<?php

class Marshaller {

    const OBJ_TYPE = '__objectType';
    const OBJ_UID = '__objectUid';
    const REF_TYPE = '__referenceType';
    const REF_UID = '__referenceUid';

    private static function isWrappedObject($obj) {
        return isset($obj[self::OBJ_TYPE]);
    }

    private static function isWrappedReference($obj) {
        return isset($obj[self::REF_TYPE]);
    }

    public static function marshall($obj) {
        switch (gettype($obj)) {
            case 'array':
                return array_map(array('Marshaller', 'marshall'), $obj);
            case 'object':
                return static::wrapObject($obj);
            default:
                return $obj;
        }
    }

    private static function wrapObject($obj) {
        $objectType = get_class($obj);
        if ($objectType == 'DateTime') {
            return array(self::OBJ_TYPE => 'DateTime', 'timestamp' => $obj->getTimestamp());
        } else if ($obj instanceof RdfObject) {
            $array = array(
                self::OBJ_TYPE => $obj->getType(),
                self::OBJ_UID => $obj->getUid()
            );
            foreach ($obj as $prop => $val) {
                $array[$prop] = static::marshall($val);
            }
            return $array;
        } else if ($obj instanceof RdfPointer) {
            return array(
                self::REF_TYPE => $obj->getType(),
                self::REF_UID => $obj->getUid()
            );
        } else {
            return static::marshall((array) $obj);
        }
    }

    public static function unmarshall($obj) {
        switch (gettype($obj)) {
            case 'object':
                $obj = (array) $obj;
            case 'array':
                if (static::isWrappedObject($obj)) {
                    return static::unwrapObject($obj);
                } else if (static::isWrappedReference($obj)) {
                    return static::unwrapReference($obj);
                } else {
                    return array_map(array('Marshaller', 'unmarshall'), $obj);
                }
            default:
                return $obj;
        }
    }

    private static function unwrapObject($obj) {
        if (isset($obj[self::OBJ_TYPE])) {
            $objectType = $obj[self::OBJ_TYPE];
            unset($obj[self::OBJ_TYPE]);
        }
        if (isset($obj[self::OBJ_UID])) {
            $objectUid = $obj[self::OBJ_UID];
            unset($obj[self::OBJ_UID]);
        }
        if ($objectType == 'DateTime') {
            $date = new DateTime();
            $date->setTimestamp($obj['timestamp']);
            return $date;
        } else if (is_subclass_of($objectType, 'RdfObject')) {
            $rdfObject = new $objectType($objectUid);
            foreach ($obj as $prop => $val) {
                $rdfObject->$prop = static::unmarshall($val);
            }
            return $rdfObject;
        } else {
            return $obj;
        }
    }

    private static function unwrapReference($ref) {
        $refType = $ref[self::REF_TYPE];
        $refUid = $ref[self::REF_UID];
        return new RdfPointer(RdfObject::typeAndUidToResourceUri($refType, $refUid));
    }
    
}

?>