<?php

class Default_Model_UserAuth {

    public function isAuthorised($request) {
        $form = new Default_Form_Login();

        if ($request->isPost()) {
            if ($form->isValid($request->getPost())) {
                $values = $form->getValues();
                $salt = $this->getSalt($values['username']);
                $encryptedPassword = $this->getEncryptedPassword($values['password'], $salt);

                if ($this->authenticate($values['username'], $encryptedPassword)) {
                    return true;
                }
            }
        }
        return false;
    }

    public function authenticate($username, $encryptedPassword) {
        // Get our authentication adapter and check credentials
        $adapter = $this->getAuthAdapter();
        $adapter->setIdentity($username);
        $adapter->setCredential($encryptedPassword);

        $auth = Zend_Auth::getInstance();
        $result = $auth->authenticate($adapter);
        if ($result->isValid()) {
            $user = $adapter->getResultRowObject();
            $auth->getStorage()->write($user);
            return true;
        }
        return false;
    }

    public function getAuthAdapter() {
        $dbAdapter = Zend_Db_Table::getDefaultAdapter();

        $authAdapter = new Zend_Auth_Adapter_DbTable($dbAdapter);
        $authAdapter->setTableName('users')
            ->setIdentityColumn('username')
            ->setCredentialColumn('password');

        return $authAdapter;
    }

    public function getEncryptedPassword($password, $salt) {
        return sha1($password . $salt);
    }

    public function getSalt($username) {
        $dbAdapter = Zend_Db_Table::getDefaultAdapter();

        $result = $dbAdapter->fetchRow($dbAdapter
                                        ->select()
                                        ->from('users', 'salt')
                                        ->where('username = ?', $username)
                                        );

        return $result['salt'];
    }

}