/** BEGIN COPYRIGHT BLOCK
 * Copyright (C) 2001 Sun Microsystems, Inc. Used by permission.
 * Copyright (C) 2005 Red Hat, Inc.
 * All rights reserved.
 *
 * License: GPL (version 3 or any later version).
 * See LICENSE for details. 
 * END COPYRIGHT BLOCK **/

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

/* parents.c - where the adults live */

#include "back-ldbm.h"

char *numsubordinates = LDBM_NUMSUBORDINATES_STR;
char *hassubordinates = "hassubordinates";
char *tombstone_numsubordinates = LDBM_TOMBSTONE_NUMSUBORDINATES_STR;

/* Routine where any in-memory modification of a parent entry happens on some
 * state-change in one of its children. vaid op values are:
 *     PARENTUPDATE_ADD == child entry newly added, 
 *     PARENTUPDATE_DEL == child entry about to be deleted;
 *     3 == child modified, in which case childmods points to the modifications. 
 * The child entry passed is in the state which reflects the mods having been 
 * appied. op ==3 HAS NOT BEEN IMPLEMENTED YET
 * The routine is allowed to modify the parent entry, and to return a set of 
 * LDAPMods reflecting the changes it made. The LDAPMods array must be freed 
 * by the called by calling ldap_free_mods(p,1)
 *
 *     PARENTUPDATE_RESURECT == turning a tombstone into an entry
 *                              tombstone_numsubordinates--
 *                              numsubordinates++
 */
/* 
 * PARENTUPDATE_CREATE_TOMBSTONE: turning an entry into a tombstone
 *                                numsubordinates--
 *                                tombstone_numsubordinates++
 * PARENTUPDATE_DELETE_TOMBSTONE: don't touch numsubordinates, and
 *                                tombstone_numsubordinates--
 */

int
parent_update_on_childchange(modify_context *mc,int op, size_t *new_sub_count )
{
	int ret = 0;
	int mod_op = 0;
	Slapi_Attr	*read_attr = NULL;
	size_t current_sub_count = 0;
	int already_present = 0;
	int repl_op = 0;
	Slapi_Mods *smods = NULL;
	char value_buffer[20]; /* enough digits for 2^64 children */

	if (new_sub_count)
		*new_sub_count = 0;

	repl_op = PARENTUPDATE_TOMBSTONE_MASK & op;
	op &= PARENTUPDATE_MASK;

	/* Check nobody is trying to use op == 3, it's not implemented yet */
	PR_ASSERT((op == PARENTUPDATE_ADD) || (op == PARENTUPDATE_DEL) || (op == PARENTUPDATE_RESURECT));

	/* We want to invent a mods set to be passed to modify_apply_mods() */

	/* For now, we're only interested in subordinatecount. 
	   We first examine the present value for the attribute. 
	   If it isn't present and we're adding, we assign value 1 to the attribute and add it.
	   If it is present, we increment or decrement depending upon whether we're adding or deleting.
	   If the value after decrementing is zero, we remove it.
	*/

	smods = slapi_mods_new();

	/* Get the present value of the subcount attr, or 0 if not present */
	ret = slapi_entry_attr_find(mc->old_entry->ep_entry,numsubordinates,&read_attr);
	if (0 == ret) {
		/* decode the value */
		Slapi_Value *sval;
		slapi_attr_first_value( read_attr, &sval );
		if (sval!=NULL) {
			const struct berval *bval = slapi_value_get_berval(sval);
			if(NULL != bval) {
			    already_present = 1;
			    current_sub_count = atol(bval->bv_val);
			}
		}
	}

	if (PARENTUPDATE_DELETE_TOMBSTONE != repl_op) {
		/* are we adding ? */
		if (((PARENTUPDATE_ADD == op) || (PARENTUPDATE_RESURECT == op)) && !already_present) {
			/* If so, and the parent entry does not already have a subcount 
			 * attribute, we need to add it */
			mod_op = LDAP_MOD_ADD;
		} else  if (PARENTUPDATE_DEL == op) {
			if (!already_present) {
				/* This means that there was a conflict.  Before coming to this point,
				 * the entry to be deleted was deleted... */
				LDAPDebug(LDAP_DEBUG_ANY, "Parent %s has no children. (op 0x%x, repl_op 0x%x)\n",
				          slapi_entry_get_dn(mc->old_entry->ep_entry), op, repl_op);
				slapi_mods_free(&smods);
				return -1;
			} else {
				if (current_sub_count == 1) {
					mod_op = LDAP_MOD_DELETE;
				} else {
					mod_op = LDAP_MOD_REPLACE;
				}
			}
		} else {
			/* (PARENTUPDATE_ADD == op) && already_present */
			mod_op = LDAP_MOD_REPLACE;
		}

		/* Now compute the new value */
		if ((PARENTUPDATE_ADD == op) || (PARENTUPDATE_RESURECT == op)) {
			current_sub_count++;
		} else {
			current_sub_count--;
		}

		if (mod_op == LDAP_MOD_DELETE) {
			slapi_mods_add(smods, mod_op | LDAP_MOD_BVALUES,
			               numsubordinates, 0, NULL);
		} else {
			sprintf(value_buffer,"%lu", (long unsigned int)current_sub_count);
			slapi_mods_add(smods, mod_op | LDAP_MOD_BVALUES, 
			               numsubordinates, strlen(value_buffer), value_buffer);
		}
		if (new_sub_count) {
			*new_sub_count = current_sub_count;
		}
	}

	/* tombstoneNumSubordinates is needed only when this is repl op
	 * and a child is being deleted */
	current_sub_count = LDAP_MAXINT;
	if ((repl_op && (PARENTUPDATE_DEL == op)) || (PARENTUPDATE_RESURECT == op)) {
		ret = slapi_entry_attr_find(mc->old_entry->ep_entry,
		                            tombstone_numsubordinates, &read_attr);
		if (0 == ret) {
			/* decode the value */
			Slapi_Value *sval;
			slapi_attr_first_value( read_attr, &sval );
			if (sval!=NULL) {
				const struct berval *bval = slapi_value_get_berval(sval);
				if(NULL != bval) {
					current_sub_count = atol(bval->bv_val);
				}
			}
		}

		if ((PARENTUPDATE_DELETE_TOMBSTONE == repl_op) || (PARENTUPDATE_RESURECT == op)) {
			/* deleting a tombstone entry: 
			 * reaping or manually deleting it */
			if ((current_sub_count != LDAP_MAXINT) && 
			    (current_sub_count > 0)) {
				current_sub_count--;
				mod_op = LDAP_MOD_REPLACE;
				sprintf(value_buffer,"%lu", (long unsigned int)current_sub_count);
				slapi_mods_add(smods, mod_op | LDAP_MOD_BVALUES, 
				               tombstone_numsubordinates,
				               strlen(value_buffer), value_buffer);
			}
		} else if (PARENTUPDATE_CREATE_TOMBSTONE == repl_op) {
			/* creating a tombstone entry */
			if (current_sub_count != LDAP_MAXINT) {
				current_sub_count++;
			} else { /* tombstonenumsubordinates does not exist */
				current_sub_count = 1;
			}
			mod_op = LDAP_MOD_REPLACE;
			sprintf(value_buffer,"%lu", (long unsigned int)current_sub_count);
			slapi_mods_add(smods, mod_op | LDAP_MOD_BVALUES,
			               tombstone_numsubordinates, 
			               strlen(value_buffer), value_buffer);
		}
	}

	ret = modify_apply_mods(mc, smods); /* smods passed in */
	return ret;
}
