#include "View.h"

#include <cmath>

#include <QtCore/QPointF>
#include <QtWidgets/QScrollBar>

namespace Map {

//////////////////////////////////////////
/////////// PUBLIC METHODS ///////////////
//////////////////////////////////////////

View::View(Scene* scene)
    : QGraphicsView(scene)
{
    // If the next lines are removed, scale() uses
    // the center of the view as the anchor, but the translate()
    // method does not work and the scrollbars are visible.

    // However, if we keep the next lines of code, the translate()
    // method works, but the scale() method does not work.

    // Remove scrollbars from view
    setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);

    // Disconnect the scrollbars to prevent interference on view's positioning
    horizontalScrollBar()->disconnect();
    verticalScrollBar()->disconnect();
}

//////////////////////////////////////////
/////////// PRIVATE METHODS //////////////
//////////////////////////////////////////

void View::mousePressEvent(QMouseEvent* event)
{
    if (event->buttons() == Qt::LeftButton) {
        mouseOrigin = event->pos();
    }
}

void View::mouseMoveEvent(QMouseEvent* event)
{
    if (event->buttons() == Qt::LeftButton) {
        QPointF oldPoint = mapToScene(mouseOrigin);
        QPointF newPoint = mapToScene(event->pos());
        // Invert the mouse movement for translation
        QPointF translation = -(oldPoint - newPoint);

        translate(translation.x(), translation.y());
        mouseOrigin = event->pos();
    }
}

void View::wheelEvent(QWheelEvent* event)
{
    QPoint degrees = event->angleDelta() / WHEEL_UNIT_PER_DEGREES;

    if (!degrees.isNull()) {
        double steps = degrees.y() / WHEEL_STEPS_PER_DEGREE;
        double scaleFactor = 1.0;

        if (steps < 0) {
            scaleFactor = std::abs(steps) * ZOOM_OUT_FACTOR;
            testDouble -= 0.1;
        } else {
            scaleFactor = std::abs(steps) * ZOOM_IN_FACTOR;
            testDouble += 0.1;
        }

        scale(scaleFactor, scaleFactor);
    }
}
}