/*
 * 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.
 *
 * @(#) Copyright (c) 1980, 1993 The Regents of the University of California.  All rights reserved.
 * @(#)ul.c     8.1 (Berkeley) 6/6/93
 * FreeBSD: head/usr.bin/ul/ul.c 245093 2013-01-06 03:08:27Z andrew $
 */

#include <err.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termcap.h>
#include <unistd.h>
#include <wchar.h>
#include <wctype.h>

#define IESC    '\033'
#define SO      '\016'
#define SI      '\017'
#define HFWD    '9'
#define HREV    '8'
#define FREV    '7'
#define MAXBUF  512

#define NORMAL  000
#define ALTSET  001     /* Reverse */
#define SUPERSC 002     /* Dim */
#define SUBSC   004     /* Dim | Ul */
#define UNDERL  010     /* Ul */
#define BOLD    020     /* Bold */

static int      must_use_uc, must_overstrike;
static const char
        *CURS_UP, *CURS_RIGHT, *CURS_LEFT,
        *ENTER_STANDOUT, *EXIT_STANDOUT, *ENTER_UNDERLINE, *EXIT_UNDERLINE,
        *ENTER_DIM, *ENTER_BOLD, *ENTER_REVERSE, *UNDER_CHAR, *EXIT_ATTRIBUTES;

struct  CHAR    {
        char    c_mode;
        wchar_t c_char;
        int     c_width;        /* width or -1 if multi-column char. filler */
} ;

static struct   CHAR    obuf[MAXBUF];
static int      col, maxcol;
static int      mode;
static int      halfpos;
static int      upln;
static int      iflag;

static void usage(void);
static void setnewmode(int);
static void initcap(void);
static void reverse(void);
static int outchar(int);
static void fwd(void);
static void initbuf(void);
static void iattr(void);
static void overstrike(void);
static void flushln(void);
static void filter(FILE *);
static void outc(wint_t, int);

#define PRINT(s)        if (s == NULL) /* void */; else tputs(s, 1, outchar)

int
main(int argc, char **argv)
{
        int c;
        const char *termtype;
        FILE *f;
        char termcap[1024];

        setlocale(LC_ALL, "");

        termtype = getenv("TERM");
        if (termtype == NULL || (argv[0][0] == 'c' && !isatty(1)))
                termtype = "lpr";
        while ((c=getopt(argc, argv, "it:T:")) != -1)
                switch(c) {

                case 't':
                case 'T': /* for nroff compatibility */
                        termtype = optarg;
                        break;
                case 'i':
                        iflag = 1;
                        break;
                default:
                        usage();
                }

        switch(tgetent(termcap, termtype)) {

        case 1:
                break;

        default:
                warnx("trouble reading termcap");
                /* FALLTHROUGH */

        case 0:
                /* No such terminal type - assume dumb */
                (void)strcpy(termcap, "dumb:os:col#80:cr=^M:sf=^J:am:");
                break;
        }
        initcap();
        if (    (tgetflag("os") && ENTER_BOLD==NULL ) ||
                (tgetflag("ul") && ENTER_UNDERLINE==NULL && UNDER_CHAR==NULL))
                        must_overstrike = 1;
        initbuf();
        if (optind == argc)
                filter(stdin);
        else for (; optind<argc; optind++) {
                f = fopen(argv[optind],"r");
                if (f == NULL)
                        err(1, "%s", argv[optind]);
                else
                        filter(f);
        }
        exit(0);
}

static void
usage(void)
{
        fprintf(stderr, "usage: ul [-i] [-t terminal] [file ...]\n");
        exit(1);
}

static void
filter(FILE *f)
{
        wint_t c;
        int i, w;

        while ((c = getwc(f)) != WEOF && col < MAXBUF) switch(c) {

        case '\b':
                if (col > 0)
                        col--;
                continue;

        case '\t':
                col = (col+8) & ~07;
                if (col > maxcol)
                        maxcol = col;
                continue;

        case '\r':
                col = 0;
                continue;

        case SO:
                mode |= ALTSET;
                continue;

        case SI:
                mode &= ~ALTSET;
                continue;

        case IESC:
                switch (c = getwc(f)) {

                case HREV:
                        if (halfpos == 0) {
                                mode |= SUPERSC;
                                halfpos--;
                        } else if (halfpos > 0) {
                                mode &= ~SUBSC;
                                halfpos--;
                        } else {
                                halfpos = 0;
                                reverse();
                        }
                        continue;

                case HFWD:
                        if (halfpos == 0) {
                                mode |= SUBSC;
                                halfpos++;
                        } else if (halfpos < 0) {
                                mode &= ~SUPERSC;
                                halfpos++;
                        } else {
                                halfpos = 0;
                                fwd();
                        }
                        continue;

                case FREV:
                        reverse();
                        continue;

                default:
                        errx(1, "unknown escape sequence in input: %o, %o", IESC, c);
                }
                continue;

        case '_':
                if (obuf[col].c_char || obuf[col].c_width < 0) {
                        while (col > 0 && obuf[col].c_width < 0)
                                col--;
                        w = obuf[col].c_width;
                        for (i = 0; i < w; i++)
                                obuf[col++].c_mode |= UNDERL | mode;
                        if (col > maxcol)
                                maxcol = col;
                        continue;
                }
                obuf[col].c_char = '_';
                obuf[col].c_width = 1;
                /* FALLTHROUGH */
        case ' ':
                col++;
                if (col > maxcol)
                        maxcol = col;
                continue;

        case '\n':
                flushln();
                continue;

        case '\f':
                flushln();
                putwchar('\f');
                continue;

        default:
                if ((w = wcwidth(c)) <= 0)      /* non printing */
                        continue;
                if (obuf[col].c_char == '\0') {
                        obuf[col].c_char = c;
                        for (i = 0; i < w; i++)
                                obuf[col + i].c_mode = mode;
                        obuf[col].c_width = w;
                        for (i = 1; i < w; i++)
                                obuf[col + i].c_width = -1;
                } else if (obuf[col].c_char == '_') {
                        obuf[col].c_char = c;
                        for (i = 0; i < w; i++)
                                obuf[col + i].c_mode |= UNDERL|mode;
                        obuf[col].c_width = w;
                        for (i = 1; i < w; i++)
                                obuf[col + i].c_width = -1;
                } else if ((wint_t)obuf[col].c_char == c) {
                        for (i = 0; i < w; i++)
                                obuf[col + i].c_mode |= BOLD|mode;
                } else {
                        w = obuf[col].c_width;
                        for (i = 0; i < w; i++)
                                obuf[col + i].c_mode = mode;
                }
                col += w;
                if (col > maxcol)
                        maxcol = col;
                continue;
        }
        if (ferror(f))
                err(1, NULL);
        if (maxcol)
                flushln();
}

static void
flushln(void)
{
        int lastmode;
        int i;
        int hadmodes = 0;

        lastmode = NORMAL;
        for (i=0; i<maxcol; i++) {
                if (obuf[i].c_mode != lastmode) {
                        hadmodes++;
                        setnewmode(obuf[i].c_mode);
                        lastmode = obuf[i].c_mode;
                }
                if (obuf[i].c_char == '\0') {
                        if (upln)
                                PRINT(CURS_RIGHT);
                        else
                                outc(' ', 1);
                } else
                        outc(obuf[i].c_char, obuf[i].c_width);
                if (obuf[i].c_width > 1)
                        i += obuf[i].c_width - 1;
        }
        if (lastmode != NORMAL) {
                setnewmode(0);
        }
        if (must_overstrike && hadmodes)
                overstrike();
        putwchar('\n');
        if (iflag && hadmodes)
                iattr();
        (void)fflush(stdout);
        if (upln)
                upln--;
        initbuf();
}

/*
 * For terminals that can overstrike, overstrike underlines and bolds.
 * We don't do anything with halfline ups and downs, or Greek.
 */
static void
overstrike(void)
{
        int i;
        wchar_t lbuf[256];
        wchar_t *cp = lbuf;
        int hadbold=0;

        /* Set up overstrike buffer */
        for (i=0; i<maxcol; i++)
                switch (obuf[i].c_mode) {
                case NORMAL:
                default:
                        *cp++ = ' ';
                        break;
                case UNDERL:
                        *cp++ = '_';
                        break;
                case BOLD:
                        *cp++ = obuf[i].c_char;
                        if (obuf[i].c_width > 1)
                                i += obuf[i].c_width - 1;
                        hadbold=1;
                        break;
                }
        putwchar('\r');
        for (*cp=' '; *cp==' '; cp--)
                *cp = 0;
        for (cp=lbuf; *cp; cp++)
                putwchar(*cp);
        if (hadbold) {
                putwchar('\r');
                for (cp=lbuf; *cp; cp++)
                        putwchar(*cp=='_' ? ' ' : *cp);
                putwchar('\r');
                for (cp=lbuf; *cp; cp++)
                        putwchar(*cp=='_' ? ' ' : *cp);
        }
}

static void
iattr(void)
{
        int i;
        wchar_t lbuf[256];
        wchar_t *cp = lbuf;

        for (i=0; i<maxcol; i++)
                switch (obuf[i].c_mode) {
                case NORMAL:    *cp++ = ' '; break;
                case ALTSET:    *cp++ = 'g'; break;
                case SUPERSC:   *cp++ = '^'; break;
                case SUBSC:     *cp++ = 'v'; break;
                case UNDERL:    *cp++ = '_'; break;
                case BOLD:      *cp++ = '!'; break;
                default:        *cp++ = 'X'; break;
                }
        for (*cp=' '; *cp==' '; cp--)
                *cp = 0;
        for (cp=lbuf; *cp; cp++)
                putwchar(*cp);
        putwchar('\n');
}

static void
initbuf(void)
{

        bzero((char *)obuf, sizeof (obuf));     /* depends on NORMAL == 0 */
        col = 0;
        maxcol = 0;
        mode &= ALTSET;
}

static void
fwd(void)
{
        int oldcol, oldmax;

        oldcol = col;
        oldmax = maxcol;
        flushln();
        col = oldcol;
        maxcol = oldmax;
}

static void
reverse(void)
{
        upln++;
        fwd();
        PRINT(CURS_UP);
        PRINT(CURS_UP);
        upln++;
}

static void
initcap(void)
{
        static char tcapbuf[512];
        char *bp = tcapbuf;

        /* This nonsense attempts to work with both old and new termcap */
        CURS_UP =               tgetstr("up", &bp);
        CURS_RIGHT =            tgetstr("ri", &bp);
        if (CURS_RIGHT == NULL)
                CURS_RIGHT =    tgetstr("nd", &bp);
        CURS_LEFT =             tgetstr("le", &bp);
        if (CURS_LEFT == NULL)
                CURS_LEFT =     tgetstr("bc", &bp);
        if (CURS_LEFT == NULL && tgetflag("bs"))
                CURS_LEFT =     "\b";

        ENTER_STANDOUT =        tgetstr("so", &bp);
        EXIT_STANDOUT =         tgetstr("se", &bp);
        ENTER_UNDERLINE =       tgetstr("us", &bp);
        EXIT_UNDERLINE =        tgetstr("ue", &bp);
        ENTER_DIM =             tgetstr("mh", &bp);
        ENTER_BOLD =            tgetstr("md", &bp);
        ENTER_REVERSE =         tgetstr("mr", &bp);
        EXIT_ATTRIBUTES =       tgetstr("me", &bp);

        if (!ENTER_BOLD && ENTER_REVERSE)
                ENTER_BOLD = ENTER_REVERSE;
        if (!ENTER_BOLD && ENTER_STANDOUT)
                ENTER_BOLD = ENTER_STANDOUT;
        if (!ENTER_UNDERLINE && ENTER_STANDOUT) {
                ENTER_UNDERLINE = ENTER_STANDOUT;
                EXIT_UNDERLINE = EXIT_STANDOUT;
        }
        if (!ENTER_DIM && ENTER_STANDOUT)
                ENTER_DIM = ENTER_STANDOUT;
        if (!ENTER_REVERSE && ENTER_STANDOUT)
                ENTER_REVERSE = ENTER_STANDOUT;
        if (!EXIT_ATTRIBUTES && EXIT_STANDOUT)
                EXIT_ATTRIBUTES = EXIT_STANDOUT;

        /*
         * Note that we use REVERSE for the alternate character set,
         * not the as/ae capabilities.  This is because we are modelling
         * the model 37 teletype (since that's what nroff outputs) and
         * the typical as/ae is more of a graphics set, not the greek
         * letters the 37 has.
         */

        UNDER_CHAR =            tgetstr("uc", &bp);
        must_use_uc = (UNDER_CHAR && !ENTER_UNDERLINE);
}

static int
outchar(int c)
{
        return (putwchar(c) != WEOF ? c : EOF);
}

static int curmode = 0;

static void
outc(wint_t c, int width)
{
        int i;

        putwchar(c);
        if (must_use_uc && (curmode&UNDERL)) {
                for (i = 0; i < width; i++)
                        PRINT(CURS_LEFT);
                for (i = 0; i < width; i++)
                        PRINT(UNDER_CHAR);
        }
}

static void
setnewmode(int newmode)
{
        if (!iflag) {
                if (curmode != NORMAL && newmode != NORMAL)
                        setnewmode(NORMAL);
                switch (newmode) {
                case NORMAL:
                        switch(curmode) {
                        case NORMAL:
                                break;
                        case UNDERL:
                                PRINT(EXIT_UNDERLINE);
                                break;
                        default:
                                /* This includes standout */
                                PRINT(EXIT_ATTRIBUTES);
                                break;
                        }
                        break;
                case ALTSET:
                        PRINT(ENTER_REVERSE);
                        break;
                case SUPERSC:
                        /*
                         * This only works on a few terminals.
                         * It should be fixed.
                         */
                        PRINT(ENTER_UNDERLINE);
                        PRINT(ENTER_DIM);
                        break;
                case SUBSC:
                        PRINT(ENTER_DIM);
                        break;
                case UNDERL:
                        PRINT(ENTER_UNDERLINE);
                        break;
                case BOLD:
                        PRINT(ENTER_BOLD);
                        break;
                default:
                        /*
                         * We should have some provision here for multiple modes
                         * on at once.  This will have to come later.
                         */
                        PRINT(ENTER_STANDOUT);
                        break;
                }
        }
        curmode = newmode;
}