/*
    SPDX-FileCopyrightText: 2017 Martin Flöser <mgraesslin@kde.org>

    SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
*/
#include <QApplication>
#include <QCursor>
#include <QMouseEvent>
#include <QPainter>
#include <QWidget>

class MouseCursorWidget : public QWidget
{
    Q_OBJECT

public:
    explicit MouseCursorWidget();
    ~MouseCursorWidget() override;

protected:
    void paintEvent(QPaintEvent *event) override;
    void mouseMoveEvent(QMouseEvent *event) override;
    void keyPressEvent(QKeyEvent *event) override;

private:
    QPoint m_cursorPos;
    QCursor m_cursors[5];
    int m_cursorIndex = 0;
};

namespace
{

QCursor createCenterHotspotCursor()
{
    QPixmap cursor(64, 64);
    cursor.fill(Qt::transparent);
    QPainter p(&cursor);
    p.setPen(Qt::black);
    const QPoint center = cursor.rect().center();
    p.drawLine(0, center.y(), center.x() - 1, center.y());
    p.drawLine(center.x() + 1, center.y(), cursor.width(), center.y());
    p.drawLine(center.x(), 0, center.x(), center.y() - 1);
    p.drawLine(center.x(), center.y() + 1, center.x(), cursor.height());
    return QCursor(cursor, 31, 31);
}

QCursor createTopLeftHotspotCursor()
{
    QPixmap cursor(64, 64);
    cursor.fill(Qt::transparent);
    QPainter p(&cursor);
    p.setPen(Qt::black);
    p.drawLine(0, 1, 0, cursor.height());
    p.drawLine(1, 0, cursor.width(), 0);
    return QCursor(cursor, 0, 0);
}

QCursor createTopRightHotspotCursor()
{
    QPixmap cursor(64, 64);
    cursor.fill(Qt::transparent);
    QPainter p(&cursor);
    p.setPen(Qt::black);
    p.drawLine(cursor.width() - 1, 1, cursor.width() - 1, cursor.height());
    p.drawLine(0, 0, cursor.width() - 2, 0);
    return QCursor(cursor, 63, 0);
}

QCursor createButtomRightHotspotCursor()
{
    QPixmap cursor(64, 64);
    cursor.fill(Qt::transparent);
    QPainter p(&cursor);
    p.setPen(Qt::black);
    p.drawLine(cursor.width() - 1, 0, cursor.width() - 1, cursor.height() - 2);
    p.drawLine(0, cursor.height() - 1, cursor.width() - 2, cursor.height() - 1);
    return QCursor(cursor, 63, 63);
}

QCursor createButtomLeftHotspotCursor()
{
    QPixmap cursor(64, 64);
    cursor.fill(Qt::transparent);
    QPainter p(&cursor);
    p.setPen(Qt::black);
    p.drawLine(0, 0, 0, cursor.height() - 2);
    p.drawLine(1, cursor.height() - 1, cursor.width(), cursor.height() - 1);
    return QCursor(cursor, 0, 63);
}

}

MouseCursorWidget::MouseCursorWidget()
    : QWidget()
{
    setMouseTracking(true);
    // create cursors
    m_cursors[0] = createCenterHotspotCursor();
    m_cursors[1] = createTopLeftHotspotCursor();
    m_cursors[2] = createTopRightHotspotCursor();
    m_cursors[3] = createButtomRightHotspotCursor();
    m_cursors[4] = createButtomLeftHotspotCursor();

    setCursor(m_cursors[m_cursorIndex]);
}

MouseCursorWidget::~MouseCursorWidget() = default;

void MouseCursorWidget::paintEvent(QPaintEvent *event)
{
    QPainter p(this);
    p.fillRect(0, 0, width(), height(), Qt::white);
    if (geometry().contains(m_cursorPos)) {
        p.setPen(Qt::red);
        p.drawPoint(m_cursorPos);
    }
}

void MouseCursorWidget::mouseMoveEvent(QMouseEvent *event)
{
    m_cursorPos = event->pos();
    update();
}

void MouseCursorWidget::keyPressEvent(QKeyEvent *event)
{
    if (event->key() == Qt::Key_Space) {
        m_cursorIndex = (m_cursorIndex + 1) % 5;
        setCursor(m_cursors[m_cursorIndex]);
    }
}

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    MouseCursorWidget widget;
    widget.show();

    return app.exec();
}

#include "cursorhotspottest.moc"
