<?php

namespace CorpusParole\Services;

use Cache;

use CorpusParole\Services\BnfResolverInterface;

class BnfResolver implements BnfResolverInterface {

    public function __construct($sparqlClient) {

        $this->sparqlClient = $sparqlClient;

    }

    private function checkBnfId($id) {

        $bnfid = $id;

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

            $bnfid = config('corpusparole.bnf_base_url').substr($id, strlen(config('corpusparole.bnf_ark_base_url')));

        }

        elseif(strpos($id, config('corpusparole.bnf_base_url')) !== 0) {

            $bnfid = config('corpusparole.bnf_base_url').$id;

        }

        $bnfid = rtrim($bnfid, '/');

        if(preg_match("/^".preg_quote(config('corpusparole.bnf_base_url'),"/")."ark\:\/12148\/[[:alnum:]]/", $bnfid) !== 1) {

            throw new BnfResolverException("the provided id \"$id\" is not a BNF id");

        }

        return $bnfid;

    }

    /**

     * Get label from BNF id

     * @param string $id The id to resolve. Can be an url starting with http://data.bnf.fr/ or http://ark.bnf.fr/

     * @return a string with the name

     */

    public function getLabel($id) {

        $res = $this->getlabels([$id,]);

        assert(array_key_exists($id,$res), "the result must contains $id");

        return $res[$id];

    }

    /**

     * Get a list of names from an array of viaf ids.

     * @param array $ids The array of ids to resolve.

     *                   Each id can be an url starting with http://data.bnf.fr/ or http://ark.bnf.fr/

     */

    public function getLabels(array $ids) {

        if(count($ids) > config('corpusparole.bnf_max_ids')) {

            throw new BnfResolverException("Too manys ids provided");

        }

        $bnfids = array_map([$this, 'checkBnfId'], $ids);

        $bnfidsMap = array_combine($bnfids, $ids);

        $results = [];

        $missingBnfids = [];

        foreach ($bnfidsMap as $bnfid => $bnfidSource) {

            $cachedValue = Cache::get("bnf:$bnfid");

            if(is_null($cachedValue)) {

                array_push($missingBnfids, $bnfid);

            } else {

                $results[$bnfidSource] = $cachedValue;

            }

        }

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

            return $results;

        }

        $query = "SELECT ?s ?o WHERE {";

        foreach ($missingBnfids as $index => $bid) {

            if($index > 0) {

                $query .= " UNION ";

            }

            $query .= "{ <$bid> <http://www.w3.org/2004/02/skos/core#prefLabel> ?o. ?s <http://www.w3.org/2004/02/skos/core#prefLabel> ?o. FILTER(?s = <$bid> && lang(?o) = \"fr\")}";

        }

        $query .= "}";

        $docs = $this->sparqlClient->query($query);

        $resultsRaw = [];

        foreach ($docs as $doc) {

            $bnfid = $doc->s->getUri();

            $bnflabel = $doc->o;

            $value = $bnflabel->getValue();

            if(!empty($value)) {

                $resultsRaw[$bnfid] = $bnflabel;

            }

        }

        foreach ($missingBnfids as $bnfid) {

            $bnfidSource = $bnfidsMap[$bnfid];

            $missingValue = (array_key_exists($bnfid,$resultsRaw) && $resultsRaw[$bnfid])?mb_strtolower($resultsRaw[$bnfid]->getValue()):"";

            if (mb_strlen($missingValue)>0) {

                Cache::put("bnf:$bnfid", $missingValue, config('corpusparole.bnf_cache_expiration'));

                $results[$bnfidSource] = $missingValue;

            }

            else {

                $results[$bnfidSource] = null;

            }

        }

        return $results;

    }

}