//
// 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/observer.h"
#include "ui/twidget.h"
#include "window/window_slide_animation.h"

namespace Window {

class Controller;

enum class Column {
	First,
	Second,
	Third,
};

class AbstractSectionWidget : public TWidget, protected base::Subscriber {
public:
	AbstractSectionWidget(QWidget *parent, not_null<Window::Controller *> controller)
	    : TWidget(parent)
	    , _controller(controller) {}

	// Float player interface.
	virtual bool wheelEventFromFloatPlayer(QEvent *e, Window::Column myColumn, Window::Column playerColumn) {
		return false;
	}
	virtual QRect rectForFloatPlayer(Window::Column myColumn, Window::Column playerColumn) {
		return mapToGlobal(rect());
	}

protected:
	not_null<Window::Controller *> controller() const {
		return _controller;
	}

private:
	not_null<Window::Controller *> _controller;
};

class SectionMemento;

struct SectionSlideParams {
	QPixmap oldContentCache;
	bool withTopBarShadow = false;
	bool withTabbedSection = false;

	explicit operator bool() const {
		return !oldContentCache.isNull();
	}
};

class SectionWidget : public AbstractSectionWidget {
public:
	SectionWidget(QWidget *parent, not_null<Window::Controller *> controller);

	virtual PeerData *peerForDialogs() const {
		return nullptr;
	}

	// When resizing the widget with top edge moved up or down and we
	// want to add this top movement to the scroll position, so inner
	// content will not move.
	void setGeometryWithTopMoved(const QRect &newGeometry, int topDelta);

	virtual bool hasTopBarShadow() const {
		return false;
	}
	void showAnimated(SlideDirection direction, const SectionSlideParams &params);
	void showFast();

	// This can be used to grab with or without top bar shadow.
	// This will be protected when animation preparation will be done inside.
	virtual QPixmap grabForShowAnimation(const SectionSlideParams &params) {
		return myGrab(this);
	}

	// Attempt to show the required section inside the existing one.
	// For example if this section already shows exactly the required
	// memento it can simply return true - it is shown already.
	//
	// If this method returns false it is not supposed to modify the memento.
	// If this method returns true it may modify the memento ("take" heavy items).
	virtual bool showInternal(not_null<SectionMemento *> memento) = 0;

	// Create a memento of that section to store it in the history stack.
	// This method may modify the section ("take" heavy items).
	virtual std::unique_ptr<SectionMemento> createMemento() = 0;

	void setInnerFocus() {
		doSetInnerFocus();
	}

	// Global shortcut handler. For now that ugly :(
	virtual bool cmd_search() {
		return false;
	}

protected:
	void paintEvent(QPaintEvent *e) override;

	// Temp variable used in resizeEvent() implementation, that is passed
	// to setGeometryWithTopMoved() to adjust the scroll position with the resize.
	int topDelta() const {
		return _topDelta;
	}

	// Called after the hideChildren() call in showAnimated().
	virtual void showAnimatedHook() {}

	// Called after the showChildren() call in showFinished().
	virtual void showFinishedHook() {}

	virtual void doSetInnerFocus() {
		setFocus();
	}

	bool animating() const {
		return _showAnimation != nullptr;
	}

private:
	void showFinished();

	std::unique_ptr<SlideAnimation> _showAnimation;

	// Saving here topDelta in resizeWithTopMoved() to get it passed to resizeEvent().
	int _topDelta = 0;
};

} // namespace Window