/* -*- c++ -*- */
/* 
 * Copyright 2019 Thomas Kolb.
 * 
 * This 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 3, or (at your option)
 * any later version.
 * 
 * This software 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 software; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <gnuradio/io_signature.h>
#include "pid_controller_impl.h"

namespace gr {
	namespace hamnet70 {

		pid_controller::sptr
		pid_controller::make(size_t interval, float p, float i, float d, float post_gain)
		{
			return gnuradio::get_initial_sptr
				(new pid_controller_impl(interval, p, i, d, post_gain));
		}

		/*
		 * The private constructor
		 */
		pid_controller_impl::pid_controller_impl(size_t interval, float p, float i, float d, float post_gain)
			: gr::sync_block("pid_controller",
					gr::io_signature::make(1, 1, sizeof(float)),
					gr::io_signature::make(0, 0, 0)),
				d_interval(interval),
				d_lastInput(0),
				d_iVal(0),
				d_postGain(post_gain)
		{
			// TODO: scale with interval?
			d_kp = p;
			d_ki = i;
			d_kd = d;

			message_port_register_out(pmt::mp("control_value"));
		}

		/*
		 * Our virtual destructor.
		 */
		pid_controller_impl::~pid_controller_impl()
		{
		}

		int
		pid_controller_impl::work(int noutput_items,
				gr_vector_const_void_star &input_items,
				gr_vector_void_star &output_items)
		{
			const float *in = (const float *) input_items[0];

			while(d_nextSampleIdx < noutput_items) {
				const float &inp = in[d_nextSampleIdx];

				// proportional part
				float control_value = d_kp * inp;

				// integral part
				d_iVal += d_ki * inp;
				control_value += d_iVal;

				// differential part
				control_value += d_kd * (inp - d_lastInput);
				d_lastInput = inp;

				message_port_pub(pmt::intern("control_value"), pmt::from_double(d_postGain * control_value));

				d_nextSampleIdx += d_interval;
			}

			d_nextSampleIdx -= noutput_items;

			// Tell runtime system how many output items we produced.
			return noutput_items;
		}

	} /* namespace hamnet70 */
} /* namespace gr */