/*
 * custom - interface for custom software and hardware interfaces
 *
 * Copyright (C) 1999-2006,2018,2021-2023,2026  Landon Curt Noll
 *
 * Calc is open software; you can redistribute it and/or modify it under
 * the terms of the version 2.1 of the GNU Lesser General Public License
 * as published by the Free Software Foundation.
 *
 * Calc is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General
 * Public License for more details.
 *
 * A copy of version 2.1 of the GNU Lesser General Public License is
 * distributed with calc under the filename COPYING-LGPL.  You should have
 * received a copy with calc; if not, write to Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * Under source code control:   1997/03/03 04:53:08
 * File existed as early as:    1997
 *
 * chongo <was here> /\oo/\     http://www.isthe.com/chongo/
 * Share and enjoy!  :-)        http://www.isthe.com/chongo/tech/comp/calc/
 */

/*
 * important <system> header includes
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <stdbool.h>

/*
 * calc local src includes
 */
#include "value.h"
#include "calc.h"
#include "custom.h"
#include "attribute.h"
#include "errtbl.h"

#include "banned.h" /* include after all other includes */

#if defined(CUSTOM)
extern const struct custom cust[]; /* custom interface table */
#endif

bool allow_custom = false; /* true => custom builtins allowed */

/*
 * custom - custom callout function
 */
/*ARGSUSED*/
VALUE
custom(char *name, int count, VALUE **vals)
{
#if defined(CUSTOM)

    const struct custom *p; /* current function */

    /*
     * error if libcustcalc was compiled with CUSTOM undefined
     */
    if (custom_compiled() != true) {
        math_error("libcustcalc was compiled with CUSTOM undefined "
                   "custom_compiled() returned: %d != %d",
                   custom_compiled(), true);
        not_reached();
    }

    /*
     * search the custom interface table for a function
     */
    for (p = cust; p->name != NULL; ++p) {

        /* look for the first match */
        if (strcmp(name, p->name) == 0) {

            /* arg count check */
            if (count < p->minargs) {
                math_error("Too few arguments for custom "
                           "function \"%s\"",
                           p->name);
                not_reached();
            }
            if (count > p->maxargs) {
                math_error("Too many arguments for custom "
                           "function \"%s\"",
                           p->name);
                not_reached();
            }

            /* call the custom function */
            return p->func(name, count, vals);
        }
    }

    /*
     * no such custom function
     */
    return error_value(E_UNK_CUSTOM);

#else

    /*
     * error if libcustcalc was compiled with CUSTOM defined
     */
    if (custom_compiled() != false) {
        math_error("libcustcalc was compiled with CUSTOM defined "
                   "custom_compiled() returned: %d != %d",
                   custom_compiled(), false);
        not_reached();
    }

    fprintf(stderr, "%sCalc was built with custom functions disabled\n", (conf->tab_ok ? "\t" : ""));
    if (conf->calc_debug & CALCDBG_CUSTOM) {
        fprintf(stderr, "%scustom function %s with %d args, %s vals not executed\n", (conf->tab_ok ? "\t" : ""), name, count,
                (vals == NULL) ? "NULL" : "non-NULL");
    }
    return error_value(E_NO_CUSTOM);

#endif
}

/*
 * showcustom - display the names and brief descriptions of custom functions
 */
/*ARGSUSED*/
void
showcustom(void)
{
#if defined(CUSTOM)

    const struct custom *p; /* current function */

    /*
     * disable custom functions unless -C was given
     */
    if (!allow_custom) {
        fprintf(stderr,
                "%sCalc must be run with a -C argument to "
                "show custom functions\n",
                (conf->tab_ok ? "\t" : ""));
        return;
    }

    /*
     * print header
     */
    printf("\nName\tArgs\tDescription\n\n");
    for (p = cust; p->name != NULL; ++p) {
        printf("%-9s ", p->name);
        if (p->maxargs == MAX_CUSTOM_ARGS) {
            printf("%d+    ", p->minargs);
        } else if (p->minargs == p->maxargs) {
            printf("%-6d", p->minargs);
        } else {
            printf("%d-%-4d", p->minargs, p->maxargs);
        }
        printf("%s\n", p->desc);
    }
    printf("\n");

#else

    fprintf(stderr, "%sCalc was built with custom functions disabled\n", (conf->tab_ok ? "\t" : ""));

#endif
}

/*
 * customhelp - standard help interface to a custom function
 *
 * This function assumes that a help file with the same name as
 * the custom function has been installed by the custom/Makefile
 * (as listed in the CUSTOM_HELP makefile variable) under the
 * CUSTOMHELPDIR == HELPDIR/custhelp directory.
 *
 * The help command first does a search in HELPDIR and later
 * in CUSTOMHELPDIR.  If a custom help file has the same name
 * as a file under HELPDIR then help will display the HELPDIR
 * file and NOT the custom file.  This function will ignore
 * and HELPDIR file and work directly with the custom help file.
 *
 * given:
 *      name    name of the custom help file to directly access
 */
/*ARGSUSED*/
void
customhelp(char *name)
{
#if defined(CUSTOM)

    char *customname;    /* a string of the form: custom/name */
    size_t snprintf_len; /* malloced snprintf buffer length */

    /*
     * firewall
     */
    if (name == NULL) {
        name = "help";
    }

    /*
     * form the custom help name
     */
    snprintf_len = sizeof("custhelp") + 1 + strlen(name) + 1;
    customname = (char *)calloc(snprintf_len + 1, 1);
    if (customname == NULL) {
        math_error("bad malloc of customname");
        not_reached();
    }
    snprintf(customname, snprintf_len, "custhelp/%s", name);
    customname[snprintf_len] = '\0'; /* paranoia */

    /*
     * give help directly to the custom file
     */
    givehelp(customname);

    /*
     * all done
     */
    free(customname);

#else

    fprintf(stderr, "%sCalc was built with custom functions disabled\n", (conf->tab_ok ? "\t" : ""));
    if (conf->calc_debug & CALCDBG_CUSTOM) {
        fprintf(stderr, "%scustom help for %s unavailable\n", (conf->tab_ok ? "\t" : ""), ((name == NULL) ? "((NULL))" : name));
    }

#endif
}
