/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */


#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <wctype.h>
#include <widec.h>
#include <dlfcn.h>
#include <locale.h>
#include <sys/param.h>
#include <string.h>

/*
 * fmt -- format the concatenation of input files or standard input
 * onto standard output.  Designed for use with Mail ~|
 *
 * Syntax: fmt [ -width | -w width ] [ -cs ] [ name ... ]
 * Author: Kurt Shoens (UCB) 12/7/78
 */

#define NOSTR   ((wchar_t *)0)  /* Null string pointer for lint */
#define MAXLINES        100     /* maximum mail header lines to verify */

wchar_t outbuf[BUFSIZ];                 /* Sandbagged output line image */
wchar_t *outp;                          /* Pointer in above */
int     filler;                         /* Filler amount in outbuf */
char sobuf[BUFSIZ];     /* Global buffer */

int     pfx;                    /* Current leading blank count */
int     width = 72;             /* Width that we will not exceed */
int     nojoin = 0;             /* split lines only, don't join short ones */
int     errs = 0;               /* Current number of errors */

enum crown_type {c_none, c_reset, c_head, c_lead, c_fixup, c_body};
enum crown_type crown_state;    /* Crown margin state */
int     crown_head;             /* The header offset */
int     crown_body;             /* The body offset */
        /* currently-known initial strings found in mail headers */
wchar_t *headnames[] = {
        L"Apparently-To", L"Bcc", L"bcc", L"Cc", L"cc", L"Confirmed-By",
        L"Content", L"content-length", L"From", L"Date", L"id",
        L"Message-I", L"MIME-Version", L"Precedence", L"Return-Path",
        L"Received", L"Reply-To", L"Status", L"Subject", L"To", L"X-IMAP",
        L"X-Lines", L"X-Sender", L"X-Sun", L"X-Status", L"X-UID",
        0};

enum hdr_type {
        off,            /* mail header processing is off */
        not_in_hdr,     /* not currently processing a mail header */
        in_hdr,         /* currently filling hdrbuf with potential hdr lines */
        flush_hdr,      /* flush hdrbuf; not a header, no special processing */
        do_hdr          /* process hdrbuf as a mail header */
};
                                /* current state of hdrbuf */
enum hdr_type   hdr_state = not_in_hdr;

wchar_t *hdrbuf[MAXLINES];      /* buffer to hold potential mail header lines */
int     h_lines;                /* index into lines of hdrbuf */

void (*(split))(wchar_t []);
extern int scrwidth(wchar_t);
extern boolean_t is_headline(const char *);


static void fill_hdrbuf(wchar_t []);
static void header_chk(void);
static void process_hdrbuf(void);
static void leadin(void);
static void tabulate(wchar_t []);
static void oflush(void);
static void pack(wchar_t []);
static void msplit(wchar_t []);
static void csplit(wchar_t []);
static void _wckind_init(void);
static void prefix(wchar_t []);
static void fmt(FILE *);
static int setopt(char *);
int _wckind(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;
        char *cp;
        int nofile;
        char *locale;

        outp = NOSTR;
        setbuf(stdout, sobuf);
        setlocale(LC_ALL, "");
        locale = setlocale(LC_CTYPE, NULL);
        if (strcmp(locale, "C") == 0) {
                split = csplit;
        } else {
                split = msplit;
                _wckind_init();
        }
        if (argc < 2) {
single:
                fmt(stdin);
                oflush();
                exit(0);
        }
        nofile = 1;
        while (--argc) {
                cp = *++argv;
                if (setopt(cp))
                        continue;
                nofile = 0;
                if ((fi = fopen(cp, "r")) == NULL) {
                        perror(cp);
                        errs++;
                        continue;
                }
                fmt(fi);
                fclose(fi);
        }
        if (nofile)
                goto single;
        oflush();
        fclose(stdout);
        return (errs);
}

/*
 * 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)
{
        wchar_t linebuf[BUFSIZ], canonb[BUFSIZ];
        wchar_t *cp, *cp2;
        int col;
        wchar_t c;
        char    cbuf[BUFSIZ];   /* stores wchar_t string as char string */

        c = getwc(fi);
        while (c != EOF) {
                /*
                 * Collect a line, doing ^H processing.
                 * Leave tabs for now.
                 */

                cp = linebuf;
                while (c != L'\n' && c != EOF && cp-linebuf < BUFSIZ-1) {
                        if (c == L'\b') {
                                if (cp > linebuf)
                                        cp--;
                                c = getwc(fi);
                                continue;
                        }
                        if (!(iswprint(c)) && c != L'\t') {
                                c = getwc(fi);
                                continue;
                        }
                        *cp++ = c;
                        c = getwc(fi);
                }
                *cp = L'\0';

                /*
                 * Toss anything remaining on the input line.
                 */

                while (c != L'\n' && c != EOF)
                        c = getwc(fi);
                /*
                 * Expand tabs on the way to canonb.
                 */

                col = 0;
                cp = linebuf;
                cp2 = canonb;
                while (c = *cp++) {
                        if (c != L'\t') {
                                col += scrwidth(c);
                                if (cp2-canonb < BUFSIZ-1)
                                        *cp2++ = c;
                                continue;
                        }
                        do {
                                if (cp2-canonb < BUFSIZ-1)
                                        *cp2++ = L' ';
                                col++;
                        } while ((col & 07) != 0);
                }

                /*
                 * Swipe trailing blanks from the line.
                 */

                for (cp2--; cp2 >= canonb && *cp2 == L' '; cp2--) {
                }
                *++cp2 = '\0';

                        /* special processing to look for mail header lines */
                switch (hdr_state) {
                case off:
                        prefix(canonb);
                        /* FALLTHROUGH */
                case not_in_hdr:
                        /* look for an initial mail header line */
                        /* skip initial blanks */
                        for (cp = canonb; *cp == L' '; cp++) {
                        }
                        /*
                         * Need to convert string from wchar_t to char,
                         * since this is what is_headline() expects.  Since we
                         * only want to make sure cp points to a "From" line
                         * of the email, we don't have to alloc
                         * BUFSIZ * MB_LEN_MAX to cbuf.
                         */
                        wcstombs(cbuf, cp, (BUFSIZ - 1));
                        if (is_headline(cbuf) == B_TRUE) {
                                hdr_state = in_hdr;
                                fill_hdrbuf(canonb);
                        } else {
                                /* no mail header line; process normally */
                                prefix(canonb);
                        }
                        break;
                case in_hdr:
                        /* already saw 1st mail header line; look for more */
                        if (canonb[0] == L'\0') {
                                /*
                                 * blank line means end of mail header;
                                 * verify current mail header buffer
                                 * then process it accordingly
                                 */
                                header_chk();
                                process_hdrbuf();
                                /* now process the current blank line */
                                prefix(canonb);
                        } else
                                /*
                                 * not a blank line--save this line as
                                 * a potential mail header line
                                 */
                                fill_hdrbuf(canonb);
                        break;
                }
                if (c != EOF)
                        c = getwc(fi);
        }
        /*
         * end of this file--make sure we process the stuff in
         * hdrbuf before we're finished
         */
        if (hdr_state == in_hdr) {
                header_chk();
                process_hdrbuf();
        }
}

/*
 * 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(wchar_t line[])
{
        wchar_t *cp;
        int np;
        int nosplit = 0;        /* flag set if line should not be split */

        if (line[0] == L'\0') {
                oflush();
                putchar('\n');
                if (crown_state != c_none)
                        crown_state = c_reset;
                return;
        }
        for (cp = line; *cp == L' '; cp++) {
        }
        np = cp - line;

        /*
         * The following horrible expression attempts to avoid linebreaks
         * when the indent changes due to a paragraph.
         */

        if (crown_state == c_none && np != pfx && (np > pfx || abs(pfx-np) > 8))
                oflush();
        /*
         * if this is a mail header line, don't split it; flush previous
         * line, if any, so we don't join this line to it
         */
        if (hdr_state == do_hdr) {
                nosplit = 1;
                oflush();
        }
        /* flush previous line so we don't join this one to it */
        if (nojoin)
                oflush();
        /* nroff-type lines starting with '.' are not split nor joined */
        if (!nosplit && (nosplit = (*cp == L'.')))
                oflush();
        pfx = np;
        switch (crown_state) {
        case c_reset:
                crown_head = pfx;
                crown_state = c_head;
                break;
        case c_lead:
                crown_body = pfx;
                crown_state = c_body;
                break;
        case c_fixup:
                crown_body = pfx;
                crown_state = c_body;
                if (outp) {
                        wchar_t s[BUFSIZ];

                        *outp = L'\0';
                        wscpy(s, &outbuf[crown_head]);
                        outp = NOSTR;
                        split(s);
                }
                break;
        }
        if (nosplit) {
                /* put whole input line onto outbuf and print it out */
                pack(cp);
                oflush();
        } else
                /*
                 * split puts current line onto outbuf, but splits it
                 * at word boundaries, if it exceeds desired length
                 */
                split(cp);
        if (nojoin)
                /*
                 * flush current line so next lines, if any,
                 * won't join to this one
                 */
                oflush();
}

/*
 * 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
csplit(wchar_t line[])
{
        wchar_t *cp, *cp2;
        wchar_t word[BUFSIZ];
        static const wchar_t *srchlist = (const wchar_t *) L".:!?";

        cp = line;
        while (*cp) {
                cp2 = word;

                /*
                 * Collect a 'word,' allowing it to contain escaped
                 * white space.
                 */

                while (*cp && !(iswspace(*cp))) {
                        if (*cp == '\\' && iswspace(cp[1]))
                                *cp2++ = *cp++;
                        *cp2++ = *cp++;
                }

                /*
                 * Guarantee a space at end of line.
                 * Two spaces after end of sentence punctuation.
                 */

                if (*cp == L'\0') {
                        *cp2++ = L' ';
                        if (wschr(srchlist, cp[-1]) != NULL)
                                *cp2++ = L' ';
                }
                while (iswspace(*cp))
                        *cp2++ = *cp++;
                *cp2 = L'\0';
                pack(word);
        }
}

static void
msplit(wchar_t line[])
{
        wchar_t *cp, *cp2, prev;
        wchar_t word[BUFSIZ];
        static const wchar_t *srchlist = (const wchar_t *) L".:!?";

        cp = line;
        while (*cp) {
                cp2 = word;
                prev = *cp;

                /*
                 * Collect a 'word,' allowing it to contain escaped
                 * white space.
                 */

                while (*cp) {
                        if (iswspace(*cp))
                                break;
                        if (_wckind(*cp) != _wckind(prev))
                                if (wcsetno(*cp) != 0 || wcsetno(prev) != 0)
                                        break;
                        if (*cp == '\\' && iswspace(cp[1]))
                                *cp2++ = *cp++;
                        prev = *cp;
                        *cp2++ = *cp++;
                }

                /*
                 * Guarantee a space at end of line.
                 * Two spaces after end of sentence punctuation.
                 */

                if (*cp == L'\0') {
                        *cp2++ = L' ';
                        if (wschr(srchlist, cp[-1]) != NULL)
                                *cp2++ = L' ';
                }
                while (iswspace(*cp))
                        *cp2++ = *cp++;
                *cp2 = L'\0';
                pack(word);
        }
}

/*
 * Output section.
 * Build up line images from the words passed in.  Prefix
 * each line with correct number of blanks.  The buffer "outbuf"
 * contains the current partial line image, including prefixed blanks.
 * "outp" points to the next available space therein.  When outp is NOSTR,
 * there ain't nothing in there yet.  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.
 */

static void
pack(wchar_t word[])
{
        wchar_t *cp;
        int s, t;

        if (outp == NOSTR)
                leadin();
        t = wscol(word);
        *outp = L'\0';
        s = wscol(outbuf);
        if (t+s <= width) {
                for (cp = word; *cp; *outp++ = *cp++) {
                }
                return;
        }
        if (s > filler) {
                oflush();
                leadin();
        }
        for (cp = word; *cp; *outp++ = *cp++) {
        }
}

/*
 * If there is anything on the current output line, send it on
 * its way.  Set outp to NOSTR to indicate the absence of the current
 * line prefix.
 */

static void
oflush(void)
{
        if (outp == NOSTR)
                return;
        *outp = L'\0';
        tabulate(outbuf);
        outp = NOSTR;
}

/*
 * Take the passed line buffer, insert leading tabs where possible, and
 * output on standard output (finally).
 */

static void
tabulate(wchar_t line[])
{
        wchar_t *cp;
        int b, t;


        /* Toss trailing blanks in the output line */
        cp = line + wslen(line) - 1;
        while (cp >= line && *cp == L' ')
                cp--;
        *++cp = L'\0';
        /* Count the leading blank space and tabulate */
        for (cp = line; *cp == L' '; cp++) {
        }
        b = cp - line;
        t = b >> 3;
        b &= 07;
        if (t > 0)
                do {
                        putc('\t', stdout);
                } while (--t);
        if (b > 0)
                do {
                        putc(' ', stdout);
                } while (--b);
        while (*cp)
                putwc(*cp++, stdout);
        putc('\n', stdout);
}

/*
 * Initialize the output line with the appropriate number of
 * leading blanks.
 */

static void
leadin(void)
{
        int b;
        wchar_t *cp;
        int l;

        switch (crown_state) {
        case c_head:
                l = crown_head;
                crown_state = c_lead;
                break;

        case c_lead:
        case c_fixup:
                l = crown_head;
                crown_state = c_fixup;
                break;

        case c_body:
                l = crown_body;
                break;

        default:
                l = pfx;
                break;
        }
        filler = l;
        for (b = 0, cp = outbuf; b < l; b++)
                *cp++ = L' ';
        outp = cp;
}

/*
 * Is s1 a prefix of s2??
 */

static int
ispref(wchar_t *s1, wchar_t *s2)
{

        while (*s1 != L'\0' && *s2 != L'\0')
                if (*s1++ != *s2++)
                        return (0);
        return (1);
}

/*
 * Set an input option
 */

static int
setopt(char *cp)
{
        static int ws = 0;

        if (*cp == '-') {
                if (cp[1] == 'c' && cp[2] == '\0') {
                        crown_state = c_reset;
                        return (1);
                }
                if (cp[1] == 's' && cp[2] == '\0') {
                        nojoin = 1;
                        return (1);
                }
                if (cp[1] == 'w' && cp[2] == '\0') {
                        ws++;
                        return (1);
                }
                width = atoi(cp+1);
        } else if (ws) {
                width = atoi(cp);
                ws = 0;
        } else
                return (0);
        if (width <= 0 || width >= BUFSIZ-2) {
                fprintf(stderr, "fmt:  bad width: %d\n", width);
                exit(1);
        }
        return (1);
}


#define LIB_WDRESOLVE   "/usr/lib/locale/%s/LC_CTYPE/wdresolve.so"
#define WCHKIND         "_wdchkind_"

static int      _wckind_c_locale(wchar_t);

static int      (*__wckind)(wchar_t) = _wckind_c_locale;
static void     *dlhandle = NULL;


static void
_wckind_init(void)
{
        char    *locale;
        char    path[MAXPATHLEN + 1];


        if (dlhandle != NULL) {
                (void) dlclose(dlhandle);
                dlhandle = NULL;
        }

        locale = setlocale(LC_CTYPE, NULL);
        if (strcmp(locale, "C") == 0)
                goto c_locale;

        (void) sprintf(path, LIB_WDRESOLVE, locale);

        if ((dlhandle = dlopen(path, RTLD_LAZY)) != NULL) {
                __wckind = (int (*)(wchar_t))dlsym(dlhandle, WCHKIND);
                if (__wckind != NULL)
                        return;
                (void) dlclose(dlhandle);
                dlhandle = NULL;
        }

c_locale:
        __wckind = _wckind_c_locale;
}


int
_wckind(wchar_t wc)
{
        return (*__wckind) (wc);
}


static int
_wckind_c_locale(wchar_t wc)
{
        int     ret;

        /*
         * DEPEND_ON_ANSIC: L notion for the character is new in
         * ANSI-C, k&r compiler won't work.
         */
        if (iswascii(wc))
                ret = (iswalnum(wc) || wc == L'_') ? 0 : 1;
        else
                ret = wcsetno(wc) + 1;

        return (ret);
}

/*
 * header_chk -
 * Called when done looking for a set mail header lines.
 * Either a blank line was seen, or EOF was reached.
 *
 * Verifies if current hdrbuf of potential mail header lines
 * is really a mail header.  A mail header must be at least 2
 * lines and more than half of them must start with one of the
 * known mail header strings in headnames.
 *
 * header_chk sets hdr_state to do_hdr if hdrbuf contained a valid
 * mail header.  Otherwise, it sets hdr_state to flush_hdr.
 *
 * h_lines = hdrbuf index for next line to be saved;
 *           also indicates current # of lines in potential header
 */
static void
header_chk(void)
{
        wchar_t  *cp;           /* ptr to current char of line */
        wchar_t **hp;           /* ptr to current char of a valid */
                                /* mail header string */
        int       l;            /* index */
                                /*
                                 * number of lines in hdrbuf that look
                                 * like mail header lines (start with
                                 * a known mail header prefix)
                                 */
        int      hdrcount = 0;
                /* header must have at least 2 lines (h_lines > 1) */
                if (h_lines < 2) {
                        hdr_state = flush_hdr;
                        return;
                }
                /*
                 * go through each line in hdrbuf and see how many
                 * look like mail header lines
                 */
                for (l = 0; l < h_lines; l++) {
                        /* skip initial blanks */
                        for (cp = hdrbuf[l]; *cp == L' '; cp++) {
                        }
                        for (hp = &headnames[0]; *hp != (wchar_t *)0; hp++)
                                if (ispref(*hp, cp)) {
                                        hdrcount++;
                                        break;
                                }
                }
                /*
                 * if over half match, we'll assume this is a header;
                 * set hdr_state to indicate whether to treat
                 * these lines as mail header (do_hdr) or not (flush_hdr)
                 */
                if (hdrcount > h_lines / 2)
                        hdr_state = do_hdr;
                else
                        hdr_state = flush_hdr;
}

/*
 * fill_hdrbuf -
 * Save given input line into next element of hdrbuf,
 * as a potential mail header line, to be processed later
 * once we decide whether or not the contents of hdrbuf is
 * really a mail header, via header_chk().
 *
 * Does not allow hdrbuf to exceed MAXLINES lines.
 * Dynamically allocates space for each line.  If we are unable
 * to allocate space for the current string, stop special mail
 * header preservation at this point and continue formatting
 * without it.
 */
static void
fill_hdrbuf(wchar_t line[])
{
        wchar_t *cp;    /* pointer to characters in input line */
        int      i;     /* index into characters a hdrbuf line */

        if (h_lines >= MAXLINES) {
                /*
                 * if we run over MAXLINES potential mail header
                 * lines, stop checking--this is most likely NOT a
                 * mail header; flush out the hdrbuf, then process
                 * the current 'line' normally.
                 */
                hdr_state = flush_hdr;
                process_hdrbuf();
                prefix(line);
                return;
        }
        hdrbuf[h_lines] = (wchar_t *)malloc(sizeof (wchar_t) *
            (wslen(line) + 1));
        if (hdrbuf[h_lines] == NULL) {
                perror("malloc");
                fprintf(stderr, "fmt: unable to do mail header preservation\n");
                errs++;
                /*
                 * Can't process mail header; flush current contents
                 * of mail header and continue with no more mail
                 * header processing
                 */
                if (h_lines == 0)
                        /* hdrbuf is empty; process this line normally */
                        prefix(line);
                else {
                        hdr_state = flush_hdr;
                        for (i = 0; i < h_lines; i++) {
                                prefix(hdrbuf[i]);
                                free(hdrbuf[i]);
                        }
                        h_lines = 0;
                }
                hdr_state = off;
                return;
        }
        /* save this line as a potential mail header line */
        for (i = 0, cp = line; (hdrbuf[h_lines][i] = *cp) != L'\0'; i++, cp++) {
        }
        h_lines++;
}

/*
 * process_hdrbuf -
 * Outputs the lines currently stored in hdrbuf, according
 * to the current hdr_state value, assumed to be either do_hdr
 * or flush_hdr.
 * This should be called after doing a header_chk() to verify
 * the hdrbuf and set the hdr_state flag.
 */
static void
process_hdrbuf(void)
{
int i;

        for (i = 0; i < h_lines; i++) {
                prefix(hdrbuf[i]);
                free(hdrbuf[i]);
        }
        hdr_state = not_in_hdr;
        h_lines = 0;
}