/**
 *  
 * Blinking LED ATTiny85 "hello world"
 *
 * Following the tutorial at:
 * http://www.instructables.com/id/Honey-I-Shrunk-the-Arduino-Moving-from-Arduino-t/?ALLSTEPS
 *  
 */

#include <avr/io.h>
// F_CPU frequency to be defined at command line
#include <util/delay.h>

#define TRUE    1
#define FALSE   0

#define LED0      PB3
#define LED1      PB2
#define LED2      PB1
#define LED3      PB0
#define LED4      PB4


const int leds[] = {LED0, LED1, LED2, LED3, LED4};
#define LED_COUNT (sizeof(leds) / sizeof(leds[0]))
uint8_t led_states[LED_COUNT];

#define DELAY_NORMAL    100;
#define DELAY_SLOW      150;
#define DELAY_FAST      50;
const int DELAY = DELAY_NORMAL;

void led_on(int led_index)
{
  PORTB |= (1 << leds[led_index]);
  led_states[led_index] = 1;
}

void led_off(int led_index)
{
  PORTB &= ~(1 << leds[led_index]);
  led_states[led_index] = 0;
}

void setup_leds()
{
  for (int i = 0; i != LED_COUNT; ++i)
  {
    DDRB |= (1 << leds[i]);
    led_off(i);
    led_states[i] = 0;
  }
}

void accumulate_next(int led_index)
{
  if(led_states[led_index])
  {
    led_off(led_index);
  }
  else
  {
    led_on(led_index);
  }
  _delay_ms(DELAY);
}

void accumulate()
{
  for (int i = 0; i != LED_COUNT; ++i)
    accumulate_next(i);
}

void accumulate_backwards()
{
  for (int i = LED_COUNT - 1; i >= 0; --i)
    accumulate_next(i);
}

void row_next(int led_index, int previous_led_index)
{
  led_on(led_index);
  led_off(previous_led_index);
  _delay_ms(DELAY);
}

void row()
{
  for (int i = 0; i != LED_COUNT; ++i)
  {
    int previous = (i + LED_COUNT - 1) % LED_COUNT;
    row_next(i, previous);
  }
}

void row_backwards()
{
  for (int i = LED_COUNT - 1; i >= 0; --i)
  {
    int previous = (i + 1) % LED_COUNT;
    row_next(i, previous);
  }
}

void all_on()
{
  for (int i = 0; i != LED_COUNT; ++i)
    led_on(i);
}

void toggle_all()
{
  for (int i = 0; i != LED_COUNT; ++i)
  {
    if(led_states[i])
      led_off(i);
    else
      led_on(i);
  }
}

void blink(int ntimes)
{
  setup_leds();
  for (int i = 0; i != ntimes * 2; ++i)
  {
    toggle_all();
    _delay_ms(DELAY);
  }
}

int main ()
{
  setup_leds();
  while (1)
  {	
    accumulate();
    accumulate_backwards();
    accumulate();
    accumulate_backwards();
    row();
    row_backwards();
    row();
    row_backwards();
    blink(5);
  }
  return 0;
}