Loader 15-06

<?php
namespace Shinoa\StudentsList;


use Shinoa\StudentsList\Exceptions\LoaderException;

class Loader
{
    //единственный экземпляр класса
    private static $root;
    private static $instance;
    private static $config;
    private static $dsn;
    private static $pdo;

    /**
     * Unreachable constructor.
     */
    private function __construct()
    {
    }

    /**
     * @param mixed $root
     */
    public static function setRoot($root)
    {
        self::$root = $root;
    }

    /**
     * @return mixed
     */
    public static function getRoot()
    {
        if (isset(self::$root)) {
            return self::$root;
        } else throw new LoaderException('Cannot get root: root is not defined.');
    }

    /**
     * @return mixed
     */
    public static function getConfig()
    {
        $configFactory = function ($root) {
            if (file_exists(appendFilePath([$root, 'Students', 'ini', 'config.xml']))) {
                $configPath = appendFilePath([$root, 'Students', 'ini', 'config.xml']);
            } elseif (file_exists(appendFilePath([$root, 'Students', 'ini', 'config_test.xml']))) {
                $configPath = appendFilePath([$root, 'Students', 'ini', 'config_test.xml']);
            } else {
                throw new LoaderException('Cannot load config!');
            }
            return simplexml_load_file($configPath);

        };

        if ( !isset(self::$config) ) {
            $root = self::getRoot();
            if ( isset($root) ) {
                self::$config = $configFactory(self::$root);
            } else throw new LoaderException('Failed to create config: root is not defined.');
        }
        return self::$config;
    }

    public static function getDSN()
    {
        $dsnFactory = function ($config) {
            if (empty($config)) {
                throw new LoaderException('Configuration is not properly loaded');
            }
            $dsn = "mysql:host=localhost;dbname={$config->database->dbname};charset=utf8";
            return $dsn;
        };

        if ( !isset(self::$config) ) {
            if ( isset(self::$config) ) {
                self::$dsn = $dsnFactory(self::$root);
            } else throw new LoaderException('Failed to create dsn: root is not defined.');
        }
        return self::$config;
    }

    public static function getPDO()
    {
        $pdoFactory = function ($config, $dsn) {
            //загружаем данные для соединения
            if (!isset($config->database->username)
                ||
                !isset($config->database->password)
            ) {
                throw new LoaderException('Config  not loaded or empty');
            } else {
                $username = $config->database->username;
                $password = $config->database->password;
            }
            //пробуем соединиться
            try {
                $opt = array(
                    \PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION,
                    \PDO::ATTR_DEFAULT_FETCH_MODE => \PDO::FETCH_ASSOC,
                    \PDO::ATTR_EMULATE_PREPARES => false,
                    \PDO::MYSQL_ATTR_FOUND_ROWS => true
                );
                $pdo = new \PDO($dsn, $username, $password, $opt);
            } catch (\PDOException $e) {
                throw new LoaderException('Ошибка при подключении к базе данных');
            }
            return $pdo;
        };

        if ( !isset(self::$pdo)) {
            if ( isset(self::$config) || isset(self::$dsn)) {
                self::$pdo = $pdoFactory(self::$config, self::$dsn);
            } else throw new LoaderException('Failed to create dsn: root is not defined.');
        }
        return self::$pdo;
    }

}