public static function readConfigFile($file = self::DEFAULT_CONFIG_FILE)
    {
        if (!is_string($file)) {
            throw new InvalidArgumentException('The config file path must be a string, type passed "'.gettype($file).'".');
        }

        $baseDir = realpath(dirname($file));
        $searchDirs = array(
            $baseDir.'/',
            $baseDir.'/../',
            $baseDir.'/../../',
            $baseDir.'/config/',
            $baseDir.'/../config/',
            $baseDir.'/../../config/'
        );

        $filename = basename($file);

        $configFile = null;
        foreach ($searchDirs as $dir) {
            if (realpath($dir.$filename) and is_readable($dir.$filename)) {
                $configFile = realpath($dir.$filename);
                break;
            }
        }

        if (is_null($configFile) and $file !== self::DEFAULT_CONFIG_FILE) {
            throw new InvalidArgumentException('The config file "'.$file.'" cannot be found or read.');
        }

        if (!$configFile) {
            return static::$config;
        }

        // Try to parse the contents
        try {
            $yaml = Yaml\Yaml::parse(file_get_contents($configFile));
        } catch (Yaml\Exception\ParseException $e) {
            throw new Exception('Unable to parse the config file: '.$e->getMessage());
        }

        return static::$config = $yaml;
    }