/****************************************************************************
 * Copyright (c) 2008 Free Software Foundation, Inc.                        *
 *                                                                          *
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 * copy of this software and associated documentation files (the            *
 * "Software"), to deal in the Software without restriction, including      *
 * without limitation the rights to use, copy, modify, merge, publish,      *
 * distribute, distribute with modifications, sublicense, and/or sell       *
 * copies of the Software, and to permit persons to whom the Software is    *
 * furnished to do so, subject to the following conditions:                 *
 *                                                                          *
 * The above copyright notice and this permission notice shall be included  *
 * in all copies or substantial portions of the Software.                   *
 *                                                                          *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
 *                                                                          *
 * Except as contained in this notice, the name(s) of the above copyright   *
 * holders shall not be used in advertising or otherwise to promote the     *
 * sale, use or other dealings in this Software without prior written       *
 * authorization.                                                           *
 ****************************************************************************/

/****************************************************************************
 *  Author: Thomas E. Dickey                        2008                    *
 ****************************************************************************/

/*
 * tabs.c --  set terminal hard-tabstops
 */

#define USE_LIBTINFO
#include <progs.priv.h>

MODULE_ID("$Id: tabs.c,v 1.11 2008/11/16 00:58:24 tom Exp $")

static void usage(void) GCC_NORETURN;

static int max_cols;

static int
putch(int c)
{
    return putchar(c);
}

static void
do_tabs(int *tab_list)
{
    int last = 1;
    int stop;

    putchar('\r');
    while ((stop = *tab_list++) > 0) {
	if (last < stop) {
	    while (last++ < stop) {
		if (last > max_cols)
		    break;
		putchar(' ');
	    }
	}
	if (stop <= max_cols) {
	    tputs(tparm(set_tab, stop), 1, putch);
	    last = stop;
	} else {
	    break;
	}
    }
    putchar('\n');
}

static int *
decode_tabs(const char *tab_list)
{
    int *result = typeCalloc(int, strlen(tab_list) + (unsigned) max_cols);
    int n = 0;
    int value = 0;
    int prior = 0;
    int ch;

    while ((ch = *tab_list++) != '\0') {
	if (isdigit(UChar(ch))) {
	    value *= 10;
	    value += (ch - '0');
	} else if (ch == ',') {
	    result[n] = value + prior;
	    if (n > 0 && value <= result[n - 1]) {
		fprintf(stderr, "tab-stops are not in increasing order\n");
		ExitProgram(EXIT_FAILURE);
	    }
	    ++n;
	    value = 0;
	    prior = 0;
	} else if (ch == '+') {
	    if (n)
		prior = result[n - 1];
	}
    }

    /*
     * If there is only one value, then it is an option such as "-8".
     */
    if ((n == 0) && (value > 0)) {
	int step = value;
	while (n < max_cols - 1) {
	    result[n++] = value;
	    value += step;
	}
    }

    /*
     * Add the last value, if any.
     */
    result[n++] = value;
    result[n] = 0;
    return result;
}

static void
print_ruler(int *tab_list)
{
    int last = 0;
    int stop;
    int n;

    /* first print a readable ruler */
    for (n = 0; n < max_cols; n += 10) {
	int ch = 1 + (n / 10);
	char buffer[20];
	sprintf(buffer, "----+----%c",
		((ch < 10)
		 ? (ch + '0')
		 : (ch + 'A' - 10)));
	printf("%.*s", ((max_cols - n) > 10) ? 10 : (max_cols - n), buffer);
    }
    putchar('\n');

    /* now, print '*' for each stop */
    for (n = 0, last = 0; (tab_list[n] > 0) && (last < max_cols); ++n) {
	stop = tab_list[n];
	while (++last < stop) {
	    if (last <= max_cols) {
		putchar('-');
	    } else {
		break;
	    }
	}
	if (last <= max_cols) {
	    putchar('*');
	    last = stop;
	} else {
	    break;
	}
    }
    while (++last <= max_cols)
	putchar('-');
    putchar('\n');
}

/*
 * Write an '*' on each tabstop, to demonstrate whether it lines up with the
 * ruler.
 */
static void
write_tabs(int *tab_list)
{
    int stop;

    while ((stop = *tab_list++) > 0 && stop <= max_cols) {
	fputs((stop == 1) ? "*" : "\t*", stdout);
    };
    /* also show a tab _past_ the stops */
    if (stop < max_cols)
	fputs("\t+", stdout);
    putchar('\n');
}

static void
usage(void)
{
    static const char *msg[] =
    {
	"Usage: tabs [options] [tabstop-list]"
	,""
	,"Options:"
	,"  -0       reset tabs"
	,"  -8       set tabs to standard interval"
	,"  -a       Assembler, IBM S/370, first format"
	,"  -a2      Assembler, IBM S/370, second format"
	,"  -c       COBOL, normal format"
	,"  -c2      COBOL compact format"
	,"  -c3      COBOL compact format extended"
	,"  -d       debug (show ruler with expected/actual tab positions)"
	,"  -f       FORTRAN"
	,"  -n       no-op (do not modify terminal settings)"
	,"  -p       PL/I"
	,"  -s       SNOBOL"
	,"  -u       UNIVAC 1100 Assembler"
	,"  -T name  use terminal type 'name'"
	,""
	,"A tabstop-list is an ordered list of column numbers, e.g., 1,11,21"
	,"or 1,+10,+10 which is the same."
    };
    unsigned n;

    fflush(stdout);
    for (n = 0; n < SIZEOF(msg); ++n) {
	fprintf(stderr, "%s\n", msg[n]);
    }
    ExitProgram(EXIT_FAILURE);
}

int
main(int argc, char *argv[])
{
    int rc = EXIT_SUCCESS;
    bool debug = FALSE;
    bool no_op = FALSE;
    int n, ch;
    NCURSES_CONST char *term_name = 0;
    const char *mar_list = 0;	/* ignored */
    char *append = 0;
    const char *tab_list = 0;

    if ((term_name = getenv("TERM")) == 0)
	term_name = "ansi+tabs";

    /* cannot use getopt, since some options are two-character */
    for (n = 1; n < argc; ++n) {
	char *option = argv[n];
	switch (option[0]) {
	case '-':
	    while ((ch = *++option) != '\0') {
		switch (ch) {
		case 'a':
		    switch (*option) {
		    case '\0':
			tab_list = "1,10,16,36,72";
			/* Assembler, IBM S/370, first format */
			break;
		    case '2':
			tab_list = "1,10,16,40,72";
			/* Assembler, IBM S/370, second format */
			break;
		    default:
			usage();
		    }
		    break;
		case 'c':
		    switch (*option) {
		    case '\0':
			tab_list = "1,8,12,16,20,55";
			/* COBOL, normal format */
			break;
		    case '2':
			tab_list = "1,6,10,14,49";
			/* COBOL compact format */
			break;
		    case '3':
			tab_list = "1,6,10,14,18,22,26,30,34,38,42,46,50,54,58,62,67";
			/* COBOL compact format extended */
			break;
		    default:
			usage();
		    }
		    break;
		case 'd':	/* ncurses extension */
		    debug = TRUE;
		    break;
		case 'f':
		    tab_list = "1,7,11,15,19,23";
		    /* FORTRAN */
		    break;
		case 'n':	/* ncurses extension */
		    no_op = TRUE;
		    break;
		case 'p':
		    tab_list = "1,5,9,13,17,21,25,29,33,37,41,45,49,53,57,61";
		    /* PL/I */
		    break;
		case 's':
		    tab_list = "1,10,55";
		    /* SNOBOL */
		    break;
		case 'u':
		    tab_list = "1,12,20,44";
		    /* UNIVAC 1100 Assembler */
		    break;
		case 'T':
		    ++n;
		    if (*++option != '\0') {
			term_name = option;
		    } else {
			term_name = argv[n++];
		    }
		    option += ((int) strlen(option)) - 1;
		    continue;
		default:
		    if (isdigit(UChar(*option))) {
			tab_list = option;
			++n;
		    } else {
			usage();
		    }
		    option += ((int) strlen(option)) - 1;
		    break;
		}
	    }
	    break;
	case '+':
	    while ((ch = *++option) != '\0') {
		switch (ch) {
		case 'm':
		    mar_list = option;
		    break;
		default:
		    usage();
		}
	    }
	    break;
	default:
	    if (isdigit(*option)) {
		if (append != 0) {
		    if (tab_list != (const char *) append) {
			/* one of the predefined options was used */
			append = strdup(option);
			tab_list = append;
		    } else {
			append = malloc(strlen(tab_list) + strlen(option) + 2);
			sprintf(append, "%s,%s", tab_list, option);
			free((char *) tab_list);
			tab_list = append;
		    }
		} else {
		    append = strdup(option);
		    tab_list = append;
		}
	    } else {
		usage();
	    }
	    break;
	}
    }

    setupterm(term_name, STDOUT_FILENO, (int *) 0);

    max_cols = (columns > 0) ? columns : 80;

    if (!VALID_STRING(clear_all_tabs)) {
	fprintf(stderr,
		"%s: terminal type '%s' cannot reset tabs\n",
		argv[0], term_name);
	rc = EXIT_FAILURE;
    } else if (!VALID_STRING(set_tab)) {
	fprintf(stderr,
		"%s: terminal type '%s' cannot set tabs\n",
		argv[0], term_name);
	rc = EXIT_FAILURE;
    } else {
	int *list = decode_tabs(tab_list);

	if (!no_op)
	    tputs(clear_all_tabs, 1, putch);

	if (list != 0) {
	    if (!no_op)
		do_tabs(list);
	    if (debug) {
		print_ruler(list);
		write_tabs(list);
	    }
	    free(list);
	}
    }
    if (append)
	free(append);
    ExitProgram(rc);
}