/*
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
*/
#pragma once

#include "core/basic_types.h"
#include <QtCore/QTimer>
#include <QtGui/QColor>

namespace Media {
namespace Clip {

class Reader;
class ReaderPointer {
public:
	ReaderPointer(std::nullptr_t = nullptr) {
	}
	explicit ReaderPointer(Reader *pointer) : _pointer(pointer) {
	}
	ReaderPointer(const ReaderPointer &other) = delete;
	ReaderPointer &operator=(const ReaderPointer &other) = delete;
	ReaderPointer(ReaderPointer &&other) : _pointer(base::take(other._pointer)) {
	}
	ReaderPointer &operator=(ReaderPointer &&other) {
		swap(other);
		return *this;
	}
	void swap(ReaderPointer &other) {
		qSwap(_pointer, other._pointer);
	}
	Reader *get() const {
		return valid() ? _pointer : nullptr;
	}
	Reader *operator->() const {
		return get();
	}
	void setBad() {
		reset();
		_pointer = BadPointer;
	}
	void reset() {
		ReaderPointer temp;
		swap(temp);
	}
	bool isBad() const {
		return (_pointer == BadPointer);
	}
	bool valid() const {
		return _pointer && !isBad();
	}
	explicit operator bool() const {
		return valid();
	}
	static inline ReaderPointer Bad() {
		ReaderPointer result;
		result.setBad();
		return result;
	}
	~ReaderPointer();

private:
	Reader *_pointer = nullptr;
	static Reader *const BadPointer;

};

class Manager;

enum Notification {
	NotificationReinit,
	NotificationRepaint,
};

} // namespace Clip
} // namespace Media

namespace anim {

enum class type {
	normal,
	instant,
};

enum class activation {
	normal,
	background,
};

using transition = Fn<float64(float64 delta, float64 dt)>;

extern transition linear;
extern transition sineInOut;
extern transition halfSine;
extern transition easeOutBack;
extern transition easeInCirc;
extern transition easeOutCirc;
extern transition easeInCubic;
extern transition easeOutCubic;
extern transition easeInQuint;
extern transition easeOutQuint;

inline transition bumpy(float64 bump) {
	auto dt0 = (bump - sqrt(bump * (bump - 1.)));
	auto k = (1 / (2 * dt0 - 1));
	return [bump, dt0, k](float64 delta, float64 dt) {
		return delta * (bump - k * (dt - dt0) * (dt - dt0));
	};
}

// Basic animated value.
class value {
public:
	using ValueType = float64;

	value() = default;
	value(float64 from) : _cur(from), _from(from) {
	}
	value(float64 from, float64 to) : _cur(from), _from(from), _delta(to - from) {
	}
	void start(float64 to) {
		_from = _cur;
		_delta = to - _from;
	}
	void restart() {
		_delta = _from + _delta - _cur;
		_from = _cur;
	}

	float64 from() const {
		return _from;
	}
	float64 current() const {
		return _cur;
	}
	float64 to() const {
		return _from + _delta;
	}
	void add(float64 delta) {
		_from += delta;
		_cur += delta;
	}
	value &update(float64 dt, transition func) {
		_cur = _from + func(_delta, dt);
		return *this;
	}
	void finish() {
		_cur = _from + _delta;
		_from = _cur;
		_delta = 0;
	}

private:
	float64 _cur = 0.;
	float64 _from = 0.;
	float64 _delta = 0.;

};

void startManager();
void stopManager();
void registerClipManager(Media::Clip::Manager *manager);

FORCE_INLINE int interpolate(int a, int b, float64 b_ratio) {
	return qRound(a + float64(b - a) * b_ratio);
}

#ifdef ARCH_CPU_32_BITS
#define SHIFTED_USE_32BIT
#endif // ARCH_CPU_32_BITS

#ifdef SHIFTED_USE_32BIT

using ShiftedMultiplier = uint32;

struct Shifted {
	Shifted() = default;
	Shifted(uint32 low, uint32 high) : low(low), high(high) {
	}
	uint32 low = 0;
	uint32 high = 0;
};

FORCE_INLINE Shifted operator+(Shifted a, Shifted b) {
	return Shifted(a.low + b.low, a.high + b.high);
}

FORCE_INLINE Shifted operator*(Shifted shifted, ShiftedMultiplier multiplier) {
	return Shifted(shifted.low * multiplier, shifted.high * multiplier);
}

FORCE_INLINE Shifted operator*(ShiftedMultiplier multiplier, Shifted shifted) {
	return Shifted(shifted.low * multiplier, shifted.high * multiplier);
}

FORCE_INLINE Shifted shifted(uint32 components) {
	return Shifted(
		(components & 0x000000FFU) | ((components & 0x0000FF00U) << 8),
		((components & 0x00FF0000U) >> 16) | ((components & 0xFF000000U) >> 8));
}

FORCE_INLINE uint32 unshifted(Shifted components) {
	return ((components.low & 0x0000FF00U) >> 8)
		| ((components.low & 0xFF000000U) >> 16)
		| ((components.high & 0x0000FF00U) << 8)
		| (components.high & 0xFF000000U);
}

FORCE_INLINE Shifted reshifted(Shifted components) {
	return Shifted((components.low >> 8) & 0x00FF00FFU, (components.high >> 8) & 0x00FF00FFU);
}

FORCE_INLINE Shifted shifted(QColor color) {
	// Make it premultiplied.
	auto alpha = static_cast<uint32>((color.alpha() & 0xFF) + 1);
	auto components = Shifted(static_cast<uint32>(color.blue() & 0xFF) | (static_cast<uint32>(color.green() & 0xFF) << 16),
		static_cast<uint32>(color.red() & 0xFF) | (static_cast<uint32>(255) << 16));
	return reshifted(components * alpha);
}

FORCE_INLINE uint32 getPremultiplied(QColor color) {
	// Make it premultiplied.
	auto alpha = static_cast<uint32>((color.alpha() & 0xFF) + 1);
	auto components = Shifted(static_cast<uint32>(color.blue() & 0xFF) | (static_cast<uint32>(color.green() & 0xFF) << 16),
		static_cast<uint32>(color.red() & 0xFF) | (static_cast<uint32>(255) << 16));
	return unshifted(components * alpha);
}

FORCE_INLINE uint32 getAlpha(Shifted components) {
	return (components.high & 0x00FF0000U) >> 16;
}

FORCE_INLINE Shifted non_premultiplied(QColor color) {
	return Shifted(static_cast<uint32>(color.blue() & 0xFF) | (static_cast<uint32>(color.green() & 0xFF) << 16),
		static_cast<uint32>(color.red() & 0xFF) | (static_cast<uint32>(color.alpha() & 0xFF) << 16));
}

FORCE_INLINE QColor color(QColor a, QColor b, float64 b_ratio) {
	auto bOpacity = snap(interpolate(0, 255, b_ratio), 0, 255) + 1;
	auto aOpacity = (256 - bOpacity);
	auto components = (non_premultiplied(a) * aOpacity + non_premultiplied(b) * bOpacity);
	return {
		static_cast<int>((components.high >> 8) & 0xFF),
		static_cast<int>((components.low >> 24) & 0xFF),
		static_cast<int>((components.low >> 8) & 0xFF),
		static_cast<int>((components.high >> 24) & 0xFF),
	};
}

#else // SHIFTED_USE_32BIT

using ShiftedMultiplier = uint64;

struct Shifted {
	Shifted() = default;
	Shifted(uint32 value) : value(value) {
	}
	Shifted(uint64 value) : value(value) {
	}
	uint64 value = 0;
};

FORCE_INLINE Shifted operator+(Shifted a, Shifted b) {
	return Shifted(a.value + b.value);
}

FORCE_INLINE Shifted operator*(Shifted shifted, ShiftedMultiplier multiplier) {
	return Shifted(shifted.value * multiplier);
}

FORCE_INLINE Shifted operator*(ShiftedMultiplier multiplier, Shifted shifted) {
	return Shifted(shifted.value * multiplier);
}

FORCE_INLINE Shifted shifted(uint32 components) {
	auto wide = static_cast<uint64>(components);
	return (wide & 0x00000000000000FFULL)
		| ((wide & 0x000000000000FF00ULL) << 8)
		| ((wide & 0x0000000000FF0000ULL) << 16)
		| ((wide & 0x00000000FF000000ULL) << 24);
}

FORCE_INLINE uint32 unshifted(Shifted components) {
	return static_cast<uint32>((components.value & 0x000000000000FF00ULL) >> 8)
		| static_cast<uint32>((components.value & 0x00000000FF000000ULL) >> 16)
		| static_cast<uint32>((components.value & 0x0000FF0000000000ULL) >> 24)
		| static_cast<uint32>((components.value & 0xFF00000000000000ULL) >> 32);
}

FORCE_INLINE Shifted reshifted(Shifted components) {
	return (components.value >> 8) & 0x00FF00FF00FF00FFULL;
}

FORCE_INLINE Shifted shifted(QColor color) {
	// Make it premultiplied.
	auto alpha = static_cast<uint64>((color.alpha() & 0xFF) + 1);
	auto components = static_cast<uint64>(color.blue() & 0xFF)
		| (static_cast<uint64>(color.green() & 0xFF) << 16)
		| (static_cast<uint64>(color.red() & 0xFF) << 32)
		| (static_cast<uint64>(255) << 48);
	return reshifted(components * alpha);
}

FORCE_INLINE uint32 getPremultiplied(QColor color) {
	// Make it premultiplied.
	auto alpha = static_cast<uint64>((color.alpha() & 0xFF) + 1);
	auto components = static_cast<uint64>(color.blue() & 0xFF)
		| (static_cast<uint64>(color.green() & 0xFF) << 16)
		| (static_cast<uint64>(color.red() & 0xFF) << 32)
		| (static_cast<uint64>(255) << 48);
	return unshifted(components * alpha);
}

FORCE_INLINE uint32 getAlpha(Shifted components) {
	return (components.value & 0x00FF000000000000ULL) >> 48;
}

FORCE_INLINE Shifted non_premultiplied(QColor color) {
	return static_cast<uint64>(color.blue() & 0xFF)
		| (static_cast<uint64>(color.green() & 0xFF) << 16)
		| (static_cast<uint64>(color.red() & 0xFF) << 32)
		| (static_cast<uint64>(color.alpha() & 0xFF) << 48);
}

FORCE_INLINE QColor color(QColor a, QColor b, float64 b_ratio) {
	auto bOpacity = snap(interpolate(0, 255, b_ratio), 0, 255) + 1;
	auto aOpacity = (256 - bOpacity);
	auto components = (non_premultiplied(a) * aOpacity + non_premultiplied(b) * bOpacity);
	return {
		static_cast<int>((components.value >> 40) & 0xFF),
		static_cast<int>((components.value >> 24) & 0xFF),
		static_cast<int>((components.value >>  8) & 0xFF),
		static_cast<int>((components.value >> 56) & 0xFF),
	};
}

#endif // SHIFTED_USE_32BIT

FORCE_INLINE QColor color(style::color a, QColor b, float64 b_ratio) {
	return color(a->c, b, b_ratio);
}

FORCE_INLINE QColor color(QColor a, style::color b, float64 b_ratio) {
	return color(a, b->c, b_ratio);
}

FORCE_INLINE QColor color(style::color a, style::color b, float64 b_ratio) {
	return color(a->c, b->c, b_ratio);
}

FORCE_INLINE QPen pen(QColor a, QColor b, float64 b_ratio) {
	return color(a, b, b_ratio);
}

FORCE_INLINE QPen pen(style::color a, QColor b, float64 b_ratio) {
	return (b_ratio > 0) ? pen(a->c, b, b_ratio) : a;
}

FORCE_INLINE QPen pen(QColor a, style::color b, float64 b_ratio) {
	return (b_ratio < 1) ? pen(a, b->c, b_ratio) : b;
}

FORCE_INLINE QPen pen(style::color a, style::color b, float64 b_ratio) {
	return (b_ratio > 0) ? ((b_ratio < 1) ? pen(a->c, b->c, b_ratio) : b) : a;
}

FORCE_INLINE QBrush brush(QColor a, QColor b, float64 b_ratio) {
	return color(a, b, b_ratio);
}

FORCE_INLINE QBrush brush(style::color a, QColor b, float64 b_ratio) {
	return (b_ratio > 0) ? brush(a->c, b, b_ratio) : a;
}

FORCE_INLINE QBrush brush(QColor a, style::color b, float64 b_ratio) {
	return (b_ratio < 1) ? brush(a, b->c, b_ratio) : b;
}

FORCE_INLINE QBrush brush(style::color a, style::color b, float64 b_ratio) {
	return (b_ratio > 0) ? ((b_ratio < 1) ? brush(a->c, b->c, b_ratio) : b) : a;
}

template <int N>
QPainterPath interpolate(QPointF (&from)[N], QPointF (&to)[N], float64 k) {
	static_assert(N > 1, "Wrong points count in path!");

	auto from_coef = 1. - k, to_coef = k;
	QPainterPath result;
	auto x = from[0].x() * from_coef + to[0].x() * to_coef;
	auto y = from[0].y() * from_coef + to[0].y() * to_coef;
	result.moveTo(x, y);
	for (int i = 1; i != N; ++i) {
		result.lineTo(from[i].x() * from_coef + to[i].x() * to_coef, from[i].y() * from_coef + to[i].y() * to_coef);
	}
	result.lineTo(x, y);
	return result;
}

template <int N>
QPainterPath path(QPointF (&from)[N]) {
	static_assert(N > 1, "Wrong points count in path!");

	QPainterPath result;
	auto x = from[0].x();
	auto y = from[0].y();
	result.moveTo(x, y);
	for (int i = 1; i != N; ++i) {
		result.lineTo(from[i].x(), from[i].y());
	}
	result.lineTo(x, y);
	return result;
}

bool Disabled();
void SetDisabled(bool disabled);

};

class BasicAnimation;

class AnimationImplementation {
public:
	virtual void start() {}
	virtual void step(BasicAnimation *a, TimeMs ms, bool timer) = 0;
	virtual ~AnimationImplementation() {}

};

class AnimationCallbacks {
public:
	AnimationCallbacks(AnimationImplementation *implementation) : _implementation(implementation) {}
	AnimationCallbacks(const AnimationCallbacks &other) = delete;
	AnimationCallbacks &operator=(const AnimationCallbacks &other) = delete;
	AnimationCallbacks(AnimationCallbacks &&other) : _implementation(other._implementation) {
		other._implementation = nullptr;
	}
	AnimationCallbacks &operator=(AnimationCallbacks &&other) {
		std::swap(_implementation, other._implementation);
		return *this;
	}

	void start() { _implementation->start();  }
	void step(BasicAnimation *a, TimeMs ms, bool timer) { _implementation->step(a, ms, timer); }
	~AnimationCallbacks() { delete base::take(_implementation); }

private:
	AnimationImplementation *_implementation;

};

class BasicAnimation {
public:
	BasicAnimation(AnimationCallbacks &&callbacks)
		: _callbacks(std::move(callbacks))
		, _animating(false) {
	}

	void start();
	void stop();

	void step(TimeMs ms, bool timer = false) {
		_callbacks.step(this, ms, timer);
	}

	void step() {
		step(getms(), false);
	}

	bool animating() const {
		return _animating;
	}

	~BasicAnimation() {
		if (_animating) stop();
	}

private:
	AnimationCallbacks _callbacks;
	bool _animating;

};

template <typename Type>
class AnimationCallbacksRelative : public AnimationImplementation {
public:
	typedef void (Type::*Method)(float64, bool);

	AnimationCallbacksRelative(Type *obj, Method method) : _obj(obj), _method(method) {
	}

	void start() {
		_started = getms();
	}

	void step(BasicAnimation *a, TimeMs ms, bool timer) {
		(_obj->*_method)(qMax(ms - _started, TimeMs(0)), timer);
	}

private:
	TimeMs _started = 0;
	Type *_obj = nullptr;
	Method _method = nullptr;

};

template <typename Type>
AnimationCallbacks animation(Type *obj, typename AnimationCallbacksRelative<Type>::Method method) {
	return AnimationCallbacks(new AnimationCallbacksRelative<Type>(obj, method));
}

template <typename Type>
class AnimationCallbacksAbsolute : public AnimationImplementation {
public:
	typedef void (Type::*Method)(TimeMs, bool);

	AnimationCallbacksAbsolute(Type *obj, Method method) : _obj(obj), _method(method) {
	}

	void step(BasicAnimation *a, TimeMs ms, bool timer) {
		(_obj->*_method)(ms, timer);
	}

private:
	Type *_obj = nullptr;
	Method _method = nullptr;

};

template <typename Type>
AnimationCallbacks animation(Type *obj, typename AnimationCallbacksAbsolute<Type>::Method method) {
	return AnimationCallbacks(new AnimationCallbacksAbsolute<Type>(obj, method));
}

template <typename Type, typename Param>
class AnimationCallbacksRelativeWithParam : public AnimationImplementation {
public:
	typedef void (Type::*Method)(Param, float64, bool);

	AnimationCallbacksRelativeWithParam(Param param, Type *obj, Method method) : _param(param), _obj(obj), _method(method) {
	}

	void start() {
		_started = getms();
	}

	void step(BasicAnimation *a, TimeMs ms, bool timer) {
		(_obj->*_method)(_param, qMax(ms - _started, TimeMs(0)), timer);
	}

private:
	TimeMs _started = 0;
	Param _param;
	Type *_obj = nullptr;
	Method _method = nullptr;

};

template <typename Type, typename Param>
AnimationCallbacks animation(Param param, Type *obj, typename AnimationCallbacksRelativeWithParam<Type, Param>::Method method) {
	return AnimationCallbacks(new AnimationCallbacksRelativeWithParam<Type, Param>(param, obj, method));
}

template <typename Type, typename Param>
class AnimationCallbacksAbsoluteWithParam : public AnimationImplementation {
public:
	typedef void (Type::*Method)(Param, TimeMs, bool);

	AnimationCallbacksAbsoluteWithParam(Param param, Type *obj, Method method) : _param(param), _obj(obj), _method(method) {
	}

	void step(BasicAnimation *a, TimeMs ms, bool timer) {
		(_obj->*_method)(_param, ms, timer);
	}

private:
	Param _param;
	Type *_obj = nullptr;
	Method _method = nullptr;

};

template <typename Type, typename Param>
AnimationCallbacks animation(Param param, Type *obj, typename AnimationCallbacksAbsoluteWithParam<Type, Param>::Method method) {
	return AnimationCallbacks(new AnimationCallbacksAbsoluteWithParam<Type, Param>(param, obj, method));
}

class Animation {
public:
	void step(TimeMs ms) {
		if (_data) {
			_data->a_animation.step(ms);
			if (_data && !_data->a_animation.animating()) {
				_data.reset();
			}
		}
	}

	bool animating() const {
		if (_data) {
			if (_data->a_animation.animating()) {
				return true;
			}
			_data.reset();
		}
		return false;
	}
	bool animating(TimeMs ms) {
		step(ms);
		return animating();
	}

	float64 current() const {
		Assert(_data != nullptr);
		return _data->value.current();
	}
	float64 current(float64 def) const {
		return animating() ? current() : def;
	}
	float64 current(TimeMs ms, float64 def) {
		return animating(ms) ? current() : def;
	}

	static constexpr auto kLongAnimationDuration = 1000;

	template <typename Lambda>
	void start(Lambda &&updateCallback, float64 from, float64 to, float64 duration, anim::transition transition = anim::linear) {
		auto isLong = (duration >= kLongAnimationDuration);
		if (_data) {
			if (!isLong) {
				_data->pause.restart();
			}
		} else {
			_data = std::make_unique<Data>(from, std::forward<Lambda>(updateCallback));
		}
		if (isLong) {
			_data->pause.release();
		}
		_data->value.start(to);
		_data->duration = duration;
		_data->transition = transition;
		_data->a_animation.start();
	}

	void finish() {
		if (_data) {
			_data->value.finish();
			_data->a_animation.stop();
			_data.reset();
		}
	}

	template <typename Lambda>
	void setUpdateCallback(Lambda &&updateCallback) {
		if (_data) {
			_data->updateCallback = std::forward<Lambda>(updateCallback);
		}
	}

private:
	struct Data {
		template <typename Lambda>
		Data(float64 from, Lambda updateCallback)
			: value(from, from)
			, a_animation(animation(this, &Data::step))
			, updateCallback(std::move(updateCallback)) {
		}
		void step(float64 ms, bool timer) {
			auto dt = (ms >= duration || anim::Disabled()) ? 1. : (ms / duration);
			if (dt >= 1) {
				value.finish();
				a_animation.stop();
				pause.release();
			} else {
				value.update(dt, transition);
			}
			updateCallback();
		}

		anim::value value;
		BasicAnimation a_animation;
		Fn<void()> updateCallback;
		float64 duration = 0.;
		anim::transition transition = anim::linear;
		MTP::PauseHolder pause;
	};
	mutable std::unique_ptr<Data> _data;

};

class AnimationManager : public QObject {
	Q_OBJECT

public:
	AnimationManager();

	void start(BasicAnimation *obj);
	void stop(BasicAnimation *obj);

public slots:
	void timeout();

	void clipCallback(Media::Clip::Reader *reader, qint32 threadIndex, qint32 notification);

private:
	using AnimatingObjects = OrderedSet<BasicAnimation*>;
	AnimatingObjects _objects, _starting, _stopping;
	QTimer _timer;
	bool _iterating;

};