/* 
   ldb database library

   Copyright (C) Andrew Tridgell 2005

     ** NOTE! The following LGPL license applies to the ldb
     ** library. This does NOT imply that all of Samba is released
     ** under the LGPL
   
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.

   This library 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.

   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
/*
  handle operational attributes
 */

/*
  createTimestamp: HIDDEN, searchable, ldaptime, alias for whenCreated
  modifyTimestamp: HIDDEN, searchable, ldaptime, alias for whenChanged

     for the above two, we do the search as normal, and if
     createTimestamp or modifyTimestamp is asked for, then do
     additional searches for whenCreated and whenChanged and fill in
     the resulting values

     we also need to replace these with the whenCreated/whenChanged
     equivalent in the search expression trees

  whenCreated: not-HIDDEN, CONSTRUCTED, SEARCHABLE
  whenChanged: not-HIDDEN, CONSTRUCTED, SEARCHABLE

     on init we need to setup attribute handlers for these so
     comparisons are done correctly. The resolution is 1 second.

     on add we need to add both the above, for current time

     on modify we need to change whenChanged


  subschemaSubentry: HIDDEN, not-searchable, 
                     points at DN CN=Aggregate,CN=Schema,CN=Configuration,$BASEDN

     for this one we do the search as normal, then add the static
     value if requested. How do we work out the $BASEDN from inside a
     module?
     

  structuralObjectClass: HIDDEN, CONSTRUCTED, not-searchable. always same as objectclass?

     for this one we do the search as normal, then if requested ask
     for objectclass, change the attribute name, and add it

  attributeTypes: in schema only
  objectClasses: in schema only
  matchingRules: in schema only
  matchingRuleUse: in schema only
  creatorsName: not supported by w2k3?
  modifiersName: not supported by w2k3?
*/


#include "includes.h"
#include "ldb/include/ldb.h"
#include "ldb/include/ldb_private.h"
#include <time.h>

/*
  a list of attribute names that should be substituted in the parse
  tree before the search is done
*/
static const struct {
	const char *attr;
	const char *replace;
} parse_tree_sub[] = {
	{ "createTimestamp", "whenCreated" },
	{ "modifyTimestamp", "whenChanged" }
};

/*
  a list of attribute names that are hidden, but can be searched for
  using another (non-hidden) name to produce the correct result
*/
static const struct {
	const char *attr;
	const char *replace;
} search_sub[] = {
	{ "createTimestamp", "whenCreated" },
	{ "modifyTimestamp", "whenChanged" },
	{ "structuralObjectClass", "objectClass" }
};

/*
  hook search operations
*/
static int operational_search_bytree(struct ldb_module *module, 
				     const struct ldb_dn *base,
				     enum ldb_scope scope, struct ldb_parse_tree *tree,
				     const char * const *attrs, 
				     struct ldb_message ***res)
{
	int i, r, a;
	int ret;
	const char **search_attrs = NULL;

	/* replace any attributes in the parse tree that are
	   searchable, but are stored using a different name in the
	   backend */
	for (i=0;i<ARRAY_SIZE(parse_tree_sub);i++) {
		ldb_parse_tree_attr_replace(tree, 
					    parse_tree_sub[i].attr, 
					    parse_tree_sub[i].replace);
	}

	/* in the list of attributes we are looking for, rename any
	   attributes to the alias for any hidden attributes that can
	   be fetched directly using non-hidden names */
	for (i=0;i<ARRAY_SIZE(search_sub);i++) {
		for (a=0;attrs[a];a++) {
			if (ldb_attr_cmp(attrs[a], search_sub[i].attr) == 0) {
				if (!search_attrs) {
					search_attrs = ldb_attr_list_copy(module, attrs);
					if (search_attrs == NULL) {
						goto oom;
					}
				}
				search_attrs[a] = search_sub[i].replace;
			}
		}
	}
	

	/* perform the search */
	ret = ldb_next_search_bytree(module, base, scope, tree, 
				     search_attrs?search_attrs:attrs, res);
	if (ret <= 0) {
		return ret;
	}

	/* for each record returned see if we have added any
	   attributes to the search, and if we have then either copy
	   them (if the aliased name was also asked for) or rename
	   them (if the aliased entry was not asked for) */
	for (r=0;r<ret;r++) {
		for (i=0;i<ARRAY_SIZE(search_sub);i++) {
			for (a=0;attrs[a];a++) {
				if (ldb_attr_cmp(attrs[a], search_sub[i].attr) != 0) {
					continue;
				}
				if (ldb_attr_in_list(attrs, search_sub[i].replace) ||
				    ldb_attr_in_list(attrs, "*")) {
					if (ldb_msg_copy_attr((*res)[r], 
							      search_sub[i].replace,
							      search_sub[i].attr) != 0) {
						goto oom;
					}
				} else {
					ldb_msg_rename_attr((*res)[r], 
							    search_sub[i].replace,
							    search_sub[i].attr);
				}
			}
		}
	}

	/* all done */
	talloc_free(search_attrs);
	return ret;

oom:
	talloc_free(search_attrs);
	ldb_oom(module->ldb);
	return -1;
}


static const struct ldb_module_ops operational_ops = {
	.name              = "operational",
	.search_bytree     = operational_search_bytree,
#if 0
	.add_record        = operational_add_record,
	.modify_record     = operational_modify_record,
	.rename_record     = operational_rename_record
#endif
};


/* the init function */
#ifdef HAVE_DLOPEN_DISABLED
 struct ldb_module *init_module(struct ldb_context *ldb, const char *options[])
#else
struct ldb_module *operational_module_init(struct ldb_context *ldb, const char *options[])
#endif
{
	struct ldb_module *ctx;

	ctx = talloc(ldb, struct ldb_module);
	if (!ctx)
		return NULL;

	ctx->private_data = NULL;
	ctx->ldb = ldb;
	ctx->prev = ctx->next = NULL;
	ctx->ops = &operational_ops;

	return ctx;
}