/*
    Copyright (C) 2020-2021 Carl Hetherington <cth@carlh.net>

    This file is part of DCP-o-matic.

    DCP-o-matic 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 2 of the License, or
    (at your option) any later version.

    DCP-o-matic 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 DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.

*/


#include "dcpomatic_time.h"
#include <boost/optional.hpp>
#include <vector>


class FrameIntervalChecker
{
public:
	FrameIntervalChecker () {}
	FrameIntervalChecker (FrameIntervalChecker const &) = delete;
	FrameIntervalChecker& operator= (FrameIntervalChecker const &) = delete;

	void feed (dcpomatic::ContentTime time, double frame_rate);

	enum Guess
	{
		AGAIN,
		PROBABLY_3D,
		PROBABLY_NOT_3D
	};

	Guess guess () const;

private:
	boost::optional<dcpomatic::ContentTime> _last;
	/** Intervals of last frames, in fractions of a frame; i.e. 1 in here
	 *  means the last two frames were one frame interval apart according
	 *  to the frame rate passed to ::feed().
	 */
	std::vector<double> _intervals;

	static int const _frames;
};