/*
 * Copyright (c) 2021 Yubico AB. All rights reserved.
 * Use of this source code is governed by a BSD-style
 * license that can be found in the LICENSE file.
 */

#include <errno.h>
#include "fido.h"

static int
timespec_to_ms(const struct timespec *ts)
{
        int64_t x, y;

        if (ts->tv_sec < 0 || ts->tv_nsec < 0 ||
            ts->tv_nsec >= 1000000000LL)
                return -1;

        if ((uint64_t)ts->tv_sec >= INT64_MAX / 1000LL)
                return -1;

        x = ts->tv_sec * 1000LL;
        y = ts->tv_nsec / 1000000LL;

        if (INT64_MAX - x < y || x + y > INT_MAX)
                return -1;

        return (int)(x + y);
}

int
fido_time_now(struct timespec *ts_now)
{
        if (clock_gettime(CLOCK_MONOTONIC, ts_now) != 0) {
                fido_log_error(errno, "%s: clock_gettime", __func__);
                return -1;
        }

        return 0;
}

int
fido_time_delta(const struct timespec *ts_start, int *ms_remain)
{
        struct timespec ts_end, ts_delta;
        int ms;

        if (*ms_remain < 0)
                return 0;

        if (clock_gettime(CLOCK_MONOTONIC, &ts_end) != 0) {
                fido_log_error(errno, "%s: clock_gettime", __func__);
                return -1;
        }

        if (timespeccmp(&ts_end, ts_start, <)) {
                fido_log_debug("%s: timespeccmp", __func__);
                return -1;
        }

        timespecsub(&ts_end, ts_start, &ts_delta);

        if ((ms = timespec_to_ms(&ts_delta)) < 0) {
                fido_log_debug("%s: timespec_to_ms", __func__);
                return -1;
        }

        if (ms > *ms_remain)
                ms = *ms_remain;

        *ms_remain -= ms;

        return 0;
}