/* -*- c++ -*- */
/* 
 * Copyright 2019 Jay Arrowfield.
 * 
 * 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 "preamble_sync_impl.h"

namespace gr
{
namespace jay
{

preamble_sync::sptr preamble_sync::make()
{
	return gnuradio::get_initial_sptr (new preamble_sync_impl());
}

/*
 * The private constructor
 */
preamble_sync_impl::preamble_sync_impl()
: gr::block("preamble_sync", gr::io_signature::make(1, 1, sizeof(uint8_t)), gr::io_signature::make(1, 1, sizeof(uint8_t)))
, m_state(Init)
, m_stateNext(Init)
, m_word(0)
, m_wordCount(0)
, m_preambleCount(0)
{
}

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

void preamble_sync_impl::forecast (int noutput_items, gr_vector_int &ninput_items_required)
{
	ninput_items_required[0] = 8*noutput_items;
}

int preamble_sync_impl::general_work (int noutput_items, gr_vector_int &ninput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items)
{
	size_t const word_size = 8;
	
	const uint8_t *in = (const uint8_t *) input_items[0];
	uint8_t *out = (uint8_t *) output_items[0];

	// Do <+signal processing+>
	size_t i = 0;
	size_t j = 0;
	for (i=0; i < ninput_items[0]; i++)
	{
		if (in[i] == 0xFF)
		{
			if (m_state != Init)
			{
				m_state = Init;
				fprintf(stderr, "Init\n");
			}
			continue;
		}
		m_word = (m_word << 1) | in[i];
		
		if (m_wordCount != 0)
		{
			m_wordCount--;
			continue;
		}
		
		m_word &= (typeof(m_word))(1 << word_size)-1;
		m_stateNext = m_state;
		switch (m_state)
		{
			case Init:
				if (m_word != 0xCC)
				{
					m_wordCount = 0;
					m_preambleCount = 8;
				}
				else
				{
					m_wordCount = word_size-1;
					if (m_preambleCount)
					{
						m_preambleCount--;
					}
					else
					{
						m_stateNext = Preamble;
						fprintf(stderr, "Preamble\n");
					}
				}
				break;
			case Preamble:
				m_wordCount = word_size-1;
				if (m_word == 0xC0)
				{
					m_stateNext = Sync;
					fprintf(stderr, "Sync 1\n");
				}
				else if (m_word == 0xCF)
				{
					m_stateNext = Sync;
					fprintf(stderr, "Sync 2\n");
				}
				else if (m_word == 0xF0)
				{
					m_wordCount = word_size/2-1;
					m_stateNext = Sync;
					fprintf(stderr, "Sync 3\n");
				}
				else if (m_word != 0xCC)
				{
					m_wordCount = 0;
					m_stateNext = Init;
				}
				break;
			case Sync:
				m_wordCount = word_size-1;
				out[j++] = m_word;
				break;
		}
		if (m_state != m_stateNext)
		{
			fprintf(stderr, "State changed\n");
		}
		m_state = m_stateNext;
	}

	// Tell runtime system how many input items we consumed on
	// each input stream.
	consume_each (i);

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

} /* namespace jay */
} /* namespace gr */