/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Adam S. Moskowitz of Menlo Consulting.
 *
 * 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 <sys/queue.h>
#include <sys/capsicum.h>

#include <capsicum_helpers.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <wchar.h>

#include <libcasper.h>
#include <casper/cap_fileargs.h>

static wchar_t *delim;
static int delimcnt;

static int parallel(char **, fileargs_t *);
static int sequential(char **, fileargs_t *);
static int tr(wchar_t *);
static void usage(void) __dead2;

static wchar_t tab[] = L"\t";

int
main(int argc, char *argv[])
{
        int ch, rval, seq;
        wchar_t *warg;
        const char *arg;
        size_t len;
        fileargs_t *fa;
        cap_rights_t rights;

        setlocale(LC_CTYPE, "");

        seq = 0;
        while ((ch = getopt(argc, argv, "d:s")) != -1)
                switch(ch) {
                case 'd':
                        arg = optarg;
                        len = mbsrtowcs(NULL, &arg, 0, NULL);
                        if (len == (size_t)-1)
                                err(1, "delimiters");
                        warg = malloc((len + 1) * sizeof(*warg));
                        if (warg == NULL)
                                err(1, NULL);
                        arg = optarg;
                        len = mbsrtowcs(warg, &arg, len + 1, NULL);
                        if (len == (size_t)-1)
                                err(1, "delimiters");
                        delimcnt = tr(delim = warg);
                        break;
                case 's':
                        seq = 1;
                        break;
                case '?':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (*argv == NULL)
                usage();
        if (!delim) {
                delimcnt = 1;
                delim = tab;
        }

        fa = fileargs_init(argc, argv, O_RDONLY, 0,
            cap_rights_init(&rights, CAP_READ, CAP_FSTAT, CAP_FCNTL), FA_OPEN);
        if (fa == NULL)
                err(1, "unable to open system.fileargs service");

        caph_cache_catpages();
        if (caph_enter_casper() < 0)
                err(1, "unable to enter capability mode");

        rval = seq ? sequential(argv, fa) : parallel(argv, fa);

        fileargs_free(fa);
        exit(rval);
}

typedef struct _list {
        STAILQ_ENTRY(_list) entries;
        FILE *fp;
        int cnt;
        char *name;
} LIST;

static STAILQ_HEAD(head, _list) lh;

static int
parallel(char **argv, fileargs_t *fa)
{
        LIST *lp;
        int cnt;
        wint_t ich;
        wchar_t ch;
        char *p;
        int opencnt, output;

        STAILQ_INIT(&lh);

        for (cnt = 0; (p = *argv); ++argv, ++cnt) {
                if ((lp = malloc(sizeof(LIST))) == NULL)
                        err(1, NULL);
                if (p[0] == '-' && !p[1])
                        lp->fp = stdin;
                else if (!(lp->fp = fileargs_fopen(fa, p, "r")))
                        err(1, "%s", p);
                lp->cnt = cnt;
                lp->name = p;

                STAILQ_INSERT_TAIL(&lh, lp, entries);
        }

        for (opencnt = cnt; opencnt;) {
                output = 0;
                STAILQ_FOREACH(lp, &lh, entries) {
                        if (!lp->fp) {
                                if (output && lp->cnt &&
                                    (ch = delim[(lp->cnt - 1) % delimcnt]))
                                        putwchar(ch);
                                continue;
                        }
                        if ((ich = getwc(lp->fp)) == WEOF) {
                                if (!--opencnt)
                                        break;
                                lp->fp = NULL;
                                if (output && lp->cnt &&
                                    (ch = delim[(lp->cnt - 1) % delimcnt]))
                                        putwchar(ch);
                                continue;
                        }
                        /*
                         * make sure that we don't print any delimiters
                         * unless there's a non-empty file.
                         */
                        if (!output) {
                                output = 1;
                                for (cnt = 0; cnt < lp->cnt; ++cnt)
                                        if ((ch = delim[cnt % delimcnt]))
                                                putwchar(ch);
                        } else if ((ch = delim[(lp->cnt - 1) % delimcnt]))
                                putwchar(ch);
                        if (ich == '\n')
                                continue;
                        do {
                                putwchar(ich);
                        } while ((ich = getwc(lp->fp)) != WEOF && ich != '\n');
                }
                if (output)
                        putwchar('\n');
        }

        return (0);
}

static int
sequential(char **argv, fileargs_t *fa)
{
        FILE *fp;
        int cnt, failed, needdelim;
        wint_t ch;
        char *p;

        failed = 0;
        for (; (p = *argv); ++argv) {
                if (p[0] == '-' && !p[1])
                        fp = stdin;
                else if (!(fp = fileargs_fopen(fa, p, "r"))) {
                        warn("%s", p);
                        failed = 1;
                        continue;
                }
                cnt = needdelim = 0;
                while ((ch = getwc(fp)) != WEOF) {
                        if (needdelim) {
                                needdelim = 0;
                                if (delim[cnt] != '\0')
                                        putwchar(delim[cnt]);
                                if (++cnt == delimcnt)
                                        cnt = 0;
                        }
                        if (ch != '\n')
                                putwchar(ch);
                        else
                                needdelim = 1;
                }
                if (needdelim)
                        putwchar('\n');
                if (fp != stdin)
                        (void)fclose(fp);
        }

        return (failed != 0);
}

static int
tr(wchar_t *arg)
{
        int cnt;
        wchar_t ch, *p;

        for (p = arg, cnt = 0; (ch = *p++); ++arg, ++cnt)
                if (ch == '\\')
                        switch(ch = *p++) {
                        case 'n':
                                *arg = '\n';
                                break;
                        case 't':
                                *arg = '\t';
                                break;
                        case '0':
                                *arg = '\0';
                                break;
                        default:
                                *arg = ch;
                                break;
                        }
                else
                        *arg = ch;

        if (!cnt)
                errx(1, "no delimiters specified");
        return(cnt);
}

static void
usage(void)
{
        (void)fprintf(stderr, "usage: paste [-s] [-d delimiters] file ...\n");
        exit(1);
}