#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>


volatile uint32_t lights = 0b11111111111111111111;

volatile uint8_t phase_DDR[4];

volatile uint8_t phase = 0;
volatile uint8_t port = 1;

volatile uint8_t OCRvalue = 0;

volatile uint16_t counter = 0;

uint8_t map[] = {
  0, 1,  // A
  1, 0,  // B
  0, 2,  // C
  2, 0,  // D
  0, 3,  // E
  3, 0,  // F
  0, 4,  // G
  4, 0,  // H
  1, 2,  // I
  2, 1,  // J
  1, 3,  // K
  3, 1,  // L
  1, 4,  // M
  4, 1,  // N
  2, 3,  // O
  3, 2,  // P
  2, 4,  // Q
  4, 2,  // R
  3, 4,  // S
  4, 3   // T
};

void plexdata(void)
{
  phase_DDR[0] = 0;
  phase_DDR[1] = 0;
  phase_DDR[2] = 0;
  phase_DDR[3] = 0;
  phase_DDR[4] = 0;

  uint8_t a;
  uint8_t b;

  a = 0;
  for(b=0; b<20; b++)
  {
    if(lights & (uint32_t) (1 << b))
    {
      phase_DDR[map[a]] |= (1 << map[a+1]);
    }

    a += 2;
  }
}

int main(void)
{
  TCCR1B = (1 << CS13) | (1 << CS12) | (1 << CS11) | (1 << CS10);
  //TCCR1B = (1 << CS12) | (1 << CS11) | (1 << CS10);
  TIMSK = (1 << OCIE1A) | (1 << TOIE1);
  OCR1A = 0;

  ADMUX = (1 << ADLAR) | (1 << MUX2);
  ADCSR = (1 << ADEN) | (1 << ADPS2) | (1 << ADPS1);

  plexdata();

  sei();

  uint8_t fade = 0;

  while(1)
  {
    ADCSR |= (1 << ADSC);
    loop_until_bit_is_set(ADCSR, ADIF);

    if(fade)
    {
      //OCRvalue--;

      if(OCRvalue == 0)
      {
        fade = 0;
      }
    }
    else
    {
      OCRvalue++;

      if(OCRvalue == 255)
      {
        fade = 1;
      }
    }

    _delay_ms(10);
  }
}

ISR(TIMER1_CMPA_vect)
{
  PORTA = 0;
}

ISR(TIMER1_OVF1_vect)
{
  if(OCRvalue > 0)
  {
    PORTA = port;
    DDRA = phase_DDR[phase] | port;
  }

  OCR1A = OCRvalue;

  sei();

  if(phase < 4)
  {
    phase++;
    port <<= 1;
  }
  else
  {
    phase = 0;
    port = 1;
  }

  counter += ADCH;

  if(counter > 2560)
  {
    counter = 0;

    plexdata();

    lights++;

    if(lights >= 0b10000000000000000000)
    {
      lights = 1;
    }
  }
}