#include "scalepicker.h"
#include <qwt_plot.h>
#include <qwt_scale_widget.h>
#include <qevent.h>
#include <qmath.h>

ScalePicker::ScalePicker( QwtPlot *plot ):
    QObject( plot )
{
    for ( uint i = 0; i < QwtAxis::PosCount; i++ )
    {
        QwtScaleWidget *scaleWidget = plot->axisWidget( i );
        if ( scaleWidget )
            scaleWidget->installEventFilter( this );
    }
}

bool ScalePicker::eventFilter( QObject *object, QEvent *event )
{
    if ( event->type() == QEvent::MouseButtonPress )
    {
        QwtScaleWidget *scaleWidget = qobject_cast<QwtScaleWidget *>( object );
        if ( scaleWidget )
        {
            QMouseEvent *mouseEvent = static_cast<QMouseEvent *>( event );
            mouseClicked( scaleWidget, mouseEvent->pos() );

            return true;
        }
    }

    return QObject::eventFilter( object, event );
}

void ScalePicker::mouseClicked( const QwtScaleWidget *scale, const QPoint &pos )
{
    QRect rect = scaleRect( scale );

    int margin = 10; // 10 pixels tolerance
    rect.setRect( rect.x() - margin, rect.y() - margin,
        rect.width() + 2 * margin, rect.height() +  2 * margin );

    if ( rect.contains( pos ) ) // No click on the title
    {
        // translate the position in a value on the scale

        double value = 0.0;
        int axis = -1;

        const QwtScaleDraw *sd = scale->scaleDraw();
        switch( scale->alignment() )
        {
            case QwtScaleDraw::LeftScale:
            {
                value = sd->scaleMap().invTransform( pos.y() );
                axis = QwtAxis::yLeft;
                break;
            }
            case QwtScaleDraw::RightScale:
            {
                value = sd->scaleMap().invTransform( pos.y() );
                axis = QwtAxis::yRight;
                break;
            }
            case QwtScaleDraw::BottomScale:
            {
                value = sd->scaleMap().invTransform( pos.x() );
                axis = QwtAxis::xBottom;
                break;
            }
            case QwtScaleDraw::TopScale:
            {
                value = sd->scaleMap().invTransform( pos.x() );
                axis = QwtAxis::xTop;
                break;
            }
        }
        Q_EMIT clicked( axis, value );
    }
}

// The rect of a scale without the title
QRect ScalePicker::scaleRect( const QwtScaleWidget *scale ) const
{
    const int bld = scale->margin();
    const int mjt = qCeil( scale->scaleDraw()->maxTickLength() );
    const int sbd = scale->startBorderDist();
    const int ebd = scale->endBorderDist();

    QRect rect;
    switch( scale->alignment() )
    {
        case QwtScaleDraw::LeftScale:
        {
            rect.setRect( scale->width() - bld - mjt, sbd,
                mjt, scale->height() - sbd - ebd );
            break;
        }
        case QwtScaleDraw::RightScale:
        {
            rect.setRect( bld, sbd,
                mjt, scale->height() - sbd - ebd );
            break;
        }
        case QwtScaleDraw::BottomScale:
        {
            rect.setRect( sbd, bld,
                scale->width() - sbd - ebd, mjt );
            break;
        }
        case QwtScaleDraw::TopScale:
        {
            rect.setRect( sbd, scale->height() - bld - mjt,
                scale->width() - sbd - ebd, mjt );
            break;
        }
    }
    return rect;
}
