/*=========================================================================

   Program: ParaView
   Module:    pqViewManager.cxx

   Copyright (c) 2005-2008 Sandia Corporation, Kitware Inc.
   All rights reserved.

   ParaView is a free software; you can redistribute it and/or modify it
   under the terms of the ParaView license version 1.2.

   See License_v1.2.txt for the full ParaView license.
   A copy of this license can be obtained by contacting
   Kitware Inc.
   28 Corporate Drive
   Clifton Park, NY 12065
   USA

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

=========================================================================*/
#include "pqViewManager.h"
#include "ui_pqEmptyView.h"

// VTK includes.
#include "QVTKWidget.h"
#include "vtkErrorCode.h"
#include "vtkImageData.h"
#include "vtkImageIterator.h"
#include "vtkPVConfig.h"
#include "vtkPVXMLElement.h"
#include "vtkSMAnimationSceneImageWriter.h"
#include "vtkSmartPointer.h"
#include "vtkSMIntVectorProperty.h"
#include "vtkSMPropertyHelper.h"
#include "vtkSMProxy.h"
#include "vtkSMProxyLocator.h"
#include "vtkSMUtilities.h"

// Qt includes.
#include <QAction>
#include <QDrag>
#include <QDragEnterEvent>
#include <QDropEvent>
#include <QList>
#include <QMap>
#include <QMenu>
#include <QMimeData>
#include <QPointer>
#include <QPushButton>
#include <QSet>
#include <QSignalMapper>
#include <QtDebug>
#include <QUuid>
#include <QApplication>
#include <QScrollArea>


// ParaView includes.
#include "pqActiveObjects.h"
#include "pqApplicationCore.h"
#include "pqCloseViewUndoElement.h"
#include "pqComparativeRenderView.h"
#include "pqEventDispatcher.h"
#include "pqImageUtil.h"
#include "pqMultiViewFrame.h"
#include "pqObjectBuilder.h"
#include "pqOptions.h"
#include "pqPluginManager.h"
#include "pqServer.h"
#include "pqServerManagerModel.h"
#include "pqSplitViewUndoElement.h"
#include "pqUndoStack.h"
#include "pqViewFrameActionGroupInterface.h"
#include "pqViewModuleInterface.h"
#include "pqXMLUtil.h"

#if WIN32
#include "process.h"
#define getpid _getpid
#else
#include "unistd.h"
#endif

template<class T>
uint qHash(const QPointer<T> key)
{
  return qHash((T*)key);
}
//-----------------------------------------------------------------------------
class pqViewManager::pqInternals
{
public:
  QPointer<pqView> ActiveView;
  QMenu ConvertMenu;


  typedef QMap<pqMultiViewFrame*, QPointer<pqView> > FrameMapType;
  FrameMapType Frames;

  QList<QPointer<pqMultiViewFrame> > PendingFrames;
  QList<QPointer<pqView> > PendingViews;

  QSize MaxWindowSize;

  bool DontCreateDeleteViewsModules;

  // When a frame is being closed, we create an undo element
  // and  save it to be pushed on the stack after the
  // view in the frame has been unregistered. The sequence
  // of operations on the undo stack is
  // * unregister view
  // * close frame
  vtkSmartPointer<vtkSMUndoElement> CloseFrameUndoElement;

  // Used by prepareForCapture and finishedCapture.
  QSize SavedMaxSize;
  QSize SavedSize;

  typedef QMap<pqMultiViewFrame*, QPointer<QLabel> > FrameOverlaysType;
  FrameOverlaysType FrameOverlays;
  QTimer OverlayCleanupTimer;
};

//-----------------------------------------------------------------------------
pqViewManager::pqViewManager(QWidget* _parent/*=null*/)
  : pqMultiView(_parent)
{
  this->Internal = new pqInternals();
  this->Internal->DontCreateDeleteViewsModules = false;
  this->Internal->MaxWindowSize = QSize(QWIDGETSIZE_MAX, QWIDGETSIZE_MAX);
  this->Internal->OverlayCleanupTimer.setInterval(2000);
  QObject::connect(&this->Internal->OverlayCleanupTimer,
    SIGNAL(timeout()),
    this, SLOT(destroyFrameOverlays()));

  pqServerManagerModel* smModel =
    pqApplicationCore::instance()->getServerManagerModel();
  if (!smModel)
    {
    qDebug() << "pqServerManagerModel instance must be created before "
      <<"pqViewManager.";
    return;
    }

  // We need to know when new view modules are added.
  QObject::connect(smModel, SIGNAL(viewAdded(pqView*)),
    this, SLOT(onViewAdded(pqView*)));
  QObject::connect(smModel, SIGNAL(viewRemoved(pqView*)),
    this, SLOT(onViewRemoved(pqView*)));

  // Record creation/removal of frames.
  QObject::connect(this, SIGNAL(frameAdded(pqMultiViewFrame*)),
    this, SLOT(onFrameAdded(pqMultiViewFrame*)));
  QObject::connect(this, SIGNAL(preFrameRemoved(pqMultiViewFrame*)),
    this, SLOT(onPreFrameRemoved(pqMultiViewFrame*)));
  QObject::connect(this, SIGNAL(frameRemoved(pqMultiViewFrame*)),
    this, SLOT(onFrameRemoved(pqMultiViewFrame*)));

  QObject::connect(this,
    SIGNAL(afterSplitView(const Index&, Qt::Orientation, float, const Index&)),
    this, SLOT(onSplittingView(const Index&, Qt::Orientation, float, const Index&)));

  QObject::connect(&this->Internal->ConvertMenu, SIGNAL(triggered(QAction*)),
    this, SLOT(onConvertToTriggered(QAction*)));

  // Creates the default empty frame.
  this->init();

  qApp->installEventFilter(this);

  // Connect the view manager to the pqActiveView.
  QObject::connect(this, SIGNAL(activeViewChanged(pqView*)),
    &pqActiveObjects::instance(), SLOT(setActiveView(pqView*)));
  QObject::connect(
    &pqActiveObjects::instance(), SIGNAL(viewChanged(pqView*)),
    this, SLOT(setActiveView(pqView*)));

  pqApplicationCore* core = pqApplicationCore::instance();

  // When server disconnects, we reset the layout.
  QObject::connect(core->getServerManagerModel(),
    SIGNAL(finishedRemovingServer()),
    this, SLOT(onServerDisconnect()));

  // This is essential since there are various GUI components such as the
  // pqAnimationManager that require a pqViewManager to perform certain tasks.
  // They get access to the pqViewManager using the pqAnimationCore.
  core->registerManager("MULTIVIEW_MANAGER", this);
  QObject::connect(core,
    SIGNAL(stateLoaded(vtkPVXMLElement*, vtkSMProxyLocator*)),
    this, SLOT(loadState(vtkPVXMLElement*, vtkSMProxyLocator*)));
  QObject::connect(core,
    SIGNAL(stateSaved(vtkPVXMLElement*)),
    this, SLOT(saveState(vtkPVXMLElement*)));
}

//-----------------------------------------------------------------------------
pqViewManager::~pqViewManager()
{
  // they will get cleared as the application quits.
  this->Internal->DontCreateDeleteViewsModules = true;
  // Cleanup all render modules.
  foreach (pqMultiViewFrame* frame , this->Internal->Frames.keys())
    {
    if (frame)
      {
      this->onFrameRemovedInternal(frame);
      }
    }
  delete this->Internal;
}

//-----------------------------------------------------------------------------
void pqViewManager::buildConvertMenu()
{
  this->Internal->ConvertMenu.clear();

  // Create actions for converting view types.
  QObjectList ifaces =
    pqApplicationCore::instance()->getPluginManager()->interfaces();
  foreach(QObject* iface, ifaces)
    {
    pqViewModuleInterface* vi = qobject_cast<pqViewModuleInterface*>(iface);
    if(vi)
      {
      QStringList viewtypes = vi->viewTypes();
      QStringList::iterator iter;
      for(iter = viewtypes.begin(); iter != viewtypes.end(); ++iter)
        {
        if ((*iter) == "TableView")
          {
          // Ignore these views for now.
          continue;
          }
        QAction* view_action = new QAction(vi->viewTypeName(*iter), this);
        view_action->setData(*iter);
        this->Internal->ConvertMenu.addAction(view_action);
        }
      }
    }

  QAction* view_action = new QAction("None", this);
  view_action->setData("None");
  this->Internal->ConvertMenu.addAction(view_action);
}

//-----------------------------------------------------------------------------
pqView* pqViewManager::getActiveView() const
{
  return this->Internal->ActiveView;
}

//-----------------------------------------------------------------------------
void pqViewManager::updateConversionActions(pqMultiViewFrame* frame)
{
  QString to_exclude;
  if (this->Internal->Frames.contains(frame))
    {
    to_exclude = this->Internal->Frames[frame]->getViewType();
    }

  bool server_exists = (pqApplicationCore::instance()->getServerManagerModel()->
    getNumberOfItems<pqServer*>() >= 1);
  foreach (QAction* action, this->Internal->ConvertMenu.actions())
    {
    action->setEnabled(server_exists && (to_exclude != action->data().toString()));
    }
}

//-----------------------------------------------------------------------------
void pqViewManager::onFrameAdded(pqMultiViewFrame* frame)
{
  // We connect drag-drop signals event for empty frames.
  QObject::connect(frame, SIGNAL(dragStart(pqMultiViewFrame*)),
    this, SLOT(frameDragStart(pqMultiViewFrame*)));
  QObject::connect(frame, SIGNAL(dragEnter(pqMultiViewFrame*,QDragEnterEvent*)),
    this, SLOT(frameDragEnter(pqMultiViewFrame*,QDragEnterEvent*)));
  QObject::connect(frame, SIGNAL(dragMove(pqMultiViewFrame*,QDragMoveEvent*)),
    this, SLOT(frameDragMove(pqMultiViewFrame*,QDragMoveEvent*)));
  QObject::connect(frame, SIGNAL(drop(pqMultiViewFrame*,QDropEvent*)),
    this, SLOT(frameDrop(pqMultiViewFrame*,QDropEvent*)));

  // We need to know when the frame is resized, so that we can update view size
  // related properties on the view proxy.
  //frame->installEventFilter(this);
  frame->MaximizeButton->show();
  frame->CloseButton->show();
  frame->SplitVerticalButton->show();
  frame->SplitHorizontalButton->show();

  frame->getContextMenu()->addSeparator();
  QAction* subAction = frame->getContextMenu()->addMenu(
    &this->Internal->ConvertMenu);
  subAction->setText("Convert To");

  QSignalMapper* sm = new QSignalMapper(frame);
  sm->setMapping(frame, frame);
  QObject::connect(frame, SIGNAL(activeChanged(bool)), sm, SLOT(map()));
  QObject::connect(sm, SIGNAL(mapped(QWidget*)),
    this, SLOT(onActivate(QWidget*)));

  sm = new QSignalMapper(frame);
  sm->setMapping(frame, frame);
  QObject::connect(frame, SIGNAL(contextMenuRequested()), sm, SLOT(map()));
  QObject::connect(sm, SIGNAL(mapped(QWidget*)),
    this, SLOT(onFrameContextMenuRequested(QWidget*)));

  // A newly added frames gets collected as an empty frame.
  // It will be used next time a view module is created.
  this->Internal->PendingFrames.removeAll(frame);
  this->Internal->PendingFrames.push_back(frame);

  frame->setActive(true);

  // HACK: When undo-redoing, a view may be registered before
  // a frame is created, in that case the view is added to
  // PendingViews and we assign it to the frame here.
  if (this->Internal->PendingViews.size() > 0)
    {
    pqView* view = this->Internal->PendingViews.takeAt(0);
    this->assignFrame(view);
    }

  // Setup the UI shown when no view is present in the frame.
  QWidget* emptyFrame = frame->emptyMainWidget();

  QScrollArea* scrollArea = new QScrollArea(emptyFrame);
  scrollArea->setFrameShape(QFrame::NoFrame);
  scrollArea->setWidgetResizable(true);
  QFrame* frame2 = new QFrame(scrollArea);
  scrollArea->setWidget(frame2);
  Ui::EmptyView ui;
  ui.setupUi(frame2);

  QVBoxLayout* vlayout = new QVBoxLayout(emptyFrame);
  vlayout->addWidget(scrollArea);

  this->buildConvertMenu();

  ui.ConvertActionsFrame->layout()->setSpacing(0);

  // Add buttons for all conversion actions.
  QList<QAction*> convertActions =
    this->Internal->ConvertMenu.actions();
  foreach (QAction* action, convertActions)
    {
    QPushButton* button = new QPushButton(action->text(), frame);
    ui.ConvertActionsFrame->layout()->addWidget(button);
    button->addAction(action);
    QObject::connect(button, SIGNAL(clicked()),
      this, SLOT(onConvertToButtonClicked()));
    }
}

//-----------------------------------------------------------------------------
void pqViewManager::onFrameRemovedInternal(pqMultiViewFrame* frame)
{
  QObject::disconnect(frame, SIGNAL(dragStart(pqMultiViewFrame*)),
    this, SLOT(frameDragStart(pqMultiViewFrame*)));
  QObject::disconnect(frame, SIGNAL(dragEnter(pqMultiViewFrame*,QDragEnterEvent*)),
    this, SLOT(frameDragEnter(pqMultiViewFrame*,QDragEnterEvent*)));
  QObject::disconnect(frame, SIGNAL(dragMove(pqMultiViewFrame*,QDragMoveEvent*)),
    this, SLOT(frameDragMove(pqMultiViewFrame*,QDragMoveEvent*)));
  QObject::disconnect(frame, SIGNAL(drop(pqMultiViewFrame*,QDropEvent*)),
    this, SLOT(frameDrop(pqMultiViewFrame*,QDropEvent*)));

  //frame->removeEventFilter(this);
  this->Internal->PendingFrames.removeAll(frame);
  if (!this->Internal->Frames.contains(frame))
    {
    // A frame with no view module has been removed.
    return;
    }

  // When a frame is removed, its render module is destroyed.
  pqView* view = this->Internal->Frames.take(frame);
  this->disconnect(frame, view);

  this->Internal->PendingFrames.removeAll(frame);

  // Generally, we destroy the view module when the frame goes away,
  // unless told otherwise.
  if (this->Internal->DontCreateDeleteViewsModules)
    {
    return;
    }

  // When a frame is removed, the contained view is also destroyed.
  if (view)
    {
    pqApplicationCore::instance()->getObjectBuilder()->destroy(view);
    }

}

//-----------------------------------------------------------------------------
void pqViewManager::onFrameRemoved(pqMultiViewFrame* frame)
{
  this->onFrameRemovedInternal(frame);

  if (this->Internal->CloseFrameUndoElement)
    {
    ADD_UNDO_ELEM(this->Internal->CloseFrameUndoElement);
    this->Internal->CloseFrameUndoElement = 0;
    END_UNDO_SET();
    }

  // Now activate some frame, so that we have an active view.
  if (this->Internal->Frames.size() > 0)
    {
    pqMultiViewFrame* new_active_frame =
      this->Internal->Frames.begin().key();
    if (new_active_frame->active())
      {
      this->onActivate(new_active_frame);
      }
    else
      {
      new_active_frame->setActive(true);
      }
    }
}

//-----------------------------------------------------------------------------
void pqViewManager::onPreFrameRemoved(pqMultiViewFrame* frame)
{
  BEGIN_UNDO_SET("Close View");

  vtkPVXMLElement* state = vtkPVXMLElement::New();
  this->saveState(state);

  pqMultiView::Index index = this->indexOf(frame);

  pqCloseViewUndoElement* elem = pqCloseViewUndoElement::New();
  elem->CloseView(index, state->GetNestedElement(0));
  this->Internal->CloseFrameUndoElement = elem;
  elem->Delete();
  state->Delete();
}

//-----------------------------------------------------------------------------
void pqViewManager::reset()
{
  QList<QWidget*> removed;
  this->reset(removed);
  foreach (QWidget* _widget, removed)
    {
    delete _widget;
    }
}

//-----------------------------------------------------------------------------
void pqViewManager::reset(QList<QWidget*> &removed)
{
  foreach (pqMultiViewFrame* frame, this->Internal->PendingFrames)
    {
    this->onFrameRemoved(frame);
    }

  this->Superclass::reset(removed);
}

//-----------------------------------------------------------------------------
void pqViewManager::connect(pqMultiViewFrame* frame, pqView* view)
{
  if (!frame || !view)
    {
    return;
    }
  this->Internal->PendingFrames.removeAll(frame);

  QWidget* viewWidget = view->getWidget();
  if(viewWidget)
    {
    if (viewWidget->metaObject()->indexOfProperty("positionReference") != -1)
      {
      viewWidget->setProperty("positionReference",
        QVariant::fromValue<QWidget*>(this));
      }

    viewWidget->setParent(frame);
    frame->setMainWidget(viewWidget);
    viewWidget->setMaximumSize(this->Internal->MaxWindowSize);
    }
  else
    {
    frame->setMainWidget(NULL);
    }

  // Search for view frame action group plugins and allow them to decide whether
  // to add their actions to this view type's frame or not.
  QObjectList ifaces =
    pqApplicationCore::instance()->getPluginManager()->interfaces();
  foreach(QObject* iface, ifaces)
    {
    pqViewFrameActionGroupInterface* agi = qobject_cast<pqViewFrameActionGroupInterface*>(iface);
    if(agi)
      {
      agi->connect(frame, view);
      }
    }

  this->Internal->Frames.insert(frame, view);
}

//-----------------------------------------------------------------------------
void pqViewManager::disconnect(pqMultiViewFrame* frame, pqView* view)
{
  if (!frame || !view)
    {
    return;
    }

  this->Internal->Frames.remove(frame);

  QWidget* viewWidget = view->getWidget();
  if(viewWidget)
    {
    viewWidget->setParent(NULL);
    viewWidget->removeEventFilter(this);
    }
  frame->setMainWidget(NULL);

  // Search for view frame action group plugins and have them remove their
  // actions for this view's frame if need be.
  QObjectList ifaces =
    pqApplicationCore::instance()->getPluginManager()->interfaces();
  foreach(QObject* iface, ifaces)
    {
    pqViewFrameActionGroupInterface* agi =
        qobject_cast<pqViewFrameActionGroupInterface*>(iface);
    if(agi)
      {
      agi->disconnect(frame, view);
      }
    }

  this->Internal->PendingFrames.push_back(frame);
}

//-----------------------------------------------------------------------------
void pqViewManager::onViewAdded(pqView* view)
{
  this->assignFrame(view);
}

//-----------------------------------------------------------------------------
void pqViewManager::assignFrame(pqView* view)
{
  pqMultiViewFrame* frame = 0;
  if (this->Internal->PendingFrames.size() == 0)
    {
    // Create a new frame.

    pqUndoStack* undoStack = pqApplicationCore::instance()->getUndoStack();
    if (undoStack && (undoStack->getInUndo() ||
      undoStack->getInRedo()))
      {
      // HACK: If undo-redoing, don't split
      // to create a new pane, it will be created
      // as a part of the undo/redo.
      this->Internal->PendingViews.push_back(view);
      return;
      }

    // Locate frame to split.
    // If there is an active view, use it.
    pqMultiViewFrame* oldFrame = 0;
    if (this->Internal->ActiveView)
      {
      oldFrame = this->getFrame(this->Internal->ActiveView);
      }
    else if (this->Internal->Frames.size() > 0)
      {
      oldFrame = this->Internal->Frames.begin().key();
      }
    else
      {
      // There are no pending frames and not used frames, how
      // can that be? Hence, we are use it will happen,
      // atleast flag an error!
      qCritical() << "Internal state of frames has got messed up!";
      return;
      }

    this->Internal->DontCreateDeleteViewsModules = true;
    QSize cur_size = oldFrame->size();
    // Before we split, make sure that no view is currently maximized.
    this->restoreWidget(0); // that a funny name for this un-maximize button.
    if (cur_size.width() > 1.15*cur_size.height())
        // give a slight preference to
        // vertical splitting.

      {
      frame = this->splitWidgetHorizontal(oldFrame);
      }
    else
      {
      frame = this->splitWidgetVertical(oldFrame);
      }
    this->Internal->DontCreateDeleteViewsModules = false;
    }
  else
    {
    // It is possible that the active frame is empty, if so,
    // we use it.
    foreach (pqMultiViewFrame* curframe, this->Internal->PendingFrames)
      {
      if (curframe->active())
        {
        frame = curframe;
        break;
        }
      }
    if (!frame)
      {
      frame = this->Internal->PendingFrames.first();
      }
    this->Internal->PendingFrames.removeAll(frame);
    }

  if (frame)
    {
    this->connect(frame, view);
    if (frame->active())
      {
      this->onActivate(frame);
      }
    else
      {
      frame->setActive(true);
      }
    }
}

//-----------------------------------------------------------------------------
pqMultiViewFrame* pqViewManager::getFrame(pqView* view) const
{
  return view?
    qobject_cast<pqMultiViewFrame*>(view->getWidget()->parentWidget()) : NULL;
}

//-----------------------------------------------------------------------------
pqView* pqViewManager::getView(pqMultiViewFrame* frame) const
{
  pqInternals::FrameMapType::iterator iter = this->Internal->Frames.find(frame);
  if (iter != this->Internal->Frames.end())
    {
    return iter.value();
    }
  return 0;
}

//-----------------------------------------------------------------------------
void pqViewManager::onViewRemoved(pqView* view)
{
  pqMultiViewFrame* frame = this->getFrame(view);
  if (frame)
    {
    this->disconnect(frame, view);
    }

  this->Internal->PendingViews.removeAll(view);

  this->onActivate(frame);
}

//-----------------------------------------------------------------------------
void pqViewManager::onConvertToButtonClicked()
{
  QPushButton* button = qobject_cast<QPushButton*>(this->sender());
  if (!button)
    {
    return;
    }

  pqMultiViewFrame* frame = 0;

  // Try to locate the frame in which this button exists.
  QWidget* button_parent = button->parentWidget();
  while (button_parent)
    {
    frame = qobject_cast<pqMultiViewFrame*>(button_parent);
    if (frame)
      {
      break;
      }
    button_parent = button_parent->parentWidget();
    }

  if (!frame)
    {
    return;
    }

  // Make the frame active.
  frame->setActive(true);
  if (button->actions().size() > 0)
    {
    QAction* action = button->actions()[0];
    this->onConvertToTriggered(action);
    }
  else
    {
    qCritical() << "No actions!" << endl;
    }
}

//-----------------------------------------------------------------------------
void pqViewManager::onConvertToTriggered(QAction* action)
{
  QString type = action->data().toString();

  // FIXME: We may want to fix this to use the active server instead.
  pqServer* server= pqApplicationCore::instance()->
    getServerManagerModel()->getItemAtIndex<pqServer*>(0);
  if (!server)
    {
    qDebug() << "No server present cannot convert view.";
    return;
    }

  BEGIN_UNDO_SET(QString("Convert View to %1").arg(type));

  pqObjectBuilder* builder =
    pqApplicationCore::instance()-> getObjectBuilder();
  if (this->Internal->ActiveView)
    {
    builder->destroy(this->Internal->ActiveView);
    }

  if(type != "None")
    {
    builder->createView(type, server);
    }

  END_UNDO_SET();
}

//-----------------------------------------------------------------------------
void pqViewManager::onFrameContextMenuRequested(QWidget* wid)
{
  this->buildConvertMenu();

  pqMultiViewFrame* frame = qobject_cast<pqMultiViewFrame*>(wid);
  if (frame)
    {
    this->updateConversionActions(frame);
    }
}

//-----------------------------------------------------------------------------
void pqViewManager::onActivate(QWidget* obj)
{
  if (!obj)
    {
    this->Internal->ActiveView = 0;
    emit this->activeViewChanged(this->Internal->ActiveView);
    return;
    }

  pqMultiViewFrame* frame = qobject_cast<pqMultiViewFrame*>(obj);
  if (!frame->active())
    {
    return;
    }


  pqView* view = this->Internal->Frames.value(frame);
  // If the frame does not have a view, view==NULL.
  this->Internal->ActiveView = view;

  // Make sure no other frame is active.
  foreach (pqMultiViewFrame* fr, this->Internal->Frames.keys())
    {
    if (fr != frame)
      {
      fr->setActive(false);
      }
    }
  foreach (pqMultiViewFrame* fr, this->Internal->PendingFrames)
    {
    if (fr != frame)
      {
      fr->setActive(false);
      }
    }

  emit this->activeViewChanged(this->Internal->ActiveView);
}

//-----------------------------------------------------------------------------
bool pqViewManager::eventFilter(QObject* caller, QEvent* e)
{
  if(e->type() == QEvent::MouseButtonPress)
    {
    QWidget* w = qobject_cast<QWidget*>(caller);
    if(w && this->isAncestorOf(w))
      {
      // If the new widget that is getting the focus is a child widget of any of the
      // frames, then the frame should be made active.
      QList<pqMultiViewFrame*> frames = this->Internal->Frames.keys();
      foreach (pqMultiViewFrame* frame, this->Internal->PendingFrames)
        {
        frames.push_back(frame);
        }

      foreach (pqMultiViewFrame* frame, frames)
        {
        if (frame->isAncestorOf(w))
          {
          frame->setActive(true);
          break;
          }
        }
      }
    }

  return pqMultiView::eventFilter(caller, e);
}

//-----------------------------------------------------------------------------
void pqViewManager::setMaxViewWindowSize(const QSize& win_size)
{
  this->Internal->MaxWindowSize = win_size.isEmpty()?
      QSize(QWIDGETSIZE_MAX, QWIDGETSIZE_MAX) : win_size;
  foreach (pqMultiViewFrame* frame, this->Internal->Frames.keys())
    {
    frame->mainWidget()->setMaximumSize(this->Internal->MaxWindowSize);
    }

  emit maxViewWindowSizeSet(!win_size.isEmpty());
}

//-----------------------------------------------------------------------------
void pqViewManager::saveState(vtkPVXMLElement* root)
{
  vtkPVXMLElement* rwRoot = vtkPVXMLElement::New();
  rwRoot->SetName("ViewManager");
  rwRoot->AddAttribute("version", PARAVIEW_VERSION_FULL);
  root->AddNestedElement(rwRoot);
  rwRoot->Delete();

  // Save the window layout.
  this->pqMultiView::saveState(rwRoot);

  // Save the render module - window mapping.
  pqInternals::FrameMapType::Iterator iter = this->Internal->Frames.begin();
  for(; iter != this->Internal->Frames.end(); ++iter)
    {
    pqMultiViewFrame* frame = iter.key();
    pqView* view = iter.value();

    pqMultiView::Index index = this->indexOf(frame);
    vtkPVXMLElement* frameElem = vtkPVXMLElement::New();
    frameElem->SetName("Frame");
    frameElem->AddAttribute("index", index.getString().toAscii().data());
    frameElem->AddAttribute("view_module", view->getProxy()->GetSelfIDAsString());
    rwRoot->AddNestedElement(frameElem);
    frameElem->Delete();
    }
}

//-----------------------------------------------------------------------------
bool pqViewManager::loadState(vtkPVXMLElement* rwRoot,
  vtkSMProxyLocator* locator)
{
  if (!rwRoot || !rwRoot->GetName())
    {
    // qDebug() << "Argument must be <ViewManager /> element.";
    return false;
    }
  if (strcmp(rwRoot->GetName(), "ViewManager") != 0)
    {
    return this->loadState(rwRoot->FindNestedElementByName("ViewManager"),
      locator);
    }

  // When state is loaded by the server manager,
  // the View Manager will have already layed out all the view modules
  // using a default/random scheme. The role of this method
  // is to re-arrange all the views based on the layout in the
  // state file.
  this->Internal->DontCreateDeleteViewsModules = true;

  // We remove all "randomly" laid out frames. Note that we are not
  // destroying the view modules, only the frames that got created
  // when the server manager state was getting loaded.
  foreach (pqMultiViewFrame* frame, this->Internal->Frames.keys())
    {
    this->removeWidget(frame);
    }
  foreach (pqMultiViewFrame* frame, this->Internal->PendingFrames)
    {
    if (frame)
      {
      this->removeWidget(frame);
      }
    }
  this->Internal->PendingFrames.clear();

  this->Superclass::loadState(rwRoot);
  this->Internal->DontCreateDeleteViewsModules = false;

  this->Internal->Frames.clear();
  for(unsigned int cc=0; cc < rwRoot->GetNumberOfNestedElements(); cc++)
    {
    vtkPVXMLElement* elem = rwRoot->GetNestedElement(cc);
    if (strcmp(elem->GetName(), "Frame") == 0)
      {
      QString index_string = elem->GetAttribute("index");

      pqMultiView::Index index;
      index.setFromString(index_string);
      int id = 0;
      elem->GetScalarAttribute("view_module", &id);
      vtkSmartPointer<vtkSMProxy> viewModule;
      viewModule = locator->LocateProxy(id);
      if (!viewModule.GetPointer())
        {
        qCritical() << "Failed to locate view module mentioned in state!";
        return false;
        }

      pqView* view = pqApplicationCore::instance()->getServerManagerModel()->
        findItem<pqView*>(viewModule);
      pqMultiViewFrame* frame = qobject_cast<pqMultiViewFrame*>(
        this->widgetOfIndex(index));
      if (frame && view)
        {
        this->connect(frame, view);
        }
      }
    }
  pqMultiViewFrame* frame = 0;
  if (this->Internal->Frames.size() > 0)
    {
    // Make the first frame active.
    frame = this->Internal->Frames.begin().key();
    }
  else if (this->Internal->PendingFrames.size() > 0)
    {
    frame = this->Internal->PendingFrames[0];
    }

  if (frame)
    {
    if (frame->active())
      {
      this->onActivate(frame);
      }
    else
      {
      frame->setActive(true);
      }
    }

  return true;
}

//-----------------------------------------------------------------------------
void pqViewManager::frameDragStart(pqMultiViewFrame* frame)
{
  QPixmap pixmap(":/pqWidgets/Icons/pqWindow16.png");

  QByteArray output;
  QDataStream dataStream(&output, QIODevice::WriteOnly);
  dataStream << frame->uniqueID();

  QString mimeType = QString("application/paraview3/%1").arg(getpid());

  QMimeData *mimeData = new QMimeData;
  mimeData->setData(mimeType, output);

  QDrag *drag = new QDrag(this);
  drag->setMimeData(mimeData);
  drag->setHotSpot(QPoint(pixmap.width()/2, pixmap.height()/2));
  drag->setPixmap(pixmap);

  drag->start();
}

//-----------------------------------------------------------------------------
void pqViewManager::frameDragEnter(pqMultiViewFrame*,
                                           QDragEnterEvent* e)
{
  QString mimeType = QString("application/paraview3/%1").arg(getpid());
  if(e->mimeData()->hasFormat(mimeType))
    {
    e->accept();
    }
  else
    {
    e->ignore();
    }
}

//-----------------------------------------------------------------------------
void pqViewManager::frameDragMove(pqMultiViewFrame*,
                                          QDragMoveEvent* e)
{
  QString mimeType = QString("application/paraview3/%1").arg(getpid());
  if(e->mimeData()->hasFormat(mimeType))
    {
    e->accept();
    }
  else
    {
    e->ignore();
    }
}

//-----------------------------------------------------------------------------
void pqViewManager::frameDrop(pqMultiViewFrame* acceptingFrame,
                                      QDropEvent* e)
{
  QString mimeType = QString("application/paraview3/%1").arg(getpid());
  if (e->mimeData()->hasFormat(mimeType))
    {
    QByteArray input= e->mimeData()->data(mimeType);
    QDataStream dataStream(&input, QIODevice::ReadOnly);

    QUuid uniqueID;
    dataStream>>uniqueID;

    pqMultiViewFrame* originatingFrame=NULL;
    pqMultiViewFrame* f;
    foreach(f, this->Internal->Frames.keys())
      {
      if(f->uniqueID()==uniqueID)
        {
        originatingFrame=f;
        break;
        }
      }
    if (!originatingFrame)
      {
      foreach (f, this->Internal->PendingFrames)
        {
        if (f->uniqueID() == uniqueID)
          {
          originatingFrame = f;
          break;
          }
        }
      }

    if(originatingFrame && originatingFrame != acceptingFrame)
      {
      this->hide();
      //Switch the originalFrame with the frame;

      Index originatingIndex=this->indexOf(originatingFrame);
      Index acceptingIndex=this->indexOf(acceptingFrame);
      pqMultiViewFrame *tempFrame= new pqMultiViewFrame;

      this->replaceView(originatingIndex,tempFrame);
      this->replaceView(acceptingIndex,originatingFrame);
      originatingIndex=this->indexOf(tempFrame);
      this->replaceView(originatingIndex,acceptingFrame);

      delete tempFrame;

      this->show();
      }
    e->accept();
    }
  else
    {
    e->ignore();
    }
}

//-----------------------------------------------------------------------------
void pqViewManager::onSplittingView(const Index& index,
  Qt::Orientation orientation, float fraction, const Index& childIndex)
{
  BEGIN_UNDO_SET("Split View");

  pqSplitViewUndoElement* elem = pqSplitViewUndoElement::New();
  elem->SplitView(index, orientation, fraction, childIndex);
  ADD_UNDO_ELEM(elem);
  elem->Delete();

  END_UNDO_SET();
}

#define PADDING_COMPENSATION QSize(16, 16);
//-----------------------------------------------------------------------------
int pqViewManager::prepareForCapture(const QSize& fullsize)
{
  this->hideDecorations();
  // update GUI
  // FIXME: It would be nice if we could block renders right now, there's not need to
  // render the views, we just need to update the GUI.
  pqEventDispatcher::processEventsAndWait(1);

  // This method cannot set the size of the widget to be greater than the
  // current size, irrespective of the image size the user requested.
  QSize currentSize = this->clientSize();
  // to avoid some unpredicable padding issues, I am reducing the size by a few
  // pixels.
  currentSize -= PADDING_COMPENSATION;

  int magnification = pqView::computeMagnification(fullsize, currentSize);

  QSize oldSize = this->size();
  QSize oldMaxSize = this->maximumSize();

  // currentSize is the client area size for the view widget which may be
  // smaller than actual size of the widget. The difference is padding.
  // pqMultiView::computeSize() returns the widget size required to achieve
  // the client size requested.
  currentSize = this->computeSize(currentSize);
  this->setMaximumSize(currentSize);
  this->resize(currentSize);
  pqEventDispatcher::processEventsAndWait(1);

  this->Internal->SavedSize = oldSize;
  this->Internal->SavedMaxSize = oldMaxSize;
  return magnification;
}

//-----------------------------------------------------------------------------
void pqViewManager::finishedCapture()
{
  this->setMaximumSize(this->Internal->SavedMaxSize);
  this->resize(this->Internal->SavedSize);
  this->showDecorations();
}

//-----------------------------------------------------------------------------
vtkImageData* pqViewManager::captureImage(int _width, int _height)
{
  int magnification = this->prepareForCapture(QSize(_width, _height));

  // Create full image data.
  vtkImageData* fullImage = vtkImageData::New();
  fullImage->SetDimensions(_width, _height, 1);
  fullImage->SetScalarTypeToUnsignedChar();
  fullImage->SetNumberOfScalarComponents(3);
  fullImage->AllocateScalars();
  unsigned char rgb[3] = {0, 0, 0};
  vtkImageIterator<unsigned char> it(fullImage, fullImage->GetExtent());
  while (!it.IsAtEnd())
    {
    unsigned char* span = it.BeginSpan();
    unsigned char* spanEnd = it.EndSpan();
    while (spanEnd != span)
      {
      *span = rgb[0]; span++;
      *span = rgb[1]; span++;
      *span = rgb[2]; span++;
      }
    it.NextSpan();
    }

  // Now iterate over each of the views and merge the rendered image into the
  // final fullImage.
  // TODO: handle the case when one view is maximized (generally speaking handle
  // case when views are not visible).
  foreach (pqView* view, this->Internal->Frames)
    {
    if (view)
      {
      vtkImageData* image = view->captureImage(magnification);
      if (image)
        {
        vtkSMAnimationSceneImageWriter::Merge(fullImage, image);
        image->Delete();
        }
      }
    }

  this->finishedCapture();
  return fullImage;
}

//-----------------------------------------------------------------------------
void pqViewManager::setActiveView(pqView* view)
{
  if (this->Internal->ActiveView == view)
    {
    return;
    }

  // Locate the frame for the view and activate it.
  pqMultiViewFrame* frame = this->getFrame(view);
  if (frame)
    {
    frame->setActive(true);
    }
  else if (this->Internal->ActiveView)
    {
    frame = this->getFrame(this->Internal->ActiveView);
    if (frame)
      {
      frame->setActive(false);
      }
    }
}

//-----------------------------------------------------------------------------
void pqViewManager::onServerDisconnect()
{
  QList<QWidget*> removed;
  this->reset(removed);
  foreach (QWidget* _widget, removed)
    {
    delete _widget;
    }
}

//-----------------------------------------------------------------------------
void pqViewManager::showFrameOverlays()
{
  // when running tests, don't show the overlay labels as they may interfere
  // with the screen captures.
  if (pqApplicationCore::instance()->getOptions()->GetDisableRegistry())
    {
    return;
    }
  this->Internal->OverlayCleanupTimer.start();

  pqInternals::FrameMapType::iterator iter;
  for (iter = this->Internal->Frames.begin();
    iter != this->Internal->Frames.end(); ++iter)
    {
    if (iter.value() == NULL)
      {
      continue;
      }
    QLabel* label = this->Internal->FrameOverlays[iter.key()];
    if (label == NULL)
      {
      label = new QLabel("Overlay Text", iter.key(), Qt::ToolTip);
      this->Internal->FrameOverlays[iter.key()] = label;
      }
    QSize curFrameSize(iter.value()->getWidget()->size());
    label->move(iter.value()->getWidget()->mapToGlobal(
        QPoint(curFrameSize.width()/2-30, curFrameSize.height()/2-10)));
    label->setText(QString(" (%1, %2) ").arg(curFrameSize.width()).arg(
        curFrameSize.height()));
    label->show();
    }
}

//-----------------------------------------------------------------------------
void pqViewManager::destroyFrameOverlays()
{
  foreach (QLabel* label, this->Internal->FrameOverlays)
    {
    delete label;
    }
  this->Internal->FrameOverlays.clear();
}
