Portable Web Dev

<?
    /**
     * Project Class
     */
    class Project {

        private static $modelName = "Project";
        private static $tableName = "project";
        public static $model_fields = array("id", "name", "description", "type");
        public static  $all_project_ids = array(3, 5, 9, 11, 16, 24, 38, 112, 215, 222);
        public $related_project_ids = array(9, 38, 215);


        /**
         * getFields
         * Return Project fields ($model_fields) items as a CSV sting,
         * with array order reversed, and all uppercase
         */
        public static function getFields() {
            $details = "";
            return $details;
        }

        /**
         * getUnrelatedProjects
         * Return array of project id's (from $all_project_ids) that are not present in $related_project_ids
         */
        public function getUnrelatedProjects() {
            return array();
        }

        /**
         * List any errors in the following function?
         * and what does it return?
         */
        public function whatIsWrongWithMe() {
            $project_time = "1hour";
            $$project_time = "2hours";
            $estimate =  empty($project_time) ? "3hours" : isset($$project_time) ? "4hours" : "5hours";
            $prj = new Project();
            return gettype($prj) . Project::tableName;
        }

    }
?>