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

  Library:   CTK

  Copyright (c) Kitware Inc.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0.txt

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

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

// Qt includes
#include <QDebug>
#include <QMouseEvent>
#include <QPointer>

// CTK includes
#include "ctkPopupWidget.h"
#include "ctkSliderWidget.h"
#include "ctkValueProxy.h"
#include "ui_ctkSliderWidget.h"

// STD includes
#include <cmath>

//-----------------------------------------------------------------------------
class ctkSliderWidgetPrivate: public Ui_ctkSliderWidget
{
  Q_DECLARE_PUBLIC(ctkSliderWidget);
protected:
  ctkSliderWidget* const q_ptr;

public:
  ctkSliderWidgetPrivate(ctkSliderWidget& object);
  virtual ~ctkSliderWidgetPrivate();

  void updateSpinBoxWidth();
  void updateSpinBoxDecimals();

  int synchronizedSpinBoxWidth() const;

  void synchronizeSiblingWidth(int width);
  void synchronizeSiblingDecimals(int decimals);
  bool equal(double spinBoxValue, double sliderValue)const
  {
    if (this->Proxy)
      {
      spinBoxValue = this->Proxy.data()->proxyValueFromValue(spinBoxValue);
      sliderValue = this->Proxy.data()->proxyValueFromValue(sliderValue);
      }
    return qAbs(sliderValue - spinBoxValue) < std::pow(10., -this->SpinBox->decimals());
  }

  bool   Tracking;
  bool   Changing;
  double ValueBeforeChange;
  bool   BlockSetSliderValue;
  ctkSliderWidget::SynchronizeSiblings SynchronizeMode;
  ctkPopupWidget* SliderPopup;
  QPointer<ctkValueProxy> Proxy;
};

// --------------------------------------------------------------------------
ctkSliderWidgetPrivate::ctkSliderWidgetPrivate(ctkSliderWidget& object)
  :q_ptr(&object)
{
  qRegisterMetaType<ctkSliderWidget::SynchronizeSiblings>(
    "ctkSliderWidget::SynchronizeSiblings");
  this->Tracking = true;
  this->Changing = false;
  this->ValueBeforeChange = 0.;
  this->BlockSetSliderValue = false;
  this->SynchronizeMode = ctkSliderWidget::SynchronizeWidth;
  this->SliderPopup = 0;
}

// --------------------------------------------------------------------------
ctkSliderWidgetPrivate::~ctkSliderWidgetPrivate()
{
}

// --------------------------------------------------------------------------
void ctkSliderWidgetPrivate::updateSpinBoxWidth()
{
  int spinBoxWidth = this->synchronizedSpinBoxWidth();
  if (this->SynchronizeMode.testFlag(ctkSliderWidget::SynchronizeWidth))
    {
    this->SpinBox->setMinimumWidth(spinBoxWidth);
    }
  else
    {
    this->SpinBox->setMinimumWidth(0);
    }

  this->synchronizeSiblingWidth(spinBoxWidth);
}

// --------------------------------------------------------------------------
void ctkSliderWidgetPrivate::updateSpinBoxDecimals()
{
  if (this->SynchronizeMode.testFlag(ctkSliderWidget::SynchronizeDecimals))
    {
    this->synchronizeSiblingDecimals(this->SpinBox->decimals());
    }
}

// --------------------------------------------------------------------------
int ctkSliderWidgetPrivate::synchronizedSpinBoxWidth()const
{
  Q_Q(const ctkSliderWidget);
  int maxWidth = this->SpinBox->sizeHint().width();
  if (!q->parent())
    {
    return maxWidth;
    }
  QList<ctkSliderWidget*> siblings =
    q->parent()->findChildren<ctkSliderWidget*>();
  foreach(ctkSliderWidget* sibling, siblings)
    {
    maxWidth = qMax(maxWidth, sibling->d_func()->SpinBox->sizeHint().width());
    }
  return maxWidth;
}

// --------------------------------------------------------------------------
void ctkSliderWidgetPrivate::synchronizeSiblingWidth(int width)
{
  Q_UNUSED(width);
  Q_Q(const ctkSliderWidget);
  QList<ctkSliderWidget*> siblings =
    q->parent()->findChildren<ctkSliderWidget*>();
  foreach(ctkSliderWidget* sibling, siblings)
    {
    if (sibling != q
      && sibling->synchronizeSiblings().testFlag(ctkSliderWidget::SynchronizeWidth))
      {
      sibling->d_func()->SpinBox->setMinimumWidth(
        this->SpinBox->minimumWidth());
      }
    }
}

// --------------------------------------------------------------------------
void ctkSliderWidgetPrivate::synchronizeSiblingDecimals(int decimals)
{
  Q_UNUSED(decimals);
  Q_Q(const ctkSliderWidget);
  QList<ctkSliderWidget*> siblings =
    q->parent()->findChildren<ctkSliderWidget*>();
  foreach(ctkSliderWidget* sibling, siblings)
    {
    if (sibling != q
      && sibling->synchronizeSiblings().testFlag(ctkSliderWidget::SynchronizeDecimals))
      {
      sibling->d_func()->SpinBox->setDecimals(this->SpinBox->decimals());
      }
    }
}

// --------------------------------------------------------------------------
ctkSliderWidget::ctkSliderWidget(QWidget* _parent) : Superclass(_parent)
  , d_ptr(new ctkSliderWidgetPrivate(*this))
{
  Q_D(ctkSliderWidget);
  
  d->setupUi(this);

  d->Slider->setMaximum(d->SpinBox->maximum());
  d->Slider->setMinimum(d->SpinBox->minimum());

  this->connect(d->SpinBox, SIGNAL(valueChanged(double)), this, SLOT(setSliderValue(double)));
  this->connect(d->SpinBox, SIGNAL(decimalsChanged(int)), this, SLOT(setDecimals(int)));

  this->connect(d->Slider, SIGNAL(sliderPressed()), this, SLOT(startChanging()));
  this->connect(d->Slider, SIGNAL(sliderReleased()), this, SLOT(stopChanging()));
  // setSpinBoxValue will fire the valueChanged signal.
  this->connect(d->Slider, SIGNAL(valueChanged(double)), this, SLOT(setSpinBoxValue(double)));
  d->SpinBox->installEventFilter(this);
}

// --------------------------------------------------------------------------
ctkSliderWidget::~ctkSliderWidget()
{
}

// --------------------------------------------------------------------------
double ctkSliderWidget::minimum()const
{
  Q_D(const ctkSliderWidget);
  Q_ASSERT(d->equal(d->SpinBox->minimum(),d->Slider->minimum()));
  return d->Slider->minimum();
}

// --------------------------------------------------------------------------
double ctkSliderWidget::maximum()const
{
  Q_D(const ctkSliderWidget);
  Q_ASSERT(d->equal(d->SpinBox->maximum(),d->Slider->maximum()));
  return d->Slider->maximum();
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setMinimum(double min)
{
  Q_D(ctkSliderWidget);
  bool wasBlockSetSliderValue = d->BlockSetSliderValue;
  d->BlockSetSliderValue = true;
  d->SpinBox->setMinimum(min);
  d->BlockSetSliderValue = wasBlockSetSliderValue;

  // SpinBox can truncate min (depending on decimals).
  // use Spinbox's min to set Slider's min
  d->Slider->setMinimum(d->SpinBox->minimum());
  Q_ASSERT(d->equal(d->SpinBox->minimum(),d->Slider->minimum()));
  Q_ASSERT(d->equal(d->SpinBox->value(),d->Slider->value()));
  Q_ASSERT(d->equal(d->SpinBox->maximum(),d->Slider->maximum()));
  d->updateSpinBoxWidth();
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setMaximum(double max)
{
  Q_D(ctkSliderWidget);
  bool wasBlockSetSliderValue = d->BlockSetSliderValue;
  d->BlockSetSliderValue = true;
  d->SpinBox->setMaximum(max);
  d->BlockSetSliderValue = wasBlockSetSliderValue;

  // SpinBox can truncate max (depending on decimals).
  // use Spinbox's max to set Slider's max
  d->Slider->setMaximum(d->SpinBox->maximum());
  Q_ASSERT(d->equal(d->SpinBox->minimum(),d->Slider->minimum()));
  Q_ASSERT(d->equal(d->SpinBox->value(),d->Slider->value()));
  Q_ASSERT(d->equal(d->SpinBox->maximum(),d->Slider->maximum()));
  d->updateSpinBoxWidth();
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setRange(double min, double max)
{
  Q_D(ctkSliderWidget);
  
  bool wasBlockSetSliderValue = d->BlockSetSliderValue;
  d->BlockSetSliderValue = true;
  d->SpinBox->setRange(min, max);
  d->BlockSetSliderValue = wasBlockSetSliderValue;
  
  // SpinBox can truncate the range (depending on decimals).
  // use Spinbox's range to set Slider's range
  d->Slider->setRange(d->SpinBox->minimum(), d->SpinBox->maximum());
  Q_ASSERT(d->equal(d->SpinBox->minimum(),d->Slider->minimum()));
  Q_ASSERT(d->equal(d->SpinBox->value(),d->Slider->value()));
  Q_ASSERT(d->equal(d->SpinBox->maximum(),d->Slider->maximum()));
  d->updateSpinBoxWidth();
}
/*
// --------------------------------------------------------------------------
double ctkSliderWidget::sliderPosition()const
{
  return d->Slider->sliderPosition();
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setSliderPosition(double position)
{
  d->Slider->setSliderPosition(position);
}
*/
/*
// --------------------------------------------------------------------------
double ctkSliderWidget::previousSliderPosition()
{
  return d->Slider->previousSliderPosition();
}
*/

// --------------------------------------------------------------------------
double ctkSliderWidget::value()const
{
  Q_D(const ctkSliderWidget);
  Q_ASSERT(d->equal(d->SpinBox->value(), d->Slider->value()));
  // The slider is the most precise as it does not round the value with the
  // decimals number.
  return d->Changing ? d->ValueBeforeChange : d->Slider->value();
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setValue(double _value)
{
  Q_D(ctkSliderWidget);
  // disable the tracking temporally to emit the
  // signal valueChanged if setSpinBoxValue() is called
  bool isChanging = d->Changing;
  d->Changing = false;
  d->SpinBox->setValue(_value);
  // Why do we need to set the value to the slider ?
  //d->Slider->setValue(d->SpinBox->value());
  //double spinBoxValue = d->SpinBox->value();
  Q_ASSERT(d->equal(d->SpinBox->minimum(),d->Slider->minimum()));
  Q_ASSERT(d->equal(d->SpinBox->value(),d->Slider->value()));
  Q_ASSERT(d->equal(d->SpinBox->maximum(),d->Slider->maximum()));
  // restore the prop
  d->Changing = isChanging;
}

// --------------------------------------------------------------------------
void ctkSliderWidget::startChanging()
{
  Q_D(ctkSliderWidget);
  if (d->Tracking)
    {
    return;
    }
  d->ValueBeforeChange = this->value();
  d->Changing = true;
}

// --------------------------------------------------------------------------
void ctkSliderWidget::stopChanging()
{
  Q_D(ctkSliderWidget);
  if (d->Tracking)
    {
    return;
    }
  d->Changing = false;
  if (qAbs(this->value() - d->ValueBeforeChange) > (this->singleStep() * 0.000000001))
    {
    emit this->valueChanged(this->value());
    }
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setSliderValue(double spinBoxValue)
{
  Q_D(ctkSliderWidget);
  if (d->BlockSetSliderValue)
    {
    return;
    }
  d->Slider->setValue(spinBoxValue);
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setSpinBoxValue(double sliderValue)
{
  Q_D(ctkSliderWidget);
  
  bool wasBlockSetSliderValue = d->BlockSetSliderValue;
  d->BlockSetSliderValue = true;
  d->SpinBox->setValue(sliderValue);
  d->BlockSetSliderValue = wasBlockSetSliderValue;
  Q_ASSERT(d->equal(d->SpinBox->value(), d->Slider->value()));
  
  if (!d->Tracking)
    {
    emit this->valueIsChanging(sliderValue);
    }
  if (!d->Changing)
    {
    emit this->valueChanged(sliderValue);
    }
}

// --------------------------------------------------------------------------
bool ctkSliderWidget::eventFilter(QObject *obj, QEvent *event)
 {
   if (event->type() == QEvent::MouseButtonPress)
     {
     QMouseEvent *mouseEvent = static_cast<QMouseEvent *>(event);
     if (mouseEvent->button() & Qt::LeftButton)
       {
       this->startChanging();
       }
     }
   else if (event->type() == QEvent::MouseButtonRelease) 
     {
     QMouseEvent *mouseEvent = static_cast<QMouseEvent *>(event);
     if (mouseEvent->button() & Qt::LeftButton)
       {
       // here we might prevent ctkSliderWidget::stopChanging
       // from sending a valueChanged() event as the spinbox might
       // send a valueChanged() after eventFilter() is done.
       this->stopChanging();
       }
     } 
   // standard event processing
   return this->Superclass::eventFilter(obj, event);
 }

// --------------------------------------------------------------------------
double ctkSliderWidget::singleStep()const
{
  Q_D(const ctkSliderWidget);
  Q_ASSERT(d->equal(d->SpinBox->singleStep(), d->Slider->singleStep()));
  return d->Slider->singleStep();
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setSingleStep(double newStep)
{
  Q_D(ctkSliderWidget);
  if (!d->Slider->isValidStep(newStep))
    {
    qWarning() << "ctkSliderWidget::setSingleStep() " << newStep << "is out of bounds." <<
      this->minimum() << this->maximum() <<this->value();
    return;
    }
  d->SpinBox->setSingleStep(newStep);
  d->Slider->setSingleStep(d->SpinBox->singleStep());
  Q_ASSERT(d->equal(d->SpinBox->minimum(),d->Slider->minimum()));
  Q_ASSERT(d->equal(d->SpinBox->value(),d->Slider->value()));
  Q_ASSERT(d->equal(d->SpinBox->maximum(),d->Slider->maximum()));
}

// --------------------------------------------------------------------------
double ctkSliderWidget::pageStep()const
{
  Q_D(const ctkSliderWidget);
  return d->Slider->pageStep();
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setPageStep(double step)
{
  Q_D(ctkSliderWidget);
  d->Slider->setPageStep(step);
}

// --------------------------------------------------------------------------
int ctkSliderWidget::decimals()const
{
  Q_D(const ctkSliderWidget);
  return d->SpinBox->decimals();
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setDecimals(int newDecimals)
{
  Q_D(ctkSliderWidget);
  d->SpinBox->setDecimals(newDecimals);
  // The number of decimals can change the range values
  // i.e. 50.55 with 2 decimals -> 51 with 0 decimals
  // As the SpinBox range change doesn't fire signals,
  // we have to do the synchronization manually here
  d->Slider->setRange(d->SpinBox->minimum(), d->SpinBox->maximum());
  Q_ASSERT(d->equal(d->SpinBox->minimum(),d->Slider->minimum()));
  Q_ASSERT(d->equal(d->SpinBox->maximum(),d->Slider->maximum()));
  // Last time the value was set on the spinbox, the value might have been
  // rounded by the previous number of decimals. The slider however never rounds
  // the value. Now, if the number of decimals is higher, such rounding is lost
  // precision. The "true" value must be set again to the spinbox to "recover"
  // the precision.
  this->setSpinBoxValue(d->Slider->value());
  Q_ASSERT(d->equal(d->SpinBox->value(),d->Slider->value()));
  d->updateSpinBoxDecimals();
  emit decimalsChanged(d->SpinBox->decimals());
}

// --------------------------------------------------------------------------
QString ctkSliderWidget::prefix()const
{
  Q_D(const ctkSliderWidget);
  return d->SpinBox->prefix();
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setPrefix(const QString& newPrefix)
{
  Q_D(ctkSliderWidget);
  d->SpinBox->setPrefix(newPrefix);
  d->updateSpinBoxWidth();
}

// --------------------------------------------------------------------------
QString ctkSliderWidget::suffix()const
{
  Q_D(const ctkSliderWidget);
  return d->SpinBox->suffix();
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setSuffix(const QString& newSuffix)
{
  Q_D(ctkSliderWidget);
  d->SpinBox->setSuffix(newSuffix);
  d->updateSpinBoxWidth();
}

// --------------------------------------------------------------------------
double ctkSliderWidget::tickInterval()const
{
  Q_D(const ctkSliderWidget);
  return d->Slider->tickInterval();
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setTickInterval(double ti)
{ 
  Q_D(ctkSliderWidget);
  d->Slider->setTickInterval(ti);
}

// --------------------------------------------------------------------------
QSlider::TickPosition ctkSliderWidget::tickPosition()const
{
  Q_D(const ctkSliderWidget);
  return d->Slider->tickPosition();
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setTickPosition(QSlider::TickPosition newTickPosition)
{
  Q_D(ctkSliderWidget);
  d->Slider->setTickPosition(newTickPosition);
}

// -------------------------------------------------------------------------
void ctkSliderWidget::reset()
{
  this->setValue(0.);
}

// -------------------------------------------------------------------------
void ctkSliderWidget::setSpinBoxAlignment(Qt::Alignment alignment)
{
  Q_D(ctkSliderWidget);
  return d->SpinBox->setAlignment(alignment);
}

// -------------------------------------------------------------------------
Qt::Alignment ctkSliderWidget::spinBoxAlignment()const
{
  Q_D(const ctkSliderWidget);
  return d->SpinBox->alignment();
}

// -------------------------------------------------------------------------
void ctkSliderWidget::setTracking(bool enable)
{
  Q_D(ctkSliderWidget);
  d->Tracking = enable;
}

// -------------------------------------------------------------------------
bool ctkSliderWidget::hasTracking()const
{
  Q_D(const ctkSliderWidget);
  return d->Tracking;
}

// --------------------------------------------------------------------------
bool ctkSliderWidget::invertedAppearance()const
{
  Q_D(const ctkSliderWidget);
  return d->Slider->invertedAppearance();
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setInvertedAppearance(bool invertedAppearance)
{
  Q_D(ctkSliderWidget);
  d->Slider->setInvertedAppearance(invertedAppearance);
}

// --------------------------------------------------------------------------
bool ctkSliderWidget::invertedControls()const
{
  Q_D(const ctkSliderWidget);
  return d->Slider->invertedControls() && d->SpinBox->invertedControls();
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setInvertedControls(bool invertedControls)
{
  Q_D(ctkSliderWidget);
  d->Slider->setInvertedControls(invertedControls);
  d->SpinBox->setInvertedControls(invertedControls);
}

// -------------------------------------------------------------------------
ctkSliderWidget::SynchronizeSiblings
ctkSliderWidget::synchronizeSiblings() const
{
  Q_D(const ctkSliderWidget);
  return d->SynchronizeMode;
}

// -------------------------------------------------------------------------
void ctkSliderWidget
::setSynchronizeSiblings(ctkSliderWidget::SynchronizeSiblings flag)
{
  Q_D(ctkSliderWidget);
  d->SynchronizeMode = flag;
  d->updateSpinBoxWidth();
  d->updateSpinBoxDecimals();
}

// -------------------------------------------------------------------------
bool ctkSliderWidget::isSpinBoxVisible()const
{
  Q_D(const ctkSliderWidget);
  return d->SpinBox->isVisibleTo(const_cast<ctkSliderWidget*>(this));
}

// -------------------------------------------------------------------------
void ctkSliderWidget::setSpinBoxVisible(bool visible)
{
  Q_D(ctkSliderWidget);
  d->SpinBox->setVisible(visible);
}

// --------------------------------------------------------------------------
bool ctkSliderWidget::hasPopupSlider()const
{
  Q_D(const ctkSliderWidget);
  return d->SliderPopup != 0;
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setPopupSlider(bool popup)
{
  Q_D(ctkSliderWidget);
  if (this->hasPopupSlider() == popup)
    {
    return;
    }
  if (popup)
    {
    d->SliderPopup = new ctkPopupWidget(this);
    d->SliderPopup->setObjectName("DoubleSliderPopup");

    QHBoxLayout* layout = new QHBoxLayout(d->SliderPopup);
    layout->setContentsMargins(0,0,0,0);
    /// If the Slider has already been created, it will try to keep its
    /// size.
    layout->addWidget(d->Slider);

    d->SliderPopup->setAlignment(Qt::AlignLeft | Qt::AlignVCenter);
    d->SliderPopup->setOrientation(Qt::Horizontal);
    d->SliderPopup->setHorizontalDirection(Qt::RightToLeft);
    }
  else
    {
    qobject_cast<QHBoxLayout*>(this->layout())->insertWidget(0,d->Slider);
    d->SliderPopup->deleteLater();
    d->SliderPopup = 0;
    }
}

// --------------------------------------------------------------------------
ctkPopupWidget* ctkSliderWidget::popup()const
{
  Q_D(const ctkSliderWidget);
  return d->SliderPopup;
}

// --------------------------------------------------------------------------
ctkDoubleSpinBox* ctkSliderWidget::spinBox()
{
  Q_D(ctkSliderWidget);
  return d->SpinBox;
}

// --------------------------------------------------------------------------
ctkDoubleSlider* ctkSliderWidget::slider()
{
  Q_D(ctkSliderWidget);
  return d->Slider;
}

// --------------------------------------------------------------------------
void ctkSliderWidget::setValueProxy(ctkValueProxy* proxy)
{
  Q_D(ctkSliderWidget);
  if (d->Proxy.data() == proxy)
    {
    return;
    }

  this->onValueProxyAboutToBeModified();

  if (d->Proxy)
    {
    disconnect(d->Proxy.data(), SIGNAL(proxyAboutToBeModified()),
               this, SLOT(onValueProxyAboutToBeModified()));
    disconnect(d->Proxy.data(), SIGNAL(proxyModified()),
               this, SLOT(onValueProxyModified()));
    }

  d->Proxy = proxy;

  if (d->Proxy)
    {
    connect(d->Proxy.data(), SIGNAL(proxyAboutToBeModified()),
            this, SLOT(onValueProxyAboutToBeModified()));
    }
  this->slider()->setValueProxy(proxy);
  this->spinBox()->setValueProxy(proxy);

  if (d->Proxy)
    {
    connect(d->Proxy.data(), SIGNAL(proxyModified()),
            this, SLOT(onValueProxyModified()));
    }
  this->onValueProxyModified();
}

// --------------------------------------------------------------------------
ctkValueProxy* ctkSliderWidget::valueProxy() const
{
  Q_D(const ctkSliderWidget);
  return d->Proxy.data();
}

// --------------------------------------------------------------------------
void ctkSliderWidget::onValueProxyAboutToBeModified()
{
}

// --------------------------------------------------------------------------
void ctkSliderWidget::onValueProxyModified()
{
  Q_D(ctkSliderWidget);
  Q_ASSERT(d->equal(d->SpinBox->minimum(),d->Slider->minimum()));
  Q_ASSERT(d->equal(d->SpinBox->maximum(),d->Slider->maximum()));
  // resync as the modification of proxy could have discarded decimals
  // in the process. The slider always keeps the exact value (no rounding).
  d->SpinBox->setValue(d->Slider->value());
  Q_ASSERT(d->equal(d->SpinBox->value(),d->Slider->value()));
}