kotatogram-desktop/Telegram/SourceFiles/inline_bots/inline_results_inner.cpp

/*
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 "inline_bots/inline_results_inner.h"

#include "api/api_common.h"
#include "chat_helpers/gifs_list_widget.h" // ChatHelpers::AddGifAction
#include "chat_helpers/send_context_menu.h" // SendMenu::FillSendMenu
#include "data/data_file_origin.h"
#include "data/data_user.h"
#include "data/data_changes.h"
#include "inline_bots/inline_bot_result.h"
#include "inline_bots/inline_bot_layout_item.h"
#include "lang/lang_keys.h"
#include "mainwindow.h"
#include "facades.h"
#include "main/main_session.h"
#include "window/window_session_controller.h"
#include "ui/widgets/popup_menu.h"
#include "ui/widgets/buttons.h"
#include "ui/widgets/labels.h"
#include "history/view/history_view_cursor_state.h"
#include "styles/style_chat_helpers.h"

#include <QtWidgets/QApplication>

namespace InlineBots {
namespace Layout {

Inner::Inner(
	QWidget *parent,
	not_null<Window::SessionController*> controller)
: RpWidget(parent)
, _controller(controller)
, _updateInlineItems([=] { updateInlineItems(); })
, _previewTimer([=] { showPreview(); }) {
	resize(st::emojiPanWidth - st::emojiScroll.width - st::roundRadiusSmall, st::inlineResultsMinHeight);

	setMouseTracking(true);
	setAttribute(Qt::WA_OpaquePaintEvent);

	_controller->session().downloaderTaskFinished(
	) | rpl::start_with_next([=] {
		update();
	}, lifetime());

	subscribe(controller->gifPauseLevelChanged(), [this] {
		if (!_controller->isGifPausedAtLeastFor(Window::GifPauseReason::InlineResults)) {
			update();
		}
	});

	_controller->session().changes().peerUpdates(
		Data::PeerUpdate::Flag::Rights
	) | rpl::filter([=](const Data::PeerUpdate &update) {
		return (update.peer.get() == _inlineQueryPeer);
	}) | rpl::start_with_next([=] {
		auto isRestricted = (_restrictedLabel != nullptr);
		if (isRestricted != isRestrictedView()) {
			auto h = countHeight();
			if (h != height()) resize(width(), h);
		}
	}, lifetime());
}

void Inner::visibleTopBottomUpdated(
		int visibleTop,
		int visibleBottom) {
	_visibleBottom = visibleBottom;
	if (_visibleTop != visibleTop) {
		_visibleTop = visibleTop;
		_lastScrolled = crl::now();
	}
}

void Inner::checkRestrictedPeer() {
	if (_inlineQueryPeer) {
		const auto error = Data::RestrictionError(
			_inlineQueryPeer,
			ChatRestriction::f_send_inline);
		if (error) {
			if (!_restrictedLabel) {
				_restrictedLabel.create(this, *error, st::stickersRestrictedLabel);
				_restrictedLabel->show();
				_restrictedLabel->move(st::inlineResultsLeft - st::roundRadiusSmall, st::stickerPanPadding);
				_restrictedLabel->resizeToNaturalWidth(width() - (st::inlineResultsLeft - st::roundRadiusSmall) * 2);
				if (_switchPmButton) {
					_switchPmButton->hide();
				}
				update();
			}
			return;
		}
	}
	if (_restrictedLabel) {
		_restrictedLabel.destroy();
		if (_switchPmButton) {
			_switchPmButton->show();
		}
		update();
	}
}

bool Inner::isRestrictedView() {
	checkRestrictedPeer();
	return (_restrictedLabel != nullptr);
}

int Inner::countHeight() {
	if (isRestrictedView()) {
		return st::stickerPanPadding + _restrictedLabel->height() + st::stickerPanPadding;
	} else if (_rows.isEmpty() && !_switchPmButton) {
		return st::stickerPanPadding + st::normalFont->height + st::stickerPanPadding;
	}
	auto result = st::stickerPanPadding;
	if (_switchPmButton) {
		result += _switchPmButton->height() + st::inlineResultsSkip;
	}
	for (int i = 0, l = _rows.count(); i < l; ++i) {
		result += _rows[i].height;
	}
	return result + st::stickerPanPadding;
}

QString Inner::tooltipText() const {
	if (const auto lnk = ClickHandler::getActive()) {
		return lnk->tooltip();
	}
	return QString();
}

QPoint Inner::tooltipPos() const {
	return _lastMousePos;
}

bool Inner::tooltipWindowActive() const {
	return Ui::AppInFocus() && Ui::InFocusChain(window());
}

rpl::producer<> Inner::inlineRowsCleared() const {
	return _inlineRowsCleared.events();
}

Inner::~Inner() = default;

void Inner::paintEvent(QPaintEvent *e) {
	Painter p(this);
	QRect r = e ? e->rect() : rect();
	if (r != rect()) {
		p.setClipRect(r);
	}
	p.fillRect(r, st::emojiPanBg);

	paintInlineItems(p, r);
}

void Inner::paintInlineItems(Painter &p, const QRect &r) {
	if (_restrictedLabel) {
		return;
	}
	if (_rows.isEmpty() && !_switchPmButton) {
		p.setFont(st::normalFont);
		p.setPen(st::noContactsColor);
		p.drawText(QRect(0, 0, width(), (height() / 3) * 2 + st::normalFont->height), tr::lng_inline_bot_no_results(tr::now), style::al_center);
		return;
	}
	auto gifPaused = _controller->isGifPausedAtLeastFor(Window::GifPauseReason::InlineResults);
	InlineBots::Layout::PaintContext context(crl::now(), false, gifPaused, false);

	auto top = st::stickerPanPadding;
	if (_switchPmButton) {
		top += _switchPmButton->height() + st::inlineResultsSkip;
	}

	auto fromx = rtl() ? (width() - r.x() - r.width()) : r.x();
	auto tox = rtl() ? (width() - r.x()) : (r.x() + r.width());
	for (auto row = 0, rows = _rows.size(); row != rows; ++row) {
		auto &inlineRow = _rows[row];
		if (top >= r.top() + r.height()) break;
		if (top + inlineRow.height > r.top()) {
			auto left = st::inlineResultsLeft - st::roundRadiusSmall;
			if (row == rows - 1) context.lastRow = true;
			for (int col = 0, cols = inlineRow.items.size(); col < cols; ++col) {
				if (left >= tox) break;

				auto item = inlineRow.items.at(col);
				auto w = item->width();
				if (left + w > fromx) {
					p.translate(left, top);
					item->paint(p, r.translated(-left, -top), &context);
					p.translate(-left, -top);
				}
				left += w;
				if (item->hasRightSkip()) {
					left += st::inlineResultsSkip;
				}
			}
		}
		top += inlineRow.height;
	}
}

void Inner::mousePressEvent(QMouseEvent *e) {
	if (e->button() != Qt::LeftButton) {
		return;
	}
	_lastMousePos = e->globalPos();
	updateSelected();

	_pressed = _selected;
	ClickHandler::pressed();
	_previewTimer.callOnce(QApplication::startDragTime());
}

void Inner::mouseReleaseEvent(QMouseEvent *e) {
	_previewTimer.cancel();

	auto pressed = std::exchange(_pressed, -1);
	auto activated = ClickHandler::unpressed();

	if (_previewShown) {
		_previewShown = false;
		return;
	}

	_lastMousePos = e->globalPos();
	updateSelected();

	if (_selected < 0 || _selected != pressed || !activated) {
		return;
	}

	if (dynamic_cast<InlineBots::Layout::SendClickHandler*>(activated.get())) {
		int row = _selected / MatrixRowShift, column = _selected % MatrixRowShift;
		selectInlineResult(row, column);
	} else {
		ActivateClickHandler(window(), activated, e->button());
	}
}

void Inner::selectInlineResult(int row, int column) {
	selectInlineResult(row, column, Api::SendOptions());
}

void Inner::selectInlineResult(
		int row,
		int column,
		Api::SendOptions options) {
	if (row >= _rows.size() || column >= _rows.at(row).items.size()) {
		return;
	}

	auto item = _rows[row].items[column];
	if (const auto inlineResult = item->getResult()) {
		if (inlineResult->onChoose(item)) {
			_resultSelectedCallback({
				.result = inlineResult,
				.bot = _inlineBot,
				.options = std::move(options)
			});
		}
	}
}

void Inner::mouseMoveEvent(QMouseEvent *e) {
	_lastMousePos = e->globalPos();
	updateSelected();
}

void Inner::leaveEventHook(QEvent *e) {
	clearSelection();
	Ui::Tooltip::Hide();
}

void Inner::leaveToChildEvent(QEvent *e, QWidget *child) {
	clearSelection();
}

void Inner::enterFromChildEvent(QEvent *e, QWidget *child) {
	_lastMousePos = QCursor::pos();
	updateSelected();
}

void Inner::contextMenuEvent(QContextMenuEvent *e) {
	if (_selected < 0 || _pressed >= 0) {
		return;
	}
	const auto row = _selected / MatrixRowShift;
	const auto column = _selected % MatrixRowShift;
	const auto type = _sendMenuType
		? _sendMenuType()
		: SendMenu::Type::Disabled;

	_menu = base::make_unique_q<Ui::PopupMenu>(this);

	const auto send = [=](Api::SendOptions options) {
		selectInlineResult(row, column, options);
	};
	SendMenu::FillSendMenu(
		_menu,
		type,
		SendMenu::DefaultSilentCallback(send),
		SendMenu::DefaultScheduleCallback(this, type, send));

	auto item = _rows[row].items[column];
	if (const auto previewDocument = item->getPreviewDocument()) {
		auto callback = [&](const QString &text, Fn<void()> &&done) {
			_menu->addAction(text, std::move(done));
		};
		ChatHelpers::AddGifAction(std::move(callback), previewDocument);
	}

	if (!_menu->empty()) {
		_menu->popup(QCursor::pos());
	}
}

void Inner::clearSelection() {
	if (_selected >= 0) {
		int srow = _selected / MatrixRowShift, scol = _selected % MatrixRowShift;
		Assert(srow >= 0 && srow < _rows.size() && scol >= 0 && scol < _rows.at(srow).items.size());
		ClickHandler::clearActive(_rows.at(srow).items.at(scol));
		setCursor(style::cur_default);
	}
	_selected = _pressed = -1;
	update();
}

void Inner::hideFinished() {
	clearHeavyData();
}

void Inner::clearHeavyData() {
	clearInlineRows(false);
	for (const auto &[result, layout] : _inlineLayouts) {
		layout->unloadHeavyPart();
	}
}

bool Inner::inlineRowsAddItem(Result *result, Row &row, int32 &sumWidth) {
	auto layout = layoutPrepareInlineResult(result, (_rows.size() * MatrixRowShift) + row.items.size());
	if (!layout) return false;

	layout->preload();
	if (inlineRowFinalize(row, sumWidth, layout->isFullLine())) {
		layout->setPosition(_rows.size() * MatrixRowShift);
	}

	sumWidth += layout->maxWidth();
	if (!row.items.isEmpty() && row.items.back()->hasRightSkip()) {
		sumWidth += st::inlineResultsSkip;
	}

	row.items.push_back(layout);
	return true;
}

bool Inner::inlineRowFinalize(Row &row, int32 &sumWidth, bool force) {
	if (row.items.isEmpty()) return false;

	auto full = (row.items.size() >= kInlineItemsMaxPerRow);
	auto big = (sumWidth >= st::emojiPanWidth - st::emojiScroll.width - st::inlineResultsLeft);
	if (full || big || force) {
		_rows.push_back(layoutInlineRow(row, (full || big) ? sumWidth : 0));
		row = Row();
		row.items.reserve(kInlineItemsMaxPerRow);
		sumWidth = 0;
		return true;
	}
	return false;
}

void Inner::inlineBotChanged() {
	refreshInlineRows(nullptr, nullptr, nullptr, true);
}

void Inner::clearInlineRows(bool resultsDeleted) {
	if (resultsDeleted) {
		_selected = _pressed = -1;
	} else {
		clearSelection();
		for_const (auto &row, _rows) {
			for_const (auto &item, row.items) {
				item->setPosition(-1);
			}
		}
	}
	_rows.clear();
}

ItemBase *Inner::layoutPrepareInlineResult(Result *result, int32 position) {
	auto it = _inlineLayouts.find(result);
	if (it == _inlineLayouts.cend()) {
		if (auto layout = ItemBase::createLayout(this, result, _inlineWithThumb)) {
			it = _inlineLayouts.emplace(result, std::move(layout)).first;
			it->second->initDimensions();
		} else {
			return nullptr;
		}
	}
	if (!it->second->maxWidth()) {
		return nullptr;
	}

	it->second->setPosition(position);
	return it->second.get();
}

void Inner::deleteUnusedInlineLayouts() {
	if (_rows.isEmpty()) { // delete all
		_inlineLayouts.clear();
	} else {
		for (auto i = _inlineLayouts.begin(); i != _inlineLayouts.cend();) {
			if (i->second->position() < 0) {
				i = _inlineLayouts.erase(i);
			} else {
				++i;
			}
		}
	}
}

Inner::Row &Inner::layoutInlineRow(Row &row, int32 sumWidth) {
	auto count = int(row.items.size());
	Assert(count <= kInlineItemsMaxPerRow);

	// enumerate items in the order of growing maxWidth()
	// for that sort item indices by maxWidth()
	int indices[kInlineItemsMaxPerRow];
	for (auto i = 0; i != count; ++i) {
		indices[i] = i;
	}
	std::sort(indices, indices + count, [&row](int a, int b) -> bool {
		return row.items.at(a)->maxWidth() < row.items.at(b)->maxWidth();
	});

	row.height = 0;
	int availw = width() - (st::inlineResultsLeft - st::roundRadiusSmall);
	for (int i = 0; i < count; ++i) {
		int index = indices[i];
		int w = sumWidth ? (row.items.at(index)->maxWidth() * availw / sumWidth) : row.items.at(index)->maxWidth();
		int actualw = qMax(w, int(st::inlineResultsMinWidth));
		row.height = qMax(row.height, row.items.at(index)->resizeGetHeight(actualw));
		if (sumWidth) {
			availw -= actualw;
			sumWidth -= row.items.at(index)->maxWidth();
			if (index > 0 && row.items.at(index - 1)->hasRightSkip()) {
				availw -= st::inlineResultsSkip;
				sumWidth -= st::inlineResultsSkip;
			}
		}
	}
	return row;
}

void Inner::preloadImages() {
	for (auto row = 0, rows = _rows.size(); row != rows; ++row) {
		for (auto col = 0, cols = _rows[row].items.size(); col != cols; ++col) {
			_rows[row].items[col]->preload();
		}
	}
}

void Inner::hideInlineRowsPanel() {
	clearInlineRows(false);
}

void Inner::clearInlineRowsPanel() {
	clearInlineRows(false);
}

void Inner::refreshSwitchPmButton(const CacheEntry *entry) {
	if (!entry || entry->switchPmText.isEmpty()) {
		_switchPmButton.destroy();
		_switchPmStartToken.clear();
	} else {
		if (!_switchPmButton) {
			_switchPmButton.create(this, nullptr, st::switchPmButton);
			_switchPmButton->show();
			_switchPmButton->setTextTransform(Ui::RoundButton::TextTransform::NoTransform);
			_switchPmButton->addClickHandler([=] { switchPm(); });
		}
		_switchPmButton->setText(rpl::single(entry->switchPmText));
		_switchPmStartToken = entry->switchPmStartToken;
		const auto buttonTop = st::stickerPanPadding;
		_switchPmButton->move(st::inlineResultsLeft - st::roundRadiusSmall, buttonTop);
		if (isRestrictedView()) {
			_switchPmButton->hide();
		}
	}
	update();
}

int Inner::refreshInlineRows(PeerData *queryPeer, UserData *bot, const CacheEntry *entry, bool resultsDeleted) {
	_inlineBot = bot;
	_inlineQueryPeer = queryPeer;
	refreshSwitchPmButton(entry);
	auto clearResults = [&] {
		if (!entry) {
			return true;
		}
		if (entry->results.empty() && entry->switchPmText.isEmpty()) {
			return true;
		}
		return false;
	};
	auto clearResultsResult = clearResults(); // Clang workaround.
	if (clearResultsResult) {
		if (resultsDeleted) {
			clearInlineRows(true);
			deleteUnusedInlineLayouts();
		}
		_inlineRowsCleared.fire({});
		return 0;
	}

	clearSelection();

	Assert(_inlineBot != 0);

	auto count = int(entry->results.size());
	auto from = validateExistingInlineRows(entry->results);
	auto added = 0;

	if (count) {
		_rows.reserve(count);
		auto row = Row();
		row.items.reserve(kInlineItemsMaxPerRow);
		auto sumWidth = 0;
		for (auto i = from; i != count; ++i) {
			if (inlineRowsAddItem(entry->results[i].get(), row, sumWidth)) {
				++added;
			}
		}
		inlineRowFinalize(row, sumWidth, true);
	}

	auto h = countHeight();
	if (h != height()) resize(width(), h);
	update();

	_lastMousePos = QCursor::pos();
	updateSelected();

	return added;
}

int Inner::validateExistingInlineRows(const Results &results) {
	int count = results.size(), until = 0, untilrow = 0, untilcol = 0;
	for (; until < count;) {
		if (untilrow >= _rows.size() || _rows[untilrow].items[untilcol]->getResult() != results[until].get()) {
			break;
		}
		++until;
		if (++untilcol == _rows[untilrow].items.size()) {
			++untilrow;
			untilcol = 0;
		}
	}
	if (until == count) { // all items are layed out
		if (untilrow == _rows.size()) { // nothing changed
			return until;
		}

		for (int i = untilrow, l = _rows.size(), skip = untilcol; i < l; ++i) {
			for (int j = 0, s = _rows[i].items.size(); j < s; ++j) {
				if (skip) {
					--skip;
				} else {
					_rows[i].items[j]->setPosition(-1);
				}
			}
		}
		if (!untilcol) { // all good rows are filled
			_rows.resize(untilrow);
			return until;
		}
		_rows.resize(untilrow + 1);
		_rows[untilrow].items.resize(untilcol);
		_rows[untilrow] = layoutInlineRow(_rows[untilrow]);
		return until;
	}
	if (untilrow && !untilcol) { // remove last row, maybe it is not full
		--untilrow;
		untilcol = _rows[untilrow].items.size();
	}
	until -= untilcol;

	for (int i = untilrow, l = _rows.size(); i < l; ++i) {
		for (int j = 0, s = _rows[i].items.size(); j < s; ++j) {
			_rows[i].items[j]->setPosition(-1);
		}
	}
	_rows.resize(untilrow);

	if (_rows.isEmpty()) {
		_inlineWithThumb = false;
		for (int i = until; i < count; ++i) {
			if (results.at(i)->hasThumbDisplay()) {
				_inlineWithThumb = true;
				break;
			}
		}
	}
	return until;
}

void Inner::inlineItemLayoutChanged(const ItemBase *layout) {
	if (_selected < 0 || !isVisible()) {
		return;
	}

	int row = _selected / MatrixRowShift, col = _selected % MatrixRowShift;
	if (row < _rows.size() && col < _rows.at(row).items.size()) {
		if (layout == _rows.at(row).items.at(col)) {
			updateSelected();
		}
	}
}

void Inner::inlineItemRepaint(const ItemBase *layout) {
	auto ms = crl::now();
	if (_lastScrolled + 100 <= ms) {
		update();
	} else {
		_updateInlineItems.callOnce(_lastScrolled + 100 - ms);
	}
}

bool Inner::inlineItemVisible(const ItemBase *layout) {
	int32 position = layout->position();
	if (position < 0 || !isVisible()) {
		return false;
	}

	int row = position / MatrixRowShift, col = position % MatrixRowShift;
	Assert((row < _rows.size()) && (col < _rows[row].items.size()));

	auto &inlineItems = _rows[row].items;
	int top = st::stickerPanPadding;
	for (int32 i = 0; i < row; ++i) {
		top += _rows.at(i).height;
	}

	return (top < _visibleBottom) && (top + _rows[row].items[col]->height() > _visibleTop);
}

Data::FileOrigin Inner::inlineItemFileOrigin() {
	return Data::FileOrigin();
}

void Inner::updateSelected() {
	if (_pressed >= 0 && !_previewShown) {
		return;
	}

	auto newSelected = -1;
	auto p = mapFromGlobal(_lastMousePos);

	int sx = (rtl() ? width() - p.x() : p.x()) - (st::inlineResultsLeft - st::roundRadiusSmall);
	int sy = p.y() - st::stickerPanPadding;
	if (_switchPmButton) {
		sy -= _switchPmButton->height() + st::inlineResultsSkip;
	}
	int row = -1, col = -1, sel = -1;
	ClickHandlerPtr lnk;
	ClickHandlerHost *lnkhost = nullptr;
	HistoryView::CursorState cursor = HistoryView::CursorState::None;
	if (sy >= 0) {
		row = 0;
		for (int rows = _rows.size(); row < rows; ++row) {
			if (sy < _rows[row].height) {
				break;
			}
			sy -= _rows[row].height;
		}
	}
	if (sx >= 0 && row >= 0 && row < _rows.size()) {
		auto &inlineItems = _rows[row].items;
		col = 0;
		for (int cols = inlineItems.size(); col < cols; ++col) {
			int width = inlineItems.at(col)->width();
			if (sx < width) {
				break;
			}
			sx -= width;
			if (inlineItems.at(col)->hasRightSkip()) {
				sx -= st::inlineResultsSkip;
			}
		}
		if (col < inlineItems.size()) {
			sel = row * MatrixRowShift + col;
			auto result = inlineItems[col]->getState(
				QPoint(sx, sy),
				HistoryView::StateRequest());
			lnk = result.link;
			cursor = result.cursor;
			lnkhost = inlineItems[col];
		} else {
			row = col = -1;
		}
	} else {
		row = col = -1;
	}
	int srow = (_selected >= 0) ? (_selected / MatrixRowShift) : -1;
	int scol = (_selected >= 0) ? (_selected % MatrixRowShift) : -1;
	if (_selected != sel) {
		if (srow >= 0 && scol >= 0) {
			Assert(srow >= 0 && srow < _rows.size() && scol >= 0 && scol < _rows.at(srow).items.size());
			_rows[srow].items[scol]->update();
		}
		_selected = sel;
		if (row >= 0 && col >= 0) {
			Assert(row >= 0 && row < _rows.size() && col >= 0 && col < _rows.at(row).items.size());
			_rows[row].items[col]->update();
		}
		if (_previewShown && _selected >= 0 && _pressed != _selected) {
			_pressed = _selected;
			if (row >= 0 && col >= 0) {
				auto layout = _rows.at(row).items.at(col);
				if (const auto previewDocument = layout->getPreviewDocument()) {
					_controller->widget()->showMediaPreview(
						Data::FileOrigin(),
						previewDocument);
				} else if (auto previewPhoto = layout->getPreviewPhoto()) {
					_controller->widget()->showMediaPreview(
						Data::FileOrigin(),
						previewPhoto);
				}
			}
		}
	}
	if (ClickHandler::setActive(lnk, lnkhost)) {
		setCursor(lnk ? style::cur_pointer : style::cur_default);
		Ui::Tooltip::Hide();
	}
	if (lnk) {
		Ui::Tooltip::Show(1000, this);
	}
}

void Inner::showPreview() {
	if (_pressed < 0) return;

	int row = _pressed / MatrixRowShift, col = _pressed % MatrixRowShift;
	if (row < _rows.size() && col < _rows.at(row).items.size()) {
		auto layout = _rows.at(row).items.at(col);
		if (const auto previewDocument = layout->getPreviewDocument()) {
			_previewShown = _controller->widget()->showMediaPreview(
				Data::FileOrigin(),
				previewDocument);
		} else if (const auto previewPhoto = layout->getPreviewPhoto()) {
			_previewShown = _controller->widget()->showMediaPreview(
				Data::FileOrigin(),
				previewPhoto);
		}
	}
}

void Inner::updateInlineItems() {
	auto ms = crl::now();
	if (_lastScrolled + 100 <= ms) {
		update();
	} else {
		_updateInlineItems.callOnce(_lastScrolled + 100 - ms);
	}
}

void Inner::switchPm() {
	if (_inlineBot && _inlineBot->isBot()) {
		_inlineBot->botInfo->startToken = _switchPmStartToken;
		_inlineBot->botInfo->inlineReturnTo = _currentDialogsEntryState;
		Ui::showPeerHistory(_inlineBot, ShowAndStartBotMsgId);
	}
}

void Inner::setSendMenuType(Fn<SendMenu::Type()> &&callback) {
	_sendMenuType = std::move(callback);
}

} // namespace Layout
} // namespace InlineBots