GLMoleculeObject_atom()
{}

void GLMoleculeObject_atom::resetIndex()
{
  const atomId_t newId = ObservedAtom->getAtomIndex();
  const size_t oldId = objectId();
  ASSERT( newId != oldId,
      "GLMoleculeObject_atom::updateIndex() - index "+toString(newId)+" did not change.");
  LOG(4, "INFO: GLMoleculeObject_atom::resetIndex() - new index is "+toString(newId)+".");
  setObjectId(newId);

  emit indexChanged(this, oldId, newId);
}

static void setArrow(
    const Vector &_position,
    const Vector &_arrow,
    const double _offset,
    GLMoleculeObject &_obj)
{
  // set position (cylinder offset is in its barymetric center)
  Vector OneFourth(_position + (_offset/_arrow.Norm()+.75) * _arrow);
  _obj.setPosition(QVector3D(OneFourth[0], OneFourth[1], OneFourth[2]));
}

void GLMoleculeObject_atom::resetPosition()
{
  const Vector Position = ObservedAtom->getAtomPosition();
  LOG(4, "INFO: GLMoleculeObject_atom::resetPosition() - new position is "+toString(Position)+".");
  setPosition(QVector3D(Position[0], Position[1], Position[2]));
  setArrow(Position, 10.*ObservedAtom->getAtomVelocity(), scaleX(), GLMoleculeObjectVelocity);
  setArrow(Position, 10.*ObservedAtom->getAtomForce(), scaleX(), GLMoleculeObjectForce);
}

static void alignArrow(
    const Vector &_arrow,
    GLMoleculeObject &_obj)
{
  if (_arrow.IsZero()) {
    _obj.setScaleZ(0.);
    return;
  }
  // calculate position
  Vector Z(unitVec[2]); // cylinder are initially aligned along the Z axis
  Vector b;
  Vector OtherAxis;
  double alpha;
  // construct rotation axis
  b = -1.*_arrow;
  b.VectorProduct(Z);
  Line axis(zeroVec, b);
  // calculate rotation angle
  alpha = _arrow.Angle(Z);
  // construct other axis to check right-hand rule
  OtherAxis = b;
  OtherAxis.VectorProduct(Z);
  // assure right-hand rule for the rotation
  if (_arrow.ScalarProduct(OtherAxis) < MYEPSILON)
    alpha = M_PI-alpha;
  // check
  Vector a_rotated = axis.rotateVector(_arrow, alpha);
  LOG(5, "DEBUG: Aligning arrow " << _arrow << " to " << a_rotated
      << " around " << b << " by " << alpha/M_PI*180. << ".");

  _obj.setScaleZ(10.*_arrow.Norm());
  _obj.setRotationVector(QVector3D(b[0], b[1], b[2]));
  _obj.setRotationAngle(alpha/M_PI*180.);
}

void GLMoleculeObject_atom::resetVelocity()
{
  const Vector Velocity = ObservedAtom->getAtomVelocity();
  LOG(4, "INFO: GLMoleculeObject_atom::resetVelocity() - new velocity is "+toString(Velocity)+".");
  alignArrow(Velocity, GLMoleculeObjectVelocity);
//  GLMoleculeObjectForce.setScaleZ(Velocity.Norm());
}

void GLMoleculeObject_atom::resetForce()
{
  const Vector Force = ObservedAtom->getAtomForce();
  LOG(4, "INFO: GLMoleculeObject_atom::resetForce() - new force is "+toString(Force)+".");
  alignArrow(Force, GLMoleculeObjectForce);
//  GLMoleculeObjectForce.setScaleZ(Force.Norm());
}

void GLMoleculeObject_atom::resetElement()
{
  size_t elementno = 0;
  const element * const _type = World::getInstance().
      getPeriode()->FindElement(ObservedAtom->getAtomElement());
  if (_type != NULL) {
    elementno = _type->getAtomicNumber();
  } else { // if no element yet, set to hydrogen
    elementno = 1;
  }
  LOG(4, "INFO: GLMoleculeObject_atom::resetElement() - new element number is "+toString(elementno)+".");

  // set materials
  QGLMaterial *elementmaterial = getMaterial(elementno);
  ASSERT(elementmaterial != NULL,
      "GLMoleculeObject_atom::resetElement() - QGLMaterial ref from getter function is NULL.");
  setMaterial(elementmaterial);

  // set scale
  double radius = 0.;
  if (_type != NULL) {
    radius = _type->getVanDerWaalsRadius();
  } else {
    radius = 0.5;
  }
  setScale( radius / 4. );
}

void GLMoleculeObject_atom::resetSelected()
{
  // we ascertain check that selection state changed as the Qt signal might be executed
  // at a later stage when the state has changed yet again
  const bool new_selected = ObservedAtom->getAtomSelected();
  m_selected = new_selected;

  emit changed();
}

void GLMoleculeObject_atom::draw(QGLPainter *painter, const QVector4D &cameraPlane)
{
  // call old hook to do the actual paining
  GLMoleculeObject::draw(painter, cameraPlane);
  GLMoleculeObjectVelocity.draw(painter, cameraPlane);
  GLMoleculeObjectForce.draw(painter, cameraPlane);
}

void GLMoleculeObject_atom::wasClicked()
{
  LOG(4, "INFO: GLMoleculeObject_atom: atom "
      << ObservedAtom->getAtomIndex() << " has been clicked");
  emit clicked(ObservedAtom->getAtomIndex());
}