<?php

/**
 * @author     Ben Borowski <ben.borowski@typeoneerror.com>
 * @copyright  Copyright (c) 2008-9 TypeOneError Studios (http://www.typeoneerror.com)
 * @license    MIT ~ http://www.opensource.org/licenses/mit-license.php
 * @version    $Id$
 * @link       http://typeoneerror.com/asra
 * @category   Asra
 * @package    Core
 */

/**
 * Handles the auto-loading of classes and files.
 *
 * @author     Ben Borowski <ben.borowski@typeoneerror.com>
 * @copyright  Copyright (c) 2008-9 TypeOneError Studios (http://www.typeoneerror.com)
 * @license    MIT ~ http://www.opensource.org/licenses/mit-license.php
 * @link       http://typeoneerror.com/asra
 * @category   Asra
 * @package    Core
 */
final class Asra_Core_Loader
{
    //---------------------------------------
    // PRIVATE VARIABLES
    //---------------------------------------

    /**
     * Load errors.
     *
     * @param string
     */
    private static $__error;

    //---------------------------------------
    // CONSTRUCTOR
    //---------------------------------------

    /**
     * Dont't allow clones
     */
    // @codeCoverageIgnoreStart
    final private function __clone()
    {
    }

    /**
     * Don't allow construction
     */
    final private function __construct()
    {
    }
    // @codeCoverageIgnoreEnd

    //---------------------------------------
    // METHODS
    //---------------------------------------

    /**
     * Performs the auto-load of classes.
     *
     * @param string $className  Name of class to load file for.
     * @return void
     */
    public static function autoload($className)
    {
        $autoload = false;

        // -- if the actual class name exists, bail
        if (class_exists($className, $autoload) || interface_exists($className, $autoload))
        {
            return;
        }

        // -- convert to pear style class name
        $file = str_replace('_', DIRECTORY_SEPARATOR, $className) . '.php';

        // -- include the converted file
        @require_once $file;

        // -- one more test
        if (!class_exists($className, $autoload) && !interface_exists($className, $autoload))
        {
            require_once 'Asra/Core/Exception.php';
            throw new Asra_Core_Exception("File \"{$file}\" does not exist or class \"{$className}\" was not found in the file");
        }
    }

    /**
     * Registers the autoload function for use.
     *
     * @return void
     */
    public static function init()
    {
        // @codeCoverageIgnoreStart
        if (!function_exists('spl_autoload_register'))
        {
            require_once 'Asra/Core/Exception.php';
            throw new Asra_Core_Exception('Required autoload function `spl_autoload_register` does not exist in PHP version ' . phpversion());
        }
        // @codeCoverageIgnoreEnd
        spl_autoload_register(array('Asra_Core_Loader', 'autoload'));
    }

    /**
     * Load a configuration file.
     *
     * @param string $file  Path to config file.
     * @param string $type  Type of config file.
     * @return array        Parsed configuration settings.
     */
    public static function loadConfig($file, $type)
    {
        if (!file_exists($file))
        {
            require_once 'Asra/Core/Exception.php';
            throw new Asra_Core_Exception("{$type} file was not present at specified location: {$file}");
        }

        /**
         * sadly, need to hijack the error handler here because
         * we want to throw an error if the parsing failed
         */
        self::$__error = null;
        set_error_handler(array('Asra_Core_Loader', '__loadConfigError'));
        $parse = parse_ini_file($file, true);
        restore_error_handler();

        if (!is_array($parse) || is_null($parse) || !is_null(self::$__error))
        {
            require_once 'Asra/Core/Exception.php';
            throw new Asra_Core_Exception("{$type} file at {$file} appears to be malformed: " . self::$__error);
        }

        return $parse;
    }

    /**
     * Handle any errors while loading config.
     *
     * @param int $errno
     * @param string $errstr
     * @param string $errfile
     * @param int $errline
     * @return void
     */
    private static function __loadConfigError($errno, $errstr, $errfile, $errline)
    {
       self::$__error = $errstr;
    }

}