// SPDX-FileCopyrightText: 2024 Lizzy Fleckenstein <lizzy@vlhl.dev>
//
// SPDX-License-Identifier: AGPL-3.0-or-later

#include "ticker.h"

static struct timespec timestamp_now()
{
	struct timespec ts;
	clock_gettime(CLOCK_REALTIME, &ts); // TODO: handle error
	return ts;
}

static uint64_t timestamp_diff(struct timespec a, struct timespec b)
{
	return ((uint64_t) a.tv_sec - b.tv_sec) * NANOS + a.tv_nsec - b.tv_nsec;
}

void ticker_init(ticker *t, uint64_t f)
{
	t->freq_nanos = f;
	t->timestamp = timestamp_now();
}

bool ticker_tick(ticker *t, uint64_t *dtime)
{
	struct timespec ts = timestamp_now();
	*dtime = timestamp_diff(ts, t->timestamp);
	if (*dtime < t->freq_nanos)
		return false;
	t->timestamp = ts;
	return true;
}

// millis
int ticker_timeout(ticker *t)
{
	uint64_t nanos = timestamp_diff(timestamp_now(), t->timestamp);
	if (t->freq_nanos > nanos)
		return (t->freq_nanos - nanos) / 1000000; // nanos to millis
	else
		return 0;
}