/*      $OpenBSD: rain.c,v 1.22 2021/10/23 11:22:49 mestre Exp $        */

/*
 * Copyright (c) 1980, 1993
 *      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.
 */

/*
 * rain 11/3/1980 EPS/CITHEP
 * cc rain.c -o rain -O -ltermlib
 */

#include <curses.h>
#include <err.h>
#include <signal.h>
#include <stdlib.h>
#include <termios.h>
#include <unistd.h>

volatile sig_atomic_t sig_caught = 0;

static void     onsig(int);


int
main(int argc, char *argv[])
{
        int x, y, j;
        long tcols, tlines;
        const char *errstr;
        struct termios term;
        struct timespec sleeptime;
        speed_t speed;
        time_t delay = 0;
        int ch;
        int xpos[5], ypos[5];

        /* set default delay based on terminal baud rate */
        if (tcgetattr(STDOUT_FILENO, &term) == 0 &&
            (speed = cfgetospeed(&term)) > B9600)
                delay = (speed / B9600) - 1;

        while ((ch = getopt(argc, argv, "d:h")) != -1)
                switch(ch) {
                case 'd':
                        delay = (time_t)strtonum(optarg, 0, 1000, &errstr);
                        if (errstr)
                            errx(1, "delay (0-1000) is %s: %s", errstr, optarg);
                        break;
                case 'h':
                default:
                        (void)fprintf(stderr, "usage: rain [-d delay]\n");
                        return 1;
                }

        /* Convert delay from ms -> ns */
        sleeptime.tv_sec = 0;
        sleeptime.tv_nsec = delay * 500000;
        timespecadd(&sleeptime, &sleeptime, &sleeptime);

        initscr();

        if (pledge("stdio tty", NULL) == -1)
                err(1, "pledge");

        tcols = COLS - 4;
        tlines = LINES - 4;

        (void)signal(SIGHUP, onsig);
        (void)signal(SIGINT, onsig);
        (void)signal(SIGQUIT, onsig);
        (void)signal(SIGSTOP, onsig);
        (void)signal(SIGTSTP, onsig);
        (void)signal(SIGTERM, onsig);
        
        curs_set(0);
        for (j = 4; j >= 0; --j) {
                xpos[j] = arc4random_uniform(tcols) + 2;
                ypos[j] = arc4random_uniform(tlines) + 2;
        }
        for (j = 0;;) {
                if (sig_caught) {
                        endwin();
                        return 0;
                }
                x = arc4random_uniform(tcols) + 2;
                y = arc4random_uniform(tlines) + 2;
                mvaddch(y, x, '.');
                mvaddch(ypos[j], xpos[j], 'o');
                if (!j--)
                        j = 4;
                mvaddch(ypos[j], xpos[j], 'O');
                if (!j--)
                        j = 4;
                mvaddch(ypos[j] - 1, xpos[j], '-');
                mvaddstr(ypos[j], xpos[j] - 1, "|.|");
                mvaddch(ypos[j] + 1, xpos[j], '-');
                if (!j--)
                        j = 4;
                mvaddch(ypos[j] - 2, xpos[j], '-');
                mvaddstr(ypos[j] - 1, xpos[j] - 1, "/ \\");
                mvaddstr(ypos[j], xpos[j] - 2, "| O |");
                mvaddstr(ypos[j] + 1, xpos[j] - 1, "\\ /");
                mvaddch(ypos[j] + 2, xpos[j], '-');
                if (!j--)
                        j = 4;
                mvaddch(ypos[j] - 2, xpos[j], ' ');
                mvaddstr(ypos[j] - 1, xpos[j] - 1, "   ");
                mvaddstr(ypos[j], xpos[j] - 2, "     ");
                mvaddstr(ypos[j] + 1, xpos[j] - 1, "   ");
                mvaddch(ypos[j] + 2, xpos[j], ' ');
                xpos[j] = x;
                ypos[j] = y;
                refresh();
                nanosleep(&sleeptime, NULL);
        }
}

static void
onsig(int dummy)
{
        sig_caught = 1;
}