/*
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 "info/settings/info_settings_widget.h"

#include "info/info_memento.h"
#include "settings/settings_common.h"
#include "settings/settings_main.h"
#include "settings/settings_information.h"
#include "ui/ui_utility.h"

namespace Info {
namespace Settings {

Memento::Memento(not_null<UserData*> self, Type type)
: ContentMemento(Tag{ self })
, _type(type) {
}

Section Memento::section() const {
	return Section(_type);
}

object_ptr<ContentWidget> Memento::createWidget(
		QWidget *parent,
		not_null<Controller*> controller,
		const QRect &geometry) {
	auto result = object_ptr<Widget>(
		parent,
		controller);
	result->setInternalState(geometry, this);
	return result;
}

Memento::~Memento() = default;

Widget::Widget(
	QWidget *parent,
	not_null<Controller*> controller)
: ContentWidget(parent, controller)
, _self(controller->key().settingsSelf())
, _type(controller->section().settingsType())
, _inner([&] {
	auto inner = _type()->create(this, controller->parentController());
	if (inner->hasFlexibleTopBar()) {
		auto filler = setInnerWidget(object_ptr<Ui::RpWidget>(this));
		filler->resize(1, 1);

		_flexibleScroll.contentHeightValue.events(
		) | rpl::start_with_next([=](int h) {
			filler->resize(filler->width(), h);
		}, filler->lifetime());

		filler->widthValue(
		) | rpl::start_to_stream(
			_flexibleScroll.fillerWidthValue,
			lifetime());

		controller->stepDataReference() = SectionCustomTopBarData{
			.backButtonEnables = _flexibleScroll.backButtonEnables.events(),
			.wrapValue = controller->wrapValue(),
		};

		// ScrollArea -> PaddingWrap -> RpWidget.
		inner->setParent(filler->parentWidget()->parentWidget());
		inner->raise();

		using InnerPtr = base::unique_qptr<::Settings::AbstractSection>;
		auto owner = filler->lifetime().make_state<InnerPtr>(
			std::move(inner.release()));
		return owner->get();
	} else {
		return setInnerWidget(std::move(inner));
	}
}())
, _pinnedToTop(_inner->createPinnedToTop(this))
, _pinnedToBottom(_inner->createPinnedToBottom(this)) {
	_inner->sectionShowOther(
	) | rpl::start_with_next([=](Type type) {
		controller->showSettings(type);
	}, _inner->lifetime());

	_inner->sectionShowBack(
	) | rpl::start_with_next([=] {
		controller->showBackFromStack();
	}, _inner->lifetime());

	_inner->setStepDataReference(controller->stepDataReference());

	_removesFromStack.events(
	) | rpl::start_with_next([=](const std::vector<Type> &types) {
		const auto sections = ranges::views::all(
			types
		) | ranges::views::transform([](Type type) {
			return Section(type);
		}) | ranges::to_vector;
		controller->removeFromStack(sections);
	}, _inner->lifetime());

	if (_pinnedToTop) {
		_inner->widthValue(
		) | rpl::start_with_next([=](int w) {
			_pinnedToTop->resizeToWidth(w);
			setScrollTopSkip(_pinnedToTop->height());
		}, _pinnedToTop->lifetime());

		_pinnedToTop->heightValue(
		) | rpl::start_with_next([=](int h) {
			setScrollTopSkip(h);
		}, _pinnedToTop->lifetime());
	}

	if (_pinnedToBottom) {
		const auto processHeight = [=](int bottomHeight, int height) {
			setScrollBottomSkip(bottomHeight);
			_pinnedToBottom->moveToLeft(
				_pinnedToBottom->x(),
				height - bottomHeight);
		};

		_inner->sizeValue(
		) | rpl::start_with_next([=](const QSize &s) {
			_pinnedToBottom->resizeToWidth(s.width());
			processHeight(_pinnedToBottom->height(), height());
		}, _pinnedToBottom->lifetime());

		rpl::combine(
			_pinnedToBottom->heightValue(),
			heightValue()
		) | rpl::start_with_next(processHeight, _pinnedToBottom->lifetime());
	}

	if (_pinnedToTop
		&& _pinnedToTop->minimumHeight()
		&& _inner->hasFlexibleTopBar()) {
		const auto heightDiff = [=] {
			return _pinnedToTop->maximumHeight()
				- _pinnedToTop->minimumHeight();
		};

		_inner->heightValue(
		) | rpl::start_with_next([=](int h) {
			_flexibleScroll.contentHeightValue.fire(h + heightDiff());
		}, _pinnedToTop->lifetime());

		scrollTopValue(
		) | rpl::start_with_next([=](int top) {
			if (!_pinnedToTop) {
				return;
			}
			const auto current = heightDiff() - top;
			_inner->moveToLeft(0, std::min(0, current));
			_pinnedToTop->resize(
				_pinnedToTop->width(),
				std::max(current + _pinnedToTop->minimumHeight(), 0));
		}, _inner->lifetime());

		_flexibleScroll.fillerWidthValue.events(
		) | rpl::start_with_next([=](int w) {
			_inner->resizeToWidth(w);
		}, _inner->lifetime());

		setPaintPadding({ 0, _pinnedToTop->minimumHeight(), 0, 0 });

		setViewport(_pinnedToTop->events(
		) | rpl::filter([](not_null<QEvent*> e) {
			return e->type() == QEvent::Wheel;
		}));
	}
}

Widget::~Widget() = default;

not_null<UserData*> Widget::self() const {
	return _self;
}

bool Widget::showInternal(not_null<ContentMemento*> memento) {
	//if (const auto myMemento = dynamic_cast<Memento*>(memento.get())) {
	//	Assert(myMemento->self() == self());

	//	if (_inner->showInternal(myMemento)) {
	//		return true;
	//	}
	//}
	return false;
}

void Widget::setInternalState(
		const QRect &geometry,
		not_null<Memento*> memento) {
	setGeometry(geometry);
	Ui::SendPendingMoveResizeEvents(this);
	restoreState(memento);
}

void Widget::saveChanges(FnMut<void()> done) {
	_inner->sectionSaveChanges(std::move(done));
}

void Widget::showFinished() {
	_inner->showFinished();

	_inner->removeFromStack(
	) | rpl::start_to_stream(_removesFromStack, lifetime());
}

void Widget::setInnerFocus() {
	_inner->setInnerFocus();
}

rpl::producer<bool> Widget::desiredShadowVisibility() const {
	return (_type == ::Settings::Main::Id()
		|| _type == ::Settings::Information::Id())
		? ContentWidget::desiredShadowVisibility()
		: rpl::single(true);
}

rpl::producer<QString> Widget::title() {
	return _inner->title();
}

std::shared_ptr<ContentMemento> Widget::doCreateMemento() {
	auto result = std::make_shared<Memento>(self(), _type);
	saveState(result.get());
	return result;
}

void Widget::enableBackButton() {
	_flexibleScroll.backButtonEnables.fire({});
}

void Widget::saveState(not_null<Memento*> memento) {
	memento->setScrollTop(scrollTopSave());
}

void Widget::restoreState(not_null<Memento*> memento) {
	scrollTopRestore(memento->scrollTop());
}

} // namespace Settings
} // namespace Info