/*
 * uptime.c - display system uptime
 * Copyright (C) 2012-2015 Craig Small <csmall@dropbear.xyz>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <errno.h>
#include <getopt.h>
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <sys/time.h>

#include "c.h"
#include "fileutils.h"
#include "nls.h"

#include <proc/misc.h>

static void print_uptime_since()
{
    double now, uptime_secs, idle_secs;
    time_t up_since_secs;
    struct tm *up_since;
    struct timeval tim;

    /* Get the current time and convert it to a double */
	if (gettimeofday(&tim, NULL) != 0)
        xerr(EXIT_FAILURE, "gettimeofday");
    now = tim.tv_sec + (tim.tv_usec / 1000000.0);

    /* Get the uptime and calculate when that was */
	if (procps_uptime(&uptime_secs, &idle_secs) < 0)
		xerr(EXIT_FAILURE, _("Cannot get system uptime"));
    up_since_secs = (time_t) ((now - uptime_secs) + 0.5);

    /* Show this */
	if ((up_since = localtime(&up_since_secs)) == NULL)
		xerrx(EXIT_FAILURE, "localtime");
    printf("%04d-%02d-%02d %02d:%02d:%02d\n",
        up_since->tm_year + 1900, up_since->tm_mon + 1, up_since->tm_mday,
        up_since->tm_hour, up_since->tm_min, up_since->tm_sec);
}

static void __attribute__ ((__noreturn__)) usage(FILE * out)
{
    fputs(USAGE_HEADER, out);
    fprintf(out, _(" %s [options]\n"), program_invocation_short_name);
    fputs(USAGE_OPTIONS, out);
    fputs(_(" -p, --pretty   show uptime in pretty format\n"), out);
    fputs(USAGE_HELP, out);
    fputs(_(" -s, --since    system up since\n"), out);
    fputs(USAGE_VERSION, out);
    fprintf(out, USAGE_MAN_TAIL("uptime(1)"));

    exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}

int main(int argc, char **argv)
{
    int c, p = 0;
    char *uptime_str;

    static const struct option longopts[] = {
        {"pretty", no_argument, NULL, 'p'},
        {"help", no_argument, NULL, 'h'},
        {"since", no_argument, NULL, 's'},
        {"version", no_argument, NULL, 'V'},
        {NULL, 0, NULL, 0}
    };

#ifdef HAVE_PROGRAM_INVOCATION_NAME
    program_invocation_name = program_invocation_short_name;
#endif
    setlocale (LC_ALL, "");
    bindtextdomain(PACKAGE, LOCALEDIR);
    textdomain(PACKAGE);
    atexit(close_stdout);

    while ((c = getopt_long(argc, argv, "phsV", longopts, NULL)) != -1)
        switch (c) {
        case 'p':
            p = 1;
            break;
        case 'h':
            usage(stdout);
        case 's':
            print_uptime_since();
            return EXIT_SUCCESS;
        case 'V':
            printf(PROCPS_NG_VERSION);
            return EXIT_SUCCESS;
        default:
            usage(stderr);
        }

    if (optind != argc)
        usage(stderr);

    if (p)
        uptime_str = procps_uptime_sprint_short();
    else
        uptime_str = procps_uptime_sprint();

    if (!uptime_str || uptime_str[0] == '\0')
       xerr(EXIT_FAILURE, _("Cannot get system uptime"));

    printf("%s\n", uptime_str);
    return EXIT_SUCCESS;
}