<?php
    class Ibis
    {
        public function getData($id)
        {
            if(!is_string($id))
                throw new Exception("'id' isn't a string.");

            $cacheFile = $this->_exist($id);
            if(!$cacheFile)
                throw new Exception("'id' doesn't exist in cache.");

            $fp = fopen($cacheFile, "r");
            if(!$fp)
                throw new Exception("'id' unable to retrieve the cache.");

            flock($fp, LOCK_UN);
            $dato = fread($fp, filesize($cacheFile));
            fclose($fp);

            return $dato;
        }

        public function updateData($id, $value)
        {
            $cacheFile = $this->_exist($id);

            if($cacheFile != false)
                unlink($cacheFile);

            $fp = fopen($this->_cacheDir.md5($id), "");
            if(!$fp)
                throw new Exception("Can not update 'id'.");

            flock($fp, LOCK_EX);
            fwrite($fp, $value);
            fclose($fp);
        }

        public function isOld($id)
        {
            $cacheFile = $this->_exist($id);

            if((filemtime($cacheFile) + $this->_timeout) <= time())
                return false;

            return true;
        }

        public function deleteId($id)
        {
            $cacheFile = $this->_exist($id);

            if(!$cacheFile)
                throw new Exception("'id' does not exist.");

            unlink($cacheFile);
        }

        private function _exist($id)
        {
            $cacheFile = $this->_cacheDir.md5($id);
            if(file_exist($cacheFile))
                return $cacheFile;

            return false;
        }

        public function setCacheDir($cacheDir)
        {
            if(!is_string($cacheDir))
                throw new Exception("'cacheDir' isn't a string.");

            $this->_cacheDir = $cacheDir;
        }

        public function getCacheDir()
        {
            return $this->_cacheDir;
        }

        public function setTimeout($time)
        {
            if(!is_int($time))
                throw new Exception("'time' isn't a int.");

            $this->_timeout = $time;
        }

        private $_cacheDir = ABSPATH."cache/";
        private $_timeout;
    }
?>