/*
  This file is part of Ingen.
  Copyright 2007-2015 David Robillard <http://drobilla.net/>

  Ingen is free software: you can redistribute it and/or modify it under the
  terms of the GNU Affero General Public License as published by the Free
  Software Foundation, either version 3 of the License, or any later version.

  Ingen 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 Affero General Public License for details.

  You should have received a copy of the GNU Affero General Public License
  along with Ingen.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <limits.h>

#include <cmath>

#include "ingen/URIs.hpp"
#include "raul/Array.hpp"
#include "raul/Maid.hpp"

#include "Buffer.hpp"
#include "Driver.hpp"
#include "Engine.hpp"
#include "GraphImpl.hpp"
#include "InputPort.hpp"
#include "InternalPlugin.hpp"
#include "OutputPort.hpp"
#include "ProcessContext.hpp"
#include "internals/Delay.hpp"
#include "util.hpp"

#define CALC_DELAY(delaytime) \
	(f_clamp (delaytime * (float)sample_rate, 1.0f, (float)(buffer_mask + 1)))

using namespace std;

namespace Ingen {
namespace Server {
namespace Internals {

static const float MAX_DELAY_SECONDS = 8.0f;

InternalPlugin* DelayNode::internal_plugin(URIs& uris) {
	return new InternalPlugin(
		uris, Raul::URI(NS_INTERNALS "Delay"), Raul::Symbol("delay"));
}

DelayNode::DelayNode(InternalPlugin*     plugin,
                     BufferFactory&      bufs,
                     const Raul::Symbol& symbol,
                     bool                polyphonic,
                     GraphImpl*          parent,
                     SampleRate          srate)
	: InternalBlock(plugin, symbol, polyphonic, parent, srate)
	, _buffer(0)
	, _buffer_length(0)
	, _buffer_mask(0)
	, _write_phase(0)
{
	const Ingen::URIs& uris = bufs.uris();
	_ports = new Raul::Array<PortImpl*>(3);

	const float default_delay = 1.0f;
	_last_delay_time = default_delay;
	_delay_samples = default_delay;

	_delay_port = new InputPort(bufs, this, Raul::Symbol("delay"), 1, _polyphony,
	                            PortType::CONTROL, 0, bufs.forge().make(default_delay));
	_delay_port->set_property(uris.lv2_name, bufs.forge().alloc("Delay"));
	_delay_port->set_property(uris.lv2_default, bufs.forge().make(default_delay));
	_delay_port->set_property(uris.lv2_minimum, bufs.forge().make((float)(1.0/(double)srate)));
	_delay_port->set_property(uris.lv2_maximum, bufs.forge().make(MAX_DELAY_SECONDS));
	_ports->at(0) = _delay_port;

	_in_port = new InputPort(bufs, this, Raul::Symbol("in"), 0, 1,
	                         PortType::AUDIO, 0, bufs.forge().make(0.0f));
	_in_port->set_property(uris.lv2_name, bufs.forge().alloc("Input"));
	_ports->at(1) = _in_port;

	_out_port = new OutputPort(bufs, this, Raul::Symbol("out"), 0, 1,
	                           PortType::AUDIO, 0, bufs.forge().make(0.0f));
	_out_port->set_property(uris.lv2_name,
	                        bufs.forge().alloc("Output"));
	_ports->at(2) = _out_port;

	//_buffer = bufs.get(PortType::AUDIO, bufs.audio_buffer_size(buffer_length_frames), true);

}

DelayNode::~DelayNode()
{
	//_buffer.reset();
	free(_buffer);
}

void
DelayNode::activate(BufferFactory& bufs)
{
	BlockImpl::activate(bufs);
	const SampleRate  rate     = bufs.engine().driver()->sample_rate();
	const SampleCount min_size = MAX_DELAY_SECONDS * rate;

	// Smallest power of two larger than min_size
	SampleCount size = 1;
	while (size < min_size)
		size <<= 1;

	_buffer = (float*)calloc(size, sizeof(float));
	_buffer_mask = size - 1;
	_buffer_length = size;
	//_buffer->clear();
	_write_phase = 0;
}

static inline float f_clamp(float x, float a, float b)
{
	const float x1 = fabs(x - a);
	const float x2 = fabs(x - b);

	x = x1 + a + b;
	x -= x2;
	x *= 0.5;

	return x;
}

static inline float cube_interp(const float fr, const float inm1, const float
                                in, const float inp1, const float inp2)
{
	return in + 0.5f * fr * (
		inp1 - inm1 + fr * (
			4.0f * inp1 + 2.0f * inm1 - 5.0f * in - inp2 + fr * (
				3.0f * (in - inp1) - inm1 + inp2)));
}

void
DelayNode::run(ProcessContext& context)
{
	Buffer* const delay_buf = _delay_port->buffer(0).get();
	Buffer* const in_buf    = _in_port->buffer(0).get();
	Buffer* const out_buf   = _out_port->buffer(0).get();

	DelayNode* plugin_data = this;

	const float* const in            = in_buf->samples();
	float* const       out           = out_buf->samples();
	const float        delay_time    = delay_buf->samples()[0];
	const uint32_t     buffer_mask   = plugin_data->_buffer_mask;
	const SampleRate   sample_rate   = context.engine().driver()->sample_rate();
	float              delay_samples = plugin_data->_delay_samples;
	int64_t            write_phase   = plugin_data->_write_phase;
	const uint32_t     sample_count  = context.nframes();

	if (write_phase == 0) {
		_last_delay_time = delay_time;
		_delay_samples   = delay_samples = CALC_DELAY(delay_time);
	}

	if (delay_time == _last_delay_time) {
		const int64_t idelay_samples = (int64_t)delay_samples;
		const float   frac           = delay_samples - idelay_samples;

		for (uint32_t i = 0; i < sample_count; i++) {
			int64_t read_phase = write_phase - (int64_t)delay_samples;
			const float read = cube_interp(frac,
			                               buffer_at(read_phase - 1),
			                               buffer_at(read_phase),
			                               buffer_at(read_phase + 1),
			                               buffer_at(read_phase + 2));
			buffer_at(write_phase++) = in[i];
			out[i] = read;
		}
	} else {
		const float next_delay_samples  = CALC_DELAY(delay_time);
		const float delay_samples_slope = (next_delay_samples - delay_samples) / sample_count;

		for (uint32_t i = 0; i < sample_count; i++) {
			delay_samples += delay_samples_slope;
			write_phase++;
			const int64_t read_phase     = write_phase - (int64_t)delay_samples;
			const int64_t idelay_samples = (int64_t)delay_samples;
			const float   frac           = delay_samples - idelay_samples;
			const float   read           = cube_interp(frac,
			                                           buffer_at(read_phase - 1),
			                                           buffer_at(read_phase),
			                                           buffer_at(read_phase + 1),
			                                           buffer_at(read_phase + 2));
			buffer_at(write_phase) = in[i];
			out[i] = read;
		}

		_last_delay_time = delay_time;
		_delay_samples   = delay_samples;
	}

	_write_phase = write_phase;
}

} // namespace Internals
} // namespace Server
} // namespace Ingen