/*
 * Usurpation – wearable device main logic
 *
 * Copyright (C) 2019 Gediminas Jakutis
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; version 2.1
 * of the License.
 *
 * 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#include <stdlib.h>

static const unsigned int internal_led = 2;

unsigned int toggleled(void);

void setup(void)
{
	pinMode(internal_led, OUTPUT);

	/* don't set pin mode here, it will get toggled at the very start of
	 * the logic loop, either way.
	 */
}

/* the logic is a placeholder right now */
void loop(void)
{
	/* sleep length to use */
	static unsigned int delta = 100;

	/* progresivelly grow the time delta while changing state*/
	delta += delta >> (6 + toggleled());

	/* sleep */
	delay(delta);
}

/* toggle the bult-in led and return current state */
unsigned int toggleled(void)
{
	static unsigned int state = 0;

	state = !state;
	/* as the cathode of the builtin diode is connected to the MCU's pin,
	 * while the anode is connected to Vcc, to turn it off, we need to set
	 * the pin to HIGH.
	 */
	digitalWrite(internal_led, state ? LOW : HIGH);

	return state;
}