<?php

set_include_path(
    dirname(dirname(__FILE__)) . '/thirdparty/'. PATH_SEPARATOR .
    get_include_path()
);
        
require_once 'Zend/Search/Lucene.php';

/**
 * Documentation Search powered by Lucene. You will need Zend_Lucene installed 
 * on your path.
 *
 * To rebuild the indexes run the {@link RebuildLuceneDocsIndex} task. You may 
 * wish to setup a cron job to remake the indexes on a regular basis.
 *
 * This class has the ability to generate an OpenSearch RSS formatted feeds 
 * simply by using the URL:
 *
 * <code>
 * yoursite.com/search/?q=Foo&format=rss. // Format can either be specified as rss or left off.
 * </code>
 *
 * To get a specific amount of results you can also use the modifiers start and 
 * limit:
 *
 * <code>
 * yoursite.com/search/?q=Foo&start=10&limit=10
 * </code>
 *
 * @package docsviewer
 */

class DocumentationSearch
{
    /**
     * @var bool - Is search enabled
     */
    private static $enabled = false;

    /**
     * @var bool - Is advanced search enabled
     */
    private static $advanced_search_enabled = true;
    
    /**
     * @var string - OpenSearch metadata. Please use {@link DocumentationSearch::set_meta_data()}
     */
    private static $meta_data = array();
    
    /**
     * @var Array Regular expression mapped to a "boost factor" for the searched document.
     * Defaults to 1.0, lower to decrease relevancy. Requires reindex.
     * Uses {@link DocumentationPage->getRelativePath()} for comparison.
     */
    private static $boost_by_path = array();
    
    /**
     * @var ArrayList - Results
     */
    private $results;
    
    /**
     * @var int
     */
    private $totalResults;
    
    /**
     * @var string
     */
    private $query;
    
    /**
     * @var Controller
     */
    private $outputController;
    
    /**
     * Optionally filter by module and version
     *
     * @var array
     */
    private $modules, $versions;
    
    public function setModules($modules)
    {
        $this->modules = $modules;
    }
    
    public function setVersions($versions)
    {
        $this->versions = $versions;
    }
    
    /**
     * Set the current search query
     *
     * @param string
     */
    public function setQuery($query)
    {
        $this->query = $query;
    }
    
    /**
     * Returns the current search query
     *
     * @return string
     */
    public function getQuery()
    {
        return $this->query;
    }
    
    /**
     * Sets the {@link DocumentationViewer} or {@link DocumentationSearch} instance which this search is rendering
     * on based on whether it is the results display or RSS feed
     *
     * @param Controller
     */
    public function setOutputController($controller)
    {
        $this->outputController = $controller;
    }
    
    /**
     * Folder name for indexes (in the temp folder).
     *
     * @config
     * @var    string 
     */
    private static $index_location;

    /**
     * @return string
     */
    public static function get_index_location()
    {
        $location = Config::inst()->get('DocumentationSearch', 'index_location');

        if (!$location) {
            return Controller::join_links(TEMP_FOLDER, 'RebuildLuceneDocsIndex');
        }
        
        return $location;
    }
    
    /**
     * Perform a search query on the index
     */
    public function performSearch()
    {
        try {
            $index = Zend_Search_Lucene::open(self::get_index_location());

            Zend_Search_Lucene::setResultSetLimit(100);
            
            $query = new Zend_Search_Lucene_Search_Query_Boolean();
            $term = Zend_Search_Lucene_Search_QueryParser::parse($this->getQuery());
            $query->addSubquery($term, true);
            
            if ($this->modules) {
                $moduleQuery = new Zend_Search_Lucene_Search_Query_MultiTerm();
                
                foreach ($this->modules as $module) {
                    $moduleQuery->addTerm(new Zend_Search_Lucene_Index_Term($module, 'Entity'));
                }
                
                $query->addSubquery($moduleQuery, true);
            }

            if ($this->versions) {
                $versionQuery = new Zend_Search_Lucene_Search_Query_MultiTerm();
                
                foreach ($this->versions as $version) {
                    $versionQuery->addTerm(new Zend_Search_Lucene_Index_Term($version, 'Version'));
                }
                
                $query->addSubquery($versionQuery, true);
            }
            
            $er = error_reporting();
            error_reporting('E_ALL ^ E_NOTICE');
            $this->results = $index->find($query);
            error_reporting($er);
            $this->totalResults = $index->numDocs();
        } catch (Zend_Search_Lucene_Exception $e) {
            user_error($e .'. Ensure you have run the rebuld task (/dev/tasks/RebuildLuceneDocsIndex)', E_USER_ERROR);
        }
    }
    
    /**
     * @return ArrayData
     */
    public function getSearchResults($request)
    {
        $pageLength = (isset($_GET['length'])) ? (int) $_GET['length'] : 10;

        $data = array(
            'Results' => null,
            'Query' => null,
            'Versions' => DBField::create_field('Text', implode(', ', $this->versions)),
            'Modules' => DBField::create_field('Text', implode(', ', $this->modules)),
            'Title' => _t('DocumentationSearch.SEARCHRESULTS', 'Search Results'),
            'TotalResults' => null,
            'TotalPages' => null,
            'ThisPage' => null,
            'StartResult' => null,
            'PageLength' => $pageLength,
            'EndResult' => null,
            'PrevUrl' => DBField::create_field('Text', 'false'),
            'NextUrl' => DBField::create_field('Text', 'false'),
            'SearchPages' => new ArrayList()
        );
    
        $start = ($request->requestVar('start')) ? (int)$request->requestVar('start') : 0;
        $query = ($request->requestVar('q')) ? $request->requestVar('q') : '';

        $currentPage = floor($start / $pageLength) + 1;
        
        $totalPages = ceil(count($this->results) / $pageLength);
        
        if ($totalPages == 0) {
            $totalPages = 1;
        }

        if ($currentPage > $totalPages) {
            $currentPage = $totalPages;
        }

        $results = new ArrayList();
        
        if ($this->results) {
            foreach ($this->results as $k => $hit) {
                if ($k < ($currentPage-1)*$pageLength || $k >= ($currentPage*$pageLength)) {
                    continue;
                }
            
                $doc = $hit->getDocument();
            
                $content = $hit->content;

                $obj = new ArrayData(
                    array(
                    'Title' => DBField::create_field('Varchar', $doc->getFieldValue('Title')),
                    'BreadcrumbTitle' => DBField::create_field('HTMLText', $doc->getFieldValue('BreadcrumbTitle')),
                    'Link' => DBField::create_field('Varchar', $doc->getFieldValue('Link')),
                    'Language' => DBField::create_field('Varchar', $doc->getFieldValue('Language')),
                    'Version' => DBField::create_field('Varchar', $doc->getFieldValue('Version')),
                    'Entity' => DBField::create_field('Varchar', $doc->getFieldValue('Entity')),
                    'Content' => DBField::create_field('HTMLText', $content),
                    'Score' => $hit->score,
                    'Number' => $k + 1,
                    'ID' => md5($doc->getFieldValue('Link'))
                    )
                );

                $results->push($obj);
            }
        }

        $data['Results'] = $results;
        $data['Query'] = DBField::create_field('Text', $query);
        $data['TotalResults'] = DBField::create_field('Text', count($this->results));
        $data['TotalPages'] = DBField::create_field('Text', $totalPages);
        $data['ThisPage'] = DBField::create_field('Text', $currentPage);
        $data['StartResult'] = $start + 1;
        $data['EndResult'] = $start + count($results);

        // Pagination links
        if ($currentPage > 1) {
            $data['PrevUrl'] = DBField::create_field(
                'Text',
                $this->buildQueryUrl(array('start' => ($currentPage - 2) * $pageLength))
            );
        }

        if ($currentPage < $totalPages) {
            $data['NextUrl'] = DBField::create_field(
                'Text',
                $this->buildQueryUrl(array('start' => $currentPage * $pageLength))
            );
        }
        
        if ($totalPages > 1) {
            // Always show a certain number of pages at the start
            for ($i = 1; $i <= $totalPages; $i++) {
                $obj = new DataObject();
                $obj->IsEllipsis = false;
                $obj->PageNumber = $i;
                $obj->Link = $this->buildQueryUrl(
                    array(
                    'start' => ($i - 1) * $pageLength
                    )
                );
                
                $obj->Current = false;
                if ($i == $currentPage) {
                    $obj->Current = true;
                }
                $data['SearchPages']->push($obj);
            }
        }

        return new ArrayData($data);
    }
    
    /**
     * Build a nice query string for the results
     *
     * @return string
     */
    private function buildQueryUrl($params)
    {
        $url = parse_url($_SERVER['REQUEST_URI']);
        if (! array_key_exists('query', $url)) {
            $url['query'] = '';
        }
        parse_str($url['query'], $url['query']);
        if (! is_array($url['query'])) {
            $url['query'] = array();
        }
        // Remove 'start parameter if it exists
        if (array_key_exists('start', $url['query'])) {
            unset($url['query']['start']);
        }
        // Add extra parameters from argument
        $url['query'] = array_merge($url['query'], $params);
        $url['query'] = http_build_query($url['query']);
        $url = $url['path'] . ($url['query'] ? '?'.$url['query'] : '');
        
        return $url;
    }
    
    /**
     * @return int
     */
    public function getTotalResults()
    {
        return (int) $this->totalResults;
    }

    /**
     * Optimizes the search indexes on the File System
     *
     * @return void
     */
    public function optimizeIndex()
    {
        $index = Zend_Search_Lucene::open(self::get_index_location());

        if ($index) {
            $index->optimize();
        }
    }
    
    /**
     * @return String
     */
    public function getTitle()
    {
        return ($this->outputController) ? $this->outputController->Title : _t('DocumentationSearch.SEARCH', 'Search');
    }
    
    /**
     * OpenSearch MetaData fields. For a list of fields consult 
     * {@link self::get_meta_data()}
     *
     * @param array
     */
    public static function set_meta_data($data)
    {
        if (is_array($data)) {
            foreach ($data as $key => $value) {
                self::$meta_data[strtolower($key)] = $value;
            }
        } else {
            user_error("set_meta_data must be passed an array", E_USER_ERROR);
        }
    }
    
    /**
     * Returns the meta data needed by opensearch.
     *
     * @return array
     */
    public static function get_meta_data()
    {
        $data = self::$meta_data;
        
        $defaults = array(
            'Description' => _t('DocumentationViewer.OPENSEARCHDESC', 'Search the documentation'),
            'Tags' => _t('DocumentationViewer.OPENSEARCHTAGS', 'documentation'),
            'Contact' => Config::inst()->get('Email', 'admin_email'),
            'ShortName' => _t('DocumentationViewer.OPENSEARCHNAME', 'Documentation Search'),
            'Author' => 'SilverStripe'
        );
        
        foreach ($defaults as $key => $value) {
            if (isset($data[$key])) {
                $defaults[$key] = $data[$key];
            }
        }
        
        return $defaults;
    }
    
    /**
     * Renders the search results into a template. Either the search results 
     * template or the Atom feed.
     */
    public function renderResults()
    {
        if (!$this->results && $this->query) {
            $this->performSearch();
        }

        if (!$this->outputController) {
            return user_error('Call renderResults() on a DocumentationViewer instance.', E_USER_ERROR);
        }
        
        $request = $this->outputController->getRequest();
        $data = $this->getSearchResults($request);
        $templates = array('DocumentationViewer_search');

        if ($request->requestVar('format') && $request->requestVar('format') == "atom") {
            // alter the fields for the opensearch xml.
            $title = ($title = $this->getTitle()) ? ' - '. $title : "";
            
            $link = Controller::join_links(
                $this->outputController->Link(), 'DocumentationOpenSearchController/description/'
            );
            
            $data->setField('Title', $data->Title . $title);
            $data->setField('DescriptionURL', $link);
            
            array_unshift($templates, 'OpenSearchResults');
        }
        
        return $this->outputController->customise($data)->renderWith($templates);
    }
}