/*      $NetBSD: fmt.c,v 1.33 2017/10/13 00:11:56 christos 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.
 */

#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1980, 1993\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)fmt.c       8.1 (Berkeley) 7/20/93";
#endif
__RCSID("$NetBSD: fmt.c,v 1.33 2017/10/13 00:11:56 christos Exp $");
#endif /* not lint */

#include <wctype.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <err.h>
#include <limits.h>
#include <string.h>
#include <locale.h>
#include "buffer.h"

/*
 * fmt -- format the concatenation of input files or standard input
 * onto standard output.  Designed for use with Mail ~|
 *
 * Syntax : fmt [ goal [ max ] ] [ name ... ]
 * Authors: Kurt Shoens (UCB) 12/7/78;
 *          Liz Allen (UMCP) 2/24/83 [Addition of goal length concept].
 */

/* LIZ@UOM 6/18/85 --New variables goal_length and max_length */
#define GOAL_LENGTH 65
#define MAX_LENGTH 75
static size_t   goal_length;    /* Target or goal line length in output */
static size_t   max_length;     /* Max line length in output */
static size_t   pfx;            /* Current leading blank count */
static int      raw;            /* Don't treat mail specially */
static int      lineno;         /* Current input line */
static int      mark;           /* Last place we saw a head line */
static int      center;
static struct buffer outbuf;

static const wchar_t *headnames[] = { L"To", L"Subject", L"Cc", NULL };

static void     usage(void) __dead;
static int      getnum(const char *, const char *, size_t *, int);
static void     fmt(FILE *);
static int      ispref(const wchar_t *, const wchar_t *);
static void     leadin(void);
static void     oflush(void);
static void     pack(const wchar_t *, size_t);
static void     prefix(const struct buffer *, int);
static void     split(const wchar_t *, int);
static void     tabulate(struct buffer *);


int             ishead(const wchar_t *);

/*
 * Drive the whole formatter by managing input files.  Also,
 * cause initialization of the output stuff and flush it out
 * at the end.
 */

int
main(int argc, char **argv)
{
        FILE *fi;
        int errs = 0;
        int compat = 1;
        int c;

        goal_length = GOAL_LENGTH;
        max_length = MAX_LENGTH;
        buf_init(&outbuf);
        lineno = 1;
        mark = -10;

        setprogname(*argv);
        (void)setlocale(LC_ALL, "");

        while ((c = getopt(argc, argv, "Cg:m:rw:")) != -1)
                switch (c) {
                case 'C':
                        center++;
                        break;
                case 'g':
                        (void)getnum(optarg, "goal", &goal_length, 1);
                        compat = 0;
                        break;
                case 'm':
                case 'w':
                        (void)getnum(optarg, "max", &max_length, 1);
                        compat = 0;
                        break;
                case 'r':
                        raw++;
                        break;
                default:
                        usage();
                }

        argc -= optind;
        argv += optind;

        /*
         * compatibility with old usage.
         */
        if (compat && argc > 0 && getnum(*argv, "goal", &goal_length, 0)) {
                argv++;
                argc--;
                if (argc > 0 && getnum(*argv, "max", &max_length, 0)) {
                        argv++;
                        argc--;
                }
        }

        if (max_length <= goal_length) {
                errx(1, "Max length (%zu) must be greater than goal "
                    "length (%zu)", max_length, goal_length);
        }
        if (argc == 0) {
                fmt(stdin);
                oflush();
                return 0;
        }
        for (;argc; argc--, argv++) {
                if ((fi = fopen(*argv, "r")) == NULL) {
                        warn("Cannot open `%s'", *argv);
                        errs++;
                        continue;
                }
                fmt(fi);
                (void)fclose(fi);
        }
        oflush();
        buf_end(&outbuf);
        return errs;
}

static void
usage(void)
{
        (void)fprintf(stderr,
            "Usage: %s [-Cr] [-g <goal>] [-m|w <max>] [<files>..]\n"
            "\t %s [-Cr] [<goal>] [<max>] [<files>]\n",
            getprogname(), getprogname());
        exit(1);
}

static int
getnum(const char *str, const char *what, size_t *res, int badnum)
{
        unsigned long ul;
        char *ep;

        errno = 0;
        ul = strtoul(str, &ep, 0);
        if (*str != '\0' && *ep == '\0') {
                 if ((errno == ERANGE && ul == ULONG_MAX) || ul > SIZE_T_MAX)
                        errx(1, "%s number `%s' too big", what, str);
                *res = (size_t)ul;
                return 1;
        } else if (badnum)
                errx(1, "Bad %s number `%s'", what, str);

        return 0;
}

/*
 * Read up characters from the passed input file, forming lines,
 * doing ^H processing, expanding tabs, stripping trailing blanks,
 * and sending each line down for analysis.
 */
static void
fmt(FILE *fi)
{
        struct buffer lbuf, cbuf;
        wchar_t *cp, *cp2;
        wint_t c;
        int add_space;
        size_t len, col, i;

        if (center) {
                for (;;) {
                        cp = fgetwln(fi, &len);
                        if (!cp)
                                return;

                        /* skip over leading space */
                        while (len > 0) {
                                if (!iswspace(*cp))
                                        break;
                                cp++;
                                len--;
                        }

                        /* clear trailing space */
                        while (len > 0) {
                                if (!iswspace((unsigned char)cp[len-1]))
                                        break;
                                len--;
                        }

                        if (len == 0) {
                                /* blank line */
                                (void)putwchar(L'\n');
                                continue;
                        }

                        if (goal_length > len) {
                                for (i = 0; i < (goal_length - len) / 2; i++) {
                                        (void)putwchar(L' ');
                                }
                        }
                        for (i = 0; i < len; i++) {
                                (void)putwchar(cp[i]);
                        }
                        (void)putwchar(L'\n');
                }
        }

        buf_init(&lbuf);
        buf_init(&cbuf);
        c = getwc(fi);

        while (c != WEOF) {
                /*
                 * Collect a line, doing ^H processing.
                 * Leave tabs for now.
                 */
                buf_reset(&lbuf);
                while (c != '\n' && c != WEOF) {
                        if (c == '\b') {
                                (void)buf_unputc(&lbuf);
                                c = getwc(fi);
                                continue;
                        }
                        if(!(iswprint(c) || c == '\t' || c >= 160)) {
                                c = getwc(fi);
                                continue;
                        }
                        buf_putc(&lbuf, c);
                        c = getwc(fi);
                }
                buf_putc(&lbuf, '\0');
                (void)buf_unputc(&lbuf);
                add_space = c != WEOF;

                /*
                 * Expand tabs on the way.
                 */
                col = 0;
                cp = lbuf.bptr;
                buf_reset(&cbuf);
                while ((c = *cp++) != '\0') {
                        if (c != '\t') {
                                col++;
                                buf_putc(&cbuf, c);
                                continue;
                        }
                        do {
                                buf_putc(&cbuf, ' ');
                                col++;
                        } while ((col & 07) != 0);
                }

                /*
                 * Swipe trailing blanks from the line.
                 */
                for (cp2 = cbuf.ptr - 1; cp2 >= cbuf.bptr && *cp2 == ' '; cp2--)
                        continue;
                cbuf.ptr = cp2 + 1;
                buf_putc(&cbuf, '\0');
                (void)buf_unputc(&cbuf);
                prefix(&cbuf, add_space);
                if (c != WEOF)
                        c = getwc(fi);
        }
        buf_end(&cbuf);
        buf_end(&lbuf);
}

/*
 * Take a line devoid of tabs and other garbage and determine its
 * blank prefix.  If the indent changes, call for a linebreak.
 * If the input line is blank, echo the blank line on the output.
 * Finally, if the line minus the prefix is a mail header, try to keep
 * it on a line by itself.
 */
static void
prefix(const struct buffer *buf, int add_space)
{
        const wchar_t *cp;
        const wchar_t **hp;
        size_t np;
        int h;

        if (buf->ptr == buf->bptr) {
                oflush();
                (void)putwchar(L'\n');
                return;
        }
        for (cp = buf->bptr; *cp == ' '; cp++)
                continue;
        np = cp - buf->bptr;

        /*
         * The following horrible expression attempts to avoid linebreaks
         * when the indent changes due to a paragraph.
         */
        if (np != pfx && (np > pfx || abs((int)(pfx - np)) > 8))
                oflush();
        if (!raw) {
                if ((h = ishead(cp)) != 0) {
                        oflush();
                        mark = lineno;
                }
                if (lineno - mark < 3 && lineno - mark > 0)
                        for (hp = &headnames[0]; *hp != NULL; hp++)
                                if (ispref(*hp, cp)) {
                                        h = 1;
                                        oflush();
                                        break;
                                }
                if (!h && (h = (*cp == '.')))
                        oflush();
        } else
                h = 0;
        pfx = np;
        if (h) {
                pack(cp, (size_t)(buf->ptr - cp));
                oflush();
        } else
                split(cp, add_space);
        lineno++;
}

/*
 * Split up the passed line into output "words" which are
 * maximal strings of non-blanks with the blank separation
 * attached at the end.  Pass these words along to the output
 * line packer.
 */
static void
split(const wchar_t line[], int add_space)
{
        const wchar_t *cp;
        struct buffer word;
        size_t wlen;

        buf_init(&word);
        cp = line;
        while (*cp) {
                buf_reset(&word);
                wlen = 0;

                /*
                 * Collect a 'word,' allowing it to contain escaped white
                 * space. 
                 */
                while (*cp && *cp != ' ') {
                        if (*cp == '\\' && iswspace(cp[1]))
                                buf_putc(&word, *cp++);
                        buf_putc(&word, *cp++);
                        wlen++;
                }

                /*
                 * Guarantee a space at end of line. Two spaces after end of
                 * sentence punctuation. 
                 */
                if (*cp == '\0' && add_space) {
                        buf_putc(&word, ' ');
                        if (strchr(".:!", cp[-1]))
                                buf_putc(&word, ' ');
                }
                while (*cp == ' ')
                        buf_putc(&word, *cp++);

                buf_putc(&word, '\0');
                (void)buf_unputc(&word);

                pack(word.bptr, wlen);
        }
        buf_end(&word);
}

/*
 * Output section.
 * Build up line images from the words passed in.  Prefix
 * each line with correct number of blanks.
 *
 * At the bottom of this whole mess, leading tabs are reinserted.
 */

/*
 * Pack a word onto the output line.  If this is the beginning of
 * the line, push on the appropriately-sized string of blanks first.
 * If the word won't fit on the current line, flush and begin a new
 * line.  If the word is too long to fit all by itself on a line,
 * just give it its own and hope for the best.
 *
 * LIZ@UOM 6/18/85 -- If the new word will fit in at less than the
 *      goal length, take it.  If not, then check to see if the line
 *      will be over the max length; if so put the word on the next
 *      line.  If not, check to see if the line will be closer to the
 *      goal length with or without the word and take it or put it on
 *      the next line accordingly.
 */

static void
pack(const wchar_t *word, size_t wlen)
{
        const wchar_t *cp;
        size_t s, t;

        if (outbuf.bptr == outbuf.ptr)
                leadin();
        /*
         * LIZ@UOM 6/18/85 -- change condition to check goal_length; s is the
         * length of the line before the word is added; t is now the length
         * of the line after the word is added
         */
        s = outbuf.ptr - outbuf.bptr;
        t = wlen + s;
        if ((t <= goal_length) || ((t <= max_length) &&
            (s <= goal_length) && (t - goal_length <= goal_length - s))) {
                /*
                 * In like flint! 
                 */
                for (cp = word; *cp;)
                        buf_putc(&outbuf, *cp++);
                return;
        }
        if (s > pfx) {
                oflush();
                leadin();
        }
        for (cp = word; *cp;)
                buf_putc(&outbuf, *cp++);
}

/*
 * If there is anything on the current output line, send it on
 * its way.  Reset outbuf.
 */
static void
oflush(void)
{
        if (outbuf.bptr == outbuf.ptr)
                return;
        buf_putc(&outbuf, '\0');
        (void)buf_unputc(&outbuf);
        tabulate(&outbuf);
        buf_reset(&outbuf);
}

/*
 * Take the passed line buffer, insert leading tabs where possible, and
 * output on standard output (finally).
 */
static void
tabulate(struct buffer *buf)
{
        wchar_t *cp;
        size_t b, t;

        /*
         * Toss trailing blanks in the output line.
         */
        for (cp = buf->ptr - 1; cp >= buf->bptr && *cp == ' '; cp--)
                continue;
        *++cp = '\0';
        
        /*
         * Count the leading blank space and tabulate.
         */
        for (cp = buf->bptr; *cp == ' '; cp++)
                continue;
        b = cp - buf->bptr;
        t = b / 8;
        b = b % 8;
        if (t > 0)
                do
                        (void)putwchar(L'\t');
                while (--t);
        if (b > 0)
                do
                        (void)putwchar(L' ');
                while (--b);
        while (*cp)
                (void)putwchar(*cp++);
        (void)putwchar(L'\n');
}

/*
 * Initialize the output line with the appropriate number of
 * leading blanks.
 */
static void
leadin(void)
{
        size_t b;

        buf_reset(&outbuf);

        for (b = 0; b < pfx; b++)
                buf_putc(&outbuf, ' ');
}

/*
 * Is s1 a prefix of s2??
 */
static int
ispref(const wchar_t *s1, const wchar_t *s2)
{

        while (*s1++ == *s2)
                continue;
        return *s1 == '\0';
}