z-bar-qt/Plugins/ZShell/Components/buttonrow.cpp

#include "buttonrow.hpp"

namespace ZShell::components {

ButtonRow::ButtonRow(QQuickItem* parent)
	: QQuickItem(parent), m_dirty(false), m_spacing(0.0) {
	setFlag(QQuickItem::ItemHasContents, true);
	QObject::connect(
		this, &ButtonRow::widthChanged, this, &ButtonRow::invalidate);
}

qreal ButtonRow::spacing() const {
	return m_spacing;
}

void ButtonRow::setSpacing(qreal spacing) {
	if (qFuzzyCompare(m_spacing + 1.0, spacing + 1.0)) return;

	m_spacing = spacing;
	emit spacingChanged();

	invalidate();
}

void ButtonRow::itemChange(
	QQuickItem::ItemChange change, const QQuickItem::ItemChangeData& data) {
	if (change == QQuickItem::ItemChildAddedChange) {
		auto* const child = data.item;
		QObject::connect(
			child,
			&QQuickItem::implicitWidthChanged,
			this,
			&ButtonRow::invalidate);
		QObject::connect(
			child,
			&QQuickItem::implicitHeightChanged,
			this,
			&ButtonRow::invalidate);
		QObject::connect(
			child, &QQuickItem::visibleChanged, this, &ButtonRow::invalidate);

		const auto* childMeta = child->metaObject();
		const auto morphSignalIdx =
			childMeta->indexOfSignal("shapeMorphExpansionChanged()");
		if (morphSignalIdx != -1)
			QObject::connect(
				child,
				childMeta->method(morphSignalIdx),
				this,
				metaObject()->method(
					metaObject()->indexOfSlot("invalidate()")));

		invalidate();
	} else if (change == QQuickItem::ItemChildRemovedChange) {
		QObject::disconnect(data.item, nullptr, this, nullptr);
		invalidate();
	}

	QQuickItem::itemChange(change, data);
}

void ButtonRow::updatePolish() {
	if (m_dirty) {
		relayout();
		m_dirty = false;
	}
}

void ButtonRow::invalidate() {
	m_dirty = true;
	polish();
}

void ButtonRow::relayout() {
	const auto allChildren = childItems();

	QList<QQuickItem*> validChildren;
	for (auto* const child : allChildren) {
		if (child->isVisible() && !child->inherits("QQuickRepeater"))
			validChildren.append(child);
	}
	const auto nChildren = validChildren.size();
	const auto totalSpacing = static_cast<qreal>(nChildren - 1) * m_spacing;

	qreal reservedWidth = 0;
	qreal unreservedWidth = 0;
	int fillWidthCount = 0;
	qreal maxHeight = 0;
	for (auto* const child : validChildren) {
		maxHeight = qMax(maxHeight, child->implicitHeight());

		const auto prop = child->property("fillWidth");
		if (!prop.isValid()) continue;

		if (prop.toBool()) {
			fillWidthCount++;
			unreservedWidth += child->implicitWidth();
		} else {
			reservedWidth += child->implicitWidth();
		}
	}

	if (fillWidthCount == 0) fillWidthCount = 1; // Avoid divide by 0

	const auto widthPerItem = (width() - totalSpacing - reservedWidth) /
							  static_cast<qreal>(fillWidthCount);

	QList<qreal> baseWidths;
	baseWidths.reserve(nChildren);
	for (auto* const child : validChildren)
		baseWidths.append(
			child->property("fillWidth").toBool() ? widthPerItem
												  : child->implicitWidth());

	qreal accX = 0;
	for (int i = 0; i < nChildren; ++i) {
		auto* const child = validChildren[i];

		// clang-format off
		auto prevExtraWidth = i > 0             ? getMorphExpansion(validChildren[i - 1]) : 0.0;
		auto nextExtraWidth = i < nChildren - 1 ? getMorphExpansion(validChildren[i + 1]) : 0.0;
		// clang-format on

		// Items at edges push by full amount, items in middle push by half
		if (i > 1) prevExtraWidth /= 2;
		if (i < nChildren - 2) nextExtraWidth /= 2;

		child->setWidth(
			baseWidths[i] + getMorphExpansion(child) - prevExtraWidth -
			nextExtraWidth);
		child->setHeight(maxHeight);

		child->setX(accX);
		child->setY(0);
		accX += child->width() + m_spacing;
	}

	setImplicitWidth(reservedWidth + unreservedWidth + totalSpacing);
	setImplicitHeight(maxHeight);
}

qreal ButtonRow::getMorphExpansion(const QQuickItem* item) {
	return item->property("shapeMorphExpansion").toReal();
}

} // namespace ZShell::components