<?php

require_once('config/Config_Db.php');

class Config {
    /**
     * static pointer to instances
     * @var array(Config)
     */
    private static $instances = array();

    /**
     * can handle several instances, distinct by instance name string
     * @var string
     */
    private $instanceName = '';

    /**
     * config object
     * @var Config_Db
     */
    private $config = null;

    /**
     * make a new Config_Db
     *
     * by using the $where statement you can limit the data that is fetched from db, i.e. only get config for zone $id
     *
     * @param string $instanceName
     * @param Zend_Db_Adapter $db
     * @param string $where
     */
    protected function __construct($instanceName = null, $db = null, $where = null) {
        if ($instanceName === null)
            throw new Exception(__METHOD__ . ': expected an instance name, got none');

        $config = new Zend_Config_Ini(APPLICATION_PATH . '/configs/application.ini', APPLICATION_ENV);
        $this->instanceName = $instanceName;

        if ($db === null)
            $db = Zend_Db::factory($config->dnssecme->db->config->pdo, $config->dnssecme->db->config);

        $this->config = new Config_Db($db, $instanceName, $where, true);
    }

    /**
     * get already existing instance, make new instance or throw an exception
     * @param string $instanceName
     * @param Zend_Db_Adapter $db
     * @param string $where
     */
    public static function getInstance($instanceName, $db = null, $where = null) {
        if ($instanceName === null)
            throw new Exception(__METHOD__ . ': expected an instance name, got none');

        // no caching if presumeably volatile data is requested
        if ($db !== null && $where !== null) {
            return new Config($instanceName, $db, $where);
        }

        if (!array_key_exists($instanceName, self::$instances)) {
            self::$instances[$instanceName] = new Config($instanceName, $db, $where);
        }

        return self::$instances[$instanceName];
    }

    /**
     * magic method that dispatches all unrecognized method calls to the config object
     *
     * @param string $param
     */
    public function __get($param) {
        return $this->config->$param;
    }

    /**
     * magic method that handles isset inquiries to attributes
     *
     * @param string $param
     */
    public function __isset($param) {
        return isset($this->config->$param);
    }

    /**
     * magic method that dispatches all unrecognized method calls to the config object
     *
     * @param string $param
     * @param string $value
     */
    public function __set($param, $value) {
        $this->config->$param = $value;
    }

    /**
     * get the config object
     * @return Zend_Config_*
     */
    public function getConfig() {
        return $this->config;
    }
}