#include "ChartAxes.h"
#include "ChartScene.h"

#include <cmath>

const QPointF ChartAxes::XLabelOffset(0, 5);
const QPointF ChartAxes::YLabelOffset(-10, -7);
const QFont ChartAxes::TickLabelFont("Sans Serif", 11);

ChartAxes::ChartAxes(ChartScene* scene, int xTickInterval):
    scene(scene), xTickInterval(xTickInterval)
{
}

void ChartAxes::paint()
{
    addAxisLines();
    addTicks();
}

void ChartAxes::addAxisLines()
{
    QPointF chartOrigin = scene->getChartOrigin();
    QRectF chartRect = scene->getChartRect();
    scene->addLine(QLineF(chartOrigin, chartRect.topLeft()));
    scene->addLine(QLineF(chartOrigin, chartRect.bottomRight()));
}

void ChartAxes::addTicks()
{
    addXTicks();
    addYTicks();
}

void ChartAxes::addXTicks()
{
    qreal tickSpacing = scene->getDataDirection() * scene->getXTickSpacing();
    QPointF pos = getTickOrigin(XTick);
    for(int i = 0; i < scene->getDataSet().size(); i++)
    {
        addLabelledXTick(i, pos);
        pos.rx() += tickSpacing;
    }
}

void ChartAxes::addLabelledXTick(int index, QPointF& pos)
{
    if(index % xTickInterval == 0)
    {
        addTick(pos, XTick);
        DataPoint point = scene->getDataSet().at(index);
        addLabel(point.label, pos, XTick);
    }
}

QPointF ChartAxes::getTickOrigin(TickOrientation orientation) const
{
    QPointF res = scene->getChartOrigin();
    if(orientation == XTick)
    {
        if(scene->getDataDirection() == 1)
            res.rx() += ChartScene::DataSetPadding.width();
        else
            res.rx() += scene->getChartRect().width();
    }
    else
        res.ry() -= ChartScene::DataSetPadding.height();
    return res;
}

void ChartAxes::addTick(const QPointF& pos, TickOrientation orientation)
{
    QPointF end = pos + getTickVector(orientation);
    scene->addLine(QLineF(pos, end));
}

QPointF ChartAxes::getTickVector(TickOrientation orientation)
{
    if(orientation == XTick)
        return QPointF(0, TickLength);
    else
        return QPointF(-TickLength, 0);
}

void ChartAxes::addLabel(const QString& labelText, const QPointF& pos,
    TickOrientation orientation)
{
    QPointF labelOffset = getLabelOffset(orientation);
    QGraphicsItem* textItem = scene->addSimpleText(labelText, TickLabelFont);    
    qreal xAlignOffset = getLabelXAlignOffset(
                textItem->boundingRect().width(), orientation);
    textItem->setPos(pos + labelOffset + QPointF(xAlignOffset, 0));
}

QPointF ChartAxes::getLabelOffset(TickOrientation orientation)
{
    if(orientation == XTick)
        return XLabelOffset;
    else
        return YLabelOffset;
}

qreal ChartAxes::getLabelXAlignOffset(qreal labelWidth, TickOrientation orientation)
{
    if(orientation == XTick)
        return -labelWidth / 2;
    else
        return -labelWidth;
}

void ChartAxes::addYTicks()
{
    int valueSpacing = scene->getYTickSpacing();
    qreal posSpacing = scene->getYPosFromValue(valueSpacing);
    QPointF pos = getTickOrigin(YTick);
    for(int value = scene->getMinY(); value <= scene->getMaxY();
        value += valueSpacing)
    {
        addLabelledYTick(value, pos, posSpacing);
        if(valueSpacing == 0)
            break;
    }
}

void ChartAxes::addLabelledYTick(int value, QPointF& pos, qreal posSpacing)
{
    addTick(pos, YTick);
    addLabel(QString::number(value), pos, YTick);
    addHRuler(pos);
    pos.ry() -= posSpacing;
}

void ChartAxes::addHRuler(const QPointF& pos)
    {
        QPointF end = pos;
        end.rx() += scene->getChartRect().width();
        scene->addLine(QLineF(pos, end), QPen(Qt::lightGray));
    }