/*
 * Copyright (c) 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Guy Harris at Network Appliance Corp.
 *
 * 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/types.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <locale.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include "randomize_fd.h"

static void usage(void) __dead2;

int
main(int argc, char *argv[])
{
        double denom;
        int ch, fd, random_exit, randomize_lines, random_type, ret,
            unique_output, unbuffer_output;
        bool selected;
        char *ep;
        const char *filename;

        denom = 0.;
        filename = "/dev/fd/0";
        random_type = RANDOM_TYPE_UNSET;
        random_exit = randomize_lines = unbuffer_output = 0;
        unique_output = 1;

        (void)setlocale(LC_CTYPE, "");

        while ((ch = getopt(argc, argv, "ef:hlruUw")) != -1)
                switch (ch) {
                case 'e':
                        random_exit = 1;
                        break;
                case 'f':
                        randomize_lines = 1;
                        if (strcmp(optarg, "-") != 0)
                                filename = optarg;
                        break;
                case 'l':
                        randomize_lines = 1;
                        random_type = RANDOM_TYPE_LINES;
                        break;
                case 'r':
                        unbuffer_output = 1;
                        break;
                case 'u':
                        randomize_lines = 1;
                        unique_output = 1;
                        break;
                case 'U':
                        randomize_lines = 1;
                        unique_output = 0;
                        break;
                case 'w':
                        randomize_lines = 1;
                        random_type = RANDOM_TYPE_WORDS;
                        break;
                default:
                case '?':
                        usage();
                        /* NOTREACHED */
                }

        argc -= optind;
        argv += optind;

        switch (argc) {
        case 0:
                denom = (randomize_lines ? 1. : 2.);
                break;
        case 1:
                errno = 0;
                denom = strtod(*argv, &ep);
                if (errno == ERANGE)
                        err(1, "%s", *argv);
                if (denom < 1. || *ep != '\0')
                        errx(1, "denominator is not valid.");
                if (random_exit && denom > 256.)
                        errx(1, "denominator must be <= 256 for random exit.");
                break;
        default:
                usage();
                /* NOTREACHED */
        }

        /*
         * Act as a filter, randomly choosing lines of the standard input
         * to write to the standard output.
         */
        if (unbuffer_output)
                setbuf(stdout, NULL);

        /*
         * Act as a filter, randomizing lines read in from a given file
         * descriptor and write the output to standard output.
         */
        if (randomize_lines) {
                if ((fd = open(filename, O_RDONLY, 0)) < 0)
                        err(1, "%s", filename);
                ret = randomize_fd(fd, random_type, unique_output, denom);
                if (!random_exit)
                        return(ret);
        }

        /* Compute a random exit status between 0 and denom - 1. */
        if (random_exit)
                return (arc4random_uniform(denom));

        /*
         * Filter stdin, selecting lines with probability 1/denom, one
         * character at a time.
         */
        do {
                selected = random_uniform_denom(denom);
                if (selected) {
                        while ((ch = getchar()) != EOF) {
                                putchar(ch);
                                if (ch == '\n')
                                        break;
                        }
                } else {
                        while ((ch = getchar()) != EOF)
                                if (ch == '\n')
                                        break;
                }
                if (ferror(stdout))
                        err(2, "stdout");
        } while (ch != EOF);
        if (ferror(stdin))
                err(2, "stdin");
        exit (0);
}

static void
usage(void)
{

        fprintf(stderr, "usage: random [-elrUuw] [-f filename] [denominator]\n");
        exit(1);
}