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

 Copyright (C) 2002-2014 Gilles Debunne. All rights reserved.

 This file is part of the QGLViewer library version 2.6.2.

 http://www.libqglviewer.com - contact@libqglviewer.com

 This file may be used under the terms of the GNU General Public License 
 versions 2.0 or 3.0 as published by the Free Software Foundation and
 appearing in the LICENSE file included in the packaging of this file.
 In addition, as a special exception, Gilles Debunne gives you certain 
 additional rights, described in the file GPL_EXCEPTION in this package.

 libQGLViewer uses dual licensing. Commercial/proprietary software must
 purchase a libQGLViewer Commercial License.

 This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

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

#include "multiSelect.h"
#include "manipulatedFrameSetConstraint.h"

#include <QGLViewer/manipulatedFrame.h>

#include <QMouseEvent>

using namespace qglviewer;

Viewer::Viewer()
{
	selectionMode_ = NONE;

	// Fill the scene with objects positionned on a regular grid.
	// Consider increasing selectBufferSize() if you use more objects.
	const int nb = 10;
	for (int i=-nb; i<=nb; ++i)
		for (int j=-nb; j<=nb; ++j)
		{
			Object* o = new Object();
			o->frame.setPosition(Vec(i/float(nb), j/float(nb), 0.0));
			objects_.append(o);
		}
}

void Viewer::init()
{
  // A ManipulatedFrameSetConstraint will apply displacements to the selection
  setManipulatedFrame(new ManipulatedFrame());
  manipulatedFrame()->setConstraint(new ManipulatedFrameSetConstraint());

  // Used to display semi-transparent relection rectangle
  glBlendFunc(GL_ONE, GL_ONE);

  restoreStateFromFile();
  help();
}

QString Viewer::helpString() const
{
  QString text("<h2>m u l t i S e l e c t </h2>");
  text += "This example illustrates an application of the <code>select()</code> function that ";
  text += "enables the selection of several objects.<br><br>";
  text += "Object selection is preformed using the left mouse button. Press <b>Shift</b> to add objects ";
  text += "to the selection, and <b>Alt</b> to remove objects from the selection.<br><br>";
  text += "Individual objects (click on them) as well as rectangular regions (click and drag mouse) can be selected. ";
  text += "To do this, the selection region size is modified and the <code>endSelection()</code> function ";
  text += "has been overloaded so that <i>all</i> the objects of the region are taken into account ";
  text += "(the default implementation only selects the closest object).<br><br>";
  text += "The selected objects can then be manipulated by pressing the <b>Control</b> key. ";
  text += "Other set operations (parameter edition, deletion...) can also easily be applied to the selected objects.";
  return text;
}


//  D r a w i n g   f u n c t i o n

void Viewer::draw()
{
  // Draws selected objects only.
  glColor3f(0.9f, 0.3f, 0.3f);
	for (QList<int>::const_iterator it=selection_.begin(), end=selection_.end(); it != end; ++it)
	  objects_.at(*it)->draw();

  // Draws all the objects. Selected ones are not repainted because of GL depth test.
  glColor3f(0.8f, 0.8f, 0.8f);
  for (int i=0; i<int(objects_.size()); i++)
	objects_.at(i)->draw();

  // Draws manipulatedFrame (the set's rotation center)
  if (manipulatedFrame()->isManipulated())
	{
	  glPushMatrix();
	  glMultMatrixd(manipulatedFrame()->matrix());
	  drawAxis(0.5);
	  glPopMatrix();
	}

  // Draws rectangular selection area. Could be done in postDraw() instead.
  if (selectionMode_ != NONE)
	drawSelectionRectangle();
}


//   C u s t o m i z e d   m o u s e   e v e n t s

void Viewer::mousePressEvent(QMouseEvent* e)
{
	// Start selection. Mode is ADD with Shift key and TOGGLE with Alt key.
	rectangle_ = QRect(e->pos(), e->pos());

	if ((e->button() == Qt::LeftButton) && (e->modifiers() == Qt::ShiftModifier))
		selectionMode_ = ADD;
	else
		if ((e->button() == Qt::LeftButton) && (e->modifiers() == Qt::AltModifier))
			selectionMode_ = REMOVE;
		else
		{
			if (e->modifiers() == Qt::ControlModifier)
				startManipulation();
			QGLViewer::mousePressEvent(e);
		}
}

void Viewer::mouseMoveEvent(QMouseEvent* e)
{
  if (selectionMode_ != NONE)
	{
	  // Updates rectangle_ coordinates and redraws rectangle
	  rectangle_.setBottomRight(e->pos());
	  updateGL();
	}
  else
	QGLViewer::mouseMoveEvent(e);
}

void Viewer::mouseReleaseEvent(QMouseEvent* e)
{
  if (selectionMode_ != NONE)
	{
	  // Actual selection on the rectangular area.
	  // Possibly swap left/right and top/bottom to make rectangle_ valid.
	  rectangle_ = rectangle_.normalized();
	  // Define selection window dimensions
	  setSelectRegionWidth(rectangle_.width());
	  setSelectRegionHeight(rectangle_.height());
	  // Compute rectangle center and perform selection
	  select(rectangle_.center());
	  // Update display to show new selected objects
	  updateGL();
	}
  else
	QGLViewer::mouseReleaseEvent(e);
}


//   C u s t o m i z e d   s e l e c t i o n   p r o c e s s

void Viewer::drawWithNames()
{
  for (int i=0; i<int(objects_.size()); i++)
	{
	  glPushName(i);
	  objects_.at(i)->draw();
	  glPopName();
	}
}

void Viewer::endSelection(const QPoint&)
{
  // Flush GL buffers
  glFlush();

  // Get the number of objects that were seen through the pick matrix frustum. Reset GL_RENDER mode.
  GLint nbHits = glRenderMode(GL_RENDER);

  if (nbHits > 0)
	{
	  // Interpret results : each object created 4 values in the selectBuffer().
	  // (selectBuffer())[4*i+3] is the id pushed on the stack.
	  for (int i=0; i<nbHits; ++i)
	switch (selectionMode_)
	  {
	  case ADD    : addIdToSelection((selectBuffer())[4*i+3]); break;
	  case REMOVE : removeIdFromSelection((selectBuffer())[4*i+3]);  break;
	  default : break;
	  }
	}
  selectionMode_ = NONE;
}

void Viewer::startManipulation()
{
  Vec averagePosition;
  ManipulatedFrameSetConstraint* mfsc = (ManipulatedFrameSetConstraint*)(manipulatedFrame()->constraint());
  mfsc->clearSet();

  for (QList<int>::const_iterator it=selection_.begin(), end=selection_.end(); it != end; ++it)
	{
	  mfsc->addObjectToSet(objects_[*it]);
	  averagePosition += objects_[*it]->frame.position();
	}

  if (selection_.size() > 0)
	manipulatedFrame()->setPosition(averagePosition / selection_.size());
}


//   S e l e c t i o n   t o o l s

void Viewer::addIdToSelection(int id)
{
  if (!selection_.contains(id))
	selection_.push_back(id);
}

void Viewer::removeIdFromSelection(int id)
{
  selection_.removeAll(id);
}

void Viewer::drawSelectionRectangle() const
{
  startScreenCoordinatesSystem();
  glDisable(GL_LIGHTING);
  glEnable(GL_BLEND);

  glColor4f(0.0, 0.0, 0.3f, 0.3f);
  glBegin(GL_QUADS);
  glVertex2i(rectangle_.left(),  rectangle_.top());
  glVertex2i(rectangle_.right(), rectangle_.top());
  glVertex2i(rectangle_.right(), rectangle_.bottom());
  glVertex2i(rectangle_.left(),  rectangle_.bottom());
  glEnd();

  glLineWidth(2.0);
  glColor4f(0.4f, 0.4f, 0.5f, 0.5f);
  glBegin(GL_LINE_LOOP);
  glVertex2i(rectangle_.left(),  rectangle_.top());
  glVertex2i(rectangle_.right(), rectangle_.top());
  glVertex2i(rectangle_.right(), rectangle_.bottom());
  glVertex2i(rectangle_.left(),  rectangle_.bottom());
  glEnd();

  glDisable(GL_BLEND);
  glEnable(GL_LIGHTING);
  stopScreenCoordinatesSystem();
}
