src/MessageLog.h

/*
 *  LDForge: LDraw parts authoring CAD
 *  Copyright (C) 2013, 2014 Santeri Piippo
 *
 *  This program 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.
 *
 *  This program 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.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#pragma once
#include <QObject>
#include <QDate>
#include "Main.h"
#include "Types.h"

class GLRenderer;
class QTimer;

//!
//! @brief Manages the list of messages at the top-left of the renderer.
//!
//! The message manager is an object which keeps track of messages that appear
//! on the renderer's screen. Each line is contained in a separate object which
//! contains the text, expiry time and alpha. The message manager is doubly
//! linked to its corresponding renderer.
//!
//! Message manager calls its @c tick() function regularly to update the messages,
//! where each line's expiry is checked for. Lines begin to fade out when nearing
//! their expiry. If the message manager's lines change, the renderer undergoes
//! repainting.
//!
class MessageManager : public QObject
{
	Q_OBJECT
	PROPERTY (public, GLRenderer*, renderer, setRenderer, STOCK_WRITE)

	public:
		//! @class MessageManager::Line
		//! A single line of the message log.
		class Line
		{
			public:
				//! Constructs a line with the given @c text
				Line (QString text);

				//! Check this line's expiry and update alpha accordingly.
				//! @c changed is updated to whether the line has somehow
				//! changed since the last update.
				//! @returns true if the line is to still stick around, false
				//! @returns if it expired.
				bool update (bool& changed);

				QString text;
				float alpha;
				QDateTime expiry;
		};

		//! Constructs the message manager.
		explicit MessageManager (QObject* parent = null);

		//! Adds a line with the given @c text to the message manager.
		void addLine (QString line);

		//! @returns all active lines in the message manager.
		const QList<Line>& getLines() const;

	private:
		QList<Line>	m_lines;
		QTimer*		m_ticker;

	private slots:
		//! Ticks the manager. This is called by the timer to update
		//! the messages.
		void tick();
};