/*
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 "ui/effects/premium_graphics.h"

#include "lang/lang_keys.h"
#include "ui/effects/animations.h"
#include "ui/effects/gradient.h"
#include "ui/effects/numbers_animation.h"
#include "ui/wrap/padding_wrap.h"
#include "ui/wrap/vertical_layout.h"
#include "styles/style_boxes.h"
#include "styles/style_layers.h"
#include "styles/style_widgets.h"

namespace Ui {
namespace Premium {
namespace {

using TextFactory = Fn<QString(int)>;

constexpr auto kDeflectionSmall = 20.;
constexpr auto kDeflection = 30.;

constexpr auto kStepBeforeDeflection = 0.75;
constexpr auto kStepAfterDeflection = kStepBeforeDeflection
	+ (1. - kStepBeforeDeflection) / 2.;

[[nodiscard]] TextFactory ProcessTextFactory(
		std::optional<tr::phrase<lngtag_count>> phrase) {
	return phrase
		? TextFactory([=](int n) { return (*phrase)(tr::now, lt_count, n); })
		: TextFactory([=](int n) { return QString::number(n); });
}

[[nodiscard]] QLinearGradient ComputeGradient(
		not_null<QWidget*> content,
		int left,
		int width) {

	// Take a full width of parent box without paddings.
	const auto fullGradientWidth = content->parentWidget()->width();
	auto fullGradient = QLinearGradient(0, 0, fullGradientWidth, 0);
	fullGradient.setStops(ButtonGradientStops());

	auto gradient = QLinearGradient(0, 0, width, 0);
	const auto fullFinal = float64(fullGradient.finalStop().x());
	left += ((fullGradientWidth - content->width()) / 2);
	gradient.setColorAt(
		.0,
		anim::gradient_color_at(fullGradient, left / fullFinal));
	gradient.setColorAt(
		1.,
		anim::gradient_color_at(fullGradient, (left + width) / fullFinal));

	return gradient;
}

class Bubble final {
public:
	using EdgeProgress = float64;

	Bubble(
		Fn<void()> updateCallback,
		TextFactory textFactory,
		const style::icon *icon);

	[[nodiscard]] int counter() const;
	[[nodiscard]] int height() const;
	[[nodiscard]] int width() const;
	[[nodiscard]] int bubbleRadius() const;
	[[nodiscard]] int countMaxWidth(int maxCounter) const;

	void setCounter(int value);
	void setTailEdge(EdgeProgress edge);
	void paintBubble(Painter &p, const QRect &r, const QBrush &brush);

	[[nodiscard]] rpl::producer<> widthChanges() const;
	[[nodiscard]] rpl::producer<> updateRequests() const;

private:
	[[nodiscard]] int filledWidth() const;

	const Fn<void()> _updateCallback;
	const TextFactory _textFactory;

	const style::font &_font;
	const style::margins &_padding;
	const style::icon *_icon;
	NumbersAnimation _numberAnimation;
	const QSize _tailSize;
	const int _height;
	const int _textTop;

	int _counter = -1;
	EdgeProgress _tailEdge = 0.;

	rpl::event_stream<> _widthChanges;

};

Bubble::Bubble(
	Fn<void()> updateCallback,
	TextFactory textFactory,
	const style::icon *icon)
: _updateCallback(std::move(updateCallback))
, _textFactory(std::move(textFactory))
, _font(st::premiumBubbleFont)
, _padding(st::premiumBubblePadding)
, _icon(icon)
, _numberAnimation(_font, _updateCallback)
, _tailSize(st::premiumBubbleTailSize)
, _height(st::premiumBubbleHeight + _tailSize.height())
, _textTop((_height - _tailSize.height() - _font->height) / 2) {
	_numberAnimation.setDisabledMonospace(true);
	_numberAnimation.setWidthChangedCallback([=] {
		_widthChanges.fire({});
	});
	_numberAnimation.setText(_textFactory(0), 0);
	_numberAnimation.finishAnimating();
}

int Bubble::counter() const {
	return _counter;
}

int Bubble::height() const {
	return _height;
}

int Bubble::bubbleRadius() const {
	return (_height - _tailSize.height()) / 2;
}

int Bubble::filledWidth() const {
	return _padding.left()
		+ _icon->width()
		+ st::premiumBubbleTextSkip
		+ _padding.right();
}

int Bubble::width() const {
	return filledWidth() + _numberAnimation.countWidth();
}

int Bubble::countMaxWidth(int maxCounter) const {
	auto numbers = Ui::NumbersAnimation(_font, [] {});
	numbers.setDisabledMonospace(true);
	numbers.setDuration(0);
	numbers.setText(_textFactory(0), 0);
	numbers.setText(_textFactory(maxCounter), maxCounter);
	numbers.finishAnimating();
	return filledWidth() + numbers.maxWidth();
}

void Bubble::setCounter(int value) {
	if (_counter != value) {
		_counter = value;
		_numberAnimation.setText(_textFactory(_counter), _counter);
	}
}

void Bubble::setTailEdge(EdgeProgress edge) {
	_tailEdge = std::clamp(edge, 0., 1.);
}

void Bubble::paintBubble(Painter &p, const QRect &r, const QBrush &brush) {
	if (_counter < 0) {
		return;
	}

	const auto penWidth = st::premiumBubblePenWidth;
	const auto penWidthHalf = penWidth / 2;
	const auto bubbleRect = r - style::margins(
		penWidthHalf,
		penWidthHalf,
		penWidthHalf,
		_tailSize.height() + penWidthHalf);
	{
		const auto radius = bubbleRadius();
		auto pathTail = QPainterPath();

		const auto tailWHalf = _tailSize.width() / 2.;
		const auto progress = _tailEdge;

		const auto tailTop = bubbleRect.y() + bubbleRect.height();
		const auto tailLeftFull = bubbleRect.x()
			+ (bubbleRect.width() * 0.5)
			- tailWHalf;
		const auto tailLeft = bubbleRect.x()
			+ (bubbleRect.width() * 0.5 * (progress + 1.))
			- tailWHalf;
		const auto tailCenter = tailLeft + tailWHalf;
		const auto tailRight = [&] {
			const auto max = bubbleRect.x() + bubbleRect.width();
			const auto right = tailLeft + _tailSize.width();
			const auto bottomMax = max - radius;
			return (right > bottomMax)
				? std::max(float64(tailCenter), float64(bottomMax))
				: right;
		}();
		pathTail.moveTo(tailLeftFull, tailTop);
		pathTail.lineTo(tailLeft, tailTop);
		pathTail.lineTo(tailCenter, tailTop + _tailSize.height());
		pathTail.lineTo(tailRight, tailTop);
		pathTail.lineTo(tailRight, tailTop - radius);
		pathTail.moveTo(tailLeftFull, tailTop);

		auto pathBubble = QPainterPath();
		pathBubble.setFillRule(Qt::WindingFill);
		pathBubble.addRoundedRect(bubbleRect, radius, radius);

		PainterHighQualityEnabler hq(p);
		p.setPen(QPen(
			brush,
			penWidth,
			Qt::SolidLine,
			Qt::RoundCap,
			Qt::RoundJoin));
		p.setBrush(brush);
		p.drawPath(pathTail + pathBubble);
	}
	p.setPen(st::activeButtonFg);
	p.setFont(_font);
	const auto iconLeft = r.x() + _padding.left();
	_icon->paint(
		p,
		iconLeft,
		bubbleRect.y() + (bubbleRect.height() - _icon->height()) / 2,
		bubbleRect.width());
	_numberAnimation.paint(
		p,
		iconLeft + _icon->width() + st::premiumBubbleTextSkip,
		r.y() + _textTop,
		width() / 2);
}

rpl::producer<> Bubble::widthChanges() const {
	return _widthChanges.events();
}

class BubbleWidget final : public Ui::RpWidget {
public:
	BubbleWidget(
		not_null<Ui::RpWidget*> parent,
		TextFactory textFactory,
		int current,
		int maxCounter,
		rpl::producer<> showFinishes,
		const style::icon *icon);

	[[nodiscard]] bool animating() const;

protected:
	void paintEvent(QPaintEvent *e) override;

private:
	const int _currentCounter;
	const int _maxCounter;
	Bubble _bubble;
	const int _maxBubbleWidth;

	Ui::Animations::Simple _appearanceAnimation;
	QSize _spaceForDeflection;

	QLinearGradient _cachedGradient;

	float64 _deflection;

	bool _ignoreDeflection = false;
	float64 _stepBeforeDeflection;
	float64 _stepAfterDeflection;

};

BubbleWidget::BubbleWidget(
	not_null<Ui::RpWidget*> parent,
	TextFactory textFactory,
	int current,
	int maxCounter,
	rpl::producer<> showFinishes,
	const style::icon *icon)
: RpWidget(parent)
, _currentCounter(current)
, _maxCounter(maxCounter)
, _bubble([=] { update(); }, std::move(textFactory), icon)
, _maxBubbleWidth(_bubble.countMaxWidth(_maxCounter))
, _deflection(kDeflection)
, _stepBeforeDeflection(kStepBeforeDeflection)
, _stepAfterDeflection(kStepAfterDeflection) {
	const auto resizeTo = [=](int w, int h) {
		_deflection = (w > st::premiumBubbleWidthLimit)
			? kDeflectionSmall
			: kDeflection;
		_spaceForDeflection = QSize(
			st::premiumBubbleSkip,
			st::premiumBubbleSkip);
		resize(QSize(w, h) + _spaceForDeflection);
	};

	resizeTo(_bubble.width(), _bubble.height());
	_bubble.widthChanges(
	) | rpl::start_with_next([=] {
		resizeTo(_bubble.width(), _bubble.height());
	}, lifetime());

	const auto moveEndPoint = _currentCounter / float64(_maxCounter);
	const auto computeLeft = [=](float64 pointRatio, float64 animProgress) {
		const auto &padding = st::boxRowPadding;
		const auto halfWidth = (_maxBubbleWidth / 2);
		const auto left = padding.left();
		const auto right = padding.right();
		return ((parent->width() - left - right)
				* pointRatio
				* animProgress)
			- halfWidth
			+ left;
	};

	std::move(
		showFinishes
	) | rpl::take(1) | rpl::start_with_next([=] {
		const auto computeEdge = [=] {
			return parent->width()
				- st::boxRowPadding.right()
				- _maxBubbleWidth;
		};
		const auto checkBubbleEdges = [&]() -> Bubble::EdgeProgress {
			const auto finish = computeLeft(moveEndPoint, 1.);
			const auto edge = computeEdge();
			return (finish >= edge)
				? (finish - edge) / (_maxBubbleWidth / 2.)
				: 0.;
		};
		const auto bubbleEdge = checkBubbleEdges();
		_ignoreDeflection = bubbleEdge;
		if (_ignoreDeflection) {
			_stepBeforeDeflection = 1.;
			_stepAfterDeflection = 1.;
		}

		_appearanceAnimation.start([=](float64 value) {
			const auto moveProgress = std::clamp(
				(value / _stepBeforeDeflection),
				0.,
				1.);
			const auto counterProgress = std::clamp(
				(value / _stepAfterDeflection),
				0.,
				1.);
			moveToLeft(
				computeLeft(moveEndPoint, moveProgress)
					- (_maxBubbleWidth / 2.) * bubbleEdge,
				0);

			const auto counter = int(0 + counterProgress * _currentCounter);
			// if (!(counter % 4) || counterProgress > 0.8) {
				_bubble.setCounter(counter);
			// }

			const auto edgeProgress = value * bubbleEdge;
			_bubble.setTailEdge(edgeProgress);
			update();
		},
		0.,
		1.,
		st::premiumBubbleSlideDuration
			* (_ignoreDeflection ? kStepBeforeDeflection : 1.),
		anim::easeOutCirc);
	}, lifetime());
}

bool BubbleWidget::animating() const {
	return _appearanceAnimation.animating();
}

void BubbleWidget::paintEvent(QPaintEvent *e) {
	if (_bubble.counter() <= 0) {
		return;
	}

	Painter p(this);

	const auto padding = QMargins(
		0,
		_spaceForDeflection.height(),
		_spaceForDeflection.width(),
		0);
	const auto bubbleRect = rect() - padding;

	if (_appearanceAnimation.animating()) {
		auto gradient = ComputeGradient(
			parentWidget(),
			x(),
			bubbleRect.width());
		_cachedGradient = std::move(gradient);

		const auto progress = _appearanceAnimation.value(1.);
		const auto scaleProgress = std::clamp(
			(progress / _stepBeforeDeflection),
			0.,
			1.);
		const auto scale = scaleProgress;
		const auto rotationProgress = std::clamp(
			(progress - _stepBeforeDeflection) / (1. - _stepBeforeDeflection),
			0.,
			1.);
		const auto rotationProgressReverse = std::clamp(
			(progress - _stepAfterDeflection) / (1. - _stepAfterDeflection),
			0.,
			1.);

		const auto offsetX = bubbleRect.x() + bubbleRect.width() / 2;
		const auto offsetY = bubbleRect.y() + bubbleRect.height();
		p.translate(offsetX, offsetY);
		p.scale(scale, scale);
		if (!_ignoreDeflection) {
			p.rotate(rotationProgress * _deflection
				- rotationProgressReverse * _deflection);
		}
		p.translate(-offsetX, -offsetY);
	}

	_bubble.paintBubble(p, bubbleRect, QBrush(_cachedGradient));
}

class Line final : public Ui::RpWidget {
public:
	Line(not_null<Ui::RpWidget*> parent, int max, TextFactory textFactory);

protected:
	void paintEvent(QPaintEvent *event) override;

private:
	void recache(const QSize &s);

	int _leftWidth = 0;
	int _rightWidth = 0;

	QPixmap _leftPixmap;
	QPixmap _rightPixmap;

	Ui::Text::String _leftText;
	Ui::Text::String _rightText;
	Ui::Text::String _rightLabel;

};

Line::Line(not_null<Ui::RpWidget*> parent, int max, TextFactory textFactory)
: Ui::RpWidget(parent)
, _leftText(st::defaultTextStyle, tr::lng_premium_free(tr::now))
, _rightText(st::defaultTextStyle, tr::lng_premium(tr::now))
, _rightLabel(st::defaultTextStyle, textFactory(max)) {
	resize(width(), st::requestsAcceptButton.height);

	sizeValue(
	) | rpl::start_with_next([=](const QSize &s) {
		_leftWidth = (s.width() / 2);
		_rightWidth = (s.width() - _leftWidth);
		recache(s);
		update();
	}, lifetime());
}

void Line::paintEvent(QPaintEvent *event) {
	Painter p(this);

	p.drawPixmap(0, 0, _leftPixmap);
	p.drawPixmap(_leftWidth, 0, _rightPixmap);

	p.setFont(st::normalFont);

	const auto textPadding = st::premiumLineTextSkip;
	const auto textTop = (height() - _leftText.minHeight()) / 2;

	p.setPen(st::windowFg);
	_leftText.drawLeft(
		p,
		textPadding,
		textTop,
		_leftWidth - textPadding,
		_leftWidth);

	p.setPen(st::activeButtonFg);
	_rightLabel.drawRight(
		p,
		textPadding,
		textTop,
		_rightWidth - textPadding,
		width(),
		style::al_right);
	_rightText.drawLeftElided(
		p,
		_leftWidth + textPadding,
		textTop,
		_rightWidth - _rightLabel.countWidth(_rightWidth) - textPadding * 2,
		_rightWidth);
}

void Line::recache(const QSize &s) {
	const auto r = QRect(0, 0, _leftWidth, s.height());
	auto pixmap = QPixmap(r.size() * style::DevicePixelRatio());
	pixmap.setDevicePixelRatio(style::DevicePixelRatio());
	pixmap.fill(Qt::transparent);

	auto pathRound = QPainterPath();
	pathRound.addRoundedRect(r, st::buttonRadius, st::buttonRadius);

	{
		auto leftPixmap = pixmap;
		Painter p(&leftPixmap);
		PainterHighQualityEnabler hq(p);
		auto pathRect = QPainterPath();
		auto halfRect = r;
		halfRect.setLeft(r.center().x());
		pathRect.addRect(halfRect);

		p.fillPath(pathRound + pathRect, st::windowShadowFgFallback);

		_leftPixmap = std::move(leftPixmap);
	}
	{
		auto rightPixmap = pixmap;
		Painter p(&rightPixmap);
		PainterHighQualityEnabler hq(p);
		auto pathRect = QPainterPath();
		auto halfRect = r;
		halfRect.setRight(r.center().x());
		pathRect.addRect(halfRect);

		auto gradient = ComputeGradient(
			this,
			(_leftPixmap.width() / style::DevicePixelRatio()) + r.x(),
			r.width());
		p.fillPath(pathRound + pathRect, QBrush(std::move(gradient)));

		_rightPixmap = std::move(rightPixmap);
	}
}

} // namespace

void AddBubbleRow(
		not_null<Ui::VerticalLayout*> parent,
		rpl::producer<> showFinishes,
		int min,
		int current,
		int max,
		std::optional<tr::phrase<lngtag_count>> phrase,
		const style::icon *icon) {
	const auto container = parent->add(
		object_ptr<Ui::FixedHeightWidget>(parent, 0));
	const auto bubble = Ui::CreateChild<BubbleWidget>(
		container,
		ProcessTextFactory(phrase),
		current,
		max,
		std::move(showFinishes),
		icon);
	rpl::combine(
		container->sizeValue(),
		bubble->sizeValue()
	) | rpl::start_with_next([=](const QSize &parentSize, const QSize &size) {
		container->resize(parentSize.width(), size.height());
	}, bubble->lifetime());
}

void AddLimitRow(
		not_null<Ui::VerticalLayout*> parent,
		int max,
		std::optional<tr::phrase<lngtag_count>> phrase) {
	const auto line = parent->add(
		object_ptr<Line>(parent, max, ProcessTextFactory(phrase)),
		st::boxRowPadding);
}

QGradientStops LimitGradientStops() {
	return {
		{ 0.0, st::premiumButtonBg1->c },
		{ .25, st::premiumButtonBg1->c },
		{ .85, st::premiumButtonBg2->c },
		{ 1.0, st::premiumButtonBg3->c },
	};
}

QGradientStops ButtonGradientStops() {
	return {
		{ 0., st::premiumButtonBg1->c },
		{ 0.6, st::premiumButtonBg2->c },
		{ 1., st::premiumButtonBg3->c },
	};
}

QGradientStops LockGradientStops() {
	return ButtonGradientStops();
}

} // namespace Premium
} // namespace Ui