#include <avr/interrupt.h>
#include "Robostix.h"
#include "timer0.h"

volatile ticks_t overflow0 = 0;
void (*timer0_handler)(ticks_t ticks) = 0;

#define TCCR0_INIT 0x0F // 0x0 0 0 0 1 1 1 1
#define TIMSK_INIT 0x02
#define COUNT_TOP 156

/**
 * This will fire every 10msec as set in init_timer0, it will also call
 * any assigned function to allow user specific processing
 */
ISR(TIMER0_COMP_vect) {
  overflow0++;

  if (timer0_handler) {
    timer0_handler(overflow0);
  }
}

void delay_10ms() {
  uint8_t prev = overflow0;

  while (prev == overflow0);
}

void delay_100ms(uint8_t num) {
  while (num--) {
    int8_t i;
    for(i = 0; i < 10; i++) {
      delay_10ms();
    }
  }
}

void init_timer0(void (*func)(ticks_t ticks)) {
  /* Assign handler */
  timer0_handler = func;
  
  /* Set the timer to use <mode> with a prescaler of <value> */
  TCCR0 = TCCR0_INIT;

  // Set "TOP" counter value.
  OCR0 = COUNT_TOP;

  /* Enable interrupt */
  TIMSK |= TIMSK_INIT;
}