/*
 * SPDX-FileCopyrightText: 2011 Peter Penz <peter.penz19@gmail.com>
 *
 * Based on the Itemviews NG project from Trolltech Labs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "kstandarditemlistgroupheader.h"

#include "kitemlistview.h"

#include <QGraphicsSceneResizeEvent>
#include <QPainter>
#include <QStyleOptionGraphicsItem>

KItemListGroupHeader::KItemListGroupHeader(QGraphicsWidget *parent)
    : QGraphicsWidget(parent)
    , m_dirtyCache(true)
    , m_role()
    , m_data()
    , m_styleOption()
    , m_scrollOrientation(Qt::Vertical)
    , m_itemIndex(-1)
    , m_collapsed(false)
    , m_separatorColor()
    , m_roleColor()
    , m_roleBounds()
{
}

KItemListGroupHeader::~KItemListGroupHeader() = default;

void KItemListGroupHeader::setRole(const QByteArray &role)
{
    if (m_role != role) {
        const QByteArray previous = m_role;
        m_role = role;
        update();
        roleChanged(role, previous);
    }
}

QByteArray KItemListGroupHeader::role() const
{
    return m_role;
}

void KItemListGroupHeader::setData(const QVariant &data)
{
    if (m_data != data) {
        const QVariant previous = m_data;
        m_data = data;
        update();
        dataChanged(data, previous);
    }
}

QVariant KItemListGroupHeader::data() const
{
    return m_data;
}

void KItemListGroupHeader::setStyleOption(const KItemListStyleOption &option)
{
    if (m_styleOption == option) {
        return;
    }

    const KItemListStyleOption previous = m_styleOption;
    m_styleOption = option;
    m_dirtyCache = true;
    styleOptionChanged(option, previous);
}

const KItemListStyleOption &KItemListGroupHeader::styleOption() const
{
    return m_styleOption;
}

void KItemListGroupHeader::setScrollOrientation(Qt::Orientation orientation)
{
    if (m_scrollOrientation != orientation) {
        const Qt::Orientation previous = m_scrollOrientation;
        m_scrollOrientation = orientation;
        if (orientation == Qt::Vertical) {
            m_dirtyCache = true;
        }
        scrollOrientationChanged(orientation, previous);
    }
}

void KItemListGroupHeader::setItemIndex(int index)
{
    if (m_itemIndex != index) {
        const int previous = m_itemIndex;
        m_itemIndex = index;
        m_dirtyCache = true;
        itemIndexChanged(m_itemIndex, previous);
    }
}

int KItemListGroupHeader::itemIndex() const
{
    return m_itemIndex;
}

void KItemListGroupHeader::setCollapsed(bool collapsed)
{
    if (m_collapsed != collapsed) {
        const bool previous = m_collapsed;
        m_collapsed = collapsed;
        update();
        collapsedChanged(collapsed, previous);
    }
}

bool KItemListGroupHeader::isCollapsed() const
{
    return m_collapsed;
}

Qt::Orientation KItemListGroupHeader::scrollOrientation() const
{
    return m_scrollOrientation;
}

void KItemListGroupHeader::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    Q_UNUSED(painter)
    Q_UNUSED(option)
    Q_UNUSED(widget)

    if (m_dirtyCache) {
        updateCache();
    }

    paintSeparator(painter, m_separatorColor);
    paintRole(painter, m_roleBounds, m_roleColor);
}

void KItemListGroupHeader::roleChanged(const QByteArray &current, const QByteArray &previous)
{
    Q_UNUSED(current)
    Q_UNUSED(previous)
}

void KItemListGroupHeader::dataChanged(const QVariant &current, const QVariant &previous)
{
    Q_UNUSED(current)
    Q_UNUSED(previous)
}

void KItemListGroupHeader::styleOptionChanged(const KItemListStyleOption &current, const KItemListStyleOption &previous)
{
    Q_UNUSED(current)
    Q_UNUSED(previous)
}

void KItemListGroupHeader::scrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous)
{
    Q_UNUSED(current)
    Q_UNUSED(previous)
}

void KItemListGroupHeader::itemIndexChanged(int current, int previous)
{
    Q_UNUSED(current)
    Q_UNUSED(previous)
}

void KItemListGroupHeader::collapsedChanged(bool current, bool previous)
{
    Q_UNUSED(current)
    Q_UNUSED(previous)
}

void KItemListGroupHeader::resizeEvent(QGraphicsSceneResizeEvent *event)
{
    QGraphicsWidget::resizeEvent(event);
    if (event->oldSize().height() != event->newSize().height()) {
        m_dirtyCache = true;
    }
    updateSize();
}

void KItemListGroupHeader::updateCache()
{
    Q_ASSERT(m_dirtyCache);

    // Calculate the role- and line-color. No alphablending is used for
    // performance reasons.
    const QColor c1 = textColor();
    const QColor c2 = baseColor();
    m_separatorColor = mixedColor(c1, c2, 10);
    m_roleColor = mixedColor(c1, c2, 60);

    updateSize();

    m_dirtyCache = false;
}

void KItemListGroupHeader::updateSize()
{
    const int padding = qMax(1, m_styleOption.padding);
    const int horizontalMargin = qMax(2, m_styleOption.horizontalMargin);

    const QFontMetrics fontMetrics(m_styleOption.font);
    const qreal roleHeight = fontMetrics.height();

    const int y = (m_scrollOrientation == Qt::Vertical) ? padding : horizontalMargin;

    m_roleBounds = QRectF(horizontalMargin + padding, y, size().width() - 2 * (padding + horizontalMargin), roleHeight);

    update();
}

QColor KItemListGroupHeader::mixedColor(const QColor &c1, const QColor &c2, int c1Percent)
{
    Q_ASSERT(c1Percent >= 0 && c1Percent <= 100);

    const int c2Percent = 100 - c1Percent;
    return QColor((c1.red() * c1Percent + c2.red() * c2Percent) / 100,
                  (c1.green() * c1Percent + c2.green() * c2Percent) / 100,
                  (c1.blue() * c1Percent + c2.blue() * c2Percent) / 100);
}

QPalette::ColorRole KItemListGroupHeader::normalTextColorRole() const
{
    return QPalette::Text;
}

QPalette::ColorRole KItemListGroupHeader::normalBaseColorRole() const
{
    return QPalette::Window;
}

QColor KItemListGroupHeader::textColor() const
{
    const QPalette::ColorGroup group = isActiveWindow() ? QPalette::Active : QPalette::Inactive;
    return styleOption().palette.color(group, normalTextColorRole());
}

QColor KItemListGroupHeader::baseColor() const
{
    const QPalette::ColorGroup group = isActiveWindow() ? QPalette::Active : QPalette::Inactive;
    return styleOption().palette.color(group, normalBaseColorRole());
}

#include "moc_kitemlistgroupheader.cpp"
