<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/*
* LimeSurvey (tm)
* Copyright (C) 2011 The LimeSurvey Project Team / Carsten Schmitz
* All rights reserved.
* License: GNU/GPL License v2 or later, see LICENSE.php
* LimeSurvey is free software. This version may have been modified pursuant
* to the GNU General Public License, and as distributed it includes or
* is derivative of works licensed under the GNU General Public License or
* other free or open source software licenses.
* See COPYRIGHT.php for copyright notices and details.
*
* @author Shubham Sachdeva
*/

/**
* Installer
*
* @todo Output code belongs into view
*
* @package LimeSurvey
* @author Shubham Sachdeva
* @copyright 2011
* @access public
*/
class InstallerController extends CController {

    /**
    * @var CDbConnection
    */
    public $connection;

    /**
    * clang
    */
    public $lang = null;

    public $layout = 'installer';
    /**
    * Checks for action specific authorization and then executes an action
    *
    * @access public
    * @param string $action
    * @return bool
    */
    public function run($action = 'index')
    {
        self::_checkInstallation();
        self::_sessioncontrol();

        switch ($action) {

            case 'welcome':
                $this->stepWelcome();
                break;

            case 'license':
                $this->stepLicense();
                break;

            case 'viewlicense':
                $this->stepViewLicense();
                break;

            case 'precheck':
                $this->stepPreInstallationCheck();
                break;

            case 'database':
                $this->stepDatabaseConfiguration();
                break;

            case 'createdb':
                $this->stepCreateDb();
                break;

            case 'populatedb':
                $this->stepPopulateDb();
                break;

            case 'optional':
                $this->stepOptionalConfiguration();
                break;

            case 'index' :
            default :
                $this->redirect(array('installer/welcome'));
                break;

        }
    }

    /**
    * Installer::_checkInstallation()
    *
    * Based on existance of 'sample_installer_file.txt' file, check if
    * installation should proceed further or not.
    * @return
    */
    function _checkInstallation()
    {
        if (file_exists(APPPATH . 'config/config.php') && empty($_POST['InstallerConfigForm']))
        {
            throw new CHttpException(500, 'Installation has been done already. Installer disabled.');
            exit();
        }
    }

    /**
    * Load and set session vars
    *
    * @access protected
    * @return void
    */
    protected function _sessioncontrol()
    {
        if (empty(Yii::app()->session['installerLang']))
            Yii::app()->session['installerLang'] = 'en';

        Yii::import('application.libraries.Limesurvey_lang');
        $this->lang = new Limesurvey_lang(Yii::app()->session['installerLang']);
        Yii::app()->setLang($this->lang);
    }

    /**
    * welcome and language selection install step
    */
    private function stepWelcome()
    {

        if (!empty($_POST['installerLang']))
        {
            Yii::app()->session['installerLang'] = $_POST['installerLang'];
            $this->redirect(array('installer/license'));
        }
        $this->loadHelper('surveytranslator');
        Yii::app()->session->remove('configFileWritten');

        $aData['clang'] = $clang = $this->lang;
        $aData['title'] = $clang->gT('Welcome');
        $aData['descp'] = $clang->gT('Welcome to the LimeSurvey installation wizard. This wizard will guide you through the installation, database setup and initial configuration of LimeSurvey.');
        $aData['classesForStep'] = array('on','off','off','off','off','off');
        $aData['progressValue'] = 10;

        if (isset(Yii::app()->session['installerLang']))
        {
            $sCurrentLanguage=Yii::app()->session['installerLang'];
        }
        else
            $sCurrentLanguage='en';

        foreach(getLanguageData(true, $sCurrentLanguage) as $sKey => $aLanguageInfo)
        {
            $aLanguages[htmlspecialchars($sKey)] = sprintf('%s - %s', $aLanguageInfo['nativedescription'], $aLanguageInfo['description']);
        }
        $aData['languages']=$aLanguages;
        $this->render('/installer/welcome_view',$aData);
    }

    /**
    * Display license
    */
    private function stepLicense()
    {
        $aData['clang'] = $clang = $this->lang;
        // $aData array contain all the information required by view.
        $aData['title'] = $clang->gT('License');
        $aData['descp'] = $clang->gT('GNU General Public License:');
        $aData['classesForStep'] = array('off','on','off','off','off','off');
        $aData['progressValue']= 15;

        if (strtolower($_SERVER['REQUEST_METHOD']) == 'post')
        {
            $this->redirect(array('installer/precheck'));
        }
        Yii::app()->session['saveCheck'] = 'save';  // Checked in next step

        $this->render('/installer/license_view',$aData);
    }

    /**
    * display the license file as IIS for example
    * does not display it via the server.
    */
    public function stepViewLicense()
    {
        header('Content-Type: text/plain; charset=UTF-8');
        readfile(dirname(BASEPATH) . '/docs/license.txt');
        exit;
    }

    /**
    * check a few writing permissions and optional settings
    */
    private function stepPreInstallationCheck()
    {
        $aData['clang'] = $clang = $this->lang;
        $oModel = new InstallerConfigForm();
        //usual data required by view
        $aData['title'] = $clang->gT('Pre-installation check');
        $aData['descp'] = $clang->gT('Pre-installation check for LimeSurvey ').Yii::app()->getConfig('versionnumber');
        $aData['classesForStep'] = array('off','off','on','off','off','off');
        $aData['progressValue'] = 20;
        $aData['phpVersion'] = phpversion();
        // variable storing next button link.initially null
        $aData['next'] = '';
        $aData['dbtypes']=$oModel->supported_db_types;

        $bProceed = $this->_check_requirements($aData);
        $aData['dbtypes']=$oModel->supported_db_types;

        if(count($aData['dbtypes'])==0)
        {
            $bProceed=false;
        }
        // after all check, if flag value is true, show next button and sabe step2 status.
        if ($bProceed)
        {
            $aData['next'] = true;
            Yii::app()->session['step2'] = true;
        }

        $this->render('/installer/precheck_view',$aData);
    }

    /**
    * Configure database screen
    */
    private function stepDatabaseConfiguration()
    {
        $this->loadHelper('surveytranslator');

        $aData['clang'] = $clang = $this->lang;
        // usual data required by view
        $aData['title'] = $clang->gT('Database configuration');
        $aData['descp'] = $clang->gT('Please enter the database settings you want to use for LimeSurvey:');
        $aData['classesForStep'] = array('off','off','off','on','off','off');
        $aData['progressValue'] = 40;
        $aData['model'] = $oModel = new InstallerConfigForm;

        if(isset($_POST['InstallerConfigForm']))
        {
            $oModel->attributes = $_POST['InstallerConfigForm'];

            //run validation, if it fails, load the view again else proceed to next step.
            if($oModel->validate()) {
                $sDatabaseType = $oModel->dbtype;
                $sDatabaseName = $oModel->dbname;
                $sDatabaseUser = $oModel->dbuser;
                $sDatabasePwd = $oModel->dbpwd;
                $sDatabasePrefix = $oModel->dbprefix;
                $sDatabaseLocation = $oModel->dblocation;
                $sDatabasePort = '';
                if (strpos($sDatabaseLocation, ':')!==false)
                {
                    list($sDatabaseLocation, $sDatabasePort) = explode(':', $sDatabaseLocation, 2);
                }
                else
                {
                    $sDatabasePort = self::_getDbPort($sDatabaseType, $sDatabasePort);
                }

                $bDBExists = false;
                $bDBConnectionWorks = false;
                $aDbConfig = compact('sDatabaseType', 'sDatabaseName', 'sDatabaseUser', 'sDatabasePwd', 'sDatabasePrefix', 'sDatabaseLocation', 'sDatabasePort');

                if (self::_dbConnect($aDbConfig, array())) {
                    $bDBExists = true;
                    $bDBConnectionWorks = true;
                } else {
                    $aDbConfig['sDatabaseName'] = '';
                    if (self::_dbConnect($aDbConfig, array())) {
                        $bDBConnectionWorks = true;
                    } else {
                        $oModel->addError('dblocation', $clang->gT('Connection with database failed. Please check database location, user name and password and try again.'));
                        $oModel->addError('dbpwd','');
                        $oModel->addError('dbuser','');
                    }
                }

                //if connection with database fail
                if ($bDBConnectionWorks)
                {
                    //saving the form data
                    foreach(array('dbname', 'dbtype', 'dbpwd', 'dbuser', 'dbprefix') as $sStatusKey) {
                        Yii::app()->session[$sStatusKey] = $oModel->$sStatusKey;
                    }
                    Yii::app()->session['dbport'] = $sDatabasePort;
                    Yii::app()->session['dblocation'] = $sDatabaseLocation;

                    //check if table exists or not
                    $bTablesDoNotExist = false;

                    // Check if the surveys table exists or not
                    if ($bDBExists == true) {
                        try {
                            if ($dataReader=$this->connection->createCommand()->select()->from('{{users}}')->query()->rowCount==0)  // DBLIB does not throw an exception on a missing table
                            $bTablesDoNotExist = true;
                        } catch(Exception $e) {
                            $bTablesDoNotExist = true;
                        }
                    }

                    $bDBExistsButEmpty = ($bDBExists && $bTablesDoNotExist);

                    //store them in session
                    Yii::app()->session['databaseexist'] = $bDBExists;
                    Yii::app()->session['tablesexist'] = !$bTablesDoNotExist;

                    // If database is up to date, redirect to administration screen.
                    if ($bDBExists && !$bTablesDoNotExist)
                    {
                        Yii::app()->session['optconfig_message'] = sprintf('<b>%s</b>', $clang->gT('The database you specified does already exist.'));
                        Yii::app()->session['step3'] = true;

                        //wrte config file! as we no longer redirect to optional view
                        $this->_writeConfigFile();

                        //$this->redirect(array("installer/loadOptView"));
                        header("refresh:5;url=".$this->createUrl("/admin"));
                        echo sprintf( $clang->gT('The database does exists and contains LimeSurvey tables. You\'ll be redirected to the database update or (if your database is already up to date) to the administration login in 5 seconds. If not, please click <a href="%s">here</a>.', 'unescaped'), $this->createUrl("/admin"));
                        exit();
                    }

                    if (in_array($oModel->dbtype, array('mysql', 'mysqli'))) {
                        //for development - use mysql in the strictest mode  //Checked)
                        if (Yii::app()->getConfig('debug')>1) {
                            $this->connection->createCommand("SET SESSION SQL_MODE='STRICT_ALL_TABLES,ANSI'")->execute();
                        }
                        $sMySQLVersion = $this->connection->getServerVersion();
                        if (version_compare($sMySQLVersion,'4.1','<'))
                        {
                            die("<br />Error: You need at least MySQL version 4.1 to run LimeSurvey. Your version:".$sMySQLVersion);
                        }
                        @$this->connection->createCommand("SET CHARACTER SET 'utf8'")->execute();  //Checked
                        @$this->connection->createCommand("SET NAMES 'utf8'")->execute();  //Checked
                    }

                    // Setting dateformat for mssql driver. It seems if you don't do that the in- and output format could be different
                    if (in_array($oModel->dbtype, array('mssql', 'sqlsrv', 'dblib'))) {
                        @$this->connection->createCommand('SET DATEFORMAT ymd;')->execute();     //Checked
                        @$this->connection->createCommand('SET QUOTED_IDENTIFIER ON;')->execute();     //Checked
                    }

                    //$aData array won't work here. changing the name
                    $aValues['title'] = $clang->gT('Database settings');
                    $aValues['descp'] = $clang->gT('Database settings');
                    $aValues['classesForStep'] = array('off','off','off','off','on','off');
                    $aValues['progressValue'] = 60;

                    //it store text content
                    $aValues['adminoutputText'] = '';
                    //it store the form code to be displayed
                    $aValues['adminoutputForm'] = '';

                    //if DB exist, check if its empty or up to date. if not, tell user LS can create it.
                    if (!$bDBExists)
                    {
                        Yii::app()->session['databaseDontExist'] = true;

                        $aValues['adminoutputText'].= "\t<tr bgcolor='#efefef'><td align='center'>\n"
                        ."<strong>".$clang->gT("Database doesn't exist!")."</strong><br /><br />\n"
                        .$clang->gT("The database you specified does not exist:")."<br /><br />\n<strong>".$oModel->dbname."</strong><br /><br />\n"
                        .$clang->gT("LimeSurvey can attempt to create this database for you.")."<br /><br />\n";

                        $aValues['next'] =  array(
                            'action' => 'installer/createdb',
                            'label' => $clang->gT('Create database'),
                            'name' => '',
                        );
                    }
                    elseif ($bDBExistsButEmpty) //&& !(returnGlobal('createdbstep2')==$clang->gT("Populate database")))
                    {
                        Yii::app()->session['populatedatabase'] = true;

                        //$this->connection->database = $model->dbname;
                        //                        //$this->connection->createCommand("USE DATABASE `".$model->dbname."`")->execute();
                        $aValues['adminoutputText'].= sprintf($clang->gT('A database named "%s" already exists.'),$oModel->dbname)."<br /><br />\n"
                        .$clang->gT("Do you want to populate that database now by creating the necessary tables?")."<br /><br />";

                        $aValues['next'] =  array(
                            'action' => 'installer/populatedb',
                            'label' => $clang->gT("Populate database"),
                            'name' => 'createdbstep2',
                        );
                    }
                    elseif (!$bDBExistsButEmpty)
                    {
                        //DB EXISTS, CHECK FOR APPROPRIATE UPGRADES
                        //$this->connection->database = $model->dbname;
                        //$this->connection->createCommand("USE DATABASE `$databasename`")->execute();
                        /* @todo Implement Upgrade */
                        //$output=CheckForDBUpgrades();
                        if ($output== '') {$aValues['adminoutput'].='<br />'.$clang->gT('LimeSurvey database is up to date. No action needed');}
                        else {$aValues['adminoutput'].=$output;}
                        $aValues['adminoutput'].= "<br />" . sprintf($clang->gT('Please <a href="%s">log in</a>.', 'unescaped'), $this->createUrl("/admin"));
                    }
                    $aValues['clang'] = $clang;
                    $this->render('/installer/dbsettings_view', $aValues);
                } else {
                    $this->render('/installer/dbconfig_view', $aData);
                }
            } else {
                $this->render('/installer/dbconfig_view', $aData);
            }
        } else {
            $this->render('/installer/dbconfig_view', $aData);
        }
    }

    /**
    * Installer::stepCreateDb()
    * Create database.
    * @return
    */
    function stepCreateDb()
    {
        // check status. to be called only when database don't exist else rdirect to proper link.
        if(!Yii::app()->session['databaseDontExist']) {
            $this->redirect(array('installer/welcome'));
        }

        $aData['clang'] = $clang = $this->lang;
        $aData['model'] = $model = new InstallerConfigForm;
        $aData['title'] = $clang->gT("Database configuration");
        $aData['descp'] = $clang->gT("Please enter the database settings you want to use for LimeSurvey:");
        $aData['classesForStep'] = array('off','off','off','on','off','off');
        $aData['progressValue'] = 40;

        $aDbConfig = self::_getDatabaseConfig();
        extract($aDbConfig);
        // unset database name for connection, since we want to create it and it doesn't already exists
        $aDbConfig['sDatabaseName'] = '';
        self::_dbConnect($aDbConfig, $aData);

        $aData['adminoutputForm'] = '';
        // Yii doesn't have a method to create a database
        $bCreateDB = true; // We are thinking positive
        switch ($sDatabaseType)
        {
            case 'mysqli':
            case 'mysql':
            try
            {
                $this->connection->createCommand("CREATE DATABASE `$sDatabaseName` DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci")->execute();
            }
            catch(Exception $e)
            {
                $bCreateDB=false;
            }
            break;
            case 'dblib':
            case 'mssql':
            case 'odbc':
            try
            {
                $this->connection->createCommand("CREATE DATABASE [$sDatabaseName];")->execute();
            }
            catch(Exception $e)
            {
                $bCreateDB=false;
            }
            break;
            case 'postgres':
            try
            {
                $this->connection->createCommand("CREATE DATABASE \"$sDatabaseName\" ENCODING 'UTF8'")->execute();
            }
            catch (Exception $e)
            {
                $createdb = false;
            }
            break;
            default:
            try
            {
                $this->connection->createCommand("CREATE DATABASE $sDatabaseName")->execute();
            }
            catch(Exception $e)
            {
                $bCreateDB=false;
            }
            break;
        }

        //$this->load->dbforge();
        if ($bCreateDB) //Database has been successfully created
        {
            $sDsn = self::_getDsn($sDatabaseType, $sDatabaseLocation, $sDatabasePort, $sDatabaseName, $sDatabaseUser, $sDatabasePwd);
            $this->connection = new CDbConnection($sDsn, $sDatabaseUser, $sDatabasePwd);

            Yii::app()->session['populatedatabase'] = true;
            Yii::app()->session['databaseexist'] = true;
            unset(Yii::app()->session['databaseDontExist']);

            $aData['adminoutputText'] = "<tr bgcolor='#efefef'><td colspan='2' align='center'> <br />"
            ."<strong><font class='successtitle'>\n"
            .$clang->gT("Database has been created.")."</font></strong><br /><br />\n"
            .$clang->gT("Please continue with populating the database.")."<br /><br />\n";
            $aData['next'] =  array(
                'action' => 'installer/populatedb',
                'label' => $clang->gT("Populate database"),
                'name' => 'createdbstep2',
            );
        }
        else
        {
            $model->addError('dblocation', $clang->gT('Try again! Connection with database failed.'));
            $this->render('/installer/dbconfig_view',$aData);
        }

        $aData['title'] = $clang->gT("Database settings");
        $aData['descp'] = $clang->gT("Database settings");
        $aData['classesForStep'] = array('off','off','off','off','on','off');
        $aData['progressValue'] = 60;
        $this->render('/installer/dbsettings_view',$aData);
    }

    /**
    * Installer::stepPopulateDb()
    * Function to populate the database.
    * @return
    */
    function stepPopulateDb()
    {
        if (!Yii::app()->session['populatedatabase'])
        {
            $this->redirect(array('installer/welcome'));
        }

        $aData['clang'] = $clang = $this->lang;
        $aData['model'] = $model = new InstallerConfigForm;
        $aData['title'] = $clang->gT("Database configuration");
        $aData['descp'] = $clang->gT("Please enter the database settings you want to use for LimeSurvey:");
        $aData['classesForStep'] = array('off','off','off','on','off','off');
        $aData['progressValue'] = 40;

        $aDbConfig = self::_getDatabaseConfig();
        extract($aDbConfig);
        self::_dbConnect($aDbConfig, $aData);

        /* @todo Use Yii as it supports various db types and would better handle this process */

        switch ($sDatabaseType)
        {
            case 'mysqli':
            case 'mysql':
                $sql_file = 'mysql';
                break;
            case 'dblib': 
            case 'sqlsrv':
            case 'mssql':
                $sql_file = 'mssql';
                break;
            case 'pgsql':
                $sql_file = 'pgsql';
                break;
            default:
                throw new Exception(sprintf('Unknown database type "%s".', $sDatabaseType));
        }

        //checking DB Connection
        $aErrors = self::_setup_tables(dirname(APPPATH).'/installer/sql/create-'.$sql_file.'.sql');
        if ($aErrors === false)
        {
            $model->addError('dblocation', $clang->gT('Try again! Connection with database failed. Reason: ').implode(', ', $aErrors));
            $this->render('/installer/dbconfig_view', $aData);
        }
        elseif (count($aErrors)==0)
        {
            //$data1['adminoutput'] = '';
            //$data1['adminoutput'] .= sprintf("Database `%s` has been successfully populated.",$dbname)."</font></strong></font><br /><br />\n";
            //$data1['adminoutput'] .= "<input type='submit' value='Main Admin Screen' onclick=''>";
            $sConfirmation = sprintf($clang->gT("Database %s has been successfully populated."), sprintf('<b>%s</b>', Yii::app()->session['dbname']));
        }
        else
        {
            $sConfirmation = $clang->gT('Database was populated but there were errors:').'<p><ul>';
            foreach ($aErrors as $sError)
            {
                $sConfirmation.='<li>'.htmlspecialchars($sError).'</li>';
            }
            $sConfirmation.='</ul>';
        }

        Yii::app()->session['tablesexist'] = true;
        Yii::app()->session['step3'] = true;
        Yii::app()->session['optconfig_message'] = $sConfirmation;
        unset(Yii::app()->session['populatedatabase']);

        $this->redirect(array('installer/optional'));
    }

    /**
    * Optional settings screen
    */
    private function stepOptionalConfiguration()
    {
        $aData['clang'] = $clang = $this->lang;
        $aData['confirmation'] = Yii::app()->session['optconfig_message'];
        $aData['title'] = $clang->gT("Optional settings");
        $aData['descp'] = $clang->gT("Optional settings to give you a head start");
        $aData['classesForStep'] = array('off','off','off','off','off','on');
        $aData['progressValue'] = 80;

        $this->loadHelper('surveytranslator');
        $aData['model'] = $model = new InstallerConfigForm('optional');

        if(isset($_POST['InstallerConfigForm']))
        {
            $model->attributes = $_POST['InstallerConfigForm'];

            //run validation, if it fails, load the view again else proceed to next step.
            if($model->validate()) {
                $sDefaultAdminUserName = $model->adminLoginName;
                $sDefaultAdminPassword = $model->adminLoginPwd;
                $sDefaultAdminRealName = $model->adminName;
                $sDefaultSiteName = $model->siteName;
                $sDefaultSiteLanguage = $model->surveylang;
                $sDefaultAdminEmail = $model->adminEmail;                

                $aData['title'] = $clang->gT("Database configuration");
                $aData['descp'] = $clang->gT("Please enter the database settings you want to use for LimeSurvey:");
                $aData['classesForStep'] = array('off','off','off','on','off','off');
                $aData['progressValue'] = 40;

                //config file is written, and we've a db in place
                $this->connection = Yii::app()->db;

                //checking DB Connection
                if ($this->connection->getActive() == true) {
                    $sPasswordHash=hash('sha256', $sDefaultAdminPassword);
                    try {
                        
                        if (User::model()->count()>0){
                            die();
                        }
                        // Save user
                        $user=new User;
                        $user->users_name=$sDefaultAdminUserName;
                        $user->password=$sPasswordHash;
                        $user->full_name=$sDefaultAdminRealName;
                        $user->parent_id=0;
                        $user->lang=$sDefaultSiteLanguage;
                        $user->email=$sDefaultAdminEmail;
                        $user->save();
                        // Save permissions
                        $permission=new Permission;
                        $permission->entity_id=0;
                        $permission->entity='global';
                        $permission->uid=$user->uid;
                        $permission->permission='superadmin';
                        $permission->read_p=1;
                        $permission->save();
                        // Save  global settings
                        $this->connection->createCommand()->insert("{{settings_global}}", array('stg_name' => 'SessionName', 'stg_value' => self::_getRandomString()));
                        $this->connection->createCommand()->insert("{{settings_global}}", array('stg_name' => 'sitename', 'stg_value' => $sDefaultSiteName));
                        $this->connection->createCommand()->insert("{{settings_global}}", array('stg_name' => 'siteadminname', 'stg_value' => $sDefaultAdminRealName));
                        $this->connection->createCommand()->insert("{{settings_global}}", array('stg_name' => 'siteadminemail', 'stg_value' => $sDefaultAdminEmail));
                        $this->connection->createCommand()->insert("{{settings_global}}", array('stg_name' => 'siteadminbounce', 'stg_value' => $sDefaultAdminEmail));
                        $this->connection->createCommand()->insert("{{settings_global}}", array('stg_name' => 'defaultlang', 'stg_value' => $sDefaultSiteLanguage));
                        // only continue if we're error free otherwise setup is broken.
                    } catch (Exception $e) {
                        throw new Exception(sprintf('Could not add optional settings: %s.', $e));
                    }

                    Yii::app()->session['deletedirectories'] = true;

                    $aData['title'] = $clang->gT("Success!");
                    $aData['descp'] = $clang->gT("LimeSurvey has been installed successfully.");
                    $aData['classesForStep'] = array('off','off','off','off','off','off');
                    $aData['progressValue'] = 100;
                    $aData['user'] = $sDefaultAdminUserName;
                    $aData['pwd'] = $sDefaultAdminPassword;

                    $this->render('/installer/success_view', $aData);
                    return;
                }
            } else {
                // if passwords don't match, redirect to proper link.
                Yii::app()->session['optconfig_message'] = sprintf('<b>%s</b>', $clang->gT("Passwords don't match."));
                $this->redirect(array('installer/optional'));
            }
        } elseif(empty(Yii::app()->session['configFileWritten'])) {
            $this->_writeConfigFile();
        }

        $this->render('/installer/optconfig_view', $aData);
    }

    /**
    * Loads a helper
    *
    * @access public
    * @param string $helper
    * @return void
    */
    public function loadHelper($helper)
    {
        Yii::import('application.helpers.' . $helper . '_helper', true);
    }

    /**
    * Loads a library
    *
    * @access public
    * @param string $helper
    * @return void
    */
    public function loadLibrary($library)
    {
        Yii::import('application.libraries.'.$library, true);
    }

    /**
    * check requirements
    *
    * @param array $data return theme variables
    * @return bool requirements met
    */
    private function _check_requirements(&$aData)
    {
        // proceed variable check if all requirements are true. If any of them is false, proceed is set false.
        $bProceed = true; //lets be optimistic!

        /**
        * check image HTML template
        *
        * @param bool $result
        */
        function check_HTML_image($result)
        {
            $aLabelYesNo = array('wrong', 'right');
            return sprintf('<img src="%s/installer/images/tick-%s.png" alt="Found" />', Yii::app()->baseUrl, $aLabelYesNo[$result]);
        }


        function is_writable_recursive($sDirectory)
        {
            $sFolder = opendir($sDirectory);
            while($sFile = readdir( $sFolder ))
                if($sFile != '.' && $sFile != '..' &&
                ( !is_writable(  $sDirectory."/".$sFile  ) ||
                (  is_dir(   $sDirectory."/".$sFile   ) && !is_writable_recursive(   $sDirectory."/".$sFile   )  ) ))
                {
                    closedir($sFolder);
                    return false;
                }
                closedir($sFolder);
            return true;
        }

        /**
        * check for a specific PHPFunction, return HTML image
        *
        * @param string $function
        * @param string $image return
        * @return bool result
        */
        function check_PHPFunction($sFunctionName, &$sImage)
        {
            $bExists = function_exists($sFunctionName);
            $sImage = check_HTML_image($bExists);
            return $bExists;
        }

        /**
        * check if file or directory exists and is writeable, returns via parameters by reference
        *
        * @param string $path file or directory to check
        * @param int $type 0:undefined (invalid), 1:file, 2:directory
        * @param string $data to manipulate
        * @param string $base key for data manipulation
        * @param string $keyError key for error data
        * @return bool result of check (that it is writeable which implies existance)
        */
        function check_PathWriteable($path, $type, &$aData, $base, $keyError, $bRecursive=false)
        {
            $bResult = false;
            $aData[$base.'Present'] = 'Not Found';
            $aData[$base.'Writable'] = '';
            switch($type) {
                case 1:
                    $exists = is_file($path);
                    break;
                case 2:
                    $exists = is_dir($path);
                    break;
                default:
                    throw new Exception('Invalid type given.');
            }
            if ($exists)
            {
                $aData[$base.'Present'] = 'Found';
                if ((!$bRecursive && is_writable($path)) || ($bRecursive && is_writable_recursive($path)))
                {
                    $aData[$base.'Writable'] = 'Writable';
                    $bResult = true;
                }
                else
                {
                    $aData[$base.'Writable'] = 'Unwritable';
                }
            }
            $bResult || $aData[$keyError] = true;

            return $bResult;
        }

        /**
        * check if file exists and is writeable, returns via parameters by reference
        *
        * @param string $file to check
        * @param string $data to manipulate
        * @param string $base key for data manipulation
        * @param string $keyError key for error data
        * @return bool result of check (that it is writeable which implies existance)
        */
        function check_FileWriteable($file, &$data, $base, $keyError)
        {
            return check_PathWriteable($file, 1, $data, $base, $keyError);
        }

        /**
        * check if directory exists and is writeable, returns via parameters by reference
        *
        * @param string $directory to check
        * @param string $data to manipulate
        * @param string $base key for data manipulation
        * @param string $keyError key for error data
        * @return bool result of check (that it is writeable which implies existance)
        */
        function check_DirectoryWriteable($directory, &$data, $base, $keyError, $bRecursive=false)
        {
            return check_PathWriteable($directory, 2, $data, $base, $keyError, $bRecursive);
        }

        //  version check
        if (version_compare(PHP_VERSION, '5.3.0', '<'))
            $bProceed = !$aData['verror'] = true;

        if ($this->return_bytes(ini_get('memory_limit'))/1024/1024<64 && ini_get('memory_limit')!=-1)
            $bProceed = !$aData['bMemoryError'] = true;
        
            
        // mbstring library check
        if (!check_PHPFunction('mb_convert_encoding', $aData['mbstringPresent']))
            $bProceed = false;

        // JSON library check
        if (!check_PHPFunction('json_encode', $aData['bJSONPresent']))
            $bProceed = false;

        // ** file and directory permissions checking **

        // config directory
        if (!check_DirectoryWriteable(Yii::app()->getConfig('rootdir').'/application/config', $aData, 'config', 'derror') )
            $bProceed = false;

        // templates directory check
        if (!check_DirectoryWriteable(Yii::app()->getConfig('tempdir').'/', $aData, 'tmpdir', 'tperror',true) )
            $bProceed = false;

        //upload directory check
        if (!check_DirectoryWriteable(Yii::app()->getConfig('uploaddir').'/', $aData, 'uploaddir', 'uerror',true) )
            $bProceed = false;

        // Session writable check
        $session = Yii::app()->session; /* @var $session CHttpSession */
        $sessionWritable = ($session->get('saveCheck', null)==='save');
        $aData['sessionWritable'] = $sessionWritable;
        $aData['sessionWritableImg'] = check_HTML_image($sessionWritable);
        if (!$sessionWritable){
            // For recheck, try to set the value again
            $session['saveCheck'] = 'save';
            $bProceed = false;
        }

        // ** optional settings check **

        // gd library check
        if (function_exists('gd_info')) {
            $aData['gdPresent'] = check_HTML_image(array_key_exists('FreeType Support', gd_info()));
        } else {
            $aData['gdPresent'] = check_HTML_image(false);
        }
        // ldap library check
        check_PHPFunction('ldap_connect', $aData['ldapPresent']);

        // php zip library check
        check_PHPFunction('zip_open', $aData['zipPresent']);

        // zlib php library check
        check_PHPFunction('zlib_get_coding_type', $aData['zlibPresent']);

        // imap php library check
        check_PHPFunction('imap_open', $aData['bIMAPPresent']);

        return $bProceed;
    }

    /**
    * Installer::_setup_tables()
    * Function that actually modify the database. Read $sqlfile and execute it.
    * @param string $sqlfile
    * @return  Empty string if everything was okay - otherwise the error messages
    */
    function _setup_tables($sFileName, $aDbConfig = array(), $sDatabasePrefix = '')
    {
        extract(empty($aDbConfig) ? self::_getDatabaseConfig() : $aDbConfig);
        switch ($sDatabaseType) {
            case 'mysql':
            case 'mysqli':
                $this->connection->createCommand("ALTER DATABASE ". $this->connection->quoteTableName($sDatabaseName) ." DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci;")->execute();
                break;
            case 'pgsql':
                if (version_compare($this->connection->getServerVersion(),'9','>=')) {
                    $this->connection->createCommand("ALTER DATABASE ". $this->connection->quoteTableName($sDatabaseName) ." SET bytea_output='escape';")->execute();
                }
                break;
        }

        return $this->_executeSQLFile($sFileName, $sDatabasePrefix);
    }

    /**
    * Executes an SQL file
    *
    * @param string $sFileName
    * @param string $sDatabasePrefix
    */
    function _executeSQLFile($sFileName, $sDatabasePrefix)
    {
        $aMessages = array();
        $sCommand = '';

        if (!is_readable($sFileName)) {
            return false;
        } else {
            $aLines = file($sFileName);
        }
        foreach ($aLines as $sLine) {
            $sLine = rtrim($sLine);
            $iLineLength = strlen($sLine);

            if ($iLineLength && $sLine[0] != '#' && substr($sLine,0,2) != '--') {
                if (substr($sLine, $iLineLength-1, 1) == ';') {
                    $line = substr($sLine, 0, $iLineLength-1);
                    $sCommand .= $sLine;
                    $sCommand = str_replace('prefix_', $sDatabasePrefix, $sCommand); // Table prefixes

                    try {
                        $this->connection->createCommand($sCommand)->execute();
                    } catch(Exception $e) {
                        $aMessages[] = "Executing: ".$sCommand." failed! Reason: ".$e;
                    }

                    $sCommand = '';
                } else {
                    $sCommand .= $sLine;
                }
            }
        }
        return $aMessages;
    }

    /**
    * Function to write given database settings in APPPATH.'config/config.php'
    */
    function _writeConfigFile()
    {
        $aData['clang'] = $clang = $this->lang;
        //write config.php if database exists and has been populated.
        if (Yii::app()->session['databaseexist'] && Yii::app()->session['tablesexist'])
        {

            extract(self::_getDatabaseConfig());
            $sDsn = self::_getDsn($sDatabaseType, $sDatabaseLocation, $sDatabasePort, $sDatabaseName, $sDatabaseUser, $sDatabasePwd);

            // mod_rewrite existence check
            // Section commented out until a better method of knowing whether the mod_rewrite actually
            // works is found. In the meantime, it is better to set $showScriptName to 'true' so it
            // works on all installations, and allow users to change it manually later.
            //if ((function_exists('apache_get_modules') && in_array('mod_rewrite', apache_get_modules())) || strtolower(getenv('HTTP_MOD_REWRITE')) == 'on')
            //{
            //    $showScriptName = 'false';
            //}
            //else
            //{
            $sShowScriptName = 'true';
            //}
            if (stripos($_SERVER['SERVER_SOFTWARE'], 'apache') !== false || (ini_get('security.limit_extensions') && ini_get('security.limit_extensions')!=''))
            {
                $sURLFormat='path';
            }
            else // Apache
            {
                $sURLFormat='get'; // Fall back to get if an Apache server cannot be determined reliably
            }

            $sConfig = "<?php if (!defined('BASEPATH')) exit('No direct script access allowed');" . "\n"
            ."/*"."\n"
            ."| -------------------------------------------------------------------"."\n"
            ."| DATABASE CONNECTIVITY SETTINGS"."\n"
            ."| -------------------------------------------------------------------"."\n"
            ."| This file will contain the settings needed to access your database."."\n"
            ."|"."\n"
            ."| For complete instructions please consult the 'Database Connection'" ."\n"
            ."| page of the User Guide."."\n"
            ."|"."\n"
            ."| -------------------------------------------------------------------"."\n"
            ."| EXPLANATION OF VARIABLES"."\n"
            ."| -------------------------------------------------------------------"."\n"
            ."|"                                                                    ."\n"
            ."|    'connectionString' Hostname, database, port and database type for " ."\n"
            ."|     the connection. Driver example: mysql. Currently supported:"       ."\n"
            ."|                 mysql, pgsql, mssql, sqlite, oci"                      ."\n"
            ."|    'username' The username used to connect to the database"            ."\n"
            ."|    'password' The password used to connect to the database"            ."\n"
            ."|    'tablePrefix' You can add an optional prefix, which will be added"  ."\n"
            ."|                 to the table name when using the Active Record class"  ."\n"
            ."|"                                                                    ."\n"
            ."*/"                                                                   ."\n"
            . "return array("                             . "\n"
            /*
            ."\t"     . "'basePath' => dirname(dirname(__FILE__))," . "\n"
            ."\t"     . "'runtimePath' => dirname(dirname(dirname(__FILE__))).DIRECTORY_SEPARATOR.'tmp'.DIRECTORY_SEPARATOR.'runtime'," . "\n"
            ."\t"     . "'name' => 'LimeSurvey',"                   . "\n"
            ."\t"     . "'defaultController' => 'survey',"          . "\n"
            ."\t"     . ""                                          . "\n"

            ."\t"     . "'import' => array("                        . "\n"
            ."\t\t"   . "'application.core.*',"                     . "\n"
            ."\t\t"   . "'application.models.*',"                   . "\n"
            ."\t\t"   . "'application.controllers.*',"              . "\n"
            ."\t\t"   . "'application.modules.*',"                  . "\n"
            ."\t"     . "),"                                        . "\n"
            ."\t"     . ""                                          . "\n"
            */
            ."\t"     . "'components' => array("                    . "\n"
            ."\t\t"   . "'db' => array("                            . "\n"
            ."\t\t\t" . "'connectionString' => '$sDsn',"            . "\n";
            if ($sDatabaseType!='sqlsrv' && $sDatabaseType!='dblib' )
            {
                $sConfig .="\t\t\t" . "'emulatePrepare' => true,"    . "\n";

            }
            $sConfig .="\t\t\t" . "'username' => '".addcslashes ($sDatabaseUser,"'")."',"  . "\n"
            ."\t\t\t" . "'password' => '".addcslashes ($sDatabasePwd,"'")."',"            . "\n"
            ."\t\t\t" . "'charset' => 'utf8',"                      . "\n"
            ."\t\t\t" . "'tablePrefix' => '$sDatabasePrefix',"      . "\n";

            if (in_array($sDatabaseType, array('mssql', 'sqlsrv', 'dblib'))) {
                $sConfig .="\t\t\t" ."'initSQLs'=>array('SET DATEFORMAT ymd;','SET QUOTED_IDENTIFIER ON;'),"    . "\n";
            }

            $sConfig .="\t\t" . "),"                                          . "\n"
            ."\t\t"   . ""                                          . "\n"
                    
            ."\t\t"   . "// Uncomment the following line if you need table-based sessions". "\n"
            ."\t\t"   . "// 'session' => array ("                      . "\n"
            ."\t\t\t" . "// 'class' => 'system.web.CDbHttpSession',"   . "\n"
            ."\t\t\t" . "// 'connectionID' => 'db',"                   . "\n"
            ."\t\t\t" . "// 'sessionTableName' => '{{sessions}}',"     . "\n"
            ."\t\t"   . "// ),"                                        . "\n"
            ."\t\t"   . ""                                          . "\n"

            /** @todo Uncomment after implementing the error controller */
            /*
            ."\t\t"   . "'errorHandler' => array("                  . "\n"
            ."\t\t\t" . "'errorAction' => 'error',"                 . "\n"
            ."\t\t"   . "),"                                        . "\n"
            ."\t\t"   . ""                                          . "\n"
            */

            ."\t\t"   . "'urlManager' => array("                    . "\n"
            ."\t\t\t" . "'urlFormat' => '{$sURLFormat}',"           . "\n"
            ."\t\t\t" . "'rules' => require('routes.php'),"         . "\n"
            ."\t\t\t" . "'showScriptName' => $sShowScriptName,"      . "\n"
            ."\t\t"   . "),"                                        . "\n"
            ."\t"     . ""                                          . "\n"

            ."\t"     . "),"                                        . "\n"
            ."\t"     . "// Use the following config variable to set modified optional settings copied from config-defaults.php". "\n"
            ."\t"     . "'config'=>array("                          . "\n"
            ."\t"     . "// debug: Set this to 1 if you are looking for errors. If you still get no errors after enabling this". "\n"
            ."\t"     . "// then please check your error-logs - either in your hosting provider admin panel or in some /logs directory". "\n"
            ."\t"     . "// on your webspace.". "\n"
            ."\t"     . "// LimeSurvey developers: Set this to 2 to additionally display STRICT PHP error messages and get full access to standard templates". "\n"
            ."\t\t"   . "'debug'=>0,"                                . "\n"
            ."\t\t"   . "'debugsql'=>0 // Set this to 1 to enanble sql logging, only active when debug = 2" . "\n"
            ."\t"     . ")"                                         . "\n"
            . ");"                                        . "\n"
            . "/* End of file config.php */"              . "\n"
            . "/* Location: ./application/config/config.php */";

            if (is_writable(APPPATH . 'config')) {
                file_put_contents(APPPATH . 'config/config.php', $sConfig);
                Yii::app()->session['configFileWritten'] = true;
                $oUrlManager = Yii::app()->getComponent('urlManager');
                /* @var $oUrlManager CUrlManager */
                $oUrlManager->setUrlFormat($sURLFormat);
            } else {
                header('refresh:5;url='.$this->createUrl("installer/welcome"));
                echo "<b>".$clang->gT("Configuration directory is not writable")."</b><br/>";
                printf($clang->gT('You will be redirected in about 5 secs. If not, click <a href="%s">here</a>.' ,'unescaped'), $this->createUrl('installer/welcome'));
                exit;
            }
        }
    }

    /**
    * Create a random ASCII string
    *
    * @return string
    */
    function _getRandomString()
    {
        $iTotalChar = 64; // number of chars in the sid
        $sResult='';
        for ($i=0;$i<$iTotalChar;$i++)
        {
           $sResult.=chr(rand(33,126));
        }
        return $sResult;
    }

    /**
    * Get the dsn for the database connection
    *
    * @param string $sDatabaseType
    * @param string $sDatabasePort
    */
    function _getDsn($sDatabaseType, $sDatabaseLocation, $sDatabasePort, $sDatabaseName, $sDatabaseUser, $sDatabasePwd)
    {
        switch ($sDatabaseType) {
            case 'mysql':
            case 'mysqli':
                // MySQL allow unix_socket for database location, then test if $sDatabaseLocation start with "/"
                if(substr($sDatabaseLocation,0,1)=="/") 
                    $sDSN = "mysql:unix_socket={$sDatabaseLocation};dbname={$sDatabaseName};";
                else
                    $sDSN = "mysql:host={$sDatabaseLocation};port={$sDatabasePort};dbname={$sDatabaseName};";
                break;
            case 'pgsql':
                if (empty($sDatabasePwd))
                {
                    // If there's no password, we need to write password=""; instead of password=;,
                    // or PostgreSQL's libpq will consider the DSN string part after "password="
                    // (including the ";" and the potential dbname) as part of the password definition.
                    $sDatabasePwd = '""';
                }
                $sDSN = "pgsql:host={$sDatabaseLocation};port={$sDatabasePort};user={$sDatabaseUser};password={$sDatabasePwd};";
                if ($sDatabaseName!='')
                {
                    $sDSN.="dbname={$sDatabaseName};";
                }
                break;

            case 'dblib' : 
                $sDSN = $sDatabaseType.":host={$sDatabaseLocation};dbname={$sDatabaseName}";
                break;
            case 'mssql' :
            case 'sqlsrv':
                if ($sDatabasePort!=''){$sDatabaseLocation=$sDatabaseLocation.','.$sDatabasePort;}
                $sDSN = $sDatabaseType.":Server={$sDatabaseLocation};Database={$sDatabaseName}";
                break;
            default:
                throw new Exception(sprintf('Unknown database type "%s".', $sDatabaseType));
        }
        return $sDSN;
    }

    /**
    * Get the default port if database port is not set
    *
    * @param string $sDatabaseType
    * @param string $sDatabasePort
    * @return string
    */
    function _getDbPort($sDatabaseType, $sDatabasePort = '')
    {
        if (is_numeric($sDatabasePort))
            return $sDatabasePort;

        switch ($sDatabaseType) {
            case 'mysql':
            case 'mysqli':
                $sDatabasePort = '3306';
                break;
            case 'pgsql':
                $sDatabasePort = '5432';
                break;
            case 'dblib' :
            case 'mssql' :
            case 'sqlsrv':
            default:
                $sDatabasePort = '';
        }

        return $sDatabasePort;
    }

    /**
    * Gets the database configuration from the session
    *
    * @return array Database Config
    */
    function _getDatabaseConfig()
    {
        $sDatabaseType = Yii::app()->session['dbtype'];
        $sDatabasePort = Yii::app()->session['dbport'];
        $sDatabaseName = Yii::app()->session['dbname'];
        $sDatabaseUser = Yii::app()->session['dbuser'];
        $sDatabasePwd = Yii::app()->session['dbpwd'];
        $sDatabasePrefix = Yii::app()->session['dbprefix'];
        $sDatabaseLocation = Yii::app()->session['dblocation'];

        return compact('sDatabaseLocation', 'sDatabaseName', 'sDatabasePort', 'sDatabasePrefix', 'sDatabasePwd', 'sDatabaseType', 'sDatabaseUser');
    }

    /**
    * Connect to the database
    *
    * Throw an error if there's an error
    */
    function _dbConnect($aDbConfig = array(), $aData = array())
    {
        extract(empty($aDbConfig) ? self::_getDatabaseConfig() : $aDbConfig);
        $sDsn = self::_getDsn($sDatabaseType, $sDatabaseLocation, $sDatabasePort, $sDatabaseName, $sDatabaseUser, $sDatabasePwd);
        $sDatabaseName = empty($sDatabaseName) ? '' : $sDatabaseName;
        $sDatabasePort = empty($sDatabasePort) ? '' : $sDatabasePort;

        try {
            $this->connection = new CDbConnection($sDsn, $sDatabaseUser, $sDatabasePwd);
            if($sDatabaseType!='sqlsrv' && $sDatabaseType!='dblib'){
                $this->connection->emulatePrepare = true;
            }

            $this->connection->active = true;
            $this->connection->tablePrefix = $sDatabasePrefix;
            return true;
        } catch(Exception $e) {
            if (!empty($aData['model']) && !empty($aData['clang'])) {
                $aData['model']->addError('dblocation', $aData['clang']->gT('Try again! Connection with database failed. Reason: ') . $e->message);
                $this->render('/installer/dbconfig_view', $aData);
            } else {
                return false;
            }
        }
    }
    
    /**
    * This function returns the full number from a PHP ini value
    * 
    * @param string $sValue
    */
    function return_bytes($sValue) {
        $sValue = trim($sValue);
        $sLast = strtolower($sValue[strlen($sValue)-1]);
        switch($sLast) {
            // The 'G' modifier is available since PHP 5.1.0
            case 'g':
                $sValue *= 1024;
            case 'm':
                $sValue *= 1024;
            case 'k':
                $sValue *= 1024;
        }

        return $sValue;
    }    

}
