/////////////////////////////////////////////////////////////////////////////////
//
//  Copyright (C) 2017-     Statoil ASA
//
//  ResInsight 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 3 of the License, or
//  (at your option) any later version.
//
//  ResInsight 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 at <http://www.gnu.org/licenses/gpl.html>
//  for more details.
//
/////////////////////////////////////////////////////////////////////////////////

#include "RiuQwtCurvePointTracker.h"

#include "RiaQDateTimeTools.h"
#include "RiuGuiTheme.h"
#include "RiuPlotCurve.h"
#include "RiuPlotCurveInfoTextProvider.h"

#include "qwt_date_scale_draw.h"
#include "qwt_plot_curve.h"
#include "qwt_plot_marker.h"
#include "qwt_symbol.h"
#include "qwt_text.h"

#include <cfloat> // For DBL_MAX

#include <QEvent>

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
RiuQwtCurvePointTracker::RiuQwtCurvePointTracker( QwtPlot*                      plot,
                                                  bool                          isMainAxisHorizontal,
                                                  RiuPlotCurveInfoTextProvider* curveInfoTextProvider )
    : QwtPlotPicker( plot->canvas() )
    , m_plot( plot )
    , m_isMainAxisHorizontal( isMainAxisHorizontal )
    , m_curveInfoTextProvider( curveInfoTextProvider )
{
    this->setTrackerMode( QwtPicker::AlwaysOn );
    m_plotMarker = new QwtPlotMarker;

    // Have this marker always on top of all curves/plot items.
    double zAlwaysOnTop = 99999999;
    m_plotMarker->setZ( zAlwaysOnTop );

    auto color = RiuGuiTheme::getColorByVariableName( "markerColor" );

    // QwtPlotMarker takes ownership of the symbol, it is deleted in destructor of QwtPlotMarker
    QwtSymbol* mySymbol = new QwtSymbol( QwtSymbol::Ellipse, Qt::NoBrush, QPen( color, 2.0 ), QSize( 12, 12 ) );
    m_plotMarker->setSymbol( mySymbol );
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
RiuQwtCurvePointTracker::~RiuQwtCurvePointTracker()
{
    m_plotMarker->detach();
    delete m_plotMarker;
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
void RiuQwtCurvePointTracker::removeMarkerOnFocusLeave()
{
    if ( m_plotMarker->plot() )
    {
        m_plotMarker->detach();

        m_plot->replot();
    }
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
bool RiuQwtCurvePointTracker::eventFilter( QObject* watched, QEvent* event )
{
    if ( event->type() == QEvent::Leave )
    {
        this->removeMarkerOnFocusLeave();
    }

    // pass the event on to the parent class
    return QwtPlotPicker::eventFilter( watched, event );
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
QwtText RiuQwtCurvePointTracker::trackerText( const QPoint& pos ) const
{
    QwtText txt;

    if ( m_plot )
    {
        QwtAxisId relatedYAxis( QwtAxis::YLeft, 0 );
        QwtAxisId relatedXAxis( QwtAxis::XBottom, 0 );

        QString curveInfoText;
        QString mainAxisValueString;
        QString valueAxisValueString;
        QPointF closestPoint =
            closestCurvePoint( pos, &curveInfoText, &valueAxisValueString, &mainAxisValueString, &relatedXAxis, &relatedYAxis );
        if ( !closestPoint.isNull() )
        {
            QString str = !curveInfoText.isEmpty() ? QString( "%1: %2" ).arg( curveInfoText ).arg( valueAxisValueString )
                                                   : valueAxisValueString;

            if ( !mainAxisValueString.isEmpty() )
            {
                str += QString( " (%1)" ).arg( mainAxisValueString );
            }

            txt.setText( str );
        }

        updateClosestCurvePointMarker( closestPoint, relatedXAxis, relatedYAxis );
    }

    auto color = RiuGuiTheme::getColorByVariableName( "markerColor" );
    txt.setColor( color );

    return txt;
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
QPointF RiuQwtCurvePointTracker::closestCurvePoint( const QPoint& cursorPosition,
                                                    QString*      curveInfoText,
                                                    QString*      valueAxisValueString,
                                                    QString*      mainAxisValueString,
                                                    QwtAxisId*    relatedXAxis,
                                                    QwtAxisId*    relatedYAxis ) const
{
    QPointF samplePoint;

    QwtPlotCurve* closestCurve            = nullptr;
    double        distMin                 = DBL_MAX;
    int           closestPointSampleIndex = -1;

    const QwtPlotItemList& itmList = m_plot->itemList();
    for ( QwtPlotItemIterator it = itmList.begin(); it != itmList.end(); it++ )
    {
        if ( ( *it )->rtti() == QwtPlotItem::Rtti_PlotCurve )
        {
            QwtPlotCurve* candidateCurve       = static_cast<QwtPlotCurve*>( *it );
            double        dist                 = DBL_MAX;
            int           candidateSampleIndex = candidateCurve->closestPoint( cursorPosition, &dist );
            if ( dist < distMin )
            {
                closestCurve            = candidateCurve;
                distMin                 = dist;
                closestPointSampleIndex = candidateSampleIndex;
            }
        }
    }

    if ( closestCurve && distMin < 50 )
    {
        samplePoint = closestCurve->sample( closestPointSampleIndex );

        if ( relatedXAxis ) *relatedXAxis = closestCurve->xAxis();
        if ( relatedYAxis ) *relatedYAxis = closestCurve->yAxis();
    }

    if ( mainAxisValueString )
    {
        const QwtScaleDraw* mainAxisScaleDraw = m_isMainAxisHorizontal ? m_plot->axisScaleDraw( *relatedXAxis )
                                                                       : m_plot->axisScaleDraw( *relatedYAxis );
        auto dateScaleDraw = dynamic_cast<const QwtDateScaleDraw*>( mainAxisScaleDraw );

        qreal mainAxisSampleVal = 0.0;
        if ( m_isMainAxisHorizontal )
            mainAxisSampleVal = samplePoint.x();
        else
            mainAxisSampleVal = samplePoint.y();

        if ( curveInfoText && closestCurve && m_curveInfoTextProvider )
        {
            *curveInfoText = m_curveInfoTextProvider->curveInfoText( dynamic_cast<RiuPlotCurve*>( closestCurve ) );
        }

        if ( dateScaleDraw )
        {
            QDateTime date = dateScaleDraw->toDateTime( mainAxisSampleVal );

            QString dateString   = RiaQDateTimeTools::toStringUsingApplicationLocale( date, "hh:mm dd.MMMM.yyyy" );
            *mainAxisValueString = dateString;
        }
        else if ( mainAxisScaleDraw )
        {
            *mainAxisValueString = mainAxisScaleDraw->label( mainAxisSampleVal ).text();
        }
    }

    if ( valueAxisValueString && closestCurve )
    {
        const QwtScaleDraw* valueAxisScaleDraw = m_isMainAxisHorizontal ? m_plot->axisScaleDraw( *relatedYAxis )
                                                                        : m_plot->axisScaleDraw( *relatedXAxis );

        qreal valueAxisSampleVal = 0.0;
        if ( m_isMainAxisHorizontal )
            valueAxisSampleVal = samplePoint.y();
        else
            valueAxisSampleVal = samplePoint.x();

        if ( valueAxisScaleDraw )
        {
            *valueAxisValueString = valueAxisScaleDraw->label( valueAxisSampleVal ).text();
        }

        auto additionalText = m_curveInfoTextProvider->additionalText( dynamic_cast<RiuPlotCurve*>( closestCurve ),
                                                                       closestPointSampleIndex );

        if ( !additionalText.isEmpty() )
        {
            *valueAxisValueString += "\n";
            *valueAxisValueString += additionalText;
        }
    }

    return samplePoint;
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
void RiuQwtCurvePointTracker::updateClosestCurvePointMarker( const QPointF& closestPoint,
                                                             QwtAxisId      relatedXAxis,
                                                             QwtAxisId      relatedYAxis ) const
{
    bool replotRequired = false;

    if ( !closestPoint.isNull() )
    {
        if ( !m_plotMarker->plot() )
        {
            m_plotMarker->attach( m_plot );

            replotRequired = true;
        }

        if ( m_plotMarker->value() != closestPoint )
        {
            m_plotMarker->setValue( closestPoint.x(), closestPoint.y() );

            // Set the axes that the marker realtes to, to make the positioning correct
            m_plotMarker->setAxes( relatedXAxis, relatedYAxis );

            // TODO : Should use a color or other visual indicator to show what axis the curve relates to

            replotRequired = true;
        }
    }
    else
    {
        if ( m_plotMarker->plot() )
        {
            m_plotMarker->detach();

            replotRequired = true;
        }
    }

    if ( replotRequired ) m_plot->replot();
}