/*
	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 <QtTest>
#include <QApplication>
#include <QDir>
#include <QIcon>
#include <QMainWindow>
#include <QStyleFactory>
#include <QToolBar>
#include <QToolButton>

#include "inkcontrast.h"
#include "qeticons.h"
#include "qetpalette.h"

/**
	Checks on QET's two icon themes, "qet" and "qet-dark", generated by
	misc/make_icon_themes.py into ico/icon-themes.qrc, and on the icon
	table that uses them.

	Every icon name must resolve in both themes. The dark theme's files
	must be light ink. A toolbar button painted with Fusion must show its
	icon at 3:1 (WCAG 1.4.11) in both themes, with the disabled state
	reading weaker than the enabled one, which is what was reversed on
	macOS before (GitHub #466, #870). And the icons the elements panel
	draws in its 50 px slots must stay small.
*/
class tst_qeticons : public QObject
{
	Q_OBJECT

	private slots:
		void initTestCase();
		void everyIconResolvesInBothThemes();
		void darkThemeFilesAreLightInk();
		void toolbarIconIsReadable_data();
		void toolbarIconIsReadable();
		void panelProjectIconStaysSmall();
};

namespace {
	const double kIconRatio = 3.0;

	QStringList iconNames(const QString &theme)
	{
		QStringList names;
		for (const QString &size : {"16x16", "22x22", "32x32", "48x48", "128x128", "scalable"})
		{
			QDir dir(QString(":/ico/themes/%1/%2").arg(theme, size));
			for (const QString &file : dir.entryList(QDir::Files))
				names << file.section('.', 0, -2);
		}
		names.removeDuplicates();
		names.sort();
		return names;
	}

	/// Lightness of the lightest visible pixel: the ink, in a dark-theme file.
	double maxLightness(const QImage &image)
	{
		double max = 0.0;
		for (int y = 0; y < image.height(); ++y)
			for (int x = 0; x < image.width(); ++x)
			{
				const QColor c = image.pixelColor(x, y);
				if (c.alpha() > 64) max = qMax(max, c.lightnessF());
			}
		return max;
	}
}

void tst_qeticons::initTestCase()
{
	QStringList paths = QIcon::themeSearchPaths();
	paths.prepend(QStringLiteral(":/ico/themes"));
	QIcon::setThemeSearchPaths(paths);
	QIcon::setThemeName(QStringLiteral("qet"));
	QVERIFY2(!iconNames("qet").isEmpty(), "light theme has no icons: is ico/icon-themes.qrc compiled in?");
}

void tst_qeticons::everyIconResolvesInBothThemes()
{
	const QStringList names = iconNames("qet");
	for (const QString &theme : {"qet", "qet-dark"})
	{
		QIcon::setThemeName(theme);
		QVERIFY(QIcon::hasThemeIcon("list-add"));
		for (const QString &name : names)
			QVERIFY2(!QIcon::fromTheme(name).isNull(),
			         qPrintable(QString("%1 missing in theme %2").arg(name, theme)));
	}
	// Names the icon table relies on that come from the alias list in
	// misc/make_icon_themes.py, not from a file of that name at 22 pixels.
	QIcon::setThemeName("qet");
	for (const QString &name : {"folio-new", "folio-delete", "folio-properties", "conductor-reset"})
		QVERIFY2(!QIcon::fromTheme(name).pixmap(22).isNull(), qPrintable(name));
}

void tst_qeticons::darkThemeFilesAreLightInk()
{
	int checked = 0;
	for (const QString &size : {"16x16", "22x22", "32x32"})
	{
		QDir dir(QString(":/ico/themes/qet-dark/%1").arg(size));
		for (const QString &file : dir.entryList({"*.png"}, QDir::Files))
		{
			const QImage dark(dir.filePath(file));
			const QImage light(QString(":/ico/themes/qet/%1/%2").arg(size, file));
			QVERIFY2(!dark.isNull() && !light.isNull(), qPrintable(file));
			// A page-shaped icon keeps its white fill dark after inversion,
			// so the mean would mislead; what matters is that the ink is light.
			QVERIFY2(maxLightness(dark) >= 0.8,
			         qPrintable(QString("%1/%2 has no light ink").arg(size, file)));
			++checked;
		}
	}
	QVERIFY(checked > 100);
}

void tst_qeticons::toolbarIconIsReadable_data()
{
	QTest::addColumn<QString>("theme");
	QTest::addColumn<QPalette>("palette");
	QTest::newRow("light") << "qet" << QET::Palette::fusionLight();
	QTest::newRow("dark") << "qet-dark" << QET::Palette::fusionDark();
}

/**
	A line-art icon on a Fusion tool button, as in the diagram editor
	toolbar. Enabled must reach 3:1; disabled must be weaker than enabled.
*/
void tst_qeticons::toolbarIconIsReadable()
{
	QFETCH(QString, theme);
	QFETCH(QPalette, palette);
	QIcon::setThemeName(theme);
	QApplication::setStyle(QStyleFactory::create("Fusion"));
	QApplication::setPalette(palette);

	QMainWindow window;
	QToolBar *toolbar = window.addToolBar("view");
	auto make = [&](const char *name, bool enabled) {
		auto *button = new QToolButton;
		button->setIcon(QIcon::fromTheme("zoom-fit-best"));
		button->setAutoRaise(true);
		button->setEnabled(enabled);
		button->setObjectName(name);
		toolbar->addWidget(button);
		return button;
	};
	QToolButton *enabled = make("enabled", true);
	QToolButton *disabled = make("disabled", false);
	window.resize(300, 100);
	window.show();
	QVERIFY(QTest::qWaitForWindowExposed(&window));

	const double enabled_contrast = QET::Test::inkContrast(QET::Test::grab(enabled, "enabled"), enabled->rect());
	const double disabled_contrast = QET::Test::inkContrast(QET::Test::grab(disabled, "disabled"), disabled->rect());
	QVERIFY2(enabled_contrast >= kIconRatio,
	         qPrintable(QString("enabled icon: %1").arg(enabled_contrast)));
	QVERIFY2(disabled_contrast < enabled_contrast,
	         qPrintable(QString("disabled %1 reads better than enabled %2")
	                    .arg(disabled_contrast).arg(enabled_contrast)));
}

/**
	The elements panel sets a 50 px icon size so element previews are
	large. Its project root item uses ProjectFileGP, whose theme name also
	has a 128 px file for the configuration dialog. On a 2x display the
	theme loader would pick that file for a 50 px request and fill the
	slot, so the entry must not resolve through the theme name.
*/
void tst_qeticons::panelProjectIconStaysSmall()
{
#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
	QSKIP("QIcon::pixmap(size, devicePixelRatio) needs Qt 6");
#else
	QIcon::setThemeName(QStringLiteral("qet"));
	QET::Icons::initIcons();

	const QPixmap panel = QET::Icons::ProjectFileGP.pixmap(QSize(50, 50), 2.0);
	QVERIFY(!panel.isNull());
	const int logical = qRound(panel.width() / panel.devicePixelRatio());
	QVERIFY2(logical <= 22, qPrintable(QString("project root icon is %1 px in a 50 px slot").arg(logical)));

	// The configuration dialog's page list still gets the large file.
	QCOMPARE(QET::Icons::Projects.pixmap(QSize(128, 128), 1.0).width(), 128);
#endif
}

int main(int argc, char **argv)
{
	if (qEnvironmentVariableIsEmpty("QT_QPA_PLATFORM"))
		qputenv("QT_QPA_PLATFORM", "offscreen");
	QApplication app(argc, argv);
	tst_qeticons test;
	QTEST_SET_MAIN_SOURCE_PATH
	return QTest::qExec(&test, argc, argv);
}

#include "tst_qeticons.moc"