/*
	Copyright 2006-2026 The QElectroTech Team
	This file is part of QElectroTech.

	QElectroTech is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 2 of the License, or
	(at your option) any later version.

	QElectroTech is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
*/
#include "shownkinds.h"

#include <QGraphicsItem>
#include <QGraphicsScene>

namespace
{
	bool hidden[ShownKinds::KindCount] = {};
}

/**
	@return true unless @a kind was hidden with setShown().
*/
bool ShownKinds::isShown(Kind kind)
{
	return kind < 0 || kind >= KindCount || !hidden[kind];
}

/**
	Show or hide @a kind for the items created from now on. Items already
	on a scene change when apply() is called on it.
*/
void ShownKinds::setShown(Kind kind, bool shown)
{
	if (kind >= 0 && kind < KindCount) {
		hidden[kind] = !shown;
	}
}

/**
	@return how many kinds are hidden, for the status bar.
*/
int ShownKinds::hiddenCount()
{
	int count = 0;
	for (bool h : hidden) {
		count += h ? 1 : 0;
	}
	return count;
}

/**
	Mark @a item as being of @a kind, and hide it now if that kind is
	hidden. Called by the item's constructor, while the item still wants to
	be visible.
*/
void ShownKinds::tag(QGraphicsItem *item, Kind kind)
{
	if (!item) {
		return;
	}
	item->setData(data_key, int(kind));
	if (!isShown(kind)) {
		item->setVisible(false);
		item->setData(hidden_key, true);
	}
}

/**
	Show or hide @a item as its own code wants, unless its kind is hidden:
	then it stays hidden, and comes back when the kind is shown again.
	Use this instead of QGraphicsItem::setVisible() in a tagged item.
*/
void ShownKinds::setVisible(QGraphicsItem *item, bool visible)
{
	if (!item) {
		return;
	}
	const QVariant kind = item->data(data_key);
	const bool vetoed = visible && kind.isValid() && !isShown(Kind(kind.toInt()));
	item->setVisible(visible && !vetoed);
	item->setData(hidden_key, vetoed ? QVariant(true) : QVariant());
}

/**
	@return true if @a item, or an item it hangs from, is of a hidden kind.
	For code that walks the items itself (DXF export) and must leave out
	what View > Show hides.
*/
bool ShownKinds::isHidden(const QGraphicsItem *item)
{
	for (; item; item = item->parentItem())
	{
		const QVariant value = item->data(data_key);
		if (value.isValid() && !isShown(Kind(value.toInt()))) {
			return true;
		}
	}
	return false;
}

/**
	Bring the items of @a kind on @a scene in line with the current state:
	hide the ones that are visible, or show again the ones hidden for it.
*/
void ShownKinds::apply(QGraphicsScene *scene, Kind kind)
{
	if (!scene) {
		return;
	}
	const bool shown = isShown(kind);
		//items() with no argument also returns the hidden items
	const QList<QGraphicsItem *> items = scene->items();
	for (QGraphicsItem *item : items)
	{
		const QVariant value = item->data(data_key);
		if (!value.isValid() || value.toInt() != kind) {
			continue;
		}
		if (!shown) {
				//Its own flag, not isVisible(): a symbol text under a
				//hidden group still wants to be visible
			if (item->isVisibleTo(item->parentItem())) {
				item->setVisible(false);
				item->setData(hidden_key, true);
			}
		} else if (item->data(hidden_key).toBool()) {
			item->setVisible(true);
			item->setData(hidden_key, QVariant());
		}
	}
}