<?php
/*
** Zabbix
** Copyright (C) 2001-2019 Zabbix SIA
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program 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 General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
**/


/**
 * Class containing methods for operations with hosts.
 */
abstract class CHostGeneral extends CHostBase {

	/**
	 * Checks if the current user has access to the given hosts and templates. Assumes the "hostid" field is valid.
	 *
	 * @param array $hostids    an array of host or template IDs
	 *
	 * @throws APIException if the user doesn't have write permissions for the given hosts.
	 */
	private function checkHostPermissions(array $hostids) {
		if ($hostids) {
			$hostids = array_unique($hostids);

			$count = API::Host()->get([
				'countOutput' => true,
				'hostids' => $hostids,
				'editable' => true
			]);

			if ($count == count($hostids)) {
				return;
			}

			$count += API::Template()->get([
				'countOutput' => true,
				'templateids' => $hostids,
				'editable' => true
			]);

			if ($count != count($hostids)) {
				self::exception(ZBX_API_ERROR_PERMISSIONS,
					_('No permissions to referred object or it does not exist!')
				);
			}
		}
	}

	/**
	 * Allows to:
	 * - add hosts to groups;
	 * - link templates to hosts;
	 * - add new macros to hosts.
	 *
	 * Supported $data parameters are:
	 * - hosts          - an array of hosts to be updated
	 * - templates      - an array of templates to be updated
	 * - groups         - an array of host groups to add the host to
	 * - templates_link - an array of templates to link to the hosts
	 * - macros         - an array of macros to create on the host
	 *
	 * @param array $data
	 *
	 * @return array
	 */
	public function massAdd(array $data) {
		$hostIds = zbx_objectValues($data['hosts'], 'hostid');
		$templateIds = zbx_objectValues($data['templates'], 'templateid');

		$allHostIds = array_merge($hostIds, $templateIds);

		// add groups
		if (!empty($data['groups'])) {
			API::HostGroup()->massAdd([
				'hosts' => $data['hosts'],
				'templates' => $data['templates'],
				'groups' => $data['groups']
			]);
		}

		// link templates
		if (!empty($data['templates_link'])) {
			$this->checkHostPermissions($allHostIds);

			$this->link(zbx_objectValues(zbx_toArray($data['templates_link']), 'templateid'), $allHostIds);
		}

		// create macros
		if (!empty($data['macros'])) {
			$data['macros'] = zbx_toArray($data['macros']);

			$hostMacrosToAdd = [];
			foreach ($data['macros'] as $hostMacro) {
				foreach ($allHostIds as $hostid) {
					$hostMacro['hostid'] = $hostid;
					$hostMacrosToAdd[] = $hostMacro;
				}
			}

			API::UserMacro()->create($hostMacrosToAdd);
		}

		$ids = ['hostids' => $hostIds, 'templateids' => $templateIds];

		return [$this->pkOption() => $ids[$this->pkOption()]];
	}

	/**
	 * Allows to:
	 * - remove hosts from groups;
	 * - unlink and clear templates from hosts;
	 * - remove macros from hosts.
	 *
	 * Supported $data parameters are:
	 * - hostids            - an array of host IDs to be updated
	 * - templateids        - an array of template IDs to be updated
	 * - groupids           - an array of host group IDs the hosts should be removed from
	 * - templateids_link   - an array of template IDs to unlink from the hosts
	 * - templateids_clear  - an array of template IDs to unlink and clear from the hosts
	 * - macros             - an array of macros to delete from the hosts
	 *
	 * @param array $data
	 *
	 * @return array
	 */
	public function massRemove(array $data) {
		$allHostIds = array_merge($data['hostids'], $data['templateids']);

		$this->checkHostPermissions($allHostIds);

		if (!empty($data['templateids_link'])) {
			$this->unlink(zbx_toArray($data['templateids_link']), $allHostIds);
		}

		if (isset($data['templateids_clear'])) {
			$this->unlink(zbx_toArray($data['templateids_clear']), $allHostIds, true);
		}

		if (isset($data['macros'])) {
			$hostMacros = API::UserMacro()->get([
				'output' => ['hostmacroid'],
				'hostids' => $allHostIds,
				'filter' => [
					'macro' => $data['macros']
				]
			]);
			$hostMacroIds = zbx_objectValues($hostMacros, 'hostmacroid');
			API::UserMacro()->delete($hostMacroIds);
		}

		if (isset($data['groupids'])) {
			API::HostGroup()->massRemove($data);
		}

		return [$this->pkOption() => $data[$this->pkOption()]];
	}

	protected function link(array $templateIds, array $targetIds) {
		$hostsLinkageInserts = parent::link($templateIds, $targetIds);

		foreach ($hostsLinkageInserts as $hostTplIds){
			Manager::Application()->link($hostTplIds['templateid'], $hostTplIds['hostid']);

			// Fist link web items, so that later regular items can use web item as their master item.
			Manager::HttpTest()->link($hostTplIds['templateid'], $hostTplIds['hostid']);

			API::Item()->syncTemplates([
				'hostids' => $hostTplIds['hostid'],
				'templateids' => $hostTplIds['templateid']
			]);

			API::DiscoveryRule()->syncTemplates([
				'hostids' => $hostTplIds['hostid'],
				'templateids' => $hostTplIds['templateid']
			]);

			API::ItemPrototype()->syncTemplates([
				'hostids' => $hostTplIds['hostid'],
				'templateids' => $hostTplIds['templateid']
			]);

			API::HostPrototype()->syncTemplates([
				'hostids' => $hostTplIds['hostid'],
				'templateids' => $hostTplIds['templateid']
			]);
		}

		// we do linkage in two separate loops because for triggers you need all items already created on host
		foreach ($hostsLinkageInserts as $hostTplIds){
			API::Trigger()->syncTemplates([
				'hostids' => $hostTplIds['hostid'],
				'templateids' => $hostTplIds['templateid']
			]);

			API::TriggerPrototype()->syncTemplates([
				'hostids' => $hostTplIds['hostid'],
				'templateids' => $hostTplIds['templateid']
			]);

			API::GraphPrototype()->syncTemplates([
				'hostids' => $hostTplIds['hostid'],
				'templateids' => $hostTplIds['templateid']
			]);

			API::Graph()->syncTemplates([
				'hostids' => $hostTplIds['hostid'],
				'templateids' => $hostTplIds['templateid']
			]);
		}

		foreach ($hostsLinkageInserts as $hostTplIds){
			API::Trigger()->syncTemplateDependencies([
				'templateids' => $hostTplIds['templateid'],
				'hostids' => $hostTplIds['hostid']
			]);

			API::TriggerPrototype()->syncTemplateDependencies([
				'templateids' => $hostTplIds['templateid'],
				'hostids' => $hostTplIds['hostid']
			]);
		}

		return $hostsLinkageInserts;
	}

	/**
	 * Unlinks the templates from the given hosts. If $targetids is set to null, the templates will be unlinked from
	 * all hosts.
	 *
	 * @param array      $templateids
	 * @param null|array $targetids		the IDs of the hosts to unlink the templates from
	 * @param bool       $clear			delete all of the inherited objects from the hosts
	 */
	protected function unlink($templateids, $targetids = null, $clear = false) {
		$flags = ($clear)
			? [ZBX_FLAG_DISCOVERY_NORMAL, ZBX_FLAG_DISCOVERY_RULE]
			: [ZBX_FLAG_DISCOVERY_NORMAL, ZBX_FLAG_DISCOVERY_RULE, ZBX_FLAG_DISCOVERY_PROTOTYPE];

		// check that all triggers on templates that we unlink, don't have items from another templates
		$sql = 'SELECT DISTINCT t.description'.
			' FROM triggers t,functions f,items i'.
			' WHERE t.triggerid=f.triggerid'.
			' AND f.itemid=i.itemid'.
			' AND '.dbConditionInt('i.hostid', $templateids).
			' AND EXISTS ('.
			'SELECT ff.triggerid'.
			' FROM functions ff,items ii'.
			' WHERE ff.itemid=ii.itemid'.
			' AND ff.triggerid=t.triggerid'.
			' AND '.dbConditionInt('ii.hostid', $templateids, true).
			')'.
			' AND t.flags='.ZBX_FLAG_DISCOVERY_NORMAL;
		if ($dbTrigger = DBfetch(DBSelect($sql, 1))) {
			self::exception(
				ZBX_API_ERROR_PARAMETERS,
				_s('Cannot unlink trigger "%s", it has items from template that is left linked to host.', $dbTrigger['description'])
			);
		}

		$templ_triggerids = [];

		$db_triggers = DBselect(
			'SELECT DISTINCT f.triggerid'.
			' FROM functions f,items i'.
			' WHERE f.itemid=i.itemid'.
				' AND '.dbConditionInt('i.hostid', $templateids)
		);

		while ($db_trigger = DBfetch($db_triggers)) {
			$templ_triggerids[] = $db_trigger['triggerid'];
		}

		$triggerids = [ZBX_FLAG_DISCOVERY_NORMAL => [], ZBX_FLAG_DISCOVERY_PROTOTYPE => []];

		if ($templ_triggerids) {
			$sql_distinct = ($targetids !== null) ? ' DISTINCT' : '';
			$sql_from = ($targetids !== null) ? ',functions f,items i' : '';
			$sql_where = ($targetids !== null)
				? ' AND t.triggerid=f.triggerid'.
					' AND f.itemid=i.itemid'.
					' AND '.dbConditionInt('i.hostid', $targetids)
				: '';

			$db_triggers = DBSelect(
				'SELECT'.$sql_distinct.' t.triggerid,t.flags'.
				' FROM triggers t'.$sql_from.
				' WHERE '.dbConditionInt('t.templateid', $templ_triggerids).
					' AND '.dbConditionInt('t.flags', $flags).
					$sql_where
			);

			while ($db_trigger = DBfetch($db_triggers)) {
				$triggerids[$db_trigger['flags']][] = $db_trigger['triggerid'];
			}
		}

		if ($triggerids[ZBX_FLAG_DISCOVERY_NORMAL]) {
			if ($clear) {
				CTriggerManager::delete($triggerids[ZBX_FLAG_DISCOVERY_NORMAL]);
			}
			else {
				DB::update('triggers', [
					'values' => ['templateid' => 0],
					'where' => ['triggerid' => $triggerids[ZBX_FLAG_DISCOVERY_NORMAL]]
				]);
			}
		}

		if ($triggerids[ZBX_FLAG_DISCOVERY_PROTOTYPE]) {
			if ($clear) {
				CTriggerPrototypeManager::delete($triggerids[ZBX_FLAG_DISCOVERY_PROTOTYPE]);
			}
			else {
				DB::update('triggers', [
					'values' => ['templateid' => 0],
					'where' => ['triggerid' => $triggerids[ZBX_FLAG_DISCOVERY_PROTOTYPE]]
				]);
			}
		}

		/* GRAPHS {{{ */
		$db_tpl_graphs = DBselect(
			'SELECT DISTINCT g.graphid'.
			' FROM graphs g,graphs_items gi,items i'.
			' WHERE g.graphid=gi.graphid'.
				' AND gi.itemid=i.itemid'.
				' AND '.dbConditionInt('i.hostid', $templateids).
				' AND '.dbConditionInt('g.flags', $flags)
		);

		$tpl_graphids = [];

		while ($db_tpl_graph = DBfetch($db_tpl_graphs)) {
			$tpl_graphids[] = $db_tpl_graph['graphid'];
		}

		if ($tpl_graphids) {
			$sql = ($targetids !== null)
				? 'SELECT DISTINCT g.graphid,g.flags'.
					' FROM graphs g,graphs_items gi,items i'.
					' WHERE g.graphid=gi.graphid'.
						' AND gi.itemid=i.itemid'.
						' AND '.dbConditionInt('g.templateid', $tpl_graphids).
						' AND '.dbConditionInt('i.hostid', $targetids)
				: 'SELECT g.graphid,g.flags'.
					' FROM graphs g'.
					' WHERE '.dbConditionInt('g.templateid', $tpl_graphids);

			$db_graphs = DBSelect($sql);

			$graphs = [
				ZBX_FLAG_DISCOVERY_NORMAL => [],
				ZBX_FLAG_DISCOVERY_PROTOTYPE => []
			];
			while ($db_graph = DBfetch($db_graphs)) {
				$graphs[$db_graph['flags']][] = $db_graph['graphid'];
			}

			if ($graphs[ZBX_FLAG_DISCOVERY_PROTOTYPE]) {
				if ($clear) {
					CGraphPrototypeManager::delete($graphs[ZBX_FLAG_DISCOVERY_PROTOTYPE]);
				}
				else {
					DB::update('graphs', [
						'values' => ['templateid' => 0],
						'where' => ['graphid' => $graphs[ZBX_FLAG_DISCOVERY_PROTOTYPE]]
					]);
				}
			}

			if ($graphs[ZBX_FLAG_DISCOVERY_NORMAL]) {
				if ($clear) {
					CGraphManager::delete($graphs[ZBX_FLAG_DISCOVERY_NORMAL]);
				}
				else {
					DB::update('graphs', [
						'values' => ['templateid' => 0],
						'where' => ['graphid' => $graphs[ZBX_FLAG_DISCOVERY_NORMAL]]
					]);
				}
			}
		}
		/* }}} GRAPHS */

		/* ITEMS, DISCOVERY RULES {{{ */
		$sqlFrom = ' items i1,items i2,hosts h';
		$sqlWhere = ' i2.itemid=i1.templateid'.
			' AND '.dbConditionInt('i2.hostid', $templateids).
			' AND '.dbConditionInt('i1.flags', $flags).
			' AND h.hostid=i1.hostid';

		if (!is_null($targetids)) {
			$sqlWhere .= ' AND '.dbConditionInt('i1.hostid', $targetids);
		}
		$sql = 'SELECT DISTINCT i1.itemid,i1.flags,i1.name,i1.hostid,h.name as host'.
			' FROM '.$sqlFrom.
			' WHERE '.$sqlWhere;
		$dbItems = DBSelect($sql);
		$items = [
			ZBX_FLAG_DISCOVERY_NORMAL => [],
			ZBX_FLAG_DISCOVERY_RULE => [],
			ZBX_FLAG_DISCOVERY_PROTOTYPE => []
		];
		while ($item = DBfetch($dbItems)) {
			$items[$item['flags']][$item['itemid']] = [
				'name' => $item['name'],
				'host' => $item['host']
			];
		}

		if (!empty($items[ZBX_FLAG_DISCOVERY_RULE])) {
			if ($clear) {
				$result = API::DiscoveryRule()->delete(array_keys($items[ZBX_FLAG_DISCOVERY_RULE]), true);
				if (!$result) self::exception(ZBX_API_ERROR_INTERNAL, _('Cannot unlink and clear discovery rules'));
			}
			else{
				DB::update('items', [
					'values' => ['templateid' => 0],
					'where' => ['itemid' => array_keys($items[ZBX_FLAG_DISCOVERY_RULE])]
				]);

				foreach ($items[ZBX_FLAG_DISCOVERY_RULE] as $discoveryRule) {
					info(_s('Unlinked: Discovery rule "%1$s" on "%2$s".', $discoveryRule['name'], $discoveryRule['host']));
				}
			}
		}

		if (!empty($items[ZBX_FLAG_DISCOVERY_NORMAL])) {
			if ($clear) {
				CItemManager::delete(array_keys($items[ZBX_FLAG_DISCOVERY_NORMAL]));
			}
			else{
				DB::update('items', [
					'values' => ['templateid' => 0],
					'where' => ['itemid' => array_keys($items[ZBX_FLAG_DISCOVERY_NORMAL])]
				]);

				foreach ($items[ZBX_FLAG_DISCOVERY_NORMAL] as $item) {
					info(_s('Unlinked: Item "%1$s" on "%2$s".', $item['name'], $item['host']));
				}
			}
		}

		if (!empty($items[ZBX_FLAG_DISCOVERY_PROTOTYPE])) {
			$item_prototypeids = array_keys($items[ZBX_FLAG_DISCOVERY_PROTOTYPE]);

			if ($clear) {
				// This will include deletion of linked application prototypes.
				CItemPrototypeManager::delete($item_prototypeids);
			}
			else {
				DB::update('items', [
					'values' => ['templateid' => 0],
					'where' => ['itemid' => $item_prototypeids]
				]);

				foreach ($items[ZBX_FLAG_DISCOVERY_PROTOTYPE] as $item) {
					info(_s('Unlinked: Item prototype "%1$s" on "%2$s".', $item['name'], $item['host']));
				}

				/*
				 * Convert templated application prototypes to normal application prototypes
				 * who are linked to these item prototypes.
				 */
				$application_prototypes = DBfetchArray(DBselect(
					'SELECT ap.application_prototypeid'.
					' FROM application_prototype ap'.
					' WHERE EXISTS ('.
						'SELECT NULL'.
						' FROM item_application_prototype iap'.
						' WHERE '.dbConditionInt('iap.itemid', $item_prototypeids).
							' AND iap.application_prototypeid=ap.application_prototypeid'.
					')'
				));

				if ($application_prototypes) {
					$application_prototypeids = zbx_objectValues($application_prototypes, 'application_prototypeid');

					DB::update('application_prototype', [
						'values' => ['templateid' => 0],
						'where' => ['application_prototypeid' => $application_prototypeids]
					]);
				}
			}
		}
		/* }}} ITEMS, DISCOVERY RULES */

		// host prototypes
		// we need only to unlink host prototypes. in case of unlink and clear they will be deleted together with LLD rules.
		if (!$clear && isset($items[ZBX_FLAG_DISCOVERY_RULE])) {
			$discoveryRuleIds = array_keys($items[ZBX_FLAG_DISCOVERY_RULE]);

			$hostPrototypes = DBfetchArrayAssoc(DBSelect(
				'SELECT DISTINCT h.hostid,h.host,h3.host AS parent_host'.
				' FROM hosts h'.
					' INNER JOIN host_discovery hd ON h.hostid=hd.hostid'.
					' INNER JOIN hosts h2 ON h.templateid=h2.hostid'.
					' INNER JOIN host_discovery hd2 ON h.hostid=hd.hostid'.
					' INNER JOIN items i ON hd.parent_itemid=i.itemid'.
					' INNER JOIN hosts h3 ON i.hostid=h3.hostid'.
				' WHERE '.dbConditionInt('hd.parent_itemid', $discoveryRuleIds)
			), 'hostid');
			if ($hostPrototypes) {
				DB::update('hosts', [
					'values' => ['templateid' => 0],
					'where' => ['hostid' => array_keys($hostPrototypes)]
				]);
				DB::update('group_prototype', [
					'values' => ['templateid' => 0],
					'where' => ['hostid' => array_keys($hostPrototypes)]
				]);
				foreach ($hostPrototypes as $hostPrototype) {
					info(_s('Unlinked: Host prototype "%1$s" on "%2$s".', $hostPrototype['host'], $hostPrototype['parent_host']));
				}
			}
		}

		// http tests
		$sqlWhere = '';
		if (!is_null($targetids)) {
			$sqlWhere = ' AND '.dbConditionInt('ht1.hostid', $targetids);
		}
		$sql = 'SELECT DISTINCT ht1.httptestid,ht1.name,h.name as host'.
				' FROM httptest ht1'.
				' INNER JOIN httptest ht2 ON ht2.httptestid=ht1.templateid'.
				' INNER JOIN hosts h ON h.hostid=ht1.hostid'.
				' WHERE '.dbConditionInt('ht2.hostid', $templateids).
				$sqlWhere;
		$dbHttpTests = DBSelect($sql);
		$httpTests = [];
		while ($httpTest = DBfetch($dbHttpTests)) {
			$httpTests[$httpTest['httptestid']] = [
				'name' => $httpTest['name'],
				'host' => $httpTest['host']
			];
		}

		if (!empty($httpTests)) {
			if ($clear) {
				$result = API::HttpTest()->delete(array_keys($httpTests), true);
				if (!$result) {
					self::exception(ZBX_API_ERROR_INTERNAL, _('Cannot unlink and clear Web scenarios.'));
				}
			}
			else {
				DB::update('httptest', [
					'values' => ['templateid' => 0],
					'where' => ['httptestid' => array_keys($httpTests)]
				]);
				foreach ($httpTests as $httpTest) {
					info(_s('Unlinked: Web scenario "%1$s" on "%2$s".', $httpTest['name'], $httpTest['host']));
				}
			}
		}

		/* APPLICATIONS {{{ */
		$sql = 'SELECT at.application_templateid,at.applicationid,h.name,h.host,h.hostid'.
			' FROM applications a1,application_template at,applications a2,hosts h'.
			' WHERE a1.applicationid=at.applicationid'.
				' AND at.templateid=a2.applicationid'.
				' AND '.dbConditionInt('a2.hostid', $templateids).
				' AND a1.hostid=h.hostid';
		if ($targetids) {
			$sql .= ' AND '.dbConditionInt('a1.hostid', $targetids);
		}
		$query = DBselect($sql);
		$applicationTemplates = [];
		while ($applicationTemplate = DBfetch($query)) {
			$applicationTemplates[] = [
				'applicationid' => $applicationTemplate['applicationid'],
				'application_templateid' => $applicationTemplate['application_templateid'],
				'name' => $applicationTemplate['name'],
				'hostid' => $applicationTemplate['hostid'],
				'host' => $applicationTemplate['host']
			];
		}

		if ($applicationTemplates) {
			// unlink applications from templates
			DB::delete('application_template', [
				'application_templateid' => zbx_objectValues($applicationTemplates, 'application_templateid')
			]);

			if ($clear) {
				// Delete inherited applications that are no longer linked to any templates and items.
				$applicationids = zbx_objectValues($applicationTemplates, 'applicationid');

				$applications = DBfetchArray(DBselect(
					'SELECT a.applicationid'.
					' FROM applications a'.
						' LEFT JOIN application_template at ON a.applicationid=at.applicationid'.
					' WHERE '.dbConditionInt('a.applicationid', $applicationids).
						' AND at.applicationid IS NULL'.
						' AND a.applicationid NOT IN ('.
							'SELECT ia.applicationid'.
							' FROM items_applications ia'.
							' WHERE '.dbConditionInt('ia.applicationid', $applicationids).
						')'
				));
				if ($applications) {
					$result = API::Application()->delete(zbx_objectValues($applications, 'applicationid'), true);
					if (!$result) {
						self::exception(ZBX_API_ERROR_INTERNAL, _('Cannot unlink and clear applications.'));
					}
				}
			}
			else {
				foreach ($applicationTemplates as $application) {
					info(_s('Unlinked: Application "%1$s" on "%2$s".', $application['name'], $application['host']));
				}
			}
		}

		/*
		 * Process discovered applications when parent is a host, not template.
		 * If a discovered application has no longer linked items, remove them.
		 */
		if ($targetids) {
			$discovered_applications = API::Application()->get([
				'output' => ['applicationid'],
				'hostids' => $targetids,
				'filter' => ['flags' => ZBX_FLAG_DISCOVERY_CREATED],
				'preservekeys' => true
			]);

			if ($discovered_applications) {
				$discovered_applications = API::Application()->get([
					'output' => ['applicationid'],
					'selectItems' => ['itemid'],
					'applicationids' => array_keys($discovered_applications),
					'filter' => ['flags' => ZBX_FLAG_DISCOVERY_CREATED]
				]);

				$applications_to_delete = [];

				foreach ($discovered_applications as $discovered_application) {
					if (!$discovered_application['items']) {
						$applications_to_delete[$discovered_application['applicationid']] = true;
					}
				}

				if ($applications_to_delete) {
					API::Application()->delete(array_keys($applications_to_delete), true);
				}
			}
		}
		/* }}} APPLICATIONS */

		parent::unlink($templateids, $targetids);
	}

	protected function addRelatedObjects(array $options, array $result) {
		$result = parent::addRelatedObjects($options, $result);

		$hostids = array_keys($result);

		// adding groups
		if ($options['selectGroups'] !== null && $options['selectGroups'] != API_OUTPUT_COUNT) {
			$relationMap = $this->createRelationMap($result, 'hostid', 'groupid', 'hosts_groups');
			$groups = API::HostGroup()->get([
				'output' => $options['selectGroups'],
				'groupids' => $relationMap->getRelatedIds(),
				'preservekeys' => true
			]);
			$result = $relationMap->mapMany($result, $groups, 'groups');
		}

		// adding templates
		if ($options['selectParentTemplates'] !== null) {
			if ($options['selectParentTemplates'] != API_OUTPUT_COUNT) {
				$relationMap = $this->createRelationMap($result, 'hostid', 'templateid', 'hosts_templates');
				$templates = API::Template()->get([
					'output' => $options['selectParentTemplates'],
					'templateids' => $relationMap->getRelatedIds(),
					'preservekeys' => true
				]);
				if (!is_null($options['limitSelects'])) {
					order_result($templates, 'host');
				}
				$result = $relationMap->mapMany($result, $templates, 'parentTemplates', $options['limitSelects']);
			}
			else {
				$templates = API::Template()->get([
					'hostids' => $hostids,
					'countOutput' => true,
					'groupCount' => true
				]);
				$templates = zbx_toHash($templates, 'hostid');
				foreach ($result as $hostid => $host) {
					$result[$hostid]['parentTemplates'] = array_key_exists($hostid, $templates)
						? $templates[$hostid]['rowscount']
						: '0';
				}
			}
		}

		// adding items
		if ($options['selectItems'] !== null) {
			if ($options['selectItems'] != API_OUTPUT_COUNT) {
				$items = API::Item()->get([
					'output' => $this->outputExtend($options['selectItems'], ['hostid', 'itemid']),
					'hostids' => $hostids,
					'nopermissions' => true,
					'preservekeys' => true
				]);

				if (!is_null($options['limitSelects'])) {
					order_result($items, 'name');
				}

				$relationMap = $this->createRelationMap($items, 'hostid', 'itemid');

				$items = $this->unsetExtraFields($items, ['hostid', 'itemid'], $options['selectItems']);
				$result = $relationMap->mapMany($result, $items, 'items', $options['limitSelects']);
			}
			else {
				$items = API::Item()->get([
					'hostids' => $hostids,
					'nopermissions' => true,
					'countOutput' => true,
					'groupCount' => true
				]);
				$items = zbx_toHash($items, 'hostid');
				foreach ($result as $hostid => $host) {
					$result[$hostid]['items'] = array_key_exists($hostid, $items) ? $items[$hostid]['rowscount'] : '0';
				}
			}
		}

		// adding discoveries
		if ($options['selectDiscoveries'] !== null) {
			if ($options['selectDiscoveries'] != API_OUTPUT_COUNT) {
				$items = API::DiscoveryRule()->get([
					'output' => $this->outputExtend($options['selectDiscoveries'], ['hostid', 'itemid']),
					'hostids' => $hostids,
					'nopermissions' => true,
					'preservekeys' => true
				]);

				if (!is_null($options['limitSelects'])) {
					order_result($items, 'name');
				}

				$relationMap = $this->createRelationMap($items, 'hostid', 'itemid');

				$items = $this->unsetExtraFields($items, ['hostid', 'itemid'], $options['selectDiscoveries']);
				$result = $relationMap->mapMany($result, $items, 'discoveries', $options['limitSelects']);
			}
			else {
				$items = API::DiscoveryRule()->get([
					'hostids' => $hostids,
					'nopermissions' => true,
					'countOutput' => true,
					'groupCount' => true
				]);
				$items = zbx_toHash($items, 'hostid');
				foreach ($result as $hostid => $host) {
					$result[$hostid]['discoveries'] = array_key_exists($hostid, $items)
						? $items[$hostid]['rowscount']
						: '0';
				}
			}
		}

		// adding triggers
		if ($options['selectTriggers'] !== null) {
			if ($options['selectTriggers'] != API_OUTPUT_COUNT) {
				// discovered items
				$res = DBselect(
					'SELECT i.hostid,f.triggerid'.
						' FROM items i,functions f'.
						' WHERE '.dbConditionInt('i.hostid', $hostids).
						' AND i.itemid=f.itemid'
				);
				$relationMap = new CRelationMap();
				while ($relation = DBfetch($res)) {
					$relationMap->addRelation($relation['hostid'], $relation['triggerid']);
				}

				$triggers = API::Trigger()->get([
					'output' => $options['selectTriggers'],
					'triggerids' => $relationMap->getRelatedIds(),
					'preservekeys' => true
				]);
				if (!is_null($options['limitSelects'])) {
					order_result($triggers, 'description');
				}
				$result = $relationMap->mapMany($result, $triggers, 'triggers', $options['limitSelects']);
			}
			else {
				$triggers = API::Trigger()->get([
					'hostids' => $hostids,
					'countOutput' => true,
					'groupCount' => true
				]);
				$triggers = zbx_toHash($triggers, 'hostid');

				foreach ($result as $hostid => $host) {
					$result[$hostid]['triggers'] = array_key_exists($hostid, $triggers)
						? $triggers[$hostid]['rowscount']
						: '0';
				}
			}
		}

		// adding graphs
		if ($options['selectGraphs'] !== null) {
			if ($options['selectGraphs'] != API_OUTPUT_COUNT) {
				// discovered items
				$res = DBselect(
					'SELECT i.hostid,gi.graphid'.
						' FROM items i,graphs_items gi'.
						' WHERE '.dbConditionInt('i.hostid', $hostids).
						' AND i.itemid=gi.itemid'
				);
				$relationMap = new CRelationMap();
				while ($relation = DBfetch($res)) {
					$relationMap->addRelation($relation['hostid'], $relation['graphid']);
				}

				$graphs = API::Graph()->get([
					'output' => $options['selectGraphs'],
					'graphids' => $relationMap->getRelatedIds(),
					'preservekeys' => true
				]);
				if (!is_null($options['limitSelects'])) {
					order_result($graphs, 'name');
				}
				$result = $relationMap->mapMany($result, $graphs, 'graphs', $options['limitSelects']);
			}
			else {
				$graphs = API::Graph()->get([
					'hostids' => $hostids,
					'countOutput' => true,
					'groupCount' => true
				]);
				$graphs = zbx_toHash($graphs, 'hostid');
				foreach ($result as $hostid => $host) {
					$result[$hostid]['graphs'] = array_key_exists($hostid, $graphs)
						? $graphs[$hostid]['rowscount']
						: '0';
				}
			}
		}

		// adding http tests
		if ($options['selectHttpTests'] !== null) {
			if ($options['selectHttpTests'] != API_OUTPUT_COUNT) {
				$httpTests = API::HttpTest()->get([
					'output' => $this->outputExtend($options['selectHttpTests'], ['hostid', 'httptestid']),
					'hostids' => $hostids,
					'nopermissions' => true,
					'preservekeys' => true
				]);

				if (!is_null($options['limitSelects'])) {
					order_result($httpTests, 'name');
				}

				$relationMap = $this->createRelationMap($httpTests, 'hostid', 'httptestid');

				$httpTests = $this->unsetExtraFields($httpTests, ['hostid', 'httptestid'], $options['selectHttpTests']);
				$result = $relationMap->mapMany($result, $httpTests, 'httpTests', $options['limitSelects']);
			}
			else {
				$httpTests = API::HttpTest()->get([
					'hostids' => $hostids,
					'nopermissions' => true,
					'countOutput' => true,
					'groupCount' => true
				]);
				$httpTests = zbx_toHash($httpTests, 'hostid');
				foreach ($result as $hostid => $host) {
					$result[$hostid]['httpTests'] = array_key_exists($hostid, $httpTests)
						? $httpTests[$hostid]['rowscount']
						: '0';
				}
			}
		}

		// adding applications
		if ($options['selectApplications'] !== null) {
			if ($options['selectApplications'] != API_OUTPUT_COUNT) {
				$applications = API::Application()->get([
					'output' => $this->outputExtend($options['selectApplications'], ['hostid', 'applicationid']),
					'hostids' => $hostids,
					'nopermissions' => true,
					'preservekeys' => true
				]);

				if (!is_null($options['limitSelects'])) {
					order_result($applications, 'name');
				}

				$relationMap = $this->createRelationMap($applications, 'hostid', 'applicationid');

				$applications = $this->unsetExtraFields($applications, ['hostid', 'applicationid'],
					$options['selectApplications']
				);
				$result = $relationMap->mapMany($result, $applications, 'applications', $options['limitSelects']);
			}
			else {
				$applications = API::Application()->get([
					'output' => $options['selectApplications'],
					'hostids' => $hostids,
					'nopermissions' => true,
					'countOutput' => true,
					'groupCount' => true
				]);

				$applications = zbx_toHash($applications, 'hostid');
				foreach ($result as $hostid => $host) {
					$result[$hostid]['applications'] = array_key_exists($hostid, $applications)
						? $applications[$hostid]['rowscount']
						: '0';
				}
			}
		}

		// adding macros
		if ($options['selectMacros'] !== null && $options['selectMacros'] != API_OUTPUT_COUNT) {
			$macros = API::UserMacro()->get([
				'output' => $this->outputExtend($options['selectMacros'], ['hostid', 'hostmacroid']),
				'hostids' => $hostids,
				'preservekeys' => true
			]);

			$relationMap = $this->createRelationMap($macros, 'hostid', 'hostmacroid');

			$macros = $this->unsetExtraFields($macros, ['hostid', 'hostmacroid'], $options['selectMacros']);
			$result = $relationMap->mapMany($result, $macros, 'macros', $options['limitSelects']);
		}

		// adding tags
		if ($options['selectTags'] !== null && $options['selectTags'] != API_OUTPUT_COUNT) {
			if ($options['selectTags'] === API_OUTPUT_EXTEND) {
				$options['selectTags'] = ['tag', 'value'];
			}

			$tags_options = [
				'output' => $this->outputExtend($options['selectTags'], ['hostid']),
				'filter' => ['hostid' => $hostids]
			];
			$tags = DBselect(DB::makeSql('host_tag', $tags_options));

			foreach ($result as &$host) {
				$host['tags'] = [];
			}
			unset($host);

			while ($tag = DBfetch($tags)) {
				$result[$tag['hostid']]['tags'][] = [
					'tag' => $tag['tag'],
					'value' => $tag['value']
				];
			}
		}

		return $result;
	}

	/**
	 * Compares input tags with tags stored in the database and performs tag deleting and inserting.
	 *
	 * @param array  $hosts
	 * @param int    $hosts[]['hostid']
	 * @param int    $hosts[]['templateid']
	 * @param array  $hosts[]['tags']
	 * @param string $hosts[]['tags'][]['tag']
	 * @param string $hosts[]['tags'][]['value']
	 * @param string $id_field
	 */
	protected function updateTags(array $hosts, $id_field) {
		$hostids = [];
		foreach ($hosts as $host) {
			if (array_key_exists('tags', $host)) {
				$hostids[] = $host[$id_field];
			}
		}

		if (!$hostids) {
			return;
		}

		$options = [
			'output' => ['hosttagid', 'hostid', 'tag', 'value'],
			'filter' => ['hostid' => $hostids]
		];

		$db_tags = DBselect(DB::makeSql('host_tag', $options));
		$db_hosts = [];
		$del_hosttagids = [];

		while ($db_tag = DBfetch($db_tags)) {
			$db_hosts[$db_tag['hostid']]['tags'][] = $db_tag;
			$del_hosttagids[$db_tag['hosttagid']] = true;
		}

		$ins_tags = [];
		foreach ($hosts as $host) {
			foreach ($host['tags'] as $tag) {
				$tag += ['value' => ''];

				if (array_key_exists($host[$id_field], $db_hosts)) {
					foreach ($db_hosts[$host[$id_field]]['tags'] as $db_tag) {
						if ($tag['tag'] === $db_tag['tag'] && $tag['value'] === $db_tag['value']) {
							unset($del_hosttagids[$db_tag['hosttagid']]);
							$tag = null;
							break;
						}
					}
				}

				if ($tag !== null) {
					$ins_tags[] = ['hostid' => $host[$id_field]] + $tag;
				}
			}
		}

		if ($del_hosttagids) {
			DB::delete('host_tag', ['hosttagid' => array_keys($del_hosttagids)]);
		}

		if ($ins_tags) {
			DB::insert('host_tag', $ins_tags);
		}
	}

	/**
	 * Validates tags.
	 *
	 * @param array  $host
	 * @param int    $host['evaltype']
	 * @param array  $host['tags']
	 * @param string $host['tags'][]['tag']
	 * @param string $host['tags'][]['value']
	 *
	 * @throws APIException if the input is invalid.
	 */
	protected function validateTags(array $host) {
		$api_input_rules = ['type' => API_OBJECT, 'fields' => [
			'evaltype'	=> ['type' => API_INT32, 'in' => implode(',', [TAG_EVAL_TYPE_AND_OR, TAG_EVAL_TYPE_OR])],
			'tags'		=> ['type' => API_OBJECTS, 'uniq' => [['tag', 'value']], 'fields' => [
				'tag'		=> ['type' => API_STRING_UTF8, 'flags' => API_REQUIRED | API_NOT_EMPTY, 'length' => DB::getFieldLength('host_tag', 'tag')],
				'value'		=> ['type' => API_STRING_UTF8, 'length' => DB::getFieldLength('host_tag', 'value'), 'default' => DB::getDefault('host_tag', 'value')]
			]]
		]];

		// Keep values only for fields with defined validation rules.
		$host = array_intersect_key($host, $api_input_rules['fields']);

		if (!CApiInputValidator::validate($api_input_rules, $host, '/', $error)) {
			self::exception(ZBX_API_ERROR_PARAMETERS, $error);
		}
	}
}
