<?php

namespace CorpusParole\Repositories;

use Config;

use Log;

use CorpusParole\Models\DocumentResult;

use CorpusParole\Models\Document;

use CorpusParole\Libraries\CorpusParoleException;

use CorpusParole\Libraries\Utils;

use CorpusParole\Libraries\Sparql\SparqlClient;

use CorpusParole\Services\LexvoResolverInterface;

use EasyRdf\Graph;

use Illuminate\Pagination\LengthAwarePaginator;

use Illuminate\Pagination\Paginator;

/**

 * Implement the DocumentRepository using EasyRdf

 * TODO: certainly split the transaction management (+add, +delete +transaction ) to an external class -> for this extend the sparql client.

 */

class RdfDocumentRepository implements DocumentRepository {

    const BASE_DOC_QUERY

        = "SELECT".

        "    ?uri".

        "    ?doc".

        "    ?title".

        "    ?issued".

        "    ?modified".

        "    ?lang".

        "    (group_concat(distinct ?publisher;separator=\", \") as ?publishers) ".

        "  WHERE {".

        "  GRAPH ?uri { ?doc a <http://www.europeana.eu/schemas/edm/ProvidedCHO>.".

        "    ?doc <http://purl.org/dc/elements/1.1/title> ?title.".

        "    OPTIONAL {?doc <http://purl.org/dc/elements/1.1/language> ?lang.} ".

        "    OPTIONAL {?doc <http://purl.org/dc/terms/issued> ?issued.} ".

        "    OPTIONAL {?doc <http://purl.org/dc/terms/modified> ?modified.} ".

        "    OPTIONAL {?doc <http://purl.org/dc/elements/1.1/publisher> ?publisher.} }".

        "  } ".

        "  GROUP BY ?uri ?doc ?title ?issued ?modified ?lang ".

        "  ORDER BY ?uri";

    const ADDITIONAL_DOC_QUERIES = [

        "SELECT".

        "    ?uri".

        "    ?doc".

        "    (sample(distinct ?ext) as ?extent) ".

        "WHERE {".

        "    GRAPH ?uri {".

        "        ?s a <http://www.europeana.eu/schemas/edm/WebResource>. ".

        "        ?uri <http://www.europeana.eu/schemas/edm/isShownBy> ?s. ".

        "        ?uri <http://www.europeana.eu/schemas/edm/aggregatedCHO> ?doc. ".

        "        OPTIONAL {?s <http://purl.org/dc/terms/extent> ?ext.}".

        "    }. ".

        "    %s".

        "} ".

        "GROUP BY ?uri ?doc",

        "SELECT".

        "    ?uri".

        "    ?doc".

        "    (sample(distinct str(?s)) as ?transcript_url) ".

        "WHERE {".

        "    GRAPH ?uri {".

        "        ?s a <http://www.europeana.eu/schemas/edm/WebResource>. ".

        "        ?uri <http://www.europeana.eu/schemas/edm/aggregatedCHO> ?doc. ".

        "        OPTIONAL {?s <http://purl.org/dc/elements/1.1/format> ?f.} ".

        "    }. ".

        "    FILTER(str(?f) IN ( \"application/xml\", \"application/pdf\" )). ".

        "    %s".

        "} ".

        "GROUP BY ?uri ?doc"

    ];

    private $sparqlClient;

    private $lexvoResolver;

    public function __construct(SparqlClient $sparqlClient, LexvoResolverInterface $lexvoResolver) {

        $this->sparqlClient = $sparqlClient;

        $this->lexvoResolver = $lexvoResolver;

    }

    public function getSparqlClient() {

        return $this->sparqlClient;

    }

    private function getResGraph($doc) {

        if(empty((array)$doc)) {

            return null;

        }

        $newGraph = new Graph($doc->uri->getUri());

        $newGraph->add($doc->uri, "rdf:type", $newGraph->resource("http://www.openarchives.org/ore/terms/Aggregation"));

        $newGraph->add($doc->uri, "http://www.europeana.eu/schemas/edm/aggregatedCHO", $doc->doc);

        $newGraph->add($doc->doc, "rdf:type", $newGraph->resource("http://www.europeana.eu/schemas/edm/ProvidedCHO"));

        if(isset($doc->title)) {

            $newGraph->add($doc->doc, "http://purl.org/dc/elements/1.1/title", $doc->title);

        }

        if(isset($doc->lang)) {

            $newGraph->add($doc->doc, "http://purl.org/dc/elements/1.1/language", $doc->lang);

        }

        if(isset($doc->issued)) {

            $newGraph->add($doc->doc, "http://purl.org/dc/terms/issued", $doc->issued);

        }

        if(isset($doc->modified)) {

            $newGraph->add($doc->doc, "http://purl.org/dc/terms/modified", $doc->modified);

        }

        if(isset($doc->publishers)) {

            $newGraph->add($doc->doc, "http://purl.org/dc/elements/1.1/publisher", $doc->publishers);

        }

        if(isset($doc->extent)) {

            $newGraph->add($doc->doc, "http://purl.org/dc/terms/extent", $doc->extent);

        }

        if(isset($doc->transcript_url)) {

            $newGraph->add($doc->doc, config('corpusparole.corpus_ontology_url').'transcript', $doc->transcript_url);

        }

        return $newGraph;

    }

    private function queryDocs($offset=null, $limit=null) {

        $resDocs = [];

        $limitsClauses = [];

        $limitsClausesStr = "";

        if(!is_null($offset)) {

            array_push($limitsClauses, "OFFSET $offset");

        }

        if(!is_null($limit)) {

            array_push($limitsClauses, "LIMIT $limit");

        }

        if(!empty($limitsClauses)) {

            $limitsClausesStr = "\n" . join(" ", $limitsClauses);

        }

        $docs = $this->sparqlClient->query(self::BASE_DOC_QUERY.$limitsClausesStr);

        foreach($docs as $doc) {

            $graph = $this->getResGraph($doc);

            if(is_null($graph)) {

                continue;

            }

            $uri = $doc->uri->getUri();

            $resDocs[$uri] = $graph;

        }

        if(count($resDocs) == 0) {

            return [];

        }

        $filterUris = "FILTER(?uri in (<".join(">, <" , array_keys($resDocs)).">)) ";

        foreach(self::ADDITIONAL_DOC_QUERIES as $query) {

            $docs = $this->sparqlClient->query(sprintf($query, $filterUris));

            foreach($docs as $doc) {

                $graph = $this->getResGraph($doc);

                if(is_null($graph)) {

                    continue;

                }

                $uri = $doc->uri->getUri();

                if(array_key_exists($uri, $resDocs)) {

                    $resDocs[$uri] = Utils::mergeGraphs($resDocs[$uri], $graph);

                } else {

                    $resDocs[$uri] = $graph;

                }

            }

        }

        return array_map(function($g) { return new DocumentResult($g->getUri(), $g); }, array_values($resDocs));

    }

    public function all() {

        return $this->queryDocs();

    }

        if(strpos($id, config('corpusparole.corpus_id_scheme')) === 0) {

            $id = substr($id, strlen(config('corpusparole.corpus_id_scheme')));

        }

        $docUri = Config::get('corpusparole.corpus_doc_id_base_uri').$id;

        // We want the CBD (Concise Bounded Description, cf. http://www.w3.org/Submission/CBD/)

        // WARNING: This seems to work in sesame for our dataset.

        $doc = $this->sparqlClient->query(

            "CONSTRUCT { ?s ?p ?o } WHERE { GRAPH <$docUri> { ?s ?p ?o } }"

        );

        //TODO: return null if not found

        if($doc->isEmpty()) {

            return null;

        }

        //print($doc->dump());

        // clone the graph to force the URI

        $DocumentKlass = $short?DocumentResult::class:Document::class;

        return new $DocumentKlass($docUri, new Graph($docUri, $doc->toRdfPhp()));

    }

    /**

     * save document.

     * @return boolean true if a transaction was started, false otherwise

     * @throws CorpusParoleException if one of the operation could not be performed

     */

    public function save(Document $doc) {

        $transactionStarted = $this->sparqlClient->startTransaction();

        try {

            foreach($doc->getDeltaList() as $delta) {

                $this->sparqlClient->deleteWhere($delta->getDeleteWhere(), $delta->getUri());

                $this->sparqlClient->delete($delta->getDeletedGraph());

                $this->sparqlClient->add($delta->getAddedGraph());

            }

            if($transactionStarted) {

                $transactionStarted = false;

                return $this->sparqlClient->commit();

            }

            else  {

                return false;

            }

        }

        catch(CorpusParoleException $e) {

            if($transactionStarted) {

                $this->sparqlClient->rollback();

            }

            throw $e;

        }

    }

    public function getCount() {

        $res = $this->sparqlClient->query("SELECT (COUNT (DISTINCT ?g) as ?count) WHERE { GRAPH ?g { ?s a <http://www.europeana.eu/schemas/edm/ProvidedCHO> } }");

        assert(!is_null($res) && $res->count()==1);

        return $res[0]->count->getValue();

    }

    //SELECT ?g WHERE { GRAPH ?g { ?s ?p ?o } }

    /**

     * Paginate all document as a paginator.

     *

     * @param  int  $perPage

     * @param  string  $pageName

     * @return \Illuminate\Contracts\Pagination\LengthAwarePaginator

     */

    public function paginateAll($perPage = 15, $pageName = 'page', $page = null)

    {

        assert(is_numeric($perPage));

        if(is_null($page)) {

            $page = Paginator::resolveCurrentPage($pageName);

        }

        assert(is_null($page) || is_numeric($page));

        $total = $this->getCount();

        $offset = max(0,($page - 1) * $perPage);

        $results = $this->queryDocs($offset, $perPage);

        return new LengthAwarePaginator($results, $total, $perPage, $page, [

            'path' => Paginator::resolveCurrentPath(),

            'pageName' => $pageName,

        ]);

    }

    /**

     * Resolve lexvo id for all documents in the list

     * this allow to optimise the call of lexvo repository

     * @param $docList Array: a list (Array) of document to resolve

     */

    public function resolveLexvo(Array $docList) {

        $languageIds = [];

        #get the list pf language needing resolving

        foreach ($docList as $doc) {

            if($doc->getLanguageValue() && is_null($doc->getLanguageResolved())) {

                $languageIds[$doc->getLanguageValue()] = true;

            }

        }

        # call LexvoResolver

        $langNames = $this->lexvoResolver->getNames(array_keys($languageIds));

        foreach ($docList as $doc) {

            if($doc->getLanguageValue() && is_null($doc->getLanguageResolved())) {

                $doc->setLanguageResolved($langNames[$doc->getLanguageValue()]);

            }

        }

        return $docList;

    }

}