/*
 * charybdis: an advanced ircd
 * substitution.c: parses substitution-keyword expansions
 *
 * Copyright (c) 2006-2007 William Pitcock <nenolod@nenolod.net>
 *
 * 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 *
 * $Id$
 */

#include "stdinc.h"
#include "s_user.h"
#include "snomask.h"
#include "match.h"
#include "substitution.h"

/*
 * Simple mappings for $foo -> 'bar'.
 * Everything is a string, so typing doesn't really matter too
 * horribly much right now.
 */
struct substitution_variable {
    char *name;
    char *value;
};

/*
 * substitution_append_var
 *
 * Inputs       - A variable list (rb_dlink_list), name -> value for mapping to make
 * Output       - none
 * Side Effects - Adds a name->value mapping to a list.
 */
void substitution_append_var(rb_dlink_list *varlist, const char *name, const char *value)
{
    struct substitution_variable *tmp = rb_malloc(sizeof(struct substitution_variable));

    tmp->name = rb_strdup(name);
    tmp->value = rb_strdup(value);

    rb_dlinkAddAlloc(tmp, varlist);
}

/*
 * substitution_free
 *
 * Inputs       - A rb_dlink_list of markup variables to free.
 * Outputs      - none
 * Side Effects - Empties a list of markup variables.
 */
void substitution_free(rb_dlink_list *varlist)
{
    rb_dlink_node *nptr, *nptr2;

    RB_DLINK_FOREACH_SAFE(nptr, nptr2, varlist->head) {
        struct substitution_variable *tmp = (struct substitution_variable *) nptr->data;

        rb_dlinkDelete(nptr, varlist);
        rb_free(tmp->name);
        rb_free(tmp->value);
        rb_free(tmp);
    }
}

/*
 * substitution_parse
 *
 * Inputs       - A markup string, rb_dlink-list of markup values
 * Output       - A string which has been markup-replaced.
 * Side Effects - Strings larger than BUFSIZE are terminated.
 */
char *substitution_parse(const char *fmt, rb_dlink_list *varlist)
{
    static char buf[BUFSIZE];
    const char *ptr;
    char *bptr = buf;

    for (ptr = fmt; *ptr != '\0' && bptr - buf < BUFSIZE; ptr++)
        if (*ptr != '$')
            *bptr++ = *ptr;
        else if (*(ptr + 1) == '{') {
            static char varname[BUFSIZE];
            char *vptr = varname;
            const char *pptr;
            rb_dlink_node *nptr;

            *vptr = '\0';

            /* break out ${var} */
            for (pptr = ptr + 2; *pptr != '\0'; pptr++) {
                if (*pptr != '}')
                    *vptr++ = *pptr;
                else {
                    *vptr++ = '\0';
                    break;
                }
            }

            s_assert(*varname != '\0');
            s_assert(*pptr != '\0');

            /* advance ptr by length of variable */
            ptr += (pptr - ptr);

            RB_DLINK_FOREACH(nptr, varlist->head) {
                struct substitution_variable *val = (struct substitution_variable *) nptr->data;

                if (!strcasecmp(varname, val->name)) {
                    rb_strlcpy(bptr, val->value, BUFSIZE - (bptr - buf));
                    bptr += strlen(val->value);
                    break;
                }
            }
        }

    *bptr = '\0';
    return buf;
}