/*
This file is part of Telegram Desktop,
the official desktop application for the Telegram messaging service.

For license and copyright information please follow this link:
https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
*/
#include "window/themes/window_theme.h"

#include "window/themes/window_theme_preview.h"
#include "mainwidget.h"
#include "auth_session.h"
#include "apiwrap.h"
#include "storage/localstorage.h"
#include "storage/localimageloader.h"
#include "storage/file_upload.h"
#include "base/parse_helper.h"
#include "base/zlib_help.h"
#include "data/data_session.h"
#include "ui/image/image.h"
#include "boxes/background_box.h"
#include "core/application.h"
#include "styles/style_widgets.h"
#include "styles/style_history.h"

namespace Window {
namespace Theme {
namespace {

constexpr auto kThemeFileSizeLimit = 5 * 1024 * 1024;
constexpr auto kThemeBackgroundSizeLimit = 4 * 1024 * 1024;
constexpr auto kBackgroundSizeLimit = 25 * 1024 * 1024;
constexpr auto kThemeSchemeSizeLimit = 1024 * 1024;
constexpr auto kNightThemeFile = str_const(":/gui/night.tdesktop-theme");

struct Applying {
	QString pathRelative;
	QString pathAbsolute;
	QByteArray content;
	QByteArray paletteForRevert;
	Cached cached;
	Fn<void()> overrideKeep;
};

NeverFreedPointer<ChatBackground> GlobalBackground;
Applying GlobalApplying;

inline bool AreTestingTheme() {
	return !GlobalApplying.paletteForRevert.isEmpty();
};

QByteArray readThemeContent(const QString &path) {
	QFile file(path);
	if (!file.exists()) {
		LOG(("Theme Error: theme file not found: %1").arg(path));
		return QByteArray();
	}

	if (file.size() > kThemeFileSizeLimit) {
		LOG(("Theme Error: theme file too large: %1 (should be less than 5 MB, got %2)").arg(path).arg(file.size()));
		return QByteArray();
	}
	if (!file.open(QIODevice::ReadOnly)) {
		LOG(("Theme Error: could not open theme file: %1").arg(path));
		return QByteArray();
	}

	return file.readAll();
}

inline uchar readHexUchar(char code, bool &error) {
	if (code >= '0' && code <= '9') {
		return ((code - '0') & 0xFF);
	} else if (code >= 'a' && code <= 'f') {
		return ((code + 10 - 'a') & 0xFF);
	} else if (code >= 'A' && code <= 'F') {
		return ((code + 10 - 'A') & 0xFF);
	}
	error = true;
	return 0xFF;
}

inline uchar readHexUchar(char char1, char char2, bool &error) {
	return ((readHexUchar(char1, error) & 0x0F) << 4) | (readHexUchar(char2, error) & 0x0F);
}

bool readNameAndValue(const char *&from, const char *end, QLatin1String *outName, QLatin1String *outValue) {
	using base::parse::skipWhitespaces;
	using base::parse::readName;

	if (!skipWhitespaces(from, end)) return true;

	*outName = readName(from, end);
	if (outName->size() == 0) {
		LOG(("Theme Error: Could not read name in the color scheme."));
		return false;
	}
	if (!skipWhitespaces(from, end)) {
		LOG(("Theme Error: Unexpected end of the color scheme."));
		return false;
	}
	if (*from != ':') {
		LOG(("Theme Error: Expected ':' between each name and value in the color scheme (while reading key '%1')").arg(*outName));
		return false;
	}
	if (!skipWhitespaces(++from, end)) {
		LOG(("Theme Error: Unexpected end of the color scheme."));
		return false;
	}
	auto valueStart = from;
	if (*from == '#') ++from;

	if (readName(from, end).size() == 0) {
		LOG(("Theme Error: Expected a color value in #rrggbb or #rrggbbaa format in the color scheme (while reading key '%1')").arg(*outName));
		return false;
	}
	*outValue = QLatin1String(valueStart, from - valueStart);

	if (!skipWhitespaces(from, end)) {
		LOG(("Theme Error: Unexpected end of the color scheme."));
		return false;
	}
	if (*from != ';') {
		LOG(("Theme Error: Expected ';' after each value in the color scheme (while reading key '%1')").arg(*outName));
		return false;
	}
	++from;
	return true;
}

enum class SetResult {
	Ok,
	Bad,
	NotFound,
};
SetResult setColorSchemeValue(QLatin1String name, QLatin1String value, Instance *out) {
	auto result = style::palette::SetResult::Ok;
	auto size = value.size();
	auto data = value.data();
	if (data[0] == '#' && (size == 7 || size == 9)) {
		auto error = false;
		auto r = readHexUchar(data[1], data[2], error);
		auto g = readHexUchar(data[3], data[4], error);
		auto b = readHexUchar(data[5], data[6], error);
		auto a = (size == 9) ? readHexUchar(data[7], data[8], error) : uchar(255);
		if (error) {
			LOG(("Theme Warning: Skipping value '%1: %2' (expected a color value in #rrggbb or #rrggbbaa or a previously defined key in the color scheme)").arg(name).arg(value));
			return SetResult::Ok;
		} else if (out) {
			result = out->palette.setColor(name, r, g, b, a);
		} else {
			result = style::main_palette::setColor(name, r, g, b, a);
		}
	} else {
		if (out) {
			result = out->palette.setColor(name, value);
		} else {
			result = style::main_palette::setColor(name, value);
		}
	}
	if (result == style::palette::SetResult::Ok) {
		return SetResult::Ok;
	} else if (result == style::palette::SetResult::KeyNotFound) {
		return SetResult::NotFound;
	} else if (result == style::palette::SetResult::ValueNotFound) {
		LOG(("Theme Warning: Skipping value '%1: %2' (expected a color value in #rrggbb or #rrggbbaa or a previously defined key in the color scheme)").arg(name).arg(value));
		return SetResult::Ok;
	} else if (result == style::palette::SetResult::Duplicate) {
		LOG(("Theme Warning: Color value appears more than once in the color scheme (while applying '%1: %2')").arg(name).arg(value));
		return SetResult::Ok;
	} else {
		LOG(("Theme Error: Unexpected internal error."));
	}
	return SetResult::Bad;
}

bool loadColorScheme(const QByteArray &content, Instance *out) {
	auto unsupported = QMap<QLatin1String, QLatin1String>();
	return ReadPaletteValues(content, [&unsupported, out](QLatin1String name, QLatin1String value) {
		// Find the named value in the already read unsupported list.
		value = unsupported.value(value, value);

		auto result = setColorSchemeValue(name, value, out);
		if (result == SetResult::Bad) {
			return false;
		} else if (result == SetResult::NotFound) {
			unsupported.insert(name, value);
		}
		return true;
	});
}

void applyBackground(QImage &&background, bool tiled, Instance *out) {
	if (out) {
		out->background = std::move(background);
		out->tiled = tiled;
	} else {
		Background()->setThemeData(std::move(background), tiled);
	}
}

bool loadThemeFromCache(const QByteArray &content, const Cached &cache) {
	if (cache.paletteChecksum != style::palette::Checksum()) {
		return false;
	}
	if (cache.contentChecksum != hashCrc32(content.constData(), content.size())) {
		return false;
	}

	QImage background;
	if (!cache.background.isEmpty()) {
		QDataStream stream(cache.background);
		QImageReader reader(stream.device());
#ifndef OS_MAC_OLD
		reader.setAutoTransform(true);
#endif // OS_MAC_OLD
		if (!reader.read(&background) || background.isNull()) {
			return false;
		}
	}

	if (!style::main_palette::load(cache.colors)) {
		return false;
	}
	Background()->saveAdjustableColors();
	if (!background.isNull()) {
		applyBackground(std::move(background), cache.tiled, nullptr);
	}

	return true;
}

enum class LoadResult {
	Loaded,
	Failed,
	NotFound,
};

LoadResult loadBackgroundFromFile(zlib::FileToRead &file, const char *filename, QByteArray *outBackground) {
	*outBackground = file.readFileContent(filename, zlib::kCaseInsensitive, kThemeBackgroundSizeLimit);
	if (file.error() == UNZ_OK) {
		return LoadResult::Loaded;
	} else if (file.error() == UNZ_END_OF_LIST_OF_FILE) {
		file.clearError();
		return LoadResult::NotFound;
	}
	LOG(("Theme Error: could not read '%1' in the theme file.").arg(filename));
	return LoadResult::Failed;
}

bool loadBackground(zlib::FileToRead &file, QByteArray *outBackground, bool *outTiled) {
	auto result = loadBackgroundFromFile(file, "background.jpg", outBackground);
	if (result != LoadResult::NotFound) return (result == LoadResult::Loaded);

	result = loadBackgroundFromFile(file, "background.png", outBackground);
	if (result != LoadResult::NotFound) return (result == LoadResult::Loaded);

	*outTiled = true;
	result = loadBackgroundFromFile(file, "tiled.jpg", outBackground);
	if (result != LoadResult::NotFound) return (result == LoadResult::Loaded);

	result = loadBackgroundFromFile(file, "tiled.png", outBackground);
	if (result != LoadResult::NotFound) return (result == LoadResult::Loaded);
	return true;
}

bool loadTheme(const QByteArray &content, Cached &cache, Instance *out = nullptr) {
	cache = Cached();
	zlib::FileToRead file(content);

	unz_global_info globalInfo = { 0 };
	file.getGlobalInfo(&globalInfo);
	if (file.error() == UNZ_OK) {
		auto schemeContent = file.readFileContent("colors.tdesktop-theme", zlib::kCaseInsensitive, kThemeSchemeSizeLimit);
		if (file.error() == UNZ_END_OF_LIST_OF_FILE) {
			file.clearError();
			schemeContent = file.readFileContent("colors.tdesktop-palette", zlib::kCaseInsensitive, kThemeSchemeSizeLimit);
		}
		if (file.error() != UNZ_OK) {
			LOG(("Theme Error: could not read 'colors.tdesktop-theme' or 'colors.tdesktop-palette' in the theme file."));
			return false;
		}
		if (!loadColorScheme(schemeContent, out)) {
			return false;
		}
		Background()->saveAdjustableColors();

		auto backgroundTiled = false;
		auto backgroundContent = QByteArray();
		if (!loadBackground(file, &backgroundContent, &backgroundTiled)) {
			return false;
		}

		if (!backgroundContent.isEmpty()) {
			auto check = QBuffer(&backgroundContent);
			auto reader = QImageReader(&check);
			const auto size = reader.size();
			if (size.isEmpty()
				|| (size.width() * size.height() > kBackgroundSizeLimit)) {
				LOG(("Theme Error: bad background image size in the theme file."));
				return false;
			}
			auto background = App::readImage(backgroundContent);
			if (background.isNull()) {
				LOG(("Theme Error: could not read background image in the theme file."));
				return false;
			}
			auto buffer = QBuffer(&cache.background);
			if (!background.save(&buffer, "BMP")) {
				LOG(("Theme Error: could not write background image as a BMP to cache."));
				return false;
			}
			cache.tiled = backgroundTiled;

			applyBackground(std::move(background), cache.tiled, out);
		}
	} else {
		// Looks like it is not a .zip theme.
		if (!loadColorScheme(content, out)) {
			return false;
		}
		Background()->saveAdjustableColors();
	}
	if (out) {
		cache.colors = out->palette.save();
	} else {
		cache.colors = style::main_palette::save();
	}
	cache.paletteChecksum = style::palette::Checksum();
	cache.contentChecksum = hashCrc32(content.constData(), content.size());

	return true;
}

QImage validateBackgroundImage(QImage image) {
	if (image.format() != QImage::Format_ARGB32_Premultiplied) {
		image = std::move(image).convertToFormat(
			QImage::Format_ARGB32_Premultiplied);
	}
	image.setDevicePixelRatio(cRetinaFactor());
	return image;
}

void WriteAppliedTheme() {
	auto saved = Saved();
	saved.pathRelative = GlobalApplying.pathRelative;
	saved.pathAbsolute = GlobalApplying.pathAbsolute;
	saved.content = std::move(GlobalApplying.content);
	saved.cache = std::move(GlobalApplying.cached);
	Local::writeTheme(saved);
}

void ClearApplying() {
	GlobalApplying = Applying();
}

} // namespace

ChatBackground::AdjustableColor::AdjustableColor(style::color data)
: item(data)
, original(data->c) {
}

ChatBackground::ChatBackground() : _adjustableColors({
		st::msgServiceBg,
		st::msgServiceBgSelected,
		st::historyScrollBg,
		st::historyScrollBgOver,
		st::historyScrollBarBg,
		st::historyScrollBarBgOver }) {
	saveAdjustableColors();
}

void ChatBackground::setThemeData(QImage &&themeImage, bool themeTile) {
	_themeImage = validateBackgroundImage(std::move(themeImage));
	_themeTile = themeTile;
}

void ChatBackground::start() {
	if (Data::details::IsUninitializedWallPaper(_paper)) {
		if (!Local::readBackground()) {
			set(Data::ThemeWallPaper());
		}
		refreshSession();
		subscribe(Core::App().authSessionChanged(), [=] {
			refreshSession();
		});
	}
}

void ChatBackground::refreshSession() {
	const auto session = AuthSession::Exists() ? &Auth() : nullptr;
	if (_session != session) {
		_session = session;
		checkUploadWallPaper();
	}
}

void ChatBackground::checkUploadWallPaper() {
	if (!_session) {
		_wallPaperUploadLifetime = rpl::lifetime();
		_wallPaperUploadId = FullMsgId();
		_wallPaperRequestId = 0;
		return;
	}
	if (const auto id = base::take(_wallPaperUploadId)) {
		_session->uploader().cancel(id);
	}
	if (const auto id = base::take(_wallPaperRequestId)) {
		_session->api().request(id).cancel();
	}
	if (!Data::IsCustomWallPaper(_paper)
		|| _original.isNull()
		|| testingPalette()) {
		return;
	}

	const auto ready = PrepareWallPaper(_original);
	const auto documentId = ready.id;
	_wallPaperUploadId = FullMsgId(0, clientMsgId());
	_session->uploader().uploadMedia(_wallPaperUploadId, ready);
	if (_wallPaperUploadLifetime) {
		return;
	}
	_wallPaperUploadLifetime = _session->uploader().documentReady(
	) | rpl::start_with_next([=](const Storage::UploadedDocument &data) {
		if (data.fullId != _wallPaperUploadId) {
			return;
		}
		_wallPaperUploadId = FullMsgId();
		_wallPaperRequestId = _session->api().request(
			MTPaccount_UploadWallPaper(
				data.file,
				MTP_string("image/jpeg"),
				_paper.mtpSettings()
			)
		).done([=](const MTPWallPaper &result) {
			result.match([&](const MTPDwallPaper &data) {
				_session->data().documentConvert(
					_session->data().document(documentId),
					data.vdocument);
			});
			if (const auto paper = Data::WallPaper::Create(result)) {
				setPaper(*paper);
				writeNewBackgroundSettings();
				notify(BackgroundUpdate(BackgroundUpdate::Type::New, tile()));
			}
		}).send();
	});
}

void ChatBackground::set(const Data::WallPaper &paper, QImage image) {
	image = ProcessBackgroundImage(std::move(image));

	const auto needResetAdjustable = Data::IsDefaultWallPaper(paper)
		&& !Data::IsDefaultWallPaper(_paper)
		&& !nightMode()
		&& _themeAbsolutePath.isEmpty();
	if (Data::IsThemeWallPaper(paper) && _themeImage.isNull()) {
		setPaper(Data::DefaultWallPaper());
	} else {
		setPaper(paper);
		if (needResetAdjustable) {
			// If we had a default color theme with non-default background,
			// and we switch to default background we must somehow switch from
			// adjusted service colors to default (non-adjusted) service colors.
			// The only way to do that right now is through full palette reset.
			restoreAdjustableColors();
		}
	}
	if (Data::IsThemeWallPaper(_paper)) {
		(nightMode() ? _tileNightValue : _tileDayValue) = _themeTile;
		setPreparedImage(_themeImage, _themeImage);
	} else if (Data::details::IsTestingThemeWallPaper(_paper)
		|| Data::details::IsTestingDefaultWallPaper(_paper)
		|| Data::details::IsTestingEditorWallPaper(_paper)) {
		if (Data::details::IsTestingDefaultWallPaper(_paper)
			|| image.isNull()) {
			image.load(qsl(":/gui/art/bg.jpg"));
			setPaper(Data::details::TestingDefaultWallPaper());
		}
		image = validateBackgroundImage(std::move(image));
		setPreparedImage(image, image);
	} else {
		if (Data::IsLegacy1DefaultWallPaper(_paper)) {
			image.load(qsl(":/gui/art/bg_initial.jpg"));
			const auto scale = cScale() * cIntRetinaFactor();
			if (scale != 100) {
				image = image.scaledToWidth(
					ConvertScale(image.width(), scale),
					Qt::SmoothTransformation);
			}
		} else if (Data::IsDefaultWallPaper(_paper)
			|| (!_paper.backgroundColor() && image.isNull())) {
			setPaper(Data::DefaultWallPaper().withParamsFrom(_paper));
			image.load(qsl(":/gui/art/bg.jpg"));
		}
		Local::writeBackground(
			_paper,
			((Data::IsDefaultWallPaper(_paper)
				|| Data::IsLegacy1DefaultWallPaper(_paper))
				? QImage()
				: image));
		if (const auto fill = _paper.backgroundColor()) {
			if (_paper.isPattern() && !image.isNull()) {
				auto prepared = validateBackgroundImage(
					Data::PreparePatternImage(
						image,
						*fill,
						Data::PatternColor(*fill),
						_paper.patternIntensity()));
				setPreparedImage(std::move(image), std::move(prepared));
			} else {
				_original = QImage();
				_pixmap = QPixmap();
				_pixmapForTiled = QPixmap();
				if (adjustPaletteRequired()) {
					adjustPaletteUsingColor(*fill);
				}
			}
		} else {
			image = validateBackgroundImage(std::move(image));
			setPreparedImage(image, image);
		}
	}
	Assert(colorForFill()
		|| (!_original.isNull()
			&& !_pixmap.isNull()
			&& !_pixmapForTiled.isNull()));

	notify(BackgroundUpdate(BackgroundUpdate::Type::New, tile()));
	if (needResetAdjustable) {
		notify(BackgroundUpdate(BackgroundUpdate::Type::TestingTheme, tile()), true);
		notify(BackgroundUpdate(BackgroundUpdate::Type::ApplyingTheme, tile()), true);
	}
	checkUploadWallPaper();
}

void ChatBackground::setPreparedImage(QImage original, QImage prepared) {
	Expects(original.format() == QImage::Format_ARGB32_Premultiplied);
	Expects(original.width() > 0 && original.height() > 0);
	Expects(prepared.format() == QImage::Format_ARGB32_Premultiplied);
	Expects(prepared.width() > 0 && prepared.height() > 0);

	_original = std::move(original);
	if (!_paper.isPattern() && _paper.isBlurred()) {
		prepared = Data::PrepareBlurredBackground(std::move(prepared));
	}
	if (adjustPaletteRequired()) {
		adjustPaletteUsingBackground(prepared);
	}
	preparePixmaps(std::move(prepared));
}

void ChatBackground::preparePixmaps(QImage image) {
	const auto width = image.width();
	const auto height = image.height();
	const auto isSmallForTiled = (width < kMinimumTiledSize)
		|| (height < kMinimumTiledSize);
	if (isSmallForTiled) {
		const auto repeatTimesX = qCeil(kMinimumTiledSize / (1. * width));
		const auto repeatTimesY = qCeil(kMinimumTiledSize / (1. * height));
		auto imageForTiled = QImage(
			width * repeatTimesX,
			height * repeatTimesY,
			QImage::Format_ARGB32_Premultiplied);
		imageForTiled.setDevicePixelRatio(image.devicePixelRatio());
		auto imageForTiledBytes = imageForTiled.bits();
		auto bytesInLine = width * sizeof(uint32);
		for (auto timesY = 0; timesY != repeatTimesY; ++timesY) {
			auto imageBytes = image.constBits();
			for (auto y = 0; y != height; ++y) {
				for (auto timesX = 0; timesX != repeatTimesX; ++timesX) {
					memcpy(imageForTiledBytes, imageBytes, bytesInLine);
					imageForTiledBytes += bytesInLine;
				}
				imageBytes += image.bytesPerLine();
				imageForTiledBytes += imageForTiled.bytesPerLine() - (repeatTimesX * bytesInLine);
			}
		}
		_pixmapForTiled = App::pixmapFromImageInPlace(std::move(imageForTiled));
	}
	_pixmap = App::pixmapFromImageInPlace(std::move(image));
	if (!isSmallForTiled) {
		_pixmapForTiled = _pixmap;
	}
}

void ChatBackground::setPaper(const Data::WallPaper &paper) {
	_paper = paper.withoutImageData();
}

bool ChatBackground::adjustPaletteRequired() {
	const auto usingThemeBackground = [&] {
		return Data::IsThemeWallPaper(_paper)
			|| Data::details::IsTestingThemeWallPaper(_paper);
	};
	const auto usingDefaultBackground = [&] {
		return Data::IsDefaultWallPaper(_paper)
			|| Data::details::IsTestingDefaultWallPaper(_paper);
	};

	if (testingPalette()) {
		return false;
	} else if (isNonDefaultThemeOrBackground() || nightMode()) {
		return !usingThemeBackground();
	}
	return !usingDefaultBackground();
}

bool ChatBackground::testingPalette() const {
	const auto path = AreTestingTheme()
		? GlobalApplying.pathAbsolute
		: _themeAbsolutePath;
	return IsPaletteTestingPath(path);
}

void ChatBackground::adjustPaletteUsingBackground(const QImage &image) {
	adjustPaletteUsingColor(CountAverageColor(image));
}

void ChatBackground::adjustPaletteUsingColor(QColor color) {
	const auto prepared = color.toHsl();
	for (const auto &adjustable : _adjustableColors) {
		const auto adjusted = AdjustedColor(adjustable.item->c, prepared);
		adjustable.item.set(
			adjusted.red(),
			adjusted.green(),
			adjusted.blue(),
			adjusted.alpha());
	}
}

std::optional<QColor> ChatBackground::colorForFill() const {
	return _pixmap.isNull() ? _paper.backgroundColor() : std::nullopt;
}

QImage ChatBackground::createCurrentImage() const {
	if (const auto fill = colorForFill()) {
		auto result = QImage(
			kMinimumTiledSize,
			kMinimumTiledSize,
			QImage::Format_ARGB32_Premultiplied);
		result.fill(*fill);
		return result;
	}
	return pixmap().toImage();
}

bool ChatBackground::tile() const {
	return nightMode() ? _tileNightValue : _tileDayValue;
}

bool ChatBackground::tileDay() const {
	if (Data::details::IsTestingThemeWallPaper(_paper) ||
		Data::details::IsTestingDefaultWallPaper(_paper)) {
		if (!nightMode()) {
			return _tileForRevert;
		}
	}
	return _tileDayValue;
}

bool ChatBackground::tileNight() const {
	if (Data::details::IsTestingThemeWallPaper(_paper) ||
		Data::details::IsTestingDefaultWallPaper(_paper)) {
		if (nightMode()) {
			return _tileForRevert;
		}
	}
	return _tileNightValue;
}

void ChatBackground::ensureStarted() {
	if (_pixmap.isNull() && !_paper.backgroundColor()) {
		// We should start first, otherwise the default call
		// to start() will reset this value to _themeTile.
		start();
	}
}

void ChatBackground::setTile(bool tile) {
	ensureStarted();
	const auto old = this->tile();
	if (nightMode()) {
		setTileNightValue(tile);
	} else {
		setTileDayValue(tile);
	}
	if (this->tile() != old) {
		if (!Data::details::IsTestingThemeWallPaper(_paper)
			&& !Data::details::IsTestingDefaultWallPaper(_paper)) {
			Local::writeUserSettings();
		}
		notify(BackgroundUpdate(BackgroundUpdate::Type::Changed, tile));
	}
}

void ChatBackground::setTileDayValue(bool tile) {
	ensureStarted();
	_tileDayValue = tile;
}

void ChatBackground::setTileNightValue(bool tile) {
	ensureStarted();
	_tileNightValue = tile;
}

void ChatBackground::setThemeAbsolutePath(const QString &path) {
	_themeAbsolutePath = path;
}

QString ChatBackground::themeAbsolutePath() const {
	return _themeAbsolutePath;
}

void ChatBackground::reset() {
	if (Data::details::IsTestingThemeWallPaper(_paper)
		|| Data::details::IsTestingDefaultWallPaper(_paper)) {
		if (_themeImage.isNull()) {
			_paperForRevert = Data::DefaultWallPaper();
			_originalForRevert = QImage();
			_tileForRevert = false;
		} else {
			_paperForRevert = Data::ThemeWallPaper();
			_originalForRevert = _themeImage;
			_tileForRevert = _themeTile;
		}
	} else {
		set(Data::ThemeWallPaper());
		restoreAdjustableColors();
		notify(BackgroundUpdate(BackgroundUpdate::Type::TestingTheme, tile()), true);
		notify(BackgroundUpdate(BackgroundUpdate::Type::ApplyingTheme, tile()), true);
	}
}

void ChatBackground::saveForRevert() {
	ensureStarted();
	if (!Data::details::IsTestingThemeWallPaper(_paper)
		&& !Data::details::IsTestingDefaultWallPaper(_paper)) {
		_paperForRevert = _paper;
		_originalForRevert = std::move(_original);
		_tileForRevert = tile();
	}
}

void ChatBackground::saveAdjustableColors() {
	for (auto &color : _adjustableColors) {
		color.original = color.item->c;
	}
}

void ChatBackground::restoreAdjustableColors() {
	for (const auto &color : _adjustableColors) {
		const auto value = color.original;
		color.item.set(value.red(), value.green(), value.blue(), value.alpha());
	}
}

void ChatBackground::setTestingTheme(Instance &&theme) {
	style::main_palette::apply(theme.palette);
	saveAdjustableColors();

	auto switchToThemeBackground = !theme.background.isNull()
		|| Data::IsThemeWallPaper(_paper)
		|| (Data::IsDefaultWallPaper(_paper)
			&& !nightMode()
			&& _themeAbsolutePath.isEmpty());
	if (AreTestingTheme()
		&& IsPaletteTestingPath(GlobalApplying.pathAbsolute)) {
		// Grab current background image if it is not already custom
		// Use prepared pixmap, not original image, because we're
		// for sure switching to a non-pattern wall-paper (testing editor).
		if (!Data::IsCustomWallPaper(_paper)) {
			saveForRevert();
			set(
				Data::details::TestingEditorWallPaper(),
				std::move(_pixmap).toImage());
		}
	} else if (switchToThemeBackground) {
		saveForRevert();
		set(
			Data::details::TestingThemeWallPaper(),
			std::move(theme.background));
		setTile(theme.tiled);
	} else {
		// Apply current background image so that service bg colors are recounted.
		set(_paper, std::move(_original));
	}
	notify(BackgroundUpdate(BackgroundUpdate::Type::TestingTheme, tile()), true);
}

void ChatBackground::setTestingDefaultTheme() {
	style::main_palette::reset();
	saveAdjustableColors();

	saveForRevert();
	set(Data::details::TestingDefaultWallPaper());
	setTile(false);
	notify(BackgroundUpdate(BackgroundUpdate::Type::TestingTheme, tile()), true);
}

void ChatBackground::keepApplied(const QString &path, bool write) {
	setThemeAbsolutePath(path);
	if (Data::details::IsTestingEditorWallPaper(_paper)) {
		setPaper(Data::CustomWallPaper());
		_themeImage = QImage();
		_themeTile = false;
		if (write) {
			writeNewBackgroundSettings();
		}
	} else if (Data::details::IsTestingThemeWallPaper(_paper)) {
		setPaper(Data::ThemeWallPaper());
		_themeImage = validateBackgroundImage(base::duplicate(_original));
		_themeTile = tile();
		if (write) {
			writeNewBackgroundSettings();
		}
	} else if (Data::details::IsTestingDefaultWallPaper(_paper)) {
		setPaper(Data::DefaultWallPaper());
		_themeImage = QImage();
		_themeTile = false;
		if (write) {
			writeNewBackgroundSettings();
		}
	}
	notify(BackgroundUpdate(BackgroundUpdate::Type::ApplyingTheme, tile()), true);
}

bool ChatBackground::isNonDefaultThemeOrBackground() {
	start();
	return nightMode()
		? (_themeAbsolutePath != NightThemePath()
			|| !Data::IsThemeWallPaper(_paper))
		: (!_themeAbsolutePath.isEmpty()
			|| !Data::IsDefaultWallPaper(_paper));
}

bool ChatBackground::isNonDefaultBackground() {
	start();
	return _themeAbsolutePath.isEmpty()
		? !Data::IsDefaultWallPaper(_paper)
		: !Data::IsThemeWallPaper(_paper);
}

void ChatBackground::writeNewBackgroundSettings() {
	if (tile() != _tileForRevert) {
		Local::writeUserSettings();
	}
	Local::writeBackground(
		_paper,
		((Data::IsThemeWallPaper(_paper)
			|| Data::IsDefaultWallPaper(_paper))
			? QImage()
			: _original));
}

void ChatBackground::revert() {
	if (Data::details::IsTestingThemeWallPaper(_paper)
		|| Data::details::IsTestingDefaultWallPaper(_paper)
		|| Data::details::IsTestingEditorWallPaper(_paper)) {
		setTile(_tileForRevert);
		set(_paperForRevert, std::move(_originalForRevert));
	} else {
		// Apply current background image so that service bg colors are recounted.
		set(_paper, std::move(_original));
	}
	notify(BackgroundUpdate(BackgroundUpdate::Type::RevertingTheme, tile()), true);
}

void ChatBackground::setNightModeValue(bool nightMode) {
	_nightMode = nightMode;
}

bool ChatBackground::nightMode() const {
	return _nightMode;
}

void ChatBackground::toggleNightMode(std::optional<QString> themePath) {
	const auto settingDefault = themePath.has_value();
	const auto oldNightMode = _nightMode;
	const auto newNightMode = !_nightMode;
	_nightMode = newNightMode;
	auto read = settingDefault ? Saved() : Local::readThemeAfterSwitch();
	auto path = read.pathAbsolute;

	_nightMode = oldNightMode;
	auto oldTileValue = (_nightMode ? _tileNightValue : _tileDayValue);
	const auto alreadyOnDisk = [&] {
		if (read.content.isEmpty()) {
			return false;
		}
		auto preview = std::make_unique<Preview>();
		preview->pathAbsolute = std::move(read.pathAbsolute);
		preview->pathRelative = std::move(read.pathRelative);
		preview->content = std::move(read.content);
		preview->instance.cached = std::move(read.cache);
		const auto loaded = loadTheme(
			preview->content,
			preview->instance.cached,
			&preview->instance);
		if (!loaded) {
			return false;
		}
		Apply(std::move(preview));
		return true;
	}();
	if (!alreadyOnDisk) {
		path = themePath
			? *themePath
			: (newNightMode ? NightThemePath() : QString());
		ApplyDefaultWithPath(path);
	}

	// Theme editor could have already reverted the testing of this toggle.
	if (AreTestingTheme()) {
		GlobalApplying.overrideKeep = [=] {
			_nightMode = newNightMode;

			// Restore the value, it was set inside theme testing.
			(oldNightMode ? _tileNightValue : _tileDayValue) = oldTileValue;

			if (!alreadyOnDisk) {
				// First-time switch to default night mode should write it.
				WriteAppliedTheme();
			}
			ClearApplying();
			keepApplied(path, settingDefault);
			if (tile() != _tileForRevert) {
				Local::writeUserSettings();
			}
			Local::writeSettings();
			if (!settingDefault && !Local::readBackground()) {
				set(Data::ThemeWallPaper());
			}
		};
	}
}

ChatBackground *Background() {
	GlobalBackground.createIfNull();
	return GlobalBackground.data();
}

bool Load(Saved &&saved) {
	if (saved.content.size() < 4) {
		LOG(("Theme Error: Could not load theme from '%1' (%2)"
			).arg(saved.pathRelative
			).arg(saved.pathAbsolute));
		return false;
	}

	GlobalBackground.createIfNull();
	if (loadThemeFromCache(saved.content, saved.cache)) {
		Background()->setThemeAbsolutePath(saved.pathAbsolute);
		return true;
	}

	if (!loadTheme(saved.content, saved.cache)) {
		return false;
	}
	Local::writeTheme(saved);
	Background()->setThemeAbsolutePath(saved.pathAbsolute);
	return true;
}

void Unload() {
	GlobalBackground.clear();
	GlobalApplying = Applying();
}

bool Apply(const QString &filepath) {
	if (auto preview = PreviewFromFile(filepath)) {
		return Apply(std::move(preview));
	}
	return false;
}

bool Apply(std::unique_ptr<Preview> preview) {
	GlobalApplying.pathRelative = std::move(preview->pathRelative);
	GlobalApplying.pathAbsolute = std::move(preview->pathAbsolute);
	GlobalApplying.content = std::move(preview->content);
	GlobalApplying.cached = std::move(preview->instance.cached);
	if (GlobalApplying.paletteForRevert.isEmpty()) {
		GlobalApplying.paletteForRevert = style::main_palette::save();
	}
	Background()->setTestingTheme(std::move(preview->instance));
	return true;
}

void ApplyDefaultWithPath(const QString &themePath) {
	if (!themePath.isEmpty()) {
		if (auto preview = PreviewFromFile(themePath)) {
			Apply(std::move(preview));
		}
	} else {
		GlobalApplying.pathRelative = QString();
		GlobalApplying.pathAbsolute = QString();
		GlobalApplying.content = QByteArray();
		GlobalApplying.cached = Cached();
		if (GlobalApplying.paletteForRevert.isEmpty()) {
			GlobalApplying.paletteForRevert = style::main_palette::save();
		}
		Background()->setTestingDefaultTheme();
	}
}

bool ApplyEditedPalette(const QString &path, const QByteArray &content) {
	Instance out;
	if (!loadColorScheme(content, &out)) {
		return false;
	}
	out.cached.colors = out.palette.save();
	out.cached.paletteChecksum = style::palette::Checksum();
	out.cached.contentChecksum = hashCrc32(content.constData(), content.size());

	GlobalApplying.pathRelative = path.isEmpty()
		? QString()
		: QDir().relativeFilePath(path);
	GlobalApplying.pathAbsolute = path.isEmpty()
		? QString()
		: QFileInfo(path).absoluteFilePath();
	GlobalApplying.content = content;
	GlobalApplying.cached = out.cached;
	if (GlobalApplying.paletteForRevert.isEmpty()) {
		GlobalApplying.paletteForRevert = style::main_palette::save();
	}
	Background()->setTestingTheme(std::move(out));
	KeepApplied();
	return true;
}

void KeepApplied() {
	if (!AreTestingTheme()) {
		return;
	} else if (GlobalApplying.overrideKeep) {
		// This callback will be destroyed while running.
		// And it won't be able to safely access captures after that.
		// So we save it on stack for the time while it is running.
		const auto onstack = base::take(GlobalApplying.overrideKeep);
		onstack();
		return;
	}
	const auto path = GlobalApplying.pathAbsolute;
	WriteAppliedTheme();
	ClearApplying();
	Background()->keepApplied(path, true);
}

void Revert() {
	if (!AreTestingTheme()) {
		return;
	}
	style::main_palette::load(GlobalApplying.paletteForRevert);
	Background()->saveAdjustableColors();

	ClearApplying();
	Background()->revert();
}

QString NightThemePath() {
	return str_const_toString(kNightThemeFile);
}

bool IsNonDefaultBackground() {
	return Background()->isNonDefaultBackground();
}

bool IsNightMode() {
	return GlobalBackground ? Background()->nightMode() : false;
}

void SetNightModeValue(bool nightMode) {
	if (GlobalBackground || nightMode) {
		Background()->setNightModeValue(nightMode);
	}
}

void ToggleNightMode() {
	Background()->toggleNightMode(std::nullopt);
}

void ToggleNightMode(const QString &path) {
	Background()->toggleNightMode(path);
}

bool LoadFromFile(const QString &path, Instance *out, QByteArray *outContent) {
	*outContent = readThemeContent(path);
	if (outContent->size() < 4) {
		LOG(("Theme Error: Could not load theme from %1").arg(path));
		return false;
	}

	return loadTheme(*outContent,  out->cached, out);
}

bool IsPaletteTestingPath(const QString &path) {
	if (path.endsWith(qstr(".tdesktop-palette"), Qt::CaseInsensitive)) {
		return QFileInfo(path).exists();
	}
	return false;
}

QColor CountAverageColor(const QImage &image) {
	Expects(image.format() == QImage::Format_ARGB32_Premultiplied);

	uint64 components[3] = { 0 };
	uint64 componentsScroll[3] = { 0 };
	const auto w = image.width();
	const auto h = image.height();
	const auto size = w * h;
	if (const auto pix = image.constBits()) {
		for (auto i = 0, l = size * 4; i != l; i += 4) {
			components[2] += pix[i + 0];
			components[1] += pix[i + 1];
			components[0] += pix[i + 2];
		}
	}
	if (size) {
		for (auto i = 0; i != 3; ++i) {
			components[i] /= size;
		}
	}
	return QColor(components[0], components[1], components[2]);
}

QColor AdjustedColor(QColor original, QColor background) {
	return QColor::fromHslF(
		background.hslHueF(),
		background.hslSaturationF(),
		original.lightnessF(),
		original.alphaF()
	).toRgb();
}

QImage ProcessBackgroundImage(QImage image) {
	constexpr auto kMaxSize = 2960;

	if (image.format() != QImage::Format_ARGB32_Premultiplied) {
		image = std::move(image).convertToFormat(
			QImage::Format_ARGB32_Premultiplied);
	}
	if (image.width() > 40 * image.height()) {
		const auto width = 40 * image.height();
		const auto height = image.height();
		image = image.copy((image.width() - width) / 2, 0, width, height);
	} else if (image.height() > 40 * image.width()) {
		const auto width = image.width();
		const auto height = 40 * image.width();
		image = image.copy(0, (image.height() - height) / 2, width, height);
	}
	if (image.width() > kMaxSize || image.height() > kMaxSize) {
		image = image.scaled(
			kMaxSize,
			kMaxSize,
			Qt::KeepAspectRatio,
			Qt::SmoothTransformation);
	}
	return image;
}

void ComputeBackgroundRects(QRect wholeFill, QSize imageSize, QRect &to, QRect &from) {
	if (uint64(imageSize.width()) * wholeFill.height() > uint64(imageSize.height()) * wholeFill.width()) {
		float64 pxsize = wholeFill.height() / float64(imageSize.height());
		int takewidth = qCeil(wholeFill.width() / pxsize);
		if (takewidth > imageSize.width()) {
			takewidth = imageSize.width();
		} else if ((imageSize.width() % 2) != (takewidth % 2)) {
			++takewidth;
		}
		to = QRect(int((wholeFill.width() - takewidth * pxsize) / 2.), 0, qCeil(takewidth * pxsize), wholeFill.height());
		from = QRect((imageSize.width() - takewidth) / 2, 0, takewidth, imageSize.height());
	} else {
		float64 pxsize = wholeFill.width() / float64(imageSize.width());
		int takeheight = qCeil(wholeFill.height() / pxsize);
		if (takeheight > imageSize.height()) {
			takeheight = imageSize.height();
		} else if ((imageSize.height() % 2) != (takeheight % 2)) {
			++takeheight;
		}
		to = QRect(0, int((wholeFill.height() - takeheight * pxsize) / 2.), wholeFill.width(), qCeil(takeheight * pxsize));
		from = QRect(0, (imageSize.height() - takeheight) / 2, imageSize.width(), takeheight);
	}
}

bool CopyColorsToPalette(const QString &path, const QByteArray &themeContent) {
	auto paletteContent = themeContent;

	zlib::FileToRead file(themeContent);

	unz_global_info globalInfo = { 0 };
	file.getGlobalInfo(&globalInfo);
	if (file.error() == UNZ_OK) {
		paletteContent = file.readFileContent("colors.tdesktop-theme", zlib::kCaseInsensitive, kThemeSchemeSizeLimit);
		if (file.error() == UNZ_END_OF_LIST_OF_FILE) {
			file.clearError();
			paletteContent = file.readFileContent("colors.tdesktop-palette", zlib::kCaseInsensitive, kThemeSchemeSizeLimit);
		}
		if (file.error() != UNZ_OK) {
			LOG(("Theme Error: could not read 'colors.tdesktop-theme' or 'colors.tdesktop-palette' in the theme file, while copying to '%1'.").arg(path));
			return false;
		}
	}

	QFile f(path);
	if (!f.open(QIODevice::WriteOnly)) {
		LOG(("Theme Error: could not open file for write '%1'").arg(path));
		return false;
	}

	if (f.write(paletteContent) != paletteContent.size()) {
		LOG(("Theme Error: could not write palette to '%1'").arg(path));
		return false;
	}
	return true;
}

bool ReadPaletteValues(const QByteArray &content, Fn<bool(QLatin1String name, QLatin1String value)> callback) {
	if (content.size() > kThemeSchemeSizeLimit) {
		LOG(("Theme Error: color scheme file too large (should be less than 1 MB, got %2)").arg(content.size()));
		return false;
	}

	auto data = base::parse::stripComments(content);
	auto from = data.constData(), end = from + data.size();
	while (from != end) {
		auto name = QLatin1String("");
		auto value = QLatin1String("");
		if (!readNameAndValue(from, end, &name, &value)) {
			return false;
		}
		if (name.size() == 0) { // End of content reached.
			return true;
		}
		if (!callback(name, value)) {
			return false;
		}
	}
	return true;
}

} // namespace Theme
} // namespace Window