/* 
   ldb database library

   Copyright (C) Simo Sorce  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 3 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, see <http://www.gnu.org/licenses/>.
*/

/*
 *  Name: ldb
 *
 *  Component: ldb server side sort control module
 *
 *  Description: this module sorts the results of a search
 *
 *  Author: Simo Sorce
 */

#include "ldb_includes.h"

struct opaque {
	struct ldb_context *ldb;
	const struct ldb_attrib_handler *h;
	const char *attribute;
	int reverse;
	int result;
};

struct sort_context {
	struct ldb_module *module;
	void *up_context;
	int (*up_callback)(struct ldb_context *, void *, struct ldb_reply *);

	char *attributeName;
	char *orderingRule;
	int reverse;

	struct ldb_request *req;
	struct ldb_message **msgs;
	char **referrals;
	struct ldb_control **controls;
	int num_msgs;
	int num_refs;

	const struct ldb_schema_attribute *a;
	int sort_result;
};

static struct ldb_handle *init_handle(void *mem_ctx, struct ldb_module *module,
					    void *context,
					    int (*callback)(struct ldb_context *, void *, struct ldb_reply *))
{
	struct sort_context *ac;
	struct ldb_handle *h;

	h = talloc_zero(mem_ctx, struct ldb_handle);
	if (h == NULL) {
		ldb_set_errstring(module->ldb, "Out of Memory");
		return NULL;
	}

	h->module = module;

	ac = talloc_zero(h, struct sort_context);
	if (ac == NULL) {
		ldb_set_errstring(module->ldb, "Out of Memory");
		talloc_free(h);
		return NULL;
	}

	h->private_data = (void *)ac;

	h->state = LDB_ASYNC_INIT;
	h->status = LDB_SUCCESS;

	ac->module = module;
	ac->up_context = context;
	ac->up_callback = callback;

	return h;
}

static int build_response(void *mem_ctx, struct ldb_control ***ctrls, int result, const char *desc)
{
	struct ldb_control **controls;
	struct ldb_sort_resp_control *resp;
	int i;

	if (*ctrls) {
		controls = *ctrls;
		for (i = 0; controls[i]; i++);
		controls = talloc_realloc(mem_ctx, controls, struct ldb_control *, i + 2);
	} else {
		i = 0;
		controls = talloc_array(mem_ctx, struct ldb_control *, 2);
	}
	if (! controls )
		return LDB_ERR_OPERATIONS_ERROR;

	*ctrls = controls;

	controls[i+1] = NULL;
	controls[i] = talloc(controls, struct ldb_control);
	if (! controls[i] )
		return LDB_ERR_OPERATIONS_ERROR;

	controls[i]->oid = LDB_CONTROL_SORT_RESP_OID;
	controls[i]->critical = 0;

	resp = talloc(controls[i], struct ldb_sort_resp_control);
	if (! resp )
		return LDB_ERR_OPERATIONS_ERROR;

	resp->result = result;
	resp->attr_desc = talloc_strdup(resp, desc);

	if (! resp->attr_desc )
		return LDB_ERR_OPERATIONS_ERROR;
	
	controls[i]->data = resp;

	return LDB_SUCCESS;
}

static int sort_compare(struct ldb_message **msg1, struct ldb_message **msg2, void *opaque)
{
	struct sort_context *ac = talloc_get_type(opaque, struct sort_context);
	struct ldb_message_element *el1, *el2;

	if (ac->sort_result != 0) {
		/* an error occurred previously,
		 * let's exit the sorting by returning always 0 */
		return 0;
	}

	el1 = ldb_msg_find_element(*msg1, ac->attributeName);
	el2 = ldb_msg_find_element(*msg2, ac->attributeName);

	if (!el1 || !el2) {
		/* the attribute was not found return and
		 * set an error */
		ac->sort_result = 53;
		return 0;
	}

	if (ac->reverse)
		return ac->a->syntax->comparison_fn(ac->module->ldb, ac, &el2->values[0], &el1->values[0]);

	return ac->a->syntax->comparison_fn(ac->module->ldb, ac, &el1->values[0], &el2->values[0]);
}

static int server_sort_search_callback(struct ldb_context *ldb, void *context, struct ldb_reply *ares)
{
	struct sort_context *ac = NULL;
	
 	if (!context || !ares) {
		ldb_set_errstring(ldb, "NULL Context or Result in callback");
		goto error;
	}	

       	ac = talloc_get_type(context, struct sort_context);

	if (ares->type == LDB_REPLY_ENTRY) {
		ac->msgs = talloc_realloc(ac, ac->msgs, struct ldb_message *, ac->num_msgs + 2);
		if (! ac->msgs) {
			goto error;
		}

		ac->msgs[ac->num_msgs + 1] = NULL;

		ac->msgs[ac->num_msgs] = talloc_move(ac->msgs, &ares->message);
		ac->num_msgs++;
	}

	if (ares->type == LDB_REPLY_REFERRAL) {
		ac->referrals = talloc_realloc(ac, ac->referrals, char *, ac->num_refs + 2);
		if (! ac->referrals) {
			goto error;
		}

		ac->referrals[ac->num_refs + 1] = NULL;
		ac->referrals[ac->num_refs] = talloc_move(ac->referrals, &ares->referral);

		ac->num_refs++;
	}

	if (ares->type == LDB_REPLY_DONE) {
		ac->controls = talloc_move(ac, &ares->controls);
	}

	talloc_free(ares);
	return LDB_SUCCESS;

error:
	talloc_free(ares);
	return LDB_ERR_OPERATIONS_ERROR;
}

static int server_sort_search(struct ldb_module *module, struct ldb_request *req)
{
	struct ldb_control *control;
	struct ldb_server_sort_control **sort_ctrls;
	struct ldb_control **saved_controls;
	struct sort_context *ac;
	struct ldb_handle *h;
	int ret;

	/* check if there's a paged request control */
	control = ldb_request_get_control(req, LDB_CONTROL_SERVER_SORT_OID);
	if (control == NULL) {
		/* not found go on */
		return ldb_next_request(module, req);
	}

	req->handle = NULL;

	if (!req->callback || !req->context) {
		ldb_set_errstring(module->ldb,
				  "Async interface called with NULL callback function or NULL context");
		return LDB_ERR_OPERATIONS_ERROR;
	}
	
	h = init_handle(req, module, req->context, req->callback);
	if (!h) {
		return LDB_ERR_OPERATIONS_ERROR;
	}
	ac = talloc_get_type(h->private_data, struct sort_context);

	sort_ctrls = talloc_get_type(control->data, struct ldb_server_sort_control *);
	if (!sort_ctrls) {
		return LDB_ERR_PROTOCOL_ERROR;
	}

	/* FIXME: we do not support more than one attribute for sorting right now */
	/* FIXME: we need to check if the attribute type exist or return an error */
		
	if (sort_ctrls[1] != NULL) {
		if (control->critical) {
			struct ldb_reply *ares;

			ares = talloc_zero(req, struct ldb_reply);
			if (!ares)
				return LDB_ERR_OPERATIONS_ERROR;

			/* 53 = unwilling to perform */
			ares->type = LDB_REPLY_DONE;
			if ((ret = build_response(ares, &ares->controls, 53, "sort control is not complete yet")) != LDB_SUCCESS) {
				return ret;
			}

			h->status = LDB_ERR_UNSUPPORTED_CRITICAL_EXTENSION;
			h->state = LDB_ASYNC_DONE;
			ret = ac->up_callback(module->ldb, ac->up_context, ares);

			return ret;
		} else {
			/* just pass the call down and don't do any sorting */
			ldb_next_request(module, req);
		}
	}

	ac->attributeName = sort_ctrls[0]->attributeName;
	ac->orderingRule = sort_ctrls[0]->orderingRule;
	ac->reverse = sort_ctrls[0]->reverse;

	ac->req = talloc(req, struct ldb_request);
	if (!ac->req)
		return LDB_ERR_OPERATIONS_ERROR;

	ac->req->operation = req->operation;
	ac->req->op.search.base = req->op.search.base;
	ac->req->op.search.scope = req->op.search.scope;
	ac->req->op.search.tree = req->op.search.tree;
	ac->req->op.search.attrs = req->op.search.attrs;
	ac->req->controls = req->controls;

	/* save it locally and remove it from the list */
	/* we do not need to replace them later as we
	 * are keeping the original req intact */
	if (!save_controls(control, ac->req, &saved_controls)) {
		return LDB_ERR_OPERATIONS_ERROR;
	}

	ac->req->context = ac;
	ac->req->callback = server_sort_search_callback;
	ldb_set_timeout_from_prev_req(module->ldb, req, ac->req);

	req->handle = h;

	return ldb_next_request(module, ac->req);
}

static int server_sort_results(struct ldb_handle *handle)
{
	struct sort_context *ac;
	struct ldb_reply *ares;
	int i, ret;

	ac = talloc_get_type(handle->private_data, struct sort_context);

	ac->a = ldb_schema_attribute_by_name(ac->module->ldb, ac->attributeName);
	ac->sort_result = 0;

	ldb_qsort(ac->msgs, ac->num_msgs,
		  sizeof(struct ldb_message *),
		  ac, (ldb_qsort_cmp_fn_t)sort_compare);

	for (i = 0; i < ac->num_msgs; i++) {
		ares = talloc_zero(ac, struct ldb_reply);
		if (!ares) {
			handle->status = LDB_ERR_OPERATIONS_ERROR;
			return handle->status;
		}

		ares->type = LDB_REPLY_ENTRY;
		ares->message = talloc_move(ares, &ac->msgs[i]);
		
		handle->status = ac->up_callback(ac->module->ldb, ac->up_context, ares);
		if (handle->status != LDB_SUCCESS) {
			return handle->status;
		}
	}

	for (i = 0; i < ac->num_refs; i++) {
		ares = talloc_zero(ac, struct ldb_reply);
		if (!ares) {
			handle->status = LDB_ERR_OPERATIONS_ERROR;
			return handle->status;
		}

		ares->type = LDB_REPLY_REFERRAL;
		ares->referral = talloc_move(ares, &ac->referrals[i]);
		
		handle->status = ac->up_callback(ac->module->ldb, ac->up_context, ares);
		if (handle->status != LDB_SUCCESS) {
			return handle->status;
		}
	}

	ares = talloc_zero(ac, struct ldb_reply);
	if (!ares) {
		handle->status = LDB_ERR_OPERATIONS_ERROR;
		return handle->status;
	}

	ares->type = LDB_REPLY_DONE;
	ares->controls = talloc_move(ares, &ac->controls);
		
	handle->status = ac->up_callback(ac->module->ldb, ac->up_context, ares);
	if (handle->status != LDB_SUCCESS) {
		return handle->status;
	}

	if ((ret = build_response(ac, &ac->controls, ac->sort_result, "sort control is not complete yet")) != LDB_SUCCESS) {
		return ret;
	}

	return LDB_SUCCESS;
}

static int server_sort_wait_once(struct ldb_handle *handle)
{
	struct sort_context *ac;
	int ret;
    
	if (!handle || !handle->private_data) {
		return LDB_ERR_OPERATIONS_ERROR;
	}

	ac = talloc_get_type(handle->private_data, struct sort_context);

	ret = ldb_wait(ac->req->handle, LDB_WAIT_NONE);

	if (ret != LDB_SUCCESS) {
		handle->status = ret;
		return ret;
	}
		
	handle->state = ac->req->handle->state;
	handle->status = ac->req->handle->status;

	if (handle->status != LDB_SUCCESS) {
		return handle->status;
	}

	if (handle->state == LDB_ASYNC_DONE) {
		ret = server_sort_results(handle);
	}

	return ret;
}

static int server_sort_wait(struct ldb_handle *handle, enum ldb_wait_type type)
{
	int ret;
 
	if (!handle || !handle->private_data) {
		return LDB_ERR_OPERATIONS_ERROR;
	}

	if (type == LDB_WAIT_ALL) {
		while (handle->state != LDB_ASYNC_DONE) {
			ret = server_sort_wait_once(handle);
			if (ret != LDB_SUCCESS) {
				return ret;
			}
		}

		return handle->status;
	}

	return server_sort_wait_once(handle);
}

static int server_sort_init(struct ldb_module *module)
{
	struct ldb_request *req;
	int ret;

	req = talloc(module, struct ldb_request);
	if (req == NULL) {
		return LDB_ERR_OPERATIONS_ERROR;
	}

	req->operation = LDB_REQ_REGISTER_CONTROL;
	req->op.reg_control.oid = LDB_CONTROL_SERVER_SORT_OID;
	req->controls = NULL;

	ret = ldb_request(module->ldb, req);
	if (ret != LDB_SUCCESS) {
		ldb_debug(module->ldb, LDB_DEBUG_WARNING, "server_sort: Unable to register control with rootdse!\n");
	}

	talloc_free(req);
	return ldb_next_init(module);
}

const struct ldb_module_ops ldb_server_sort_module_ops = {
	.name		   = "server_sort",
	.search            = server_sort_search,
	.wait              = server_sort_wait,
	.init_context	   = server_sort_init
};