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

#define F_CPU 16000000UL

typedef enum
{
  intermediate,
  yellowstate,
  intermediate1,
  yellowstate1
}trafficstate;

volatile trafficstate currentstate = intermediate;

void init(void)
{
  DDRD |= (1 << PD0) | (1 << PB1) | (1 << PD2);
  DDRC |= 0b00000111;

  TCCR1A |= (1 << COM1A1);
  TCCR1B |= (1 << WGM12) | (1 << CS12) | (1 << CS10);
  OCR1A = 15624;
  TIMSK1 |= (1 << OCIE1A);

  sei();
}

void updatelights(void)
{
  switch(currentstate)
  {
    case intermediate:
    PORTD = (1 << PD0);
    PORTC = (1 << PC2);
    break;
    case yellowstate:
    PORTD = (1 << PD1);
    break;
    case intermediate1:
    PORTD = (1 << PD2);
    PORTC = (1 << PC0);
    break;
    case yellowstate1:
    PORTC = (1 << PC1);
    break;
  }
}

ISR(TIMER1_COMPA_vect)
{
  static uint8_t timeinstate = 0;
  timeinstate++;
  switch(currentstate)
  {
    case intermediate:
    if(timeinstate >= 7)
    {
      currentstate = yellowstate;
      timeinstate = 0;
    }
    break;
    case yellowstate:
    if(timeinstate >= 5)
    {
      currentstate = intermediate1;
      timeinstate = 0;
    }
    break;
    case intermediate1:
    if(timeinstate >= 7)
    {
      currentstate = yellowstate1;
      timeinstate = 0;
    }
    break;
    case yellowstate1:
    if(timeinstate >= 5)
    {
      currentstate = intermediate;
      timeinstate = 0;
    }
    break;
  }
  updatelights();
}

int main(void)
{
  init();
  updatelights();

  while(1)
  {

  }
  return 0;
}