#include <QColor>
#include <QCoreApplication>
#include <QEvent>
#include <QPainter>

#include "ToggleButton.h"

void
Toggle::paintEvent(QPaintEvent *event)
{
        Q_UNUSED(event);
}

Toggle::Toggle(QWidget *parent)
  : QAbstractButton{parent}
{
        init();

        connect(this, &QAbstractButton::toggled, this, &Toggle::setState);
}

void
Toggle::setState(bool isEnabled)
{
        setChecked(isEnabled);
        thumb_->setShift(isEnabled ? Position::Left : Position::Right);
        setupProperties();
}

void
Toggle::init()
{
        track_ = new ToggleTrack(this);
        thumb_ = new ToggleThumb(this);

        setCursor(QCursor(Qt::PointingHandCursor));
        setCheckable(true);
        setChecked(false);

        setState(false);
        setupProperties();

        QCoreApplication::processEvents();
}

void
Toggle::setupProperties()
{
        if (isEnabled()) {
                Position position = thumb_->shift();

                thumb_->setThumbColor(trackColor());

                if (position == Position::Left)
                        track_->setTrackColor(activeColor());
                else if (position == Position::Right)
                        track_->setTrackColor(inactiveColor());
        }

        update();
}

void
Toggle::setDisabledColor(const QColor &color)
{
        disabledColor_ = color;
        setupProperties();
}

void
Toggle::setActiveColor(const QColor &color)
{
        activeColor_ = color;
        setupProperties();
}

void
Toggle::setInactiveColor(const QColor &color)
{
        inactiveColor_ = color;
        setupProperties();
}

void
Toggle::setTrackColor(const QColor &color)
{
        trackColor_ = color;
        setupProperties();
}

ToggleThumb::ToggleThumb(Toggle *parent)
  : QWidget{parent}
  , toggle_{parent}
  , position_{Position::Right}
  , offset_{0}
{
        parent->installEventFilter(this);
}

void
ToggleThumb::setShift(Position position)
{
        if (position_ != position) {
                position_ = position;
                updateOffset();
        }
}

bool
ToggleThumb::eventFilter(QObject *obj, QEvent *event)
{
        const QEvent::Type type = event->type();

        if (QEvent::Resize == type || QEvent::Move == type) {
                setGeometry(toggle_->rect().adjusted(8, 8, -8, -8));
                updateOffset();
        }

        return QWidget::eventFilter(obj, event);
}

void
ToggleThumb::paintEvent(QPaintEvent *event)
{
        Q_UNUSED(event)

        QPainter painter(this);
        painter.setRenderHint(QPainter::Antialiasing);

        QBrush brush;
        brush.setStyle(Qt::SolidPattern);
        brush.setColor(toggle_->isEnabled() ? thumbColor_ : Qt::white);

        painter.setBrush(brush);
        painter.setPen(Qt::NoPen);

        int s;
        QRectF r;

        s = height() - 10;
        r = QRectF(5 + offset_, 5, s, s);

        painter.drawEllipse(r);

        if (!toggle_->isEnabled()) {
                brush.setColor(toggle_->disabledColor());
                painter.setBrush(brush);
                painter.drawEllipse(r);
        }
}

void
ToggleThumb::updateOffset()
{
        const QSize s(size());
        offset_ = position_ == Position::Left ? static_cast<qreal>(s.width() - s.height()) : 0;
        update();
}

ToggleTrack::ToggleTrack(Toggle *parent)
  : QWidget{parent}
  , toggle_{parent}
{
        Q_ASSERT(parent);

        parent->installEventFilter(this);
}

void
ToggleTrack::setTrackColor(const QColor &color)
{
        trackColor_ = color;
        update();
}

bool
ToggleTrack::eventFilter(QObject *obj, QEvent *event)
{
        const QEvent::Type type = event->type();

        if (QEvent::Resize == type || QEvent::Move == type) {
                setGeometry(toggle_->rect());
        }

        return QWidget::eventFilter(obj, event);
}

void
ToggleTrack::paintEvent(QPaintEvent *event)
{
        Q_UNUSED(event)

        QPainter painter(this);
        painter.setRenderHint(QPainter::Antialiasing);

        QBrush brush;
        if (toggle_->isEnabled()) {
                brush.setColor(trackColor_);
                painter.setOpacity(0.8);
        } else {
                brush.setColor(toggle_->disabledColor());
                painter.setOpacity(0.6);
        }

        brush.setStyle(Qt::SolidPattern);
        painter.setBrush(brush);
        painter.setPen(Qt::NoPen);

        const int h = height() / 2;
        const QRect r(0, h / 2, width(), h);
        painter.drawRoundedRect(r.adjusted(14, 4, -14, -4), h / 2 - 4, h / 2 - 4);
}