/*
 * Copyright (C) 2011-2017 Paul Davis <paul@linuxaudiosystems.com>
 * Copyright (C) 2011 Carl Hetherington <carl@carlh.net>
 * Copyright (C) 2013 John Emmas <john@creativepost.co.uk>
 * Copyright (C) 2014 Robin Gareus <robin@gareus.org>
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>

#include <iostream>
#include <string>

#ifdef COMPILER_MSVC
#include <malloc.h>
#endif

#include "pbd/cartesian.h"
#include "pbd/compose.h"

#include "ardour/amp.h"
#include "ardour/audio_buffer.h"
#include "ardour/buffer_set.h"
#include "ardour/pan_controllable.h"
#include "ardour/pannable.h"
#include "ardour/speakers.h"

#include "vbap.h"
#include "vbap_speakers.h"

#include "pbd/i18n.h"

using namespace PBD;
using namespace ARDOUR;
using namespace std;

static PanPluginDescriptor _descriptor = {
	"VBAP 2D panner",
	"http://ardour.org/plugin/panner_vbap",
	"http://ardour.org/plugin/panner_vbap#ui",
	-1, -1,
	10,
	VBAPanner::factory
};

extern "C" ARDOURPANNER_API PanPluginDescriptor*
panner_descriptor ()
{
	return &_descriptor;
}

VBAPanner::Signal::Signal (VBAPanner&, uint32_t, uint32_t n_speakers)
{
	resize_gains (n_speakers);

	desired_gains[0] = desired_gains[1] = desired_gains[2] = 0;
	outputs[0] = outputs[1] = outputs[2] = -1;
	desired_outputs[0] = desired_outputs[1] = desired_outputs[2] = -1;
}

void
VBAPanner::Signal::resize_gains (uint32_t n)
{
	gains.assign (n, 0.0);
}

VBAPanner::VBAPanner (std::shared_ptr<Pannable> p, std::shared_ptr<Speakers> s)
	: Panner (p)
	, _speakers (new VBAPSpeakers (s))
{
	_pannable->pan_azimuth_control->Changed.connect_same_thread (*this, std::bind (&VBAPanner::update, this));
	_pannable->pan_elevation_control->Changed.connect_same_thread (*this, std::bind (&VBAPanner::update, this));
	_pannable->pan_width_control->Changed.connect_same_thread (*this, std::bind (&VBAPanner::update, this));
	if (!_pannable->has_state ()) {
		reset ();
	}

	update ();
}

VBAPanner::~VBAPanner ()
{
	clear_signals ();
}

void
VBAPanner::clear_signals ()
{
	for (vector<Signal*>::iterator i = _signals.begin (); i != _signals.end (); ++i) {
		delete *i;
	}
	_signals.clear ();
}

void
VBAPanner::configure_io (ChanCount in, ChanCount /* ignored - we use Speakers */)
{
	uint32_t n = in.n_audio ();

	clear_signals ();

	for (uint32_t i = 0; i < n; ++i) {
		Signal* s = new Signal (*this, i, _speakers->n_speakers ());
		_signals.push_back (s);
	}

	update ();
}

void
VBAPanner::update ()
{
	_can_automate_list.clear ();
	_can_automate_list.insert (Evoral::Parameter (PanAzimuthAutomation));
	if (_signals.size () > 1) {
		_can_automate_list.insert (Evoral::Parameter (PanWidthAutomation));
	}
	if (_speakers->dimension () == 3) {
		_can_automate_list.insert (Evoral::Parameter (PanElevationAutomation));
	}

	/* recompute signal directions based on panner azimuth and, if relevant, width (diffusion) and elevation parameters */
	double elevation = _pannable->pan_elevation_control->get_value () * 90.0;

	if (_signals.size () > 1) {
		double w                   = -(_pannable->pan_width_control->get_value ());
		double signal_direction    = 1.0 - (_pannable->pan_azimuth_control->get_value () + (w / 2));
		double grd_step_per_signal = w / (_signals.size () - 1);
		for (vector<Signal*>::iterator s = _signals.begin (); s != _signals.end (); ++s) {
			Signal* signal = *s;

			int over = signal_direction;
			over -= (signal_direction >= 0) ? 0 : 1;
			signal_direction -= (double)over;

			signal->direction = AngularVector (signal_direction * 360.0, elevation);
			compute_gains (signal->desired_gains, signal->desired_outputs, signal->direction.azi, signal->direction.ele);
			signal_direction += grd_step_per_signal;
		}
	} else if (_signals.size () == 1) {
		double center = (1.0 - _pannable->pan_azimuth_control->get_value ()) * 360.0;

		/* width has no role to play if there is only 1 signal: VBAP does not do "diffusion" of a single channel */

		Signal* s    = _signals.front ();
		s->direction = AngularVector (center, elevation);
		compute_gains (s->desired_gains, s->desired_outputs, s->direction.azi, s->direction.ele);
	}

	SignalPositionChanged (); /* emit */
}

void
VBAPanner::compute_gains (double gains[3], int speaker_ids[3], int azi, int ele)
{
	/* calculates gain factors using loudspeaker setup and given direction */
	double    cartdir[3];
	double    power;
	int       i, j, k;
	double    small_g;
	double    big_sm_g, gtmp[3];
	const int dimension = _speakers->dimension ();
	assert (dimension == 2 || dimension == 3);

	spherical_to_cartesian (azi, ele, 1.0, cartdir[0], cartdir[1], cartdir[2]);
	big_sm_g = -100000.0;

	gains[0] = gains[1] = gains[2] = 0;
	speaker_ids[0] = speaker_ids[1] = speaker_ids[2] = 0;

	for (i = 0; i < _speakers->n_tuples (); i++) {
		small_g = 10000000.0;

		for (j = 0; j < dimension; j++) {
			gtmp[j] = 0.0;

			for (k = 0; k < dimension; k++) {
				gtmp[j] += cartdir[k] * _speakers->matrix (i)[j * dimension + k];
			}

			if (gtmp[j] < small_g) {
				small_g = gtmp[j];
			}
		}

		if (small_g > big_sm_g) {
			big_sm_g = small_g;

			gains[0] = gtmp[0];
			gains[1] = gtmp[1];

			speaker_ids[0] = _speakers->speaker_for_tuple (i, 0);
			speaker_ids[1] = _speakers->speaker_for_tuple (i, 1);

			if (_speakers->dimension () == 3) {
				gains[2]       = gtmp[2];
				speaker_ids[2] = _speakers->speaker_for_tuple (i, 2);
			} else {
				gains[2]       = 0.0;
				speaker_ids[2] = -1;
			}
		}
	}

	power = sqrt (gains[0] * gains[0] + gains[1] * gains[1] + gains[2] * gains[2]);

	if (power > 0) {
		gains[0] /= power;
		gains[1] /= power;
		gains[2] /= power;
	}
}

void
VBAPanner::distribute (BufferSet& inbufs, BufferSet& obufs, gain_t gain_coefficient, pframes_t nframes)
{
	uint32_t                  n;
	vector<Signal*>::iterator s;

	assert (inbufs.count ().n_audio () == _signals.size ());

	for (s = _signals.begin (), n = 0; s != _signals.end (); ++s, ++n) {
		Signal* signal (*s);

		distribute_one (inbufs.get_audio (n), obufs, gain_coefficient, nframes, n);

		memcpy (signal->outputs, signal->desired_outputs, sizeof (signal->outputs));
	}
}

void
VBAPanner::distribute_one (AudioBuffer& srcbuf, BufferSet& obufs, gain_t gain_coefficient, pframes_t nframes, uint32_t which)
{
	Sample* const src = srcbuf.data ();
	Signal*       signal (_signals[which]);

	/* VBAP may distribute the signal across up to 3 speakers depending on
	 * the configuration of the speakers.
	 *
	 * But the set of speakers in use "this time" may be different from
	 * the set of speakers "the last time". So we have up to 6 speakers
	 * involved, and we have to interpolate so that those no longer
	 * in use are rapidly faded to silence and those newly in use
	 * are rapidly faded to their correct level. This prevents clicks
	 * as we change the set of speakers used to put the signal in
	 * a given position.
	 *
	 * However, the speakers are represented by output buffers, and other
	 * speakers may write to the same buffers, so we cannot use
	 * anything here that will simply assign new (sample) values
	 * to the output buffers - everything must be done via mixing
	 * functions and not assignment/copying.
	 */

	vector<double>::size_type sz = signal->gains.size ();

	assert (sz == obufs.count ().n_audio ());

	int8_t* outputs = (int8_t*)alloca (sz); // on the stack, no malloc

	/* set initial state of each output "record"
         */

	for (uint32_t o = 0; o < sz; ++o) {
		outputs[o] = 0;
	}

	/* for all outputs used this time and last time,
				 * change the output record to show what has
				 * happened.
				 */

	for (int o = 0; o < 3; ++o) {
		if (signal->outputs[o] != -1) {
			/* used last time */
			outputs[signal->outputs[o]] |= 1;
		}

		if (signal->desired_outputs[o] != -1) {
			/* used this time */
			outputs[signal->desired_outputs[o]] |= 1 << 1;
		}
	}

	/* at this point, we can test a speaker's status:
	 *
	 * (*outputs[o] & 1)      <= in use before
	 * (*outputs[o] & 2)      <= in use this time
	 * (*outputs[o] & 3) == 3 <= in use both times
	 * *outputs[o] == 0      <= not in use either time
	 *
	 */

	for (int o = 0; o < 3; ++o) {
		pan_t pan;
		int   output = signal->desired_outputs[o];

		if (output == -1) {
			continue;
		}

		pan = gain_coefficient * signal->desired_gains[o];

		if (pan == 0.0 && signal->gains[output] == 0.0) {
			/* nothing deing delivered to this output */

			signal->gains[output] = 0.0;

		} else if (fabs (pan - signal->gains[output]) > 0.00001) {
			/* signal to this output but the gain coefficient has changed, so
			 * interpolate between them.
			 */

			AudioBuffer& buf (obufs.get_audio (output));
			buf.accumulate_with_ramped_gain_from (srcbuf.data (), nframes, signal->gains[output], pan, 0);
			signal->gains[output] = pan;

		} else {
			/* signal to this output, same gain as before so just copy with gain */

			mix_buffers_with_gain (obufs.get_audio (output).data (), src, nframes, pan);
			signal->gains[output] = pan;
		}
	}

	/* clean up the outputs that were used last time but not this time */

	for (uint32_t o = 0; o < sz; ++o) {
		if (outputs[o] == 1) {
			/* take signal and deliver with a rapid fade out */
			AudioBuffer& buf (obufs.get_audio (o));
			buf.accumulate_with_ramped_gain_from (srcbuf.data (), nframes, signal->gains[o], 0.0, 0);
			signal->gains[o] = 0.0;
		}
	}

	/* note that the output buffers were all silenced at some point
	 * so anything we didn't write to with this signal (or any others)
	 * is just as it should be.
	 */
}

void
VBAPanner::distribute_one_automated (AudioBuffer& /*src*/, BufferSet& /*obufs*/,
                                     samplepos_t /*start*/, samplepos_t /*end*/,
                                     pframes_t /*nframes*/, pan_t** /*buffers*/, uint32_t /*which*/)
{
	/* XXX to be implemented */
}

XMLNode&
VBAPanner::get_state () const
{
	XMLNode& node (Panner::get_state ());
	node.set_property (X_ ("uri"), _descriptor.panner_uri);
	/* this is needed to allow new sessions to load with old Ardour: */
	node.set_property (X_ ("type"), _descriptor.name);
	return node;
}

Panner*
VBAPanner::factory (std::shared_ptr<Pannable> p, std::shared_ptr<Speakers> s)
{
	return new VBAPanner (p, s);
}

ChanCount
VBAPanner::in () const
{
	return ChanCount (DataType::AUDIO, _signals.size ());
}

ChanCount
VBAPanner::out () const
{
	return ChanCount (DataType::AUDIO, _speakers->n_speakers ());
}

string
VBAPanner::value_as_string (std::shared_ptr<const AutomationControl> ac) const
{
	double val = ac->get_value ();

	switch (ac->parameter ().type ()) {
		case PanAzimuthAutomation: /* direction */
			return string_compose (_ (u8"%1\u00B0"), (int(rint (val * 360.0)) + 180) % 360);

		case PanWidthAutomation: /* diffusion */
			return string_compose (_ ("%1%%"), (int)floor (100.0 * fabs (val)));

		case PanElevationAutomation: /* elevation */
			return string_compose (_ (u8"%1\u00B0"), (int)floor (90.0 * fabs (val)));

		default:
			return _ ("unused");
	}
}

AngularVector
VBAPanner::signal_position (uint32_t n) const
{
	if (n < _signals.size ()) {
		return _signals[n]->direction;
	}

	return AngularVector ();
}

std::shared_ptr<Speakers>
VBAPanner::get_speakers () const
{
	return _speakers->parent ();
}

void
VBAPanner::set_position (double p)
{
	/* map into 0..1 range */
	int over = p;
	over -= (p >= 0) ? 0 : 1;
	p -= (double)over;
	_pannable->pan_azimuth_control->set_value (p, Controllable::NoGroup);
}

void
VBAPanner::set_width (double w)
{
	_pannable->pan_width_control->set_value (min (1.0, max (-1.0, w)), Controllable::NoGroup);
}

void
VBAPanner::set_elevation (double e)
{
	_pannable->pan_elevation_control->set_value (min (1.0, max (0.0, e)), Controllable::NoGroup);
}

void
VBAPanner::reset ()
{
	set_position (.5);
	if (_signals.size () > 1) {
		set_width (1.0 - (1.0 / (double)_signals.size ()));
	} else {
		set_width (1.0);
	}
	set_elevation (0);

	update ();
}