/*
    Copyright (C) 2013-2018 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 "audio_mapping.h"
#include "util.h"
#include "digester.h"
#include "audio_processor.h"
#include <dcp/raw_convert.h>
#include <libcxml/cxml.h>
#include <libxml++/libxml++.h>
#include <boost/regex.hpp>
#include <iostream>

using std::list;
using std::cout;
using std::make_pair;
using std::pair;
using std::string;
using std::min;
using std::vector;
using std::abs;
using boost::shared_ptr;
using boost::dynamic_pointer_cast;
using boost::optional;
using dcp::raw_convert;

AudioMapping::AudioMapping ()
	: _input_channels (0)
	, _output_channels (0)
{

}

/** Create an empty AudioMapping.
 *  @param input_channels Number of input channels.
 *  @param output_channels Number of output channels.
 */
AudioMapping::AudioMapping (int input_channels, int output_channels)
{
	setup (input_channels, output_channels);
}

void
AudioMapping::setup (int input_channels, int output_channels)
{
	DCPOMATIC_ASSERT (input_channels >= 0);
	DCPOMATIC_ASSERT (output_channels >= 0);

	_input_channels = input_channels;
	_output_channels = output_channels;

	_gain.resize (static_cast<size_t>(_input_channels));
	for (int i = 0; i < _input_channels; ++i) {
		_gain[i].resize (static_cast<size_t>(_output_channels));
	}

	make_zero ();
}

void
AudioMapping::make_zero ()
{
	for (int i = 0; i < _input_channels; ++i) {
		for (int j = 0; j < _output_channels; ++j) {
			_gain[i][j] = 0;
		}
	}
}

struct ChannelRegex
{
	ChannelRegex (string regex_, int channel_)
		: regex (regex_)
		, channel (channel_)
	{}

	string regex;
	int channel;
};

void
AudioMapping::make_default (AudioProcessor const * processor, optional<boost::filesystem::path> filename)
{
	static ChannelRegex const regex[] = {
		ChannelRegex(".*[\\._-]L[\\._-].*", 0),
		ChannelRegex(".*[\\._-]R[\\._-].*", 1),
		ChannelRegex(".*[\\._-]C[\\._-].*", 2),
		ChannelRegex(".*[\\._-]Lfe[\\._-].*", 3),
		ChannelRegex(".*[\\._-]LFE[\\._-].*", 3),
		ChannelRegex(".*[\\._-]Lss[\\._-].*", 4),
		ChannelRegex(".*[\\._-]Lsr[\\._-].*", 6),
		ChannelRegex(".*[\\._-]Ls[\\._-].*", 4),
		ChannelRegex(".*[\\._-]Rss[\\._-].*", 5),
		ChannelRegex(".*[\\._-]Rsr[\\._-].*", 7),
		ChannelRegex(".*[\\._-]Rs[\\._-].*", 5),
	};

	static int const regexes = sizeof(regex) / sizeof(*regex);

	if (processor) {
		processor->make_audio_mapping_default (*this);
	} else {
		make_zero ();
		if (input_channels() == 1) {
			bool guessed = false;

			/* See if we can guess where this stream should go */
			if (filename) {
				for (int i = 0; i < regexes; ++i) {
					boost::regex e (regex[i].regex, boost::regex::icase);
					if (boost::regex_match(filename->string(), e) && regex[i].channel < output_channels()) {
						set (0, regex[i].channel, 1);
						guessed = true;
					}
				}
			}

			if (!guessed) {
				/* If we have no idea, just put it on centre */
				set (0, static_cast<int>(dcp::CENTRE), 1);
			}
		} else {
			/* 1:1 mapping */
			for (int i = 0; i < min (input_channels(), output_channels()); ++i) {
				set (i, i, 1);
			}
		}
	}
}

AudioMapping::AudioMapping (cxml::ConstNodePtr node, int state_version)
{
	if (state_version < 32) {
		setup (node->number_child<int> ("ContentChannels"), MAX_DCP_AUDIO_CHANNELS);
	} else {
		setup (node->number_child<int> ("InputChannels"), node->number_child<int> ("OutputChannels"));
	}

	if (state_version <= 5) {
		/* Old-style: on/off mapping */
		list<cxml::NodePtr> const c = node->node_children ("Map");
		for (list<cxml::NodePtr>::const_iterator i = c.begin(); i != c.end(); ++i) {
			set ((*i)->number_child<int> ("ContentIndex"), static_cast<dcp::Channel> ((*i)->number_child<int> ("DCP")), 1);
		}
	} else {
		list<cxml::NodePtr> const c = node->node_children ("Gain");
		for (list<cxml::NodePtr>::const_iterator i = c.begin(); i != c.end(); ++i) {
			if (state_version < 32) {
				set (
					(*i)->number_attribute<int> ("Content"),
					static_cast<dcp::Channel> ((*i)->number_attribute<int> ("DCP")),
					raw_convert<float> ((*i)->content ())
					);
			} else {
				set (
					(*i)->number_attribute<int> ("Input"),
					(*i)->number_attribute<int> ("Output"),
					raw_convert<float> ((*i)->content ())
					);
			}
		}
	}
}

void
AudioMapping::set (int input_channel, int output_channel, float g)
{
	DCPOMATIC_ASSERT (input_channel >= 0 && input_channel < int(_gain.size()));
	DCPOMATIC_ASSERT (output_channel >= 0 && output_channel < int(_gain[0].size()));
	_gain[static_cast<size_t>(input_channel)][static_cast<size_t>(output_channel)] = g;
}

float
AudioMapping::get (int input_channel, int output_channel) const
{
	DCPOMATIC_ASSERT (input_channel >= 0 && input_channel < int(_gain.size()));
	DCPOMATIC_ASSERT (output_channel >= 0 && output_channel < int(_gain[0].size()));
	return _gain[static_cast<size_t>(input_channel)][static_cast<size_t>(output_channel)];
}

void
AudioMapping::as_xml (xmlpp::Node* node) const
{
	node->add_child ("InputChannels")->add_child_text (raw_convert<string> (_input_channels));
	node->add_child ("OutputChannels")->add_child_text (raw_convert<string> (_output_channels));

	for (int c = 0; c < _input_channels; ++c) {
		for (int d = 0; d < _output_channels; ++d) {
			xmlpp::Element* t = node->add_child ("Gain");
			t->set_attribute ("Input", raw_convert<string> (c));
			t->set_attribute ("Output", raw_convert<string> (d));
			t->add_child_text (raw_convert<string> (get (c, d)));
		}
	}
}

/** @return a string which is unique for a given AudioMapping configuration, for
 *  differentiation between different AudioMappings.
 */
string
AudioMapping::digest () const
{
	Digester digester;
	digester.add (_input_channels);
	digester.add (_output_channels);
	for (size_t i = 0; i < static_cast<size_t>(_input_channels); ++i) {
		for (int j = 0; j < static_cast<size_t>(_output_channels); ++j) {
			digester.add (_gain[i][j]);
		}
	}

	return digester.get ();
}

list<int>
AudioMapping::mapped_output_channels () const
{
	static float const minus_96_db = 0.000015849;

	list<int> mapped;

	for (vector<vector<float> >::const_iterator i = _gain.begin(); i != _gain.end(); ++i) {
		for (size_t j = 0; j < i->size(); ++j) {
			if (abs ((*i)[j]) > minus_96_db) {
				mapped.push_back (j);
			}
		}
	}

	mapped.sort ();
	mapped.unique ();

	return mapped;
}

void
AudioMapping::unmap_all ()
{
	for (vector<vector<float> >::iterator i = _gain.begin(); i != _gain.end(); ++i) {
		for (vector<float>::iterator j = i->begin(); j != i->end(); ++j) {
			*j = 0;
		}
	}
}