<?php


class Sabre_DAVACL_PrincipalBackend_Std implements Sabre_DAVACL_IPrincipalBackend
{

	/**
	 * Principals prefix
	 *
	 * @var string
	 */
	public $prefix = 'principals/users';

	/**
	 * @var Sabre_DAV_Auth_Backend_AbstractBasic $authBackend;
	 */
	protected $authBackend;

	public function __construct(&$authBackend)
	{

		$this->authBackend = &$authBackend;

	}


	/**
	 * @var Sabre_DAVACL_IPrincipalBackend|null
	 */
	private static $intstance = null;

	/**
	 * @static
	 * @return Sabre_DAVACL_IPrincipalBackend
	 */
	public static function &getInstance() {
		if (is_null(self::$intstance)) {
			$authBackend              = Sabre_DAV_Auth_Backend_Std::getInstance();
			self::$intstance = new Sabre_DAVACL_PrincipalBackend_Std($authBackend);
		}
		return self::$intstance;
	}

	/**
	 * Returns a list of principals based on a prefix.
	 *
	 * This prefix will often contain something like 'principals'. You are only
	 * expected to return principals that are in this base path.
	 *
	 * You are expected to return at least a 'uri' for every user, you can
	 * return any additional properties if you wish so. Common properties are:
	 *   {DAV:}displayname
	 *   {http://sabredav.org/ns}email-address - This is a custom SabreDAV
	 *     field that's actualy injected in a number of other properties. If
	 *     you have an email address, use this property.
	 *
	 * @param string $prefixPath
	 * @return array
	 */
	public function getPrincipalsByPrefix($prefixPath)
	{

		// This backend only support principals in one collection
		if ($prefixPath !== $this->prefix) return [];

		$users = [];

		$r = q("SELECT `nickname` FROM `user` WHERE `nickname` = '%s'", escape_tags($this->authBackend->getCurrentUser()) );
		foreach ($r as $t) {
			$users[] = [
				'uri'               => $this->prefix . '/' . strtolower($t['nickname']),
				'{DAV:}displayname' => $t['nickname'],
			];
		}

		return $users;

	}

	/**
	 * Returns a specific principal, specified by it's path.
	 * The returned structure should be the exact same as from
	 * getPrincipalsByPrefix.
	 *
	 * @param string $path
	 * @return array
	 */
	public function getPrincipalByPath($path)
	{

		list($prefixPath, $userName) = Sabre_DAV_URLUtil::splitPath($path);

		// This backend only support principals in one collection
		if ($prefixPath !== $this->prefix) return null;

		$r = q("SELECT `nickname` FROM `user` WHERE `nickname` = '%s'", escape_tags($userName) );
		if (count($r) == 0) return [];

		return [
			'uri'               => $this->prefix . '/' . strtolower($r[0]['nickname']),
			'{DAV:}displayname' => $r[0]['nickname'],
		];

	}


	function getGroupMemberSet($principal)
	{
		return [];
	}

	function getGroupMembership($principal)
	{
		return [];
	}


	/**
	 * Updates the list of group members for a group principal.
	 *
	 * The principals should be passed as a list of uri's.
	 *
	 * @param string $principal
	 * @param array $members
	 * @throws Sabre_DAV_Exception
	 * @return void
	 */
	public function setGroupMemberSet($principal, array $members)
	{
		throw new Sabre_DAV_Exception('Operation not supported');
	}

	/**
	 * Updates one ore more webdav properties on a principal.
	 *
	 * The list of mutations is supplied as an array. Each key in the array is
	 * a propertyname, such as {DAV:}displayname.
	 *
	 * Each value is the actual value to be updated. If a value is null, it
	 * must be deleted.
	 *
	 * This method should be atomic. It must either completely succeed, or
	 * completely fail. Success and failure can simply be returned as 'true' or
	 * 'false'.
	 *
	 * It is also possible to return detailed failure information. In that case
	 * an array such as this should be returned:
	 *
	 * array(
	 *   200 => array(
	 *      '{DAV:}prop1' => null,
	 *   ),
	 *   201 => array(
	 *      '{DAV:}prop2' => null,
	 *   ),
	 *   403 => array(
	 *      '{DAV:}prop3' => null,
	 *   ),
	 *   424 => array(
	 *      '{DAV:}prop4' => null,
	 *   ),
	 * );
	 *
	 * In this previous example prop1 was successfully updated or deleted, and
	 * prop2 was succesfully created.
	 *
	 * prop3 failed to update due to '403 Forbidden' and because of this prop4
	 * also could not be updated with '424 Failed dependency'.
	 *
	 * This last example was actually incorrect. While 200 and 201 could appear
	 * in 1 response, if there's any error (403) the other properties should
	 * always fail with 423 (failed dependency).
	 *
	 * But anyway, if you don't want to scratch your head over this, just
	 * return true or false.
	 *
	 * @param string $path
	 * @param array $mutations
	 * @return array|bool
	 */
	function updatePrincipal($path, $mutations)
	{
		// TODO: Implement updatePrincipal() method.
	}

	/**
	 * This method is used to search for principals matching a set of
	 * properties.
	 *
	 * This search is specifically used by RFC3744's principal-property-search
	 * REPORT. You should at least allow searching on
	 * http://sabredav.org/ns}email-address.
	 *
	 * The actual search should be a unicode-non-case-sensitive search. The
	 * keys in searchProperties are the WebDAV property names, while the values
	 * are the property values to search on.
	 *
	 * If multiple properties are being searched on, the search should be
	 * AND'ed.
	 *
	 * This method should simply return an array with full principal uri's.
	 *
	 * If somebody attempted to search on a property the backend does not
	 * support, you should simply return 0 results.
	 *
	 * You can also just return 0 results if you choose to not support
	 * searching at all, but keep in mind that this may stop certain features
	 * from working.
	 *
	 * @param string $prefixPath
	 * @param array $searchProperties
	 * @return array
	 */
	function searchPrincipals($prefixPath, array $searchProperties)
	{
		// TODO: Implement searchPrincipals() method.
	}
}