<?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) 2016 (original work) Open Assessment Technologies SA (under the project TAO-PRODUCT);
 *
 */

namespace oat\taoQtiItem\model\style;

use \tao_models_classes_Service;
use \core_kernel_classes_Class;
use \core_kernel_classes_Resource;
use oat\taoQtiItem\model\ItemModel;
use \taoItems_models_classes_ItemsService;
use SimpleXMLElement;
use oat\taoQtiItem\model\qti\Service;

class StyleService extends tao_models_classes_Service
{
    
    /**
     * The regex pattern of valid style names
     */
    const STYLE_NAME_PATTERN = '([a-zA-Z0-9_-]*)';
    
    /**
     * Check if the resource in argument is a valid qti item
     * @param core_kernel_classes_Resource $itemResource
     * @return boolean
     */
    private function isQtiItem(core_kernel_classes_Resource $itemResource)
    {
        $itemService = taoItems_models_classes_ItemsService::singleton();
        return $itemService->hasItemModel($itemResource, [ItemModel::MODEL_URI]);
    }

    /**
     * Get the item content for a qti item resource
     *
     * @param core_kernel_classes_Resource $itemResource
     * @param string $langCode
     * @return SimpleXMLElement
     */
    private function getItemContent(core_kernel_classes_Resource $itemResource, $langCode = '')
    {
        if ($this->isQtiItem($itemResource)) {
            $itemContent  = Service::singleton()
                ->getDataItemByRdfItem($itemResource, $langCode)
                ->toXML();
            if (!empty($itemContent)) {
                return simplexml_load_string($itemContent);
            }
        }

        return null;
    }

    /**
     * Set the item content for a qti item resource
     *
     * @param SimpleXMLElement $content
     * @param core_kernel_classes_Resource $itemResource
     * @return bool
     */
    private function setItemContent(SimpleXMLElement $content, core_kernel_classes_Resource $itemResource)
    {
        if ($this->isQtiItem($itemResource)) {
            return Service::singleton()->saveXmlItemToRdfItem($content->asXML(), $itemResource);
        }

        return false;
    }
    
    /**
     * Get the array of body style classes set to the itemBody of a qti item
     *
     * @param core_kernel_classes_Resource $itemResource
     * @param string $langCode
     * @return array
     * @throws \common_Exception
     */
    public function getBodyStyles(core_kernel_classes_Resource $itemResource, $langCode = '')
    {
        $itemContent = $this->getItemContent($itemResource, $langCode);
        if (is_null($itemContent)) {
            throw new \common_Exception('cannot find valid qti item content');
        } else {
            $classAttr = (string) $itemContent->itemBody['class'];
            preg_match_all('/x-tao-style-' . self::STYLE_NAME_PATTERN . '/', $classAttr, $matches);
            if (isset($matches[1])) {
                return $matches[1];
            }
        }
    }
    
    /**
     * Add an array of body style classes to the itemBody of a qti item
     *
     * @param core_kernel_classes_Resource $itemResource
     * @param string $langCode
     * @return boolean
     * @throws \common_Exception
     */
    public function addBodyStyles($styleNames, core_kernel_classes_Resource $itemResource, $langCode = '')
    {
        $itemContent = $this->getItemContent($itemResource, $langCode);
        if (!is_null($itemContent) && !empty($styleNames)) {
            $classAttr = (string) $itemContent->itemBody['class'];
            foreach ($styleNames as $styleName) {
                if (!empty($styleName) && preg_match(self::STYLE_NAME_PATTERN, $styleName)) {
                    $newClass = 'x-tao-style-' . $styleName;
                    if (strpos($classAttr, $styleName) === false) {
                        $classAttr .= ' ' . $newClass;
                    }
                } else {
                    throw new \common_Exception('invalid style name');
                }
            }
            $itemContent->itemBody['class'] = trim($classAttr);
            return $this->setItemContent($itemContent, $itemResource);
        }
        return false;
    }
    
    /**
     * Remove an array of body style classes set to the itemBody of a qti item
     *
     * @param array $styleNames
     * @param core_kernel_classes_Resource $itemResource
     * @param string $langCode
     * @throws \common_Exception
     */
    public function removeBodyStyles($styleNames, core_kernel_classes_Resource $itemResource, $langCode = '')
    {
        $itemContent = $this->getItemContent($itemResource, $langCode);
        if (!is_null($itemContent) && !empty($styleNames)) {
            $classAttr = (string) $itemContent->itemBody['class'];
            foreach ($styleNames as $styleName) {
                if (!empty($styleName) && preg_match(self::STYLE_NAME_PATTERN, $styleName)) {
                    $styleName = 'x-tao-style-' . $styleName;
                    $classAttr = preg_replace('/(?:^|\\s)' . $styleName . '(?:\\s|$)/', ' ', $classAttr);
                } else {
                    throw new \common_Exception('invalid style name');
                }
            }
            $itemContent->itemBody['class'] = trim($classAttr);
            return $this->setItemContent($itemContent, $itemResource);
        }
        return false;
    }
    
    /**
     * Get an array that give the style usage within an tao item subclasses.
     * It only takes into account qti item with a no-empty content
     *
     * @param core_kernel_classes_Class $itemClass
     * @return array
     */
    public function getClassBodyStyles(core_kernel_classes_Class $itemClass)
    {
        $usages = [];
        $union = [];
        $intersect = [];
        $items = $itemClass->getInstances(true);
        $i = 0;
        foreach ($items as $item) {
            if ($this->isQtiItem($item)) {
                try {
                    $styles = $this->getBodyStyles($item);
                    $usages[$item->getUri()] = $styles;
                    if ($i) {
                        $intersect = array_intersect($styles, $intersect);
                    } else {
                        $intersect = $styles;
                    }
                    $union = array_unique(array_merge($styles, $union));
                    $i++;
                } catch (\common_Exception $e) {
                }
            }
        }
        return [
            'all' => $union,
            'checked' => $intersect,
            'indeterminate' => array_values(array_diff($union, $intersect))
        ];
    }
    
    /**
     * Add an array of body style classes to the itemBody of all qti items in given class
     *
     * @param array $styleNames
     * @param core_kernel_classes_Class $itemClass
     * @param boolean $recursive
     */
    public function addClassBodyStyles($styleNames, core_kernel_classes_Class $itemClass, $recursive = true)
    {
        $updatedItems = [];
        $items = $itemClass->getInstances($recursive);
        foreach ($items as $item) {
            if ($this->isQtiItem($item)) {
                if ($this->addBodyStyles($styleNames, $item)) {
                    $updatedItems[] = $item;
                }
            }
        }
        return $updatedItems;
    }
    
    /**
     * Remove  an array of body style classes from the itemBody of all qti items in given class
     *
     * @param array $styleNames
     * @param core_kernel_classes_Class $itemClass
     * @param boolean $recursive
     */
    public function removeClassBodyStyles($styleNames, core_kernel_classes_Class $itemClass, $recursive = true)
    {
        $updatedItems = [];
        $items = $itemClass->getInstances($recursive);
        foreach ($items as $item) {
            if ($this->isQtiItem($item)) {
                if ($this->removeBodyStyles($styleNames, $item)) {
                    $updatedItems[] = $item;
                }
            }
        }
        return $updatedItems;
    }
}