/*
    Copyright (C) 2012-2021 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/>.

*/


/** @file src/lib/filter_graph.cc
 *  @brief A graph of FFmpeg filters.
 */


#include "filter_graph.h"
#include "filter.h"
#include "exceptions.h"
#include "image.h"
extern "C" {
#include <libavfilter/buffersrc.h>
#include <libavfilter/buffersink.h>
#include <libavformat/avio.h>
}
#include <iostream>

#include "i18n.h"


using std::string;
using std::list;
using std::pair;
using std::make_pair;
using std::cout;
using std::vector;
using std::shared_ptr;
using std::weak_ptr;
using dcp::Size;


void
FilterGraph::setup(vector<Filter> const& filters)
{
	auto const filters_string = Filter::ffmpeg_string (filters);
	if (filters.empty()) {
		return;
	}

	_copy = false;

	_frame = av_frame_alloc ();

	_graph = avfilter_graph_alloc();
	if (!_graph) {
		throw DecodeError (N_("could not create filter graph."));
	}

	auto const buffer_src = avfilter_get_by_name (src_name().c_str());
	if (!buffer_src) {
		throw DecodeError (N_("could not find buffer src filter"));
	}

	auto const buffer_sink = avfilter_get_by_name (sink_name().c_str());
	if (!buffer_sink) {
		throw DecodeError (N_("Could not create buffer sink filter"));
	}

	if (avfilter_graph_create_filter (&_buffer_src_context, buffer_src, N_("in"), src_parameters().c_str(), 0, _graph) < 0) {
		throw DecodeError (N_("could not create buffer source"));
	}

#ifdef DCPOMATIC_FFMPEG_8
	_buffer_sink_context = avfilter_graph_alloc_filter(_graph, buffer_sink, N_("out"));
	if (!_buffer_sink_context) {
		throw DecodeError(N_("could not allocate buffer sink."));
	}
#else
	if (avfilter_graph_create_filter (&_buffer_sink_context, buffer_sink, N_("out"), nullptr, nullptr, _graph) < 0) {
		throw DecodeError (N_("could not create buffer sink."));
	}
#endif

	set_parameters (_buffer_sink_context);

#ifdef DCPOMATIC_FFMPEG_8
	if (avfilter_init_dict(_buffer_sink_context, nullptr) < 0) {
		throw DecodeError(N_("could not initialise buffer sink."));
	}
#endif

	auto outputs = avfilter_inout_alloc ();
	outputs->name = av_strdup(N_("in"));
	outputs->filter_ctx = _buffer_src_context;
	outputs->pad_idx = 0;
	outputs->next = 0;

	auto inputs = avfilter_inout_alloc ();
	inputs->name = av_strdup(N_("out"));
	inputs->filter_ctx = _buffer_sink_context;
	inputs->pad_idx = 0;
	inputs->next = 0;

	if (avfilter_graph_parse (_graph, filters_string.c_str(), inputs, outputs, 0) < 0) {
		throw DecodeError (N_("could not set up filter graph."));
	}

	int e = avfilter_graph_config (_graph, 0);
	if (e < 0) {
		throw DecodeError (fmt::format(N_("could not configure filter graph ({})"), e));
	}
}


FilterGraph::~FilterGraph ()
{
	if (_frame) {
		av_frame_free (&_frame);
	}

	if (_graph) {
		avfilter_graph_free (&_graph);
	}
}


AVFilterContext *
FilterGraph::get (string name)
{
	return avfilter_graph_get_filter (_graph, name.c_str());
}