/*
 *    Filename: heart.c
 * Description: fps 에 한번씩 호출되는 "심장" 이다.
 *
 *      Author: 비엽 aka. Cronan
 */
#define __LIBTHECORE__
#include "stdafx.h"

extern volatile int num_events_called;

LPHEART heart_new(int opt_usec, HEARTFUNC func)
{
    LPHEART ht;

    if (!func)
    {
	sys_err("no function defined");
	return NULL;
    }

    CREATE(ht, HEART, 1);

    ht->func = func;
    ht->opt_time.tv_sec = 0;
    ht->opt_time.tv_usec = opt_usec;
    ht->passes_per_sec = 1000000 / opt_usec;
    gettimeofday(&ht->last_time, (struct timezone *) 0);
    gettimeofday(&ht->before_sleep, (struct timezone *) 0);
    return (ht);
}

void heart_delete(LPHEART ht)
{
    free(ht);
}

int heart_idle(LPHEART ht)
{
    struct timeval now, process_time, timeout, temp_time;
    int missed_pulse;

    gettimeofday(&ht->before_sleep, (struct timezone *) 0);
    process_time = *timediff(&ht->before_sleep, &ht->last_time);

    /*
     * If we were asleep for more than one pass, count missed pulses and sleep
     * until we're resynchronized with the next upcoming pulse.
     */
    if (process_time.tv_sec == 0 && process_time.tv_usec < ht->opt_time.tv_usec)
    {
	missed_pulse = 0;
    }
    else
    {
	missed_pulse = process_time.tv_sec * ht->passes_per_sec;
	missed_pulse += process_time.tv_usec / ht->opt_time.tv_usec;
    }

	// 바빠서 pulse도 놓쳤는데 잘 시간이 어딨어...
	// 펄스 fps 어차피 틀어져있는데, 정확히 맞추는 건 중요하지 않아.
	if (missed_pulse > 0)
	{
		gettimeofday(&ht->last_time, (struct timezone *) 0);
	}
	else
	{
		/* Calculate the time we should wake up */
		temp_time = *timediff(&ht->opt_time, &process_time);
		ht->last_time = *timeadd(&ht->before_sleep, &temp_time);

		/* Now keep sleeping until that time has come */
		gettimeofday(&now, (struct timezone *) 0);
		timeout = *timediff(&ht->last_time, &now);

		thecore_sleep(&timeout);
	}

    ++missed_pulse;

    if (missed_pulse <= 0)
    {
	sys_err("missed_pulse is not positive! (%d)", missed_pulse);
	missed_pulse = 1;
    }

    if (missed_pulse > (30 * ht->passes_per_sec))
    {
	sys_err("losing %d seconds. (lag occured)", missed_pulse / ht->passes_per_sec);
	missed_pulse = 30 * ht->passes_per_sec;
    }

    return missed_pulse;
}