/*
 * ircd-ratbox: an advanced Internet Relay Chat Daemon(ircd).
 * cache.c - code for caching files
 *
 * Copyright (C) 2003 Lee Hardy <lee@leeh.co.uk>
 * Copyright (C) 2003-2005 ircd-ratbox development team
 *
 * 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.
 *
 */

#include "stdinc.h"
#include "ircd_defs.h"
#include "common.h"
#include "s_conf.h"
#include "client.h"
#include "hash.h"
#include "cache.h"
#include "irc_dictionary.h"
#include "numeric.h"

struct cachefile *user_motd = NULL;
struct cachefile *oper_motd = NULL;
struct cacheline *emptyline = NULL;
rb_dlink_list links_cache_list;
char user_motd_changed[MAX_DATE_STRING];

struct Dictionary *help_dict_oper = NULL;
struct Dictionary *help_dict_user = NULL;

/* init_cache()
 *
 * inputs	-
 * outputs	-
 * side effects - inits the file/line cache blockheaps, loads motds
 */
void
init_cache(void)
{
    /* allocate the emptyline */
    emptyline = rb_malloc(sizeof(struct cacheline));
    emptyline->data[0] = ' ';
    emptyline->data[1] = '\0';
    user_motd_changed[0] = '\0';

    user_motd = cache_file(MPATH, "ircd.motd", 0);
    oper_motd = cache_file(OPATH, "opers.motd", 0);
    memset(&links_cache_list, 0, sizeof(links_cache_list));

    help_dict_oper = irc_dictionary_create(strcasecmp);
    help_dict_user = irc_dictionary_create(strcasecmp);
}

/*
 * removes tabs from src, replaces with 8 spaces, and returns the length
 * of the new string.  if the new string would be greater than destlen,
 * it is truncated to destlen - 1
 */
static size_t
untabify(char *dest, const char *src, size_t destlen)
{
    size_t x = 0, i;
    const char *s = src;
    char *d = dest;

    while(*s != '\0' && x < destlen - 1) {
        if(*s == '\t') {
            for(i = 0; i < 8 && x < destlen - 1; i++, x++, d++)
                *d = ' ';
            s++;
        } else {
            *d++ = *s++;
            x++;
        }
    }
    *d = '\0';
    return x;
}

/* cache_file()
 *
 * inputs	- file to cache, files "shortname", flags to set
 * outputs	- pointer to file cached, else NULL
 * side effects -
 */
struct cachefile *
cache_file(const char *filename, const char *shortname, int flags)
{
    FILE *in;
    struct cachefile *cacheptr;
    struct cacheline *lineptr;
    char line[BUFSIZE];
    char *p;

    if((in = fopen(filename, "r")) == NULL)
        return NULL;


    cacheptr = rb_malloc(sizeof(struct cachefile));

    rb_strlcpy(cacheptr->name, shortname, sizeof(cacheptr->name));
    cacheptr->flags = flags;

    /* cache the file... */
    while(fgets(line, sizeof(line), in) != NULL) {
        if((p = strpbrk(line, "\r\n")) != NULL)
            *p = '\0';

        if(!EmptyString(line)) {
            lineptr = rb_malloc(sizeof(struct cacheline));
            untabify(lineptr->data, line, sizeof(lineptr->data));
            rb_dlinkAddTail(lineptr, &lineptr->linenode, &cacheptr->contents);
        } else
            rb_dlinkAddTailAlloc(emptyline, &cacheptr->contents);
    }

    if (0 == rb_dlink_list_length(&cacheptr->contents)) {
        /* No contents. Don't cache it after all. */
        rb_free(cacheptr);
        cacheptr = NULL;
    }

    fclose(in);
    return cacheptr;
}

void
cache_links(void *unused)
{
    struct Client *target_p;
    rb_dlink_node *ptr;
    rb_dlink_node *next_ptr;
    char *links_line;

    RB_DLINK_FOREACH_SAFE(ptr, next_ptr, links_cache_list.head) {
        rb_free(ptr->data);
        rb_free_rb_dlink_node(ptr);
    }

    links_cache_list.head = links_cache_list.tail = NULL;
    links_cache_list.length = 0;

    RB_DLINK_FOREACH(ptr, global_serv_list.head) {
        target_p = ptr->data;

        /* skip ourselves (done in /links) and hidden servers */
        if(IsMe(target_p) ||
           (IsHidden(target_p) && !ConfigServerHide.disable_hidden))
            continue;

        /* if the below is ever modified, change LINKSLINELEN */
        links_line = rb_malloc(LINKSLINELEN);
        rb_snprintf(links_line, LINKSLINELEN, "%s %s :1 %s",
                    target_p->name, me.name,
                    target_p->info[0] ? target_p->info :
                    "(Unknown Location)");

        rb_dlinkAddTailAlloc(links_line, &links_cache_list);
    }
}

/* free_cachefile()
 *
 * inputs	- cachefile to free
 * outputs	-
 * side effects - cachefile and its data is free'd
 */
void
free_cachefile(struct cachefile *cacheptr)
{
    rb_dlink_node *ptr;
    rb_dlink_node *next_ptr;

    if(cacheptr == NULL)
        return;

    RB_DLINK_FOREACH_SAFE(ptr, next_ptr, cacheptr->contents.head) {
        if(ptr->data != emptyline)
            rb_free(ptr->data);
    }

    rb_free(cacheptr);
}

/* load_help()
 *
 * inputs	-
 * outputs	-
 * side effects - old help cache deleted
 *		- contents of help directories are loaded.
 */
void
load_help(void)
{
    DIR *helpfile_dir = NULL;
    struct dirent *ldirent= NULL;
    char filename[MAXPATHLEN];
    struct cachefile *cacheptr;
    struct DictionaryIter iter;

#if defined(S_ISLNK) && defined(HAVE_LSTAT)
    struct stat sb;
#endif

    DICTIONARY_FOREACH(cacheptr, &iter, help_dict_oper) {
        irc_dictionary_delete(help_dict_oper, cacheptr->name);
        free_cachefile(cacheptr);
    }
    DICTIONARY_FOREACH(cacheptr, &iter, help_dict_user) {
        irc_dictionary_delete(help_dict_user, cacheptr->name);
        free_cachefile(cacheptr);
    }

    helpfile_dir = opendir(HPATH);

    if(helpfile_dir == NULL)
        return;

    while((ldirent = readdir(helpfile_dir)) != NULL) {
        if(ldirent->d_name[0] == '.')
            continue;
        rb_snprintf(filename, sizeof(filename), "%s/%s", HPATH, ldirent->d_name);
        cacheptr = cache_file(filename, ldirent->d_name, HELP_OPER);
        irc_dictionary_add(help_dict_oper, cacheptr->name, cacheptr);
    }

    closedir(helpfile_dir);
    helpfile_dir = opendir(UHPATH);

    if(helpfile_dir == NULL)
        return;

    while((ldirent = readdir(helpfile_dir)) != NULL) {
        if(ldirent->d_name[0] == '.')
            continue;
        rb_snprintf(filename, sizeof(filename), "%s/%s", UHPATH, ldirent->d_name);

#if defined(S_ISLNK) && defined(HAVE_LSTAT)
        if(lstat(filename, &sb) < 0)
            continue;

        /* ok, if its a symlink, we work on the presumption if an
         * oper help exists of that name, its a symlink to that --fl
         */
        if(S_ISLNK(sb.st_mode)) {
            cacheptr = irc_dictionary_retrieve(help_dict_oper, ldirent->d_name);

            if(cacheptr != NULL) {
                cacheptr->flags |= HELP_USER;
                continue;
            }
        }
#endif

        cacheptr = cache_file(filename, ldirent->d_name, HELP_USER);
        irc_dictionary_add(help_dict_user, cacheptr->name, cacheptr);
    }

    closedir(helpfile_dir);
}

/* send_user_motd()
 *
 * inputs	- client to send motd to
 * outputs	- client is sent motd if exists, else ERR_NOMOTD
 * side effects -
 */
void
send_user_motd(struct Client *source_p)
{
    struct cacheline *lineptr;
    rb_dlink_node *ptr;
    const char *myname = get_id(&me, source_p);
    const char *nick = get_id(source_p, source_p);
    if(user_motd == NULL || rb_dlink_list_length(&user_motd->contents) == 0) {
        sendto_one(source_p, form_str(ERR_NOMOTD), myname, nick);
        return;
    }

    sendto_one(source_p, form_str(RPL_MOTDSTART), myname, nick, me.name);

    RB_DLINK_FOREACH(ptr, user_motd->contents.head) {
        lineptr = ptr->data;
        sendto_one(source_p, form_str(RPL_MOTD), myname, nick, lineptr->data);
    }

    sendto_one(source_p, form_str(RPL_ENDOFMOTD), myname, nick);
}

void
cache_user_motd(void)
{
    struct stat sb;
    struct tm *local_tm;

    if(stat(MPATH, &sb) == 0) {
        local_tm = localtime(&sb.st_mtime);

        if(local_tm != NULL) {
            rb_snprintf(user_motd_changed, sizeof(user_motd_changed),
                        "%d/%d/%d %d:%d",
                        local_tm->tm_mday, local_tm->tm_mon + 1,
                        1900 + local_tm->tm_year, local_tm->tm_hour,
                        local_tm->tm_min);
        }
    }
    free_cachefile(user_motd);
    user_motd = cache_file(MPATH, "ircd.motd", 0);
}


/* send_oper_motd()
 *
 * inputs	- client to send motd to
 * outputs	- client is sent oper motd if exists
 * side effects -
 */
void
send_oper_motd(struct Client *source_p)
{
    struct cacheline *lineptr;
    rb_dlink_node *ptr;

    if(oper_motd == NULL || rb_dlink_list_length(&oper_motd->contents) == 0)
        return;

    sendto_one(source_p, form_str(RPL_OMOTDSTART),
               me.name, source_p->name);

    RB_DLINK_FOREACH(ptr, oper_motd->contents.head) {
        lineptr = ptr->data;
        sendto_one(source_p, form_str(RPL_OMOTD),
                   me.name, source_p->name, lineptr->data);
    }

    sendto_one(source_p, form_str(RPL_ENDOFOMOTD),
               me.name, source_p->name);
}
