<?php

/**
 * Super singleton registry that manages application context.
 */
class XHTMLCompiler
{
    
    // SINGLETON FUNCTIONALITY
    
    /** Private instance of singleton */
    private static $_instance;
    
    /** Private constructor, prevents other people from making it */
    private function __construct() {
        $this->loadConf();
    }
    
    /** Retrieves the single instance of the object */
    static public function getInstance() {
        if(is_null(self::$_instance)) {
            self::$_instance = new self();
        }
        return self::$_instance;
    }
    
    /**
     * Overloads the instance with another one, usually a mock object
     * @param Object substitute for XHTMLCompiler
     */
    static public function setInstance($stub) {
        self::$_instance = $stub;
    }
    
    // REGISTRY FUNCTIONALITY
    
    /** Private instance of PHP wrapper */
    private static $_PHPWrapperInstance;
    
    /** Retrieves the single instance of the PHP wrapper */
    static public function getPHPWrapper() {
        if(is_null(self::$_PHPWrapperInstance)) {
            self::$_PHPWrapperInstance = new XHTMLCompiler_PHP();
        }
        return self::$_PHPWrapperInstance;
    }
    
    /**
     * Overloads the instance with another one, usually a mock object
     * @param Object substitute for XHTMLCompiler
     */
    static public function setPHPWrapper($stub) {
        self::$_PHPWrapperInstance = $stub;
    }
    
    // PLUGIN/CONFIGURATION FUNCTIONALITY
    
    protected $configKeys = array('allowed_dirs', 'directory_index',
        'indexed_dirs', 'web_path', 'web_domain', 'viewvc_url',
        'svn_headurl_munge', 'debug', 'error_xsl', 'admin_email',
        'error_log', 'error_mute');
    protected $config = array();
    protected $filterManager;
    
    public function loadConf() {
        $filters = new XHTMLCompiler_FilterManager();
        require 'config.default.php'; // defaults
        
        // user configuration
        if (file_exists($f = dirname(__FILE__) . '/conf/config.php')) require $f;
        if (file_exists($f = dirname(__FILE__) . '/config.php')) require $f;
        
        $this->config = compact($this->configKeys);
        $this->filterManager = $filters;
    }
    public function getConf($key) {
        if (!isset($this->config[$key])) throw new Exception('No such configuration keypair');
        return $this->config[$key];
    }
    public function getFilterManager() {return $this->filterManager;}
    
}

?>