#include "ChartView.h"
#include <QApplication>
#include <QValueAxis>

ChartView::ChartView( QWidget *parent)
    : QChartView( parent)
{
    m_isPress = false;
    m_ctrlPress = false;
    m_alreadySaveRange = false;
    m_coordItem = nullptr;

    this->setDragMode(QGraphicsView::RubberBandDrag);
    this->setMouseTracking(false);
    setCursor(QCursor(Qt::PointingHandCursor)); //设置鼠标指针为手指形
}

ChartView::~ChartView()
{
}
void ChartView::SetChart(QChart *chart){
    setChart(chart);
}
void ChartView::mousePressEvent(QMouseEvent *event)
{
    if (event->button() == Qt::LeftButton)
    {
        m_lastPoint = event->pos();
        m_isPress = true;
    }
}

void ChartView::mouseMoveEvent(QMouseEvent *event)
{
    if (!m_coordItem)
    {
        m_coordItem = new QGraphicsSimpleTextItem(this->chart());
        m_coordItem->setZValue(5);
        m_coordItem->setPos(100, 20);
        m_coordItem->show();
    }
    const QPoint curPos = event->pos();
    QPointF curVal = this->chart()->mapToValue(QPointF(curPos));
    QString coordStr = QString("X = %1, Y = %2").arg(curVal.x()).arg(curVal.y());
    m_coordItem->setText(coordStr);

    if (m_isPress)
    {
        QPoint offset = curPos - m_lastPoint;
        m_lastPoint = curPos;
        if (!m_alreadySaveRange)
        {
            this->saveAxisRange();
            m_alreadySaveRange = true;
        }
        this->chart()->scroll(-offset.x(), offset.y());
    }
}

void ChartView::mouseReleaseEvent(QMouseEvent *event)
{
    m_isPress = false;
    if (event->button() == Qt::RightButton)
    {
        if (m_alreadySaveRange)
        {
            this->chart()->axisX()->setRange(m_xMin, m_xMax);
            this->chart()->axisY()->setRange(m_yMin, m_yMax);
        }
    }else if(event->button() == Qt::LeftButton)
    {
        return;
    }
}

void ChartView::wheelEvent(QWheelEvent *event)
{
    const QPoint curPos = event->pos();
    QPointF curVal = this->chart()->mapToValue(QPointF(curPos));

    if (!m_alreadySaveRange)
    {
        this->saveAxisRange();
        m_alreadySaveRange = true;
    }

    const double factor = 1.5;//缩放比例
    if (m_ctrlPress)
    {//Y轴
        QValueAxis *axisY = dynamic_cast<QValueAxis*>(this->chart()->axisY());
        const double yMin = axisY->min();
        const double yMax = axisY->max();
        const double yCentral = curVal.y();

        double bottomOffset;
        double topOffset;
        if (event->delta() > 0)
        {//放大
            bottomOffset = 1.0 / factor * (yCentral - yMin);
            topOffset = 1.0 / factor * (yMax - yCentral);
        }
        else
        {//缩小
            bottomOffset = 1.0 * factor * (yCentral - yMin);
            topOffset = 1.0 * factor * (yMax - yCentral);
        }

        this->chart()->axisY()->setRange(yCentral - bottomOffset, yCentral + topOffset);
    }
    else
    {//X轴
        QValueAxis *axisX = dynamic_cast<QValueAxis*>(this->chart()->axisX());
        const double xMin = axisX->min();
        const double xMax = axisX->max();
        const double xCentral = curVal.x();

        double leftOffset;
        double rightOffset;
        if (event->delta() > 0)
        {//放大
            leftOffset = 1.0 / factor * (xCentral - xMin);
            rightOffset = 1.0 / factor * (xMax - xCentral);
        }
        else
        {//缩小
            leftOffset = 1.0 * factor * (xCentral - xMin);
            rightOffset = 1.0 * factor * (xMax - xCentral);
        }

        this->chart()->axisX()->setRange(xCentral - leftOffset, xCentral + rightOffset);
    }
}

void ChartView::keyPressEvent(QKeyEvent *event)
{
    if (event->key() == Qt::Key_Control)
    {
        m_ctrlPress = true;
    }
}

void ChartView::keyReleaseEvent(QKeyEvent *event)
{
    if (event->key() == Qt::Key_Control)
    {
        m_ctrlPress = false;
    }
}

void ChartView::saveAxisRange()
{
    QValueAxis *axisX = dynamic_cast<QValueAxis*>(this->chart()->axisX());
    m_xMin = axisX->min();
    m_xMax = axisX->max();
    QValueAxis *axisY = dynamic_cast<QValueAxis*>(this->chart()->axisY());
    m_yMin = axisY->min();
    m_yMax = axisY->max();
}