<?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) 2002-2008 (original work) Public Research Centre Henri Tudor & University of Luxembourg (under the project TAO & TAO2);
 *               2008-2010 (update and modification) 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);
 *               2014      (update and modification) Open Assessment Technologies SA;
 */

namespace oat\tao\model\menu;

/**
 * @author joel bout, <joel@taotesting.com>
 */
class MenuService
{

    /**
     * identifier to use to cache the structures
     * @var string
     */
    const CACHE_KEY = 'tao_structures';
    
    /**
     * Use caching mechanism for the structure.
     * For performances issues, cache should be enabled.
     * @var boolean
     */
    const USE_CACHE = true;

    /**
     * to stock the extension structure
     *
     * @access protected
     * @var array
     */
    protected static $structure = [];

    // --- OPERATIONS ---

    /**
     * Load the extension structure file.
     * Return the SimpleXmlElement object (don't forget to cast it)
     *
     * @access protected
     * @author Jerome Bogaerts, <jerome@taotesting.com>
     * @param  string extensionId
     * @return SimpleXMLElement
     */
    public static function getStructuresFilePath($extensionId)
    {
        $extension = \common_ext_ExtensionsManager::singleton()->getExtensionById($extensionId);
        $extra = $extension->getManifest()->getExtra();
        if (isset($extra['structures'])) {
            $structureFilePath = $extra['structures'];
        } else {
            $structureFilePath = $extension->getDir() . 'actions/structures.xml';
        }
        
        if (file_exists($structureFilePath)) {
            return $structureFilePath;
        } else {
            return null;
        }
    }
    
    /**
     * Get the structure content (from the structure.xml file) of each extension filtered by group.
     * @param $groupId
     * @return array
     */
    public static function getPerspectivesByGroup($groupId)
    {
        $perspectives = [];
        foreach (self::getAllPerspectives() as $perspective) {
            if ($perspective -> getGroup() === $groupId) {
                $perspectives[] = $perspective;
            }
        }
        return $perspectives;
    }

    /**
     * Get the structure content (from the structure.xml file) of each extension.
     * @return array
     */
    public static function getAllPerspectives()
    {
        $structure = self::readStructure();
        return $structure['perspectives'];
    }
    
    /**
     * Reads the structure data.
     * This method manages to cache the structure if needed.
     * @return array() the structure data
     */
    public static function readStructure()
    {
        if (count(self::$structure) == 0) {
            if (self::USE_CACHE == false) {
                //rebuild structure each time
                self::$structure = self::buildStructures();
            } else {
                //cache management
                try {
                    self::$structure = \common_cache_FileCache::singleton()->get(self::CACHE_KEY);
                } catch (\common_cache_NotFoundException $e) {
                    self::$structure = self::buildStructures();
                    \common_cache_FileCache::singleton()->put(self::$structure, self::CACHE_KEY);
                }
            }
        }
        return self::$structure;
    }

    /**
     * Get the structure content (from the structure.xml file) of each extension.
     * @return array
     */
    protected static function buildStructures()
    {
        $perspectives = [];
        $toAdd = [];
        $sorted = \helpers_ExtensionHelper::sortByDependencies(\common_ext_ExtensionsManager::singleton()->getEnabledExtensions());
        foreach (array_keys($sorted) as $extId) {
            $file = self::getStructuresFilePath($extId);
            if (!is_null($file)) {
                $xmlStructures = new \SimpleXMLElement($file, null, true);
                $extStructures = $xmlStructures->xpath("/structures/structure");
                foreach ($extStructures as $xmlStructure) {
                    $perspective = Perspective::fromSimpleXMLElement($xmlStructure, $extId);
                    if (!isset($perspectives[$perspective->getId()])) {
                        $perspectives[$perspective->getId()] = $perspective;
                    } else {
                        foreach ($perspective->getChildren() as $section) {
                            $perspectives[$perspective->getId()]->addSection($section);
                        }
                    }
                }
                foreach ($xmlStructures->xpath("/structures/toolbar/toolbaraction") as $xmlStructure) {
                    $perspective = Perspective::fromLegacyToolbarAction($xmlStructure, $extId);
                    $perspectives[$perspective->getId()] = $perspective;
                    if (isset($xmlStructure['structure'])) {
                        $toAdd[$perspective->getId()] = (string)$xmlStructure['structure'];
                    }
                }
            }
        }
        
        foreach ($toAdd as $to => $from) {
            if (isset($perspectives[$from]) && isset($perspectives[$to])) {
                foreach ($perspectives[$from]->getChildren() as $section) {
                    $perspectives[$to]->addSection($section);
                }
            }
        }

        usort($perspectives, function ($a, $b) {
            return $a->getLevel() - $b->getLevel();
        });

        return [
            'perspectives' => $perspectives
        ];
    }

    /**
     * Get the perspective for the extension/section in parameters
     * or null if not found
     *
     * @access public
     * @author Jerome Bogaerts, <jerome@taotesting.com>
     * @param  string extension
     * @param  string perspectiveId
     * @return Structure
     */
    public static function getPerspective($extension, $perspectiveId)
    {
        $returnValue = null;

        foreach (self::getAllPerspectives() as $perspective) {
            if ($perspective->getId() == $perspectiveId) {
                $returnValue = $perspective;
                break;
            }
        }
        if (empty($returnValue)) {
            \common_logger::w('Structure ' . $perspectiveId . ' not found for extension ' . $extension);
        }

        return $returnValue;
    }

    /**
     * Short description of method getSection
     *
     * @access public
     * @author Jerome Bogaerts, <jerome@taotesting.com>
     * @param  string extension
     * @param  string perspectiveId
     * @param  string sectionId
     * @return Section
     */
    public static function getSection($extension, $perspectiveId, $sectionId)
    {
        $returnValue = null;

        $structure = self::getPerspective($extension, $perspectiveId);
        foreach ($structure->getChildren() as $section) {
            if ($section->getId() == $sectionId) {
                $returnValue = $section;
                break;
            }
        }
        if (empty($returnValue)) {
            \common_logger::w('Section ' . $sectionId . ' not found found for perspective ' . $perspectiveId);
        }

        return $returnValue;
    }
    
    
    public static function flushCache()
    {
        self::$structure = [];
        \common_cache_FileCache::singleton()->remove(self::CACHE_KEY);
    }
}