<?php defined('SYSPATH') OR die('No direct access allowed.');

class Auth {

    protected static $config;
    protected static $current_user;
    protected static $instance;

    public static function instance()
    {
        if ( ! isset(Auth::$instance))
            Auth::$instance = new Auth;

        return Auth::$instance;
    }

    public function init()
    {
        Auth::$config = Kohana::config('auth');
        Auth::$current_user = ORM::factory('user', Session::instance()->get(Auth::$config['session_key']));
    }

    public function load_user()
    {
        if (Auth::$current_user->loaded())
            return Auth::$current_user;

        return FALSE;
    }

    public function login($account, $unique_key, $password, $remember = FALSE)
	{
        $user = ORM::factory('user')->where(array(
            Auth::$config['unique_key'] => $unique_key,
            'password' => Auth::hash_password($password)
        ))->find();

        if ($user->loaded())
        {
            $session->regenerate();
            Session::instance()->set(Auth::$config['session_key'], $user->id);

            return $user;
        }

        return FALSE;
	}

    public static function logout($destroy = TRUE)
    {
		if ($destroy === TRUE)
		{
			Session::instance()->destroy();
		}
		else
		{
			Session::instance()->delete($this->config['session_key']);
			Session::instance()->regenerate();
		}
    }

	public static function hash_password($password)
	{
		return hash(Auth::$config['hash_method'], $password.$this->salt($password));
	}

    private function salt($password)
	{
		$salt = '';
        $salt_pattern = preg_split('/,\s*/', $this->config['salt_pattern']);

		foreach ($salt_pattern as $i => $offset)
			$salt .= substr($password, $offset + $i, 1);

		return $salt;
	}

	public function auto_login()
	{
		if ($token = cookie::get('authautologin'))
		{
			// Load the token and user
			$token = ORM::factory('user_token', array('token' => $token));

			if ($token->loaded() AND $token->user->loaded())
			{
				if ($token->user_agent === sha1(Request::$user_agent))
				{
					// Save the token to create a new unique token
					$token->save();

					// Set the new token
					cookie::set('authautologin', $token->token, $token->expires - time());

					// Complete the login with the found data
					$this->complete_login($token->user);

					// Automatic login was successful
					return TRUE;
				}

				// Token is invalid
				$token->delete();
			}
		}

		return FALSE;
	}

    public static function generate_password($length = 8)
    {
        $password = '';

        $chars = "023456789bcdfghjkmnpqrstvwxyz";
        $i = 0;
        while ($i < $length)
        {
            $char = substr($chars, mt_rand(0, strlen($chars)-1), 1);

            if (!strstr($password, $char))
            {
                $password .= $char;
                $i++;
            }
        }
        return $password;
    }
}