/*
    Copyright (C) 2013 Carl Hetherington <cth@carlh.net>

    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 2 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, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <boost/shared_ptr.hpp>
#include <stdint.h>
#include "trimmer.h"

using std::cout;
using std::max;
using boost::shared_ptr;

/** @param audio_sample_rate Audio sampling rate, or 0 if there is no audio */
Trimmer::Trimmer (
	shared_ptr<Log> log,
	int video_trim_start,
	int video_trim_end,
	int video_length,
	int audio_sample_rate,
	float frames_per_second,
	int dcp_frames_per_second
	)
	: AudioVideoProcessor (log)
	, _video_start (video_trim_start)
	, _video_end (video_length - video_trim_end)
	, _video_in (0)
	, _audio_in (0)
{
	FrameRateConversion frc (frames_per_second, dcp_frames_per_second);

	if (frc.skip) {
		_video_start /= 2;
		_video_end /= 2;
	} else if (frc.repeat) {
		_video_start *= 2;
		_video_end *= 2;
	}

	if (audio_sample_rate) {
		_audio_start = video_frames_to_audio_frames (_video_start, audio_sample_rate, frames_per_second);
		_audio_end = video_frames_to_audio_frames (_video_end, audio_sample_rate, frames_per_second);
	}

	/* XXX: this is a hack; if there is no trim at the end, set
	   the audio end point to infinity so that
	   shorter-video-than-audio does not trim audio (which breaks
	   the current set of regression tests).  This could be
	   removed if a) the regression tests are regenerated and b) I
	   can work out what DCP length should be.

	   There is also a problem whereby black video frames inserted
	   at the start of the output by the matcher are not taken into account,
	   so if black frames are inserted it means more gets trimmed off the
	   end than should be.  Hack around this in similar fashion with the
	   _video_end = INT_MAX line.
	*/
	if (video_trim_end == 0) {
		_video_end = INT_MAX;
		_audio_end = INT64_MAX;
	}
}

void
Trimmer::process_video (shared_ptr<const Image> image, bool same, shared_ptr<Subtitle> sub)
{
	if (_video_in >= _video_start && _video_in < _video_end) {
		Video (image, same, sub);
	}
	
	++_video_in;
}

void
Trimmer::process_audio (shared_ptr<const AudioBuffers> audio)
{
	int64_t offset = _audio_start - _audio_in;
	if (offset > audio->frames()) {
		/* we haven't reached the start of the untrimmed section yet */
		_audio_in += audio->frames ();
		return;
	}

	if (offset < 0) {
		offset = 0;
	}

	int64_t length = _audio_end - max (_audio_in, _audio_start);
	if (length < 0) {
		_audio_in += audio->frames ();
		return;
	}

	if (length > (audio->frames() - offset)) {
		length = audio->frames () - offset;
	}

	_audio_in += audio->frames ();
	
	if (offset != 0 || length != audio->frames ()) {
		shared_ptr<AudioBuffers> copy (new AudioBuffers (audio));
		copy->move (offset, 0, length);
		copy->set_frames (length);
		audio = copy;
	}
	
	Audio (audio);
}