/*
 * Copyright (C) 2018 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.
 */

#pragma once

#include <string>
#include <vector>

#include "readable.h"
#include "zeta-convolver.h"

namespace ZeroConvoLV2
{
class DelayLine
{
public:
	DelayLine ();
	~DelayLine ();
	void clear ();
	void reset (uint32_t delay);
	void run (float* buf, uint32_t n_samples);

private:
	float*   _buf;
	bool     _written;
	uint32_t _delay;
	uint32_t _pos;
};

class TimeDomainConvolver
{
public:
	TimeDomainConvolver ();
	void reset ();
	void configure (Readable*, float gain, uint32_t delay);
	void run (float* out, float const* in, uint32_t) const;

private:
	bool  _enabled;
	float _ir[64];
};

class Convolver
{
public:
	enum IRChannelConfig {
		Mono,         ///< 1 in, 1 out; 1ch IR
		MonoToStereo, ///< 1 in, 2 out, stereo IR  M -> L, M -> R
		Stereo,       ///< 2 in, 2 out, stereo IR  L -> L, R -> R || 4 chan IR  L -> L, L -> R, R -> R, R -> L
	};

	struct IRSettings {
		IRSettings ()
		{
			gain               = 1.0;
			pre_delay          = 0.0;
			artificial_latency = 0;
			sum_inputs         = false;

			channel_gain[0] = channel_gain[1] = channel_gain[2] = channel_gain[3] = 1.0;
			channel_delay[0] = channel_delay[1] = channel_delay[2] = channel_delay[3] = 0;
		};

		float   gain;
		int32_t pre_delay;
		int32_t artificial_latency;
		float   channel_gain[4];
		int32_t channel_delay[4];
		bool    sum_inputs;
	};

	Convolver (std::string const&,
	           uint32_t        sample_rate,
	           int             sched_policy,
	           int             sched_priority,
	           IRChannelConfig irc = Mono,
	           IRSettings      irs = IRSettings ());
	~Convolver ();

	void reconfigure (uint32_t, bool threaded = true);

	void run_buffered_mono (float*, uint32_t);
	void run_buffered_stereo (float* L, float* R, uint32_t);

	void run_mono (float*, uint32_t);
	void run_stereo (float* L, float* R, uint32_t);

	/* gain coefficients */
	void set_output_gain (float dry, float wet, bool interpolate = true);

	/* status */
	uint32_t latency   () const { return _n_samples; }
	uint32_t n_inputs  () const { return _irc < Stereo ? 1 : 2; }
	uint32_t n_outputs () const { return _irc == Mono  ? 1 : 2; }

	std::string const& path () const { return _path; }
	IRSettings const&  settings () const { return _ir_settings; }
	bool sum_inputs () const { return _ir_settings.sum_inputs; }
	int32_t artificial_latency () const { return _artificial_latency; }

	bool ready () const;
	bool reset ();

private:
	void interpolate_gain ();
	void output (float* dest, const float* src, uint32_t n) const;

	Readable*              _fs;
	std::vector<Readable*> _readables;
	Convproc               _convproc;

	std::string     _path;
	IRChannelConfig _irc;
	int             _sched_policy;
	int             _sched_priority;
	double          _period_ns;
	IRSettings      _ir_settings;

	TimeDomainConvolver _tdc[4];
	DelayLine           _dly[2];

	uint32_t _samplerate;
	uint32_t _n_samples;
	uint32_t _max_size;
	uint32_t _offset;
	int32_t  _artificial_latency;
	bool     _configured;

	float _dry;
	float _wet;
	float _dry_target;
	float _wet_target;
	float _a;
};

} /* namespace */