/****************************************************************************

 Copyright (C) 2002-2006 Gilles Debunne (Gilles.Debunne@imag.fr)

This file is part of the QGLViewer library.
 Version 2.2.4-1, released on December 12, 2006.

 http://artis.imag.fr/Members/Gilles.Debunne/QGLViewer

 libQGLViewer 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.

 libQGLViewer 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 libQGLViewer; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

*****************************************************************************/

#include "constrainedFrame.h"

using namespace qglviewer;
using namespace std;

static AxisPlaneConstraint::Type nextTranslationConstraintType(const AxisPlaneConstraint::Type& type)
{
  switch (type)
    {
    case AxisPlaneConstraint::FREE  : return AxisPlaneConstraint::PLANE; break;
    case AxisPlaneConstraint::PLANE : return AxisPlaneConstraint::AXIS;  break;
    case AxisPlaneConstraint::AXIS  : return AxisPlaneConstraint::FORBIDDEN;  break;
    case AxisPlaneConstraint::FORBIDDEN : return AxisPlaneConstraint::FREE; break;
    default : return AxisPlaneConstraint::FREE;
    }
}

static AxisPlaneConstraint::Type nextRotationConstraintType(const AxisPlaneConstraint::Type& type)
{
  switch (type)
    {
    case AxisPlaneConstraint::FREE  : return AxisPlaneConstraint::AXIS; break;
    case AxisPlaneConstraint::AXIS  : return AxisPlaneConstraint::FORBIDDEN;  break;
    case AxisPlaneConstraint::PLANE :
    case AxisPlaneConstraint::FORBIDDEN : return AxisPlaneConstraint::FREE; break;
    default : return AxisPlaneConstraint::FREE;
    }
}

void Viewer::changeConstraint()
{
  unsigned short previous = activeConstraint;
  activeConstraint = (activeConstraint+1)%3;

  constraints[activeConstraint]->setTranslationConstraintType(constraints[previous]->translationConstraintType());
  constraints[activeConstraint]->setTranslationConstraintDirection(constraints[previous]->translationConstraintDirection());
  constraints[activeConstraint]->setRotationConstraintType(constraints[previous]->rotationConstraintType());
  constraints[activeConstraint]->setRotationConstraintDirection(constraints[previous]->rotationConstraintDirection());

  frame->setConstraint(constraints[activeConstraint]);
}

void Viewer::init()
{
  constraints[0] = new LocalConstraint();
  constraints[1] = new WorldConstraint();
  constraints[2] = new CameraConstraint(camera());

  transDir = 0; // X direction
  rotDir   = 0; // X direction
  activeConstraint = 0;

  frame = new ManipulatedFrame();
  setManipulatedFrame(frame);
  frame->setConstraint(constraints[activeConstraint]);

#if QT_VERSION < 0x040000
  // Preserve CAMERA bindings, see setHandlerKeyboardModifiers documentation.
  setHandlerKeyboardModifiers(QGLViewer::CAMERA, Qt::AltButton);
  // The frames can be move without any key pressed
  setHandlerKeyboardModifiers(QGLViewer::FRAME, Qt::NoButton);
  // The camera can always be moved with the Control key.
  setHandlerKeyboardModifiers(QGLViewer::CAMERA, Qt::ControlButton);

  setMouseBinding(Qt::ShiftButton | Qt::LeftButton,  QGLViewer::FRAME, QGLViewer::ROTATE,    false);
  setMouseBinding(Qt::ShiftButton | Qt::RightButton, QGLViewer::FRAME, QGLViewer::TRANSLATE, false);
  setMouseBinding(Qt::ShiftButton | Qt::MidButton,   QGLViewer::FRAME, QGLViewer::ZOOM,      false);
  setWheelBinding(Qt::ShiftButton,                   QGLViewer::FRAME, QGLViewer::ZOOM,      false);
#else
  setHandlerKeyboardModifiers(QGLViewer::CAMERA, Qt::AltModifier);
  setHandlerKeyboardModifiers(QGLViewer::FRAME, Qt::NoModifier);
  setHandlerKeyboardModifiers(QGLViewer::CAMERA, Qt::ControlModifier);

  setMouseBinding(Qt::ShiftModifier | Qt::LeftButton,  QGLViewer::FRAME, QGLViewer::ROTATE,    false);
  setMouseBinding(Qt::ShiftModifier | Qt::RightButton, QGLViewer::FRAME, QGLViewer::TRANSLATE, false);
  setMouseBinding(Qt::ShiftModifier | Qt::MidButton,   QGLViewer::FRAME, QGLViewer::ZOOM,      false);
  setWheelBinding(Qt::ShiftModifier,                   QGLViewer::FRAME, QGLViewer::ZOOM,      false);
#endif

  setAxisIsDrawn();

  setKeyDescription(Qt::Key_G, "Change translation constraint direction");
  setKeyDescription(Qt::Key_D, "Change rotation constraint direction");
  setKeyDescription(Qt::Key_Space, "Change constraint reference");
  setKeyDescription(Qt::Key_T, "Change translation constraint type");
  setKeyDescription(Qt::Key_R, "Change rotation constraint type");

  restoreStateFromFile();
  help();
}

void Viewer::draw()
{
  glMultMatrixd(frame->matrix());
  drawAxis(0.4);
  const float scale = 0.3;
  glScalef(scale, scale, scale);

  const float nbSteps = 200.0;
  glBegin(GL_QUAD_STRIP);
  for (float i=0; i<nbSteps; ++i)
    {
      float ratio = i/nbSteps;
      float angle = 21.0*ratio;
      float c = cos(angle);
      float s = sin(angle);
      float r1 = 1.0 - 0.8*ratio;
      float r2 = 0.8 - 0.8*ratio;
      float alt = ratio - 0.5;
      const float nor = .5;
      const float up = sqrt(1.0-nor*nor);
      glColor3f(1-ratio, .2 , ratio);
      glNormal3f(nor*c*scale, up*scale, nor*s*scale);
      glVertex3f(r1*c, alt, r1*s);
      glVertex3f(r2*c, alt+0.05, r2*s);
    }
  glEnd();

  displayText();
}

void Viewer::keyPressEvent(QKeyEvent *e)
{
  switch (e->key())
    {
    case Qt::Key_G : transDir = (transDir+1)%3; break;
    case Qt::Key_D : rotDir   = (rotDir+1)%3;   break;
    case Qt::Key_Space: changeConstraint();     break;
    case Qt::Key_T :
      constraints[activeConstraint]->setTranslationConstraintType(nextTranslationConstraintType(constraints[activeConstraint]->translationConstraintType()));
      break;
    case Qt::Key_R :
      constraints[activeConstraint]->setRotationConstraintType(nextRotationConstraintType(constraints[activeConstraint]->rotationConstraintType()));
      break;
    default:
      QGLViewer::keyPressEvent(e);
    }

  Vec dir(0.0,0.0,0.0);
  dir[transDir] = 1.0;
  constraints[activeConstraint]->setTranslationConstraintDirection(dir);

  dir = Vec(0.0,0.0,0.0);
  dir[rotDir] = 1.0;
  constraints[activeConstraint]->setRotationConstraintDirection(dir);

  updateGL();
}

void Viewer::displayType(const AxisPlaneConstraint::Type type, const int x, const int y, const char c)
{
  QString text;
  switch (type)
    {
    case AxisPlaneConstraint::FREE:  text = QString("FREE (%1)").arg(c);  break;
    case AxisPlaneConstraint::PLANE: text = QString("PLANE (%1)").arg(c); break;
    case AxisPlaneConstraint::AXIS:  text = QString("AXIS (%1)").arg(c); break;
    case AxisPlaneConstraint::FORBIDDEN: text = QString("FORBIDDEN (%1)").arg(c); break;
    }
  drawText(x, y, text);
}

void Viewer::displayDir(const unsigned short dir, const int x, const int y, const char c)
{
  QString text;
  switch (dir)
    {
    case 0: text = QString("X (%1)").arg(c); break;
    case 1: text = QString("Y (%1)").arg(c); break;
    case 2: text = QString("Z (%1)").arg(c); break;
    }
  drawText(x, y, text);
}

void Viewer::displayText()
{
  qglColor(foregroundColor());
  glDisable(GL_LIGHTING);
  drawText(10, height()-30, "TRANSLATION :");
  displayDir(transDir, 190, height()-30, 'G');
  displayType(constraints[activeConstraint]->translationConstraintType(), 10, height()-60, 'T');

  drawText(width()-220,height()-30, "ROTATION");
  displayDir(rotDir, width()-100, height()-30, 'D');
  displayType(constraints[activeConstraint]->rotationConstraintType(), width()-220, height()-60, 'R');

  switch (activeConstraint)
    {
    case 0 : drawText(20,20, "Constraint direction defined w/r to LOCAL (SPACE)"); break;
    case 1 : drawText(20,20, "Constraint direction defined w/r to WORLD (SPACE)"); break;
    case 2 : drawText(20,20, "Constraint direction defined w/r to CAMERA (SPACE)"); break;
    }
  glEnable(GL_LIGHTING);
}

QString Viewer::helpString() const
{
  QString text("<h2>C o n s t r a i n e d F r a m e</h2>");
  text += "A manipulated frame can be constrained in its displacement.<br><br>";
  text += "Try the different translation (press <b>G</b> and <b>T</b>) and rotation ";
  text += "(<b>D</b> and <b>R</b>) constraints while moving the frame with the mouse.<br><br>";
  text += "The constraints can be defined with respect to various coordinates";
  text += "systems : press <b>Space</b> to switch.<br><br>";
  text += "Press the <b>Control</b> key while moving the mouse to move the camera.<br>";
  text += "Press the <b>Shift</b> key to temporally disable the constraint.<br><br>";
  text += "You can easily define your own constraints to create a specific frame behavior.";
  return text;
}