<?php
/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; under version 2
 * of the License (non-upgradable).
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * Copyright (c) 2008-2010 (original work) Deutsche Institut für Internationale Pädagogische Forschung (under the project TAO-TRANSFER);
 *               2009-2012 (update and modification) Public Research Centre Henri Tudor (under the project TAO-SUSTAIN & TAO-DEV);
 *
 */

/**
 * The context class enables you to define some context to the application
 * and to check statically which context/mode is actually loaded.
 *
 * @author Cedric Alfonsi, <cedric.alfonsi@tudor.lu>
 * @package tao

 */
class tao_helpers_Context
{

    /**
     * The list of current loaded modes. This array contains strings.
     *
     * @access protected
     * @var array
     */
    protected static $current = [];


    /**
     * load a new current mode
     *
     * @author Cedric Alfonsi, <cedric.alfonsi@tudor.lu>
     * @param  string mode
     * @throws InvalidArgumentException If the mode variable is not a string or is empty.
     */
    public static function load($mode)
    {
        if (!is_string($mode)) {
            throw new InvalidArgumentException('Try to load an irregular mode in the context. The mode must be a string, ' . gettype($mode) . ' given.');
        } elseif (empty($mode)) {
            throw new InvalidArgumentException('Cannot load an empty mode in the context.');
        }
        
        if (!in_array($mode, self::$current)) {
            self::$current[] = $mode;
        }
    }

    /**
     * check if the mode in parameter is loaded in the context.
     *
     * @author Cedric Alfonsi, <cedric.alfonsi@tudor.lu>
     * @param  string mode The mode you want to check it is loaded or not.
     * @return boolean
     * @throws InvalidArgumentException If the mode variable is not a string or is empty.
     */
    public static function check($mode)
    {
        $returnValue = (bool) false;
        
        if (!is_string($mode)) {
            throw new InvalidArgumentException('Try to check an irregular mode. The mode must be a string, ' . gettype($mode) . ' given.');
        } elseif (empty($mode)) {
            throw new InvalidArgumentException('Cannot check an empty mode.');
        }
        
        $returnValue = in_array($mode, self::$current);

        return (bool) $returnValue;
    }

    /**
     * reset the context.
     *
     * @author Cedric Alfonsi, <cedric.alfonsi@tudor.lu>
     */
    public static function reset()
    {
        self::$current = [];
    }

    /**
     * Unload a specific mode.
     *
     * @author Cedric Alfonsi, <cedric.alfonsi@tudor.lu>
     * @param  string mode
     * @throws InvalidArgumentException If the mode variable has not the right type (string) or is empty.
     */
    public static function unload($mode)
    {

        if (!is_string($mode)) {
            throw new InvalidArgumentException('Try to unload an irregular mode in the context. The mode must be a string, ' . gettype($mode) . ' given.');
        } elseif (empty($mode)) {
            throw new InvalidArgumentException('Cannot unload an empty mode in the context.');
        }
        
        if (in_array($mode, self::$current)) {
            $index = array_search($mode, self::$current);
            if ($index !== false) {
                unset(self::$current[$index]);
            }
        }
    }
    
    /**
     * Get the set of currently loaded modes.
     *
     * @author Jerome Bogaerts, <jerome@taotesting.com>
     * @return array An array of strings that representent current modes.
     */
    public static function get()
    {
        return self::$current;
    }
}