/*
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1983, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>

#include <protocols/rwhod.h>

#include <dirent.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

static struct hs {
        struct  whod hs_wd;
        int     hs_nusers;
} *hs;
#define LEFTEARTH(h)    (now - (h) > 4*24*60*60)
#define ISDOWN(h)       (now - (h)->hs_wd.wd_recvtime > 11 * 60)
#define WHDRSIZE        __offsetof(struct whod, wd_we)

static size_t nhosts;
static time_t now;
static int rflg = 1;
static DIR *dirp;

static int       hscmp(const void *, const void *);
static char     *interval(time_t, const char *);
static int       iwidth(int);
static int       lcmp(const void *, const void *);
static void      ruptime(const char *, int, int (*)(const void *, const void *));
static int       tcmp(const void *, const void *);
static int       ucmp(const void *, const void *);
static void      usage(void);

int
main(int argc, char *argv[])
{
        int (*cmp)(const void *, const void *);
        int aflg, ch;

        aflg = 0;
        cmp = hscmp;
        while ((ch = getopt(argc, argv, "alrut")) != -1)
                switch (ch) {
                case 'a':
                        aflg = 1;
                        break;
                case 'l':
                        cmp = lcmp;
                        break;
                case 'r':
                        rflg = -1;
                        break;
                case 't':
                        cmp = tcmp;
                        break;
                case 'u':
                        cmp = ucmp;
                        break;
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (chdir(_PATH_RWHODIR) || (dirp = opendir(".")) == NULL)
                err(1, "%s", _PATH_RWHODIR);

        ruptime(*argv, aflg, cmp);
        while (*argv++ != NULL) {
                if (*argv == NULL)
                        break;
                ruptime(*argv, aflg, cmp);
        }
        exit(0);
}

static char *
interval(time_t tval, const char *updown)
{
        static char resbuf[32];
        int days, hours, minutes;

        if (tval < 0) {
                (void)snprintf(resbuf, sizeof(resbuf), "%s      ??:??", updown);
                return (resbuf);
        }
        /* Round to minutes. */
        minutes = (tval + (60 - 1)) / 60;
        hours = minutes / 60;
        minutes %= 60;
        days = hours / 24;
        hours %= 24;
        if (days)
                (void)snprintf(resbuf, sizeof(resbuf),
                    "%s %4d+%02d:%02d", updown, days, hours, minutes);
        else
                (void)snprintf(resbuf, sizeof(resbuf),
                    "%s      %2d:%02d", updown, hours, minutes);
        return (resbuf);
}

/* Width to print a small nonnegative integer. */
static int
iwidth(int w)
{
        if (w < 10)
                return (1);
        if (w < 100)
                return (2);
        if (w < 1000)
                return (3);
        if (w < 10000)
                return (4);
        return (5);
}

#define HS(a)   ((const struct hs *)(a))

/* Alphabetical comparison. */
static int
hscmp(const void *a1, const void *a2)
{
        return (rflg *
            strcmp(HS(a1)->hs_wd.wd_hostname, HS(a2)->hs_wd.wd_hostname));
}

/* Load average comparison. */
static int
lcmp(const void *a1, const void *a2)
{
        if (ISDOWN(HS(a1)))
                if (ISDOWN(HS(a2)))
                        return (tcmp(a1, a2));
                else
                        return (rflg);
        else if (ISDOWN(HS(a2)))
                return (-rflg);
        else
                return (rflg *
                   (HS(a2)->hs_wd.wd_loadav[0] - HS(a1)->hs_wd.wd_loadav[0]));
}

static void
ruptime(const char *host, int aflg, int (*cmp)(const void *, const void *))
{
        struct hs *hsp;
        struct whod *wd;
        struct whoent *we;
        struct dirent *dp;
        int fd, hostnamewidth, i, loadavwidth[3], userswidth, w;
        size_t hspace;
        ssize_t cc;

        rewinddir(dirp);
        hsp = NULL;
        hostnamewidth = 0;
        loadavwidth[0] = 4;
        loadavwidth[1] = 4;
        loadavwidth[2] = 4;
        userswidth = 1;
        (void)time(&now);
        for (nhosts = hspace = 0; (dp = readdir(dirp)) != NULL;) {
                if (dp->d_ino == 0 || strncmp(dp->d_name, "whod.", 5) != 0)
                        continue;
                if ((fd = open(dp->d_name, O_RDONLY, 0)) < 0) {
                        warn("%s", dp->d_name);
                        continue;
                }

                if (nhosts == hspace) {
                        if ((hs =
                            realloc(hs, (hspace += 40) * sizeof(*hs))) == NULL)
                                err(1, NULL);
                        hsp = hs + nhosts;
                }

                wd = &hsp->hs_wd;
                cc = read(fd, wd, sizeof(*wd));
                (void)close(fd);
                if (cc < (ssize_t)WHDRSIZE)
                        continue;

                if (host != NULL && strcasecmp(wd->wd_hostname, host) != 0)
                        continue;
                if (LEFTEARTH(wd->wd_recvtime))
                        continue;

                if (hostnamewidth < (int)strlen(wd->wd_hostname))
                        hostnamewidth = (int)strlen(wd->wd_hostname);

                if (!ISDOWN(hsp)) {
                        for (i = 0; i < 3; i++) {
                                w = iwidth(wd->wd_loadav[i] / 100) + 3;
                                if (loadavwidth[i] < w)
                                        loadavwidth[i] = w;
                        }
                        for (hsp->hs_nusers = 0, we = &wd->wd_we[0];
                             (char *)(we + 1) <= (char *)wd + cc; we++)
                                if (aflg || we->we_idle < 3600)
                                        ++hsp->hs_nusers;
                        if (userswidth < iwidth(hsp->hs_nusers))
                                userswidth = iwidth(hsp->hs_nusers);
                }

                ++hsp;
                ++nhosts;
        }
        if (nhosts == 0) {
                if (host == NULL)
                        errx(1, "no hosts in %s", _PATH_RWHODIR);
                else
                        warnx("host %s not in %s", host, _PATH_RWHODIR);
        }

        qsort(hs, nhosts, sizeof(hs[0]), cmp);
        w = userswidth + loadavwidth[0] + loadavwidth[1] + loadavwidth[2];
        if (hostnamewidth + w > 41)
                hostnamewidth = 41 - w; /* limit to 79 cols */
        for (i = 0; i < (int)nhosts; i++) {
                hsp = &hs[i];
                wd = &hsp->hs_wd;
                if (ISDOWN(hsp)) {
                        (void)printf("%-*.*s  %s\n",
                            hostnamewidth, hostnamewidth, wd->wd_hostname,
                            interval(now - hsp->hs_wd.wd_recvtime, "down"));
                        continue;
                }
                (void)printf(
                    "%-*.*s  %s,  %*d user%s  load %*.2f, %*.2f, %*.2f\n",
                    hostnamewidth, hostnamewidth, wd->wd_hostname,
                    interval((time_t)wd->wd_sendtime -
                        (time_t)wd->wd_boottime, "  up"),
                    userswidth, hsp->hs_nusers,
                    hsp->hs_nusers == 1 ? ", " : "s,",
                    loadavwidth[0], wd->wd_loadav[0] / 100.0,
                    loadavwidth[1], wd->wd_loadav[1] / 100.0,
                    loadavwidth[2], wd->wd_loadav[2] / 100.0);
        }
        free(hs);
        hs = NULL;
}

/* Number of users comparison. */
static int
ucmp(const void *a1, const void *a2)
{
        if (ISDOWN(HS(a1)))
                if (ISDOWN(HS(a2)))
                        return (tcmp(a1, a2));
                else
                        return (rflg);
        else if (ISDOWN(HS(a2)))
                return (-rflg);
        else
                return (rflg * (HS(a2)->hs_nusers - HS(a1)->hs_nusers));
}

/* Uptime comparison. */
static int
tcmp(const void *a1, const void *a2)
{
        return (rflg * (
                (ISDOWN(HS(a2)) ? HS(a2)->hs_wd.wd_recvtime - now
                    : HS(a2)->hs_wd.wd_sendtime - HS(a2)->hs_wd.wd_boottime)
                -
                (ISDOWN(HS(a1)) ? HS(a1)->hs_wd.wd_recvtime - now
                    : HS(a1)->hs_wd.wd_sendtime - HS(a1)->hs_wd.wd_boottime)
        ));
}

static void
usage(void)
{
        (void)fprintf(stderr, "usage: ruptime [-alrtu] [host ...]\n");
        exit(1);
}