#include "multitouchscreenfix.h"

#include <QApplication>
#include <QDebug>

void MultiTouchScreenFix::install(QWidget *wgt) {
	new MultiTouchScreenFix(wgt);
}

bool MultiTouchScreenFix::eventFilter(QObject *o, QEvent *e) {
	QEvent::Type eventType = e->type();
	const bool isTouchEvent = eventType == QEvent::TouchBegin || eventType == QEvent::TouchCancel || eventType == QEvent::TouchUpdate || eventType == QEvent::TouchEnd;

	if(isTouchEvent) {
		QTouchEvent *te = static_cast<QTouchEvent *>(e);

		// Touch points that are updated in the event are not leftovers
		for(auto &tp: te->touchPoints())
			leftoverTouchPoints_.remove(tp.id());

		// If there are some leftover touch points that are not reported in the event, send an event reporting them as released - this is the core of this workaround
		if(!leftoverTouchPoints_.isEmpty()) {
			for(QTouchEvent::TouchPoint &p: leftoverTouchPoints_)
				p.setState(Qt::TouchPointReleased);

			QTouchEvent ee(QEvent::TouchEnd, te->device(), te->modifiers(), Qt::TouchPointReleased, QList<QTouchEvent::TouchPoint>(leftoverTouchPoints_.begin(), leftoverTouchPoints_.end()));
			QApplication::sendEvent(o, &ee);
		}

		// Again fill leftover touch points
		for(auto &tp: te->touchPoints()) {
			if(tp.state() == Qt::TouchPointReleased)
				leftoverTouchPoints_.remove(tp.id());
			else
				leftoverTouchPoints_[tp.id()] = tp;
		}
	}

	return false;
}

MultiTouchScreenFix::MultiTouchScreenFix(QWidget *wgt) : QObject(wgt) {
	wgt->installEventFilter(this);
}