<?php

	/**
	 * Elgg objects
	 * Functions to manage multiple or single objects in an Elgg install
	 * 
	 * @package Elgg
	 * @subpackage Core
	 * @license http://www.gnu.org/licenses/old-licenses/gpl-2.0.html GNU Public License version 2
	 * @author Curverider Ltd
	 * @copyright Curverider Ltd 2008
	 * @link http://elgg.org/
	 */

	/**
	 * @class ElggObject
	 * Representation of an "object" in the system.
	 */
	class ElggObject extends ElggEntity
	{
		/**
		 * Initialise the attributes array. 
		 * This is vital to distinguish between metadata and base parameters.
		 * 
		 * Place your base parameters here.
		 */
		protected function initialise_attributes()
		{
			parent::initialise_attributes();
			
			$this->attributes['type'] = "object";
			$this->attributes['title'] = "";
			$this->attributes['description'] = "";
			
			
		}
				
		/**
		 * Construct a new object entity, optionally from a given id value.
		 *
		 * @param mixed $guid If an int, load that GUID. 
		 * 	If a db row then will attempt to load the rest of the data.
		 * @throws Exception if there was a problem creating the object. 
		 */
		function __construct($guid = null) 
		{			
			$this->initialise_attributes();
			
			if (!empty($guid))
			{
				// Is $guid is a DB row - either a entity row, or a object table row.
				if ($guid instanceof stdClass) {					
					// Load the rest
					$this->load($guid->guid);
				}
				
				// Is $guid is an ElggObject? Use a copy constructor
				else if ($guid instanceof ElggObject)
				{					
					 foreach ($guid->attributes as $key => $value)
					 	$this->attributes[$key] = $value;
				}
				
				// Is this is an ElggEntity but not an ElggObject = ERROR!
				else if ($guid instanceof ElggEntity)
					throw new InvalidParameterException("Passing a non-ElggObject to an ElggObject constructor!");
										
				// We assume if we have got this far, $guid is an int
				else if (is_int($guid)) {					
					if (!$this->load($guid)) throw new IOException("Could not create a new ElggObject object from GUID:$guid");
				}
			}
		}
		
		function __get($name) { return $this->get($name); }
		function __set($name, $value) { return $this->set($name, $value); }
		
		/**
		 * Override the load function.
		 * This function will ensure that all data is loaded (were possible), so
		 * if only part of the ElggObject is loaded, it'll load the rest.
		 * 
		 * @param int $guid
		 * @return true|false 
		 */
		protected function load($guid)
		{			
			// Test to see if we have the generic stuff
			if (!parent::load($guid)) 
				return false;

			// Check the type
			if ($this->attributes['type']!='object')
				throw new InvalidClassException("GUID:$guid is not a valid ElggObject");
				
			// Load missing data
			$row = get_object_entity_as_row($guid);
						
			// Now put these into the attributes array as core values
			$objarray = (array) $row;
			foreach($objarray as $key => $value) 
				$this->attributes[$key] = $value;
			
			return true;
		}
		
		/**
		 * Override the save function.
		 * @return true|false
		 */
		public function save()
		{
			// Save generic stuff
			if (!parent::save())
				return false;
			
			// Now save specific stuff
			return create_object_entity($this->get('guid'), $this->get('title'), $this->get('description'));
		}
		
		/**
		 * Delete this object.
		 * @return true|false
		 */
		public function delete() 
		{ 
			if (!parent::delete())
				return false;
				
			return delete_object_entity($guid);
		}
	
		/**
		 * Get sites that this object is a member of
		 *
		 * @param string $subtype Optionally, the subtype of result we want to limit to
		 * @param int $limit The number of results to return
		 * @param int $offset Any indexing offset
		 */
		function getSites($subtype="", $limit = 10, $offset = 0) {
			return get_site_objects($this->getGUID(), $subtype, $limit, $offset);
		}
		
		/**
		 * Add this object to a particular site
		 *
		 * @param int $site_guid The guid of the site to add it to
		 * @return true|false
		 */
		function addToSite($site_guid) {
			return add_site_object($this->getGUID(), $site_guid); 
		}

		/**
		 * Get the collections associated with a object.
		 *
		 * @param string $subtype Optionally, the subtype of result we want to limit to
		 * @param int $limit The number of results to return
		 * @param int $offset Any indexing offset
		 * @return unknown
		 */
		public function getCollections($subtype="", $limit = 10, $offset = 0) { get_object_collections($this->getGUID(), $subtype, $limit, $offset); }
		
	}

	/**
	 * Return the object specific details of a object by a row.
	 * 
	 * @param int $guid
	 */
	function get_object_entity_as_row($guid)
	{
		global $CONFIG;
		
		$guid = (int)$guid;
		
		return get_data_row("SELECT * from {$CONFIG->dbprefix}objects_entity where guid=$guid");
	}
	
	/**
	 * Create or update the extras table for a given object.
	 * Call create_entity first.
	 * 
	 * @param int $guid
	 * @param string $title
	 * @param string $description
	 */
	function create_object_entity($guid, $title, $description)
	{
		global $CONFIG;
		
		$guid = (int)$guid;
		$title = sanitise_string($title);
		$description = sanitise_string($description);
		
		$row = get_entity_as_row($guid);
		
		if ($row)
		{
			// Exists and you have access to it
			
			// Delete any existing stuff
			delete_object_entity($guid);

			// Insert it
			$result = insert_data("INSERT into {$CONFIG->dbprefix}objects_entity (guid, title, description) values ($guid, '$title','$description')");
			if ($result!==false) 
				return true;
		}
		
		return false;
	}
	
	/**
	 * Delete a object's extra data.
	 * 
	 * @param int $guid
	 */
	function delete_object_entity($guid)
	{
		global $CONFIG;
		
		$guid = (int)$guid;
		
		$row = get_entity_as_row($guid);
		
		// Check to see if we have access and it exists
		if ($row) 
		{
			// Delete any existing stuff
			return delete_data("DELETE from {$CONFIG->dbprefix}objects_entity where guid=$guid");
		}
		
		return false;
	}

	/**
	 * Get the sites this object is part of
	 *
	 * @param int $object_guid The object's GUID
	 * @param int $limit Number of results to return
	 * @param int $offset Any indexing offset
	 * @return false|array On success, an array of ElggSites
	 */
	function get_object_sites($object_guid, $limit = 10, $offset = 0) {
		$object_guid = (int)$object_guid;
		$limit = (int)$limit;
		$offset = (int)$offset;
		
		return get_entities_from_relationship("member_of_site", $object_guid, false, "site", "", 0, "time_created desc", $limit, $offset);
	}
		
?>