#include <kernel/syscalls.h>
#include <time.h>
#include <kernel/scheduler.h>
#include <logging.h>

#define ITIMER_REAL 0
#define ITIMER_VIRTUAL 1
#define ITIMER_PROF 2

typedef struct {
	timeval_t interval;
	timeval_t value;
} itimerval_t;

static itimer_t *selectitimer(int which) {
	itimer_t *itimer = NULL;
	if (which == ITIMER_REAL)
		itimer = &current_thread()->proc->timer.realtime;
	else if (which == ITIMER_VIRTUAL)
		itimer = &current_thread()->proc->timer.virtualtime;
	else if (which == ITIMER_PROF)
		itimer = &current_thread()->proc->timer.profiling;

	return itimer;
}

syscallret_t syscall_getitimer(context_t *context, int which, itimerval_t *value) {
	syscallret_t ret = {
		.ret = -1
	};

	if (which != ITIMER_REAL) {
		ret.errno = EOPNOTSUPP;
		return ret;
	}

	itimer_t *itimer = selectitimer(which);
	if (itimer == NULL) {
		ret.errno = EINVAL;
		return ret;
	}

	MUTEX_ACQUIRE(&current_thread()->proc->timer.mutex);

	uintmax_t oldremaining, oldrepeat;
	itimer_pause(itimer, &oldremaining, &oldrepeat);
	if (oldremaining)
		itimer_resume(itimer);

	MUTEX_RELEASE(&current_thread()->proc->timer.mutex);

	itimerval_t tmp;

	tmp.interval.s = oldrepeat / 1000000;
	tmp.interval.us = oldrepeat % 1000000;
	tmp.value.s = oldremaining / 1000000;
	tmp.value.us = oldremaining % 1000000;
	ret.errno = usercopy_touser(value, &tmp, sizeof(tmp));
	ret.ret = ret.errno ? -1 : 0;
	return ret;
}

syscallret_t syscall_setitimer(context_t *context, int which, itimerval_t *unew, itimerval_t *uold) {
	syscallret_t ret = {
		.ret = -1
	};

	if (which != ITIMER_REAL) {
		ret.errno = EOPNOTSUPP;
		return ret;
	}

	itimer_t *itimer = selectitimer(which);
	if (itimer == NULL) {
		ret.errno = EINVAL;
		return ret;
	}

	itimerval_t val = {0};
	if (unew) {
		ret.errno = usercopy_fromuser(&val, unew, sizeof(val));
		if (ret.errno)
			return ret;
	}

	MUTEX_ACQUIRE(&current_thread()->proc->timer.mutex);
	uintmax_t oldremaining, oldrepeat;
	itimer_pause(itimer, &oldremaining, &oldrepeat);

	uintmax_t repeatus = val.interval.s * 1000000 + val.interval.us;
	uintmax_t newus = val.value.s * 1000000 + val.value.us;
	itimer_set(itimer, newus, repeatus);

	if (newus)
		itimer_resume(itimer);

	MUTEX_RELEASE(&current_thread()->proc->timer.mutex);

	ret.errno = 0;
	if (uold) {
		itimerval_t tmp;
		uold->interval.s = oldrepeat / 1000000;
		uold->interval.us = oldrepeat % 1000000;
		uold->value.s = oldremaining / 1000000;
		uold->value.us = oldremaining % 1000000;
		ret.errno = usercopy_touser(uold, &tmp, sizeof(tmp));
	}

	ret.ret = ret.errno ? -1 : 0;

	return ret;
}