/*
    QRoundProgressBar - a circular progress bar Qt widget.

    Sintegrial Technologies (c) 2015-now

    The software is freeware and is distributed "as is" with the complete source codes.
    Anybody is free to use it in any software projects, either commercial or non-commercial.
    Please do not remove this copyright message and remain the name of the author unchanged.

    It is very appreciated if you produce some feedback to us case you are going to use
    the software.

    Please send your questions, suggestions, and information about found issues to the

    sintegrial@gmail.com

*/

#include "QRoundProgressBar.h"

#include <QPainter>
#include <QPainterPath>

QRoundProgressBar::QRoundProgressBar(QWidget *parent)
    : QWidget(parent), m_min(0), m_max(100), m_value(25), m_nullPosition(PositionTop), m_barStyle(StyleDonut),
      m_outlinePenWidth(1), m_dataPenWidth(1), m_rebuildBrush(false), m_format("%p%"), m_decimals(1),
      m_updateFlags(UF_PERCENT)
{
}

void QRoundProgressBar::setRange(double min, double max)
{
    m_min = min;
    m_max = max;

    if (m_max < m_min)
        qSwap(m_max, m_min);

    if (m_value < m_min)
        m_value = m_min;
    else if (m_value > m_max)
        m_value = m_max;

    if (!m_gradientData.isEmpty())
        m_rebuildBrush = true;

    update();
}

void QRoundProgressBar::setMinimum(double min)
{
    setRange(min, m_max);
}

void QRoundProgressBar::setMaximum(double max)
{
    setRange(m_min, max);
}

void QRoundProgressBar::setValue(double val)
{
    if (m_value != val)
    {
        if (val < m_min)
            m_value = m_min;
        else if (val > m_max)
            m_value = m_max;
        else
            m_value = val;

        update();
    }
}

void QRoundProgressBar::setValue(int val)
{
    setValue(double(val));
}

void QRoundProgressBar::setNullPosition(double position)
{
    if (position != m_nullPosition)
    {
        m_nullPosition = position;

        if (!m_gradientData.isEmpty())
            m_rebuildBrush = true;

        update();
    }
}

void QRoundProgressBar::setBarStyle(QRoundProgressBar::BarStyle style)
{
    if (style != m_barStyle)
    {
        m_barStyle = style;

        update();
    }
}

void QRoundProgressBar::setOutlinePenWidth(double penWidth)
{
    if (penWidth != m_outlinePenWidth)
    {
        m_outlinePenWidth = penWidth;

        update();
    }
}

void QRoundProgressBar::setDataPenWidth(double penWidth)
{
    if (penWidth != m_dataPenWidth)
    {
        m_dataPenWidth = penWidth;

        update();
    }
}

void QRoundProgressBar::setDataColors(const QGradientStops &stopPoints)
{
    if (stopPoints != m_gradientData)
    {
        m_gradientData = stopPoints;
        m_rebuildBrush = true;

        update();
    }
}

void QRoundProgressBar::setFormat(const QString &format)
{
    if (format != m_format)
    {
        m_format = format;

        valueFormatChanged();
    }
}

void QRoundProgressBar::resetFormat()
{
    m_format.clear();
    valueFormatChanged();
}

void QRoundProgressBar::setDecimals(int count)
{
    if (count >= 0 && count != m_decimals)
    {
        m_decimals = count;

        valueFormatChanged();
    }
}

void QRoundProgressBar::paintEvent(QPaintEvent * /*event*/)
{
#if 0
    double outerRadius = qMin(width(), height());
    QRectF baseRect(1, 1, outerRadius-2, outerRadius-2);

    QImage buffer(outerRadius, outerRadius, QImage::Format_ARGB32_Premultiplied);

    QPainter p(&buffer);
    p.setRenderHint(QPainter::Antialiasing);

    // data brush
    rebuildDataBrushIfNeeded();

    // background
    drawBackground(p, buffer.rect());

    // base circle
    drawBase(p, baseRect);

    // data circle
    double arcStep = 360.0 / (m_max - m_min) * m_value;
    drawValue(p, baseRect, m_value, arcStep);

    // center circle
    double innerRadius(0);
    QRectF innerRect;
    calculateInnerRect(baseRect, outerRadius, innerRect, innerRadius);
    drawInnerBackground(p, innerRect);

    // text
    drawText(p, innerRect, innerRadius, m_value);

    // finally draw the bar
    p.end();

    QPainter painter(this);
    painter.fillRect(baseRect, palette().background());
    painter.drawImage(0,0, buffer);
#endif
    double outerRadius = qMin(width(), height());
    QRectF baseRect(1, 1, outerRadius - 2, outerRadius - 2);
    QPainter p(this);
    //painter.fillRect(baseRect, palette().window());
    p.setRenderHint(QPainter::Antialiasing);
    p.fillRect(baseRect, Qt::NoBrush);
    drawBase(p, baseRect);
    // data circle
    double arcStep = 360.0 / (m_max - m_min) * m_value;
    drawValue(p, baseRect, m_value, arcStep);

    // center circle
    double innerRadius(0);
    QRectF innerRect;
    calculateInnerRect(baseRect, outerRadius, innerRect, innerRadius);
    drawInnerBackground(p, innerRect);

    // text
    drawText(p, innerRect, innerRadius, m_value);
}

void QRoundProgressBar::drawBackground(QPainter &p, const QRectF &baseRect)
{
    p.fillRect(baseRect, palette().window());
}

void QRoundProgressBar::drawBase(QPainter &p, const QRectF &baseRect)
{
    switch (m_barStyle)
    {
        case StyleDonut:
            p.setPen(QPen(palette().shadow().color(), m_outlinePenWidth));
            p.setBrush(palette().base());
            p.drawEllipse(baseRect);
            break;

        case StylePie:
            p.setPen(QPen(palette().base().color(), m_outlinePenWidth));
            p.setBrush(palette().base());
            p.drawEllipse(baseRect);
            break;

        case StyleLine:
            p.setPen(QPen(palette().base().color(), m_outlinePenWidth));
            p.setBrush(Qt::NoBrush);
            p.drawEllipse(baseRect.adjusted(m_outlinePenWidth / 2, m_outlinePenWidth / 2, -m_outlinePenWidth / 2,
                                            -m_outlinePenWidth / 2));
            break;

        default:;
    }
}

void QRoundProgressBar::drawValue(QPainter &p, const QRectF &baseRect, double value, double arcLength)
{
    // nothing to draw
    if (value == m_min)
        return;

    // for Line style
    if (m_barStyle == StyleLine)
    {
        p.setPen(QPen(palette().highlight().color(), m_dataPenWidth));
        p.setBrush(Qt::NoBrush);
        p.drawArc(baseRect.adjusted(m_outlinePenWidth / 2, m_outlinePenWidth / 2, -m_outlinePenWidth / 2,
                                    -m_outlinePenWidth / 2),
                  m_nullPosition * 16, -arcLength * 16);
        return;
    }

    // for Pie and Donut styles
    QPainterPath dataPath;
    dataPath.setFillRule(Qt::WindingFill);

    // pie segment outer
    dataPath.moveTo(baseRect.center());
    dataPath.arcTo(baseRect, m_nullPosition, -arcLength);
    dataPath.lineTo(baseRect.center());

    p.setBrush(palette().highlight());
    p.setPen(QPen(palette().shadow().color(), m_dataPenWidth));
    p.drawPath(dataPath);
}

void QRoundProgressBar::calculateInnerRect(const QRectF & /*baseRect*/, double outerRadius, QRectF &innerRect,
                                           double &innerRadius)
{
    // for Line style
    if (m_barStyle == StyleLine)
    {
        innerRadius = outerRadius - m_outlinePenWidth;
    }
    else // for Pie and Donut styles
    {
        innerRadius = outerRadius * 0.75;
    }

    double delta = (outerRadius - innerRadius) / 2;
    innerRect    = QRectF(delta, delta, innerRadius, innerRadius);
}

void QRoundProgressBar::drawInnerBackground(QPainter &p, const QRectF &innerRect)
{
    if (m_barStyle == StyleDonut)
    {
        p.setBrush(palette().alternateBase());
        p.drawEllipse(innerRect);
    }
}

void QRoundProgressBar::drawText(QPainter &p, const QRectF &innerRect, double innerRadius, double value)
{
    if (m_format.isEmpty())
        return;

    // !!! to revise
    QFont f(font());
    f.setPixelSize(innerRadius * qMax(0.05, (0.35 - (double)m_decimals * 0.08)));
    p.setFont(f);

    QRectF textRect(innerRect);
    p.setPen(palette().text().color());
    p.drawText(textRect, Qt::AlignCenter, valueToText(value));
}

QString QRoundProgressBar::valueToText(double value) const
{
    QString textToDraw(m_format);

    if (m_updateFlags & UF_VALUE)
        textToDraw.replace("%v", QString::number(value, 'f', m_decimals));

    if (m_updateFlags & UF_PERCENT)
    {
        double procent = (value - m_min) / (m_max - m_min) * 100.0;
        textToDraw.replace("%p", QString::number(procent, 'f', m_decimals));
    }

    if (m_updateFlags & UF_MAX)
        textToDraw.replace("%m", QString::number(m_max - m_min + 1, 'f', m_decimals));

    return textToDraw;
}

void QRoundProgressBar::valueFormatChanged()
{
    m_updateFlags = 0;

    if (m_format.contains("%v"))
        m_updateFlags |= UF_VALUE;

    if (m_format.contains("%p"))
        m_updateFlags |= UF_PERCENT;

    if (m_format.contains("%m"))
        m_updateFlags |= UF_MAX;

    update();
}

void QRoundProgressBar::rebuildDataBrushIfNeeded()
{
    if (m_rebuildBrush)
    {
        m_rebuildBrush = false;

        QConicalGradient dataBrush;
        dataBrush.setCenter(0.5, 0.5);
        dataBrush.setCoordinateMode(QGradient::StretchToDeviceMode);

        // invert colors
        for (int i = 0; i < m_gradientData.count(); i++)
        {
            dataBrush.setColorAt(1.0 - m_gradientData.at(i).first, m_gradientData.at(i).second);
        }

        // angle
        dataBrush.setAngle(m_nullPosition);

        QPalette p(palette());
        p.setBrush(QPalette::Highlight, dataBrush);
        setPalette(p);
    }
}
