//
// This file is part of Kepka,
// an unofficial desktop version of Telegram messaging app,
// see https://github.com/procxx/kepka
//
// Kepka is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// It is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// In addition, as a special exception, the copyright holders give permission
// to link the code of portions of this program with the OpenSSL library.
//
// Full license: https://github.com/procxx/kepka/blob/master/LICENSE
// Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
// Copyright (c) 2017- Kepka Contributors, https://github.com/procxx
//
#pragma once

#include "base/flags.h"
#include "base/object_ptr.h"
#include "styles/palette.h"
#include "styles/style_basic.h"
#include "ui/style/style_core.h"
#include <QEvent>
#include <QFontMetrics>
#include <QPainter>
#include <QPointer>
#include <QString>
#include <QWidget>


namespace Fonts {

void Start();
QString GetOverride(const QString &familyName);

} // namespace Fonts

enum class RectPart {
	None = 0,

	TopLeft = (1 << 0),
	Top = (1 << 1),
	TopRight = (1 << 2),
	Left = (1 << 3),
	Center = (1 << 4),
	Right = (1 << 5),
	BottomLeft = (1 << 6),
	Bottom = (1 << 7),
	BottomRight = (1 << 8),

	FullTop = TopLeft | Top | TopRight,
	NoTopBottom = Left | Center | Right,
	FullBottom = BottomLeft | Bottom | BottomRight,
	NoTop = NoTopBottom | FullBottom,
	NoBottom = FullTop | NoTopBottom,

	FullLeft = TopLeft | Left | BottomLeft,
	NoLeftRight = Top | Center | Bottom,
	FullRight = TopRight | Right | BottomRight,
	NoLeft = NoLeftRight | FullRight,
	NoRight = FullLeft | NoLeftRight,

	CornersMask = TopLeft | TopRight | BottomLeft | BottomRight,
	SidesMask = Top | Bottom | Left | Right,

	Full = FullTop | NoTop,
};
using RectParts = base::flags<RectPart>;
inline constexpr auto is_flag_type(RectPart) {
	return true;
};

inline bool IsTopCorner(RectPart corner) {
	return (corner == RectPart::TopLeft) || (corner == RectPart::TopRight);
}

inline bool IsBottomCorner(RectPart corner) {
	return (corner == RectPart::BottomLeft) || (corner == RectPart::BottomRight);
}

inline bool IsLeftCorner(RectPart corner) {
	return (corner == RectPart::TopLeft) || (corner == RectPart::BottomLeft);
}

inline bool IsRightCorner(RectPart corner) {
	return (corner == RectPart::TopRight) || (corner == RectPart::BottomRight);
}

class Painter : public QPainter {
public:
	explicit Painter(QPaintDevice *device)
	    : QPainter(device) {}

	void drawTextLeft(int x, int y, int outerw, const QString &text, int textWidth = -1) {
		QFontMetrics m(fontMetrics());
		if (rtl() && textWidth < 0) textWidth = m.width(text);
		drawText(rtl() ? (outerw - x - textWidth) : x, y + m.ascent(), text);
	}
	void drawTextRight(int x, int y, int outerw, const QString &text, int textWidth = -1) {
		QFontMetrics m(fontMetrics());
		if (!rtl() && textWidth < 0) textWidth = m.width(text);
		drawText(rtl() ? x : (outerw - x - textWidth), y + m.ascent(), text);
	}
	void drawPixmapLeft(int x, int y, int outerw, const QPixmap &pix, const QRect &from) {
		drawPixmap(QPoint(rtl() ? (outerw - x - (from.width() / pix.devicePixelRatio())) : x, y), pix, from);
	}
	void drawPixmapLeft(const QPoint &p, int outerw, const QPixmap &pix, const QRect &from) {
		return drawPixmapLeft(p.x(), p.y(), outerw, pix, from);
	}
	void drawPixmapLeft(int x, int y, int w, int h, int outerw, const QPixmap &pix, const QRect &from) {
		drawPixmap(QRect(rtl() ? (outerw - x - w) : x, y, w, h), pix, from);
	}
	void drawPixmapLeft(const QRect &r, int outerw, const QPixmap &pix, const QRect &from) {
		return drawPixmapLeft(r.x(), r.y(), r.width(), r.height(), outerw, pix, from);
	}
	void drawPixmapLeft(int x, int y, int outerw, const QPixmap &pix) {
		drawPixmap(QPoint(rtl() ? (outerw - x - (pix.width() / pix.devicePixelRatio())) : x, y), pix);
	}
	void drawPixmapLeft(const QPoint &p, int outerw, const QPixmap &pix) {
		return drawPixmapLeft(p.x(), p.y(), outerw, pix);
	}
	void drawPixmapRight(int x, int y, int outerw, const QPixmap &pix, const QRect &from) {
		drawPixmap(QPoint(rtl() ? x : (outerw - x - (from.width() / pix.devicePixelRatio())), y), pix, from);
	}
	void drawPixmapRight(const QPoint &p, int outerw, const QPixmap &pix, const QRect &from) {
		return drawPixmapRight(p.x(), p.y(), outerw, pix, from);
	}
	void drawPixmapRight(int x, int y, int w, int h, int outerw, const QPixmap &pix, const QRect &from) {
		drawPixmap(QRect(rtl() ? x : (outerw - x - w), y, w, h), pix, from);
	}
	void drawPixmapRight(const QRect &r, int outerw, const QPixmap &pix, const QRect &from) {
		return drawPixmapRight(r.x(), r.y(), r.width(), r.height(), outerw, pix, from);
	}
	void drawPixmapRight(int x, int y, int outerw, const QPixmap &pix) {
		drawPixmap(QPoint(rtl() ? x : (outerw - x - (pix.width() / pix.devicePixelRatio())), y), pix);
	}
	void drawPixmapRight(const QPoint &p, int outerw, const QPixmap &pix) {
		return drawPixmapRight(p.x(), p.y(), outerw, pix);
	}

	void setTextPalette(const style::TextPalette &palette) {
		_textPalette = &palette;
	}
	void restoreTextPalette() {
		_textPalette = nullptr;
	}
	const style::TextPalette &textPalette() const {
		return _textPalette ? *_textPalette : st::defaultTextPalette;
	}

private:
	const style::TextPalette *_textPalette = nullptr;
};

class PainterHighQualityEnabler {
public:
	PainterHighQualityEnabler(Painter &p)
	    : _painter(p) {
		static constexpr QPainter::RenderHint Hints[] = {QPainter::Antialiasing, QPainter::SmoothPixmapTransform,
		                                                 QPainter::TextAntialiasing, QPainter::HighQualityAntialiasing};

		auto hints = _painter.renderHints();
		for_const (auto hint, Hints) {
			if (!(hints & hint)) {
				_hints |= hint;
			}
		}
		if (_hints) {
			_painter.setRenderHints(_hints);
		}
	}
	PainterHighQualityEnabler(const PainterHighQualityEnabler &other) = delete;
	PainterHighQualityEnabler &operator=(const PainterHighQualityEnabler &other) = delete;
	~PainterHighQualityEnabler() {
		if (_hints) {
			_painter.setRenderHints(_hints, false);
		}
	}

private:
	Painter &_painter;
	QPainter::RenderHints _hints = 0;
};

class TWidget;

template <typename Base> class TWidgetHelper : public Base {
public:
	using Base::Base;

	virtual QMargins getMargins() const {
		return QMargins();
	}

	void moveToLeft(int x, int y, int outerw = 0) {
		auto margins = getMargins();
		x -= margins.left();
		y -= margins.top();
		Base::move(rtl() ? ((outerw > 0 ? outerw : Base::parentWidget()->width()) - x - Base::width()) : x, y);
	}
	void moveToRight(int x, int y, int outerw = 0) {
		auto margins = getMargins();
		x -= margins.right();
		y -= margins.top();
		Base::move(rtl() ? x : ((outerw > 0 ? outerw : Base::parentWidget()->width()) - x - Base::width()), y);
	}
	void setGeometryToLeft(int x, int y, int w, int h, int outerw = 0) {
		auto margins = getMargins();
		x -= margins.left();
		y -= margins.top();
		w -= margins.left() - margins.right();
		h -= margins.top() - margins.bottom();
		Base::setGeometry(rtl() ? ((outerw > 0 ? outerw : Base::parentWidget()->width()) - x - w) : x, y, w, h);
	}
	void setGeometryToRight(int x, int y, int w, int h, int outerw = 0) {
		auto margins = getMargins();
		x -= margins.right();
		y -= margins.top();
		w -= margins.left() - margins.right();
		h -= margins.top() - margins.bottom();
		Base::setGeometry(rtl() ? x : ((outerw > 0 ? outerw : Base::parentWidget()->width()) - x - w), y, w, h);
	}
	QPoint myrtlpoint(int x, int y) const {
		return rtlpoint(x, y, Base::width());
	}
	QPoint myrtlpoint(const QPoint point) const {
		return rtlpoint(point, Base::width());
	}
	QRect myrtlrect(int x, int y, int w, int h) const {
		return rtlrect(x, y, w, h, Base::width());
	}
	QRect myrtlrect(const QRect &rect) const {
		return rtlrect(rect, Base::width());
	}
	void rtlupdate(const QRect &rect) {
		Base::update(myrtlrect(rect));
	}
	void rtlupdate(int x, int y, int w, int h) {
		Base::update(myrtlrect(x, y, w, h));
	}

	QPoint mapFromGlobal(const QPoint &point) const {
		return Base::mapFromGlobal(point);
	}
	QPoint mapToGlobal(const QPoint &point) const {
		return Base::mapToGlobal(point);
	}
	QRect mapFromGlobal(const QRect &rect) const {
		return QRect(mapFromGlobal(rect.topLeft()), rect.size());
	}
	QRect mapToGlobal(const QRect &rect) {
		return QRect(mapToGlobal(rect.topLeft()), rect.size());
	}

protected:
	void enterEvent(QEvent *e) final override {
		if (auto parent = tparent()) {
			parent->leaveToChildEvent(e, this);
		}
		return enterEventHook(e);
	}
	virtual void enterEventHook(QEvent *e) {
		return Base::enterEvent(e);
	}

	void leaveEvent(QEvent *e) final override {
		if (auto parent = tparent()) {
			parent->enterFromChildEvent(e, this);
		}
		return leaveEventHook(e);
	}
	virtual void leaveEventHook(QEvent *e) {
		return Base::leaveEvent(e);
	}

	// e - from enterEvent() of child TWidget
	virtual void leaveToChildEvent(QEvent *e, QWidget *child) {}

	// e - from leaveEvent() of child TWidget
	virtual void enterFromChildEvent(QEvent *e, QWidget *child) {}

private:
	TWidget *tparent() {
		return qobject_cast<TWidget *>(Base::parentWidget());
	}
	const TWidget *tparent() const {
		return qobject_cast<const TWidget *>(Base::parentWidget());
	}

	template <typename OtherBase> friend class TWidgetHelper;
};

class TWidget : public TWidgetHelper<QWidget> {
	Q_OBJECT

public:
	TWidget(QWidget *parent = nullptr)
	    : TWidgetHelper<QWidget>(parent) {}
	virtual void grabStart() {}
	virtual void grabFinish() {}

	bool inFocusChain() const;

	void hideChildren() {
		for (auto child : children()) {
			if (auto widget = qobject_cast<QWidget *>(child)) {
				widget->hide();
			}
		}
	}
	void showChildren() {
		for (auto child : children()) {
			if (auto widget = qobject_cast<QWidget *>(child)) {
				widget->show();
			}
		}
	}

	// Get the size of the widget as it should be.
	// Negative return value means no default width.
	virtual int naturalWidth() const {
		return -1;
	}

	// Count new height for width=newWidth and resize to it.
	void resizeToWidth(int newWidth) {
		auto margins = getMargins();
		auto fullWidth = margins.left() + newWidth + margins.right();
		auto fullHeight = margins.top() + resizeGetHeight(newWidth) + margins.bottom();
		auto newSize = QSize(fullWidth, fullHeight);
		if (newSize != size()) {
			resize(newSize);
			update();
		}
	}

	// Resize to minimum of natural width and available width.
	void resizeToNaturalWidth(int newWidth) {
		auto maxWidth = naturalWidth();
		resizeToWidth((maxWidth >= 0) ? qMin(newWidth, maxWidth) : newWidth);
	}

	QRect rectNoMargins() const {
		return rect().marginsRemoved(getMargins());
	}

	int widthNoMargins() const {
		return rectNoMargins().width();
	}

	int heightNoMargins() const {
		return rectNoMargins().height();
	}

	int bottomNoMargins() const {
		auto rectWithoutMargins = rectNoMargins();
		return y() + rectWithoutMargins.y() + rectWithoutMargins.height();
	}

	QSize sizeNoMargins() const {
		return rectNoMargins().size();
	}

	// Updates the area that is visible inside the scroll container.
	virtual void setVisibleTopBottom(int visibleTop, int visibleBottom) {}

signals:
	// Child widget is responsible for emitting this signal.
	void heightUpdated();

protected:
	// Resizes content and counts natural widget height for the desired width.
	virtual int resizeGetHeight(int newWidth) {
		return height();
	}
};

template <typename Widget> QPointer<Widget> weak(Widget *object) {
	return QPointer<Widget>(object);
}

template <typename Widget> QPointer<const Widget> weak(const Widget *object) {
	return QPointer<const Widget>(object);
}

void myEnsureResized(QWidget *target);
QPixmap myGrab(TWidget *target, QRect rect = QRect(), QColor bg = QColor(255, 255, 255, 0));
QImage myGrabImage(TWidget *target, QRect rect = QRect(), QColor bg = QColor(255, 255, 255, 0));

class SingleQueuedInvokation : public QObject {
public:
	SingleQueuedInvokation(Fn<void()> callback)
	    : _callback(callback) {}
	void call() {
		if (_pending.testAndSetAcquire(0, 1)) {
			InvokeQueued(this, [this] {
				if (_pending.testAndSetRelease(1, 0)) {
					_callback();
				}
			});
		}
	}

private:
	Fn<void()> _callback;
	QAtomicInt _pending = {0};
};

void sendSynteticMouseEvent(QWidget *widget, QEvent::Type type, Qt::MouseButton button, const QPoint &globalPoint);

inline void sendSynteticMouseEvent(QWidget *widget, QEvent::Type type, Qt::MouseButton button) {
	return sendSynteticMouseEvent(widget, type, button, QCursor::pos());
}