<?php

namespace CorpusParole\Services;

use CorpusParole\Services\ViafResolverInterface;

use Cache;

use Config;

use EasyRdf\Graph;

use GuzzleHttp\Client;

use GuzzleHttp\Exception\RequestException;

use GuzzleHttp\Exception\ClientException;

use GuzzleHttp\Exception\GuzzleException;

use Illuminate\Contracts\Cache\Repository as CacheRepository;

class ViafResolver implements ViafResolverInterface {

    private $client = null;

    public function __construct(Client $httpClient) {

        $this->client = $httpClient;

    }

    /**

     * make the viaf query.

     */

    public function queryName($id) {

        $url = config('corpusparole.viaf_base_url').$id;

        try {

            $response = $this->client->get($url."/", ['headers'=>['Accept' => 'application/rdf+xml'],]);

        }

        catch(ClientException $e) {

            if($e->getResponse()->getStatusCode() === 404) {

                return null;

            } else {

                throw new ViafResolverException(

                    $e->getMessage(),

                    $e->getResponse()->getStatusCode(),

                    $e

                );

            }

        }

        catch(RequestException $e) {

            throw new ViafResolverException(

                $e->getMessage(),

                $e->hasResponse()?$e->getResponse()->getStatusCode():500,

                $e

            );

        }

        $graph = new Graph($url, $response->getBody());

        $names = [];

        foreach ($graph->allLiterals("<$url>", "schema:name") as $nameLit) {

            $lang = $nameLit->getLang();

            if(!$lang && !isset($names[''])) {

                $names[''] = $nameLit->getvalue();

            } elseif (strpos($lang, 'fr') === 0 && !isset($names['fr'])) {

                $names['fr'] = $nameLit->getvalue();

            } elseif (strpos($lang, 'en') === 0 && !isset($names['en'])) {

                $names['en'] = $nameLit->getvalue();

            } else {

                $names[$lang] = $nameLit->getvalue();

            }

        }

        $firstVal = reset($names);

        if($firstVal === false) {

            $firstVal = null;

        }

        return (isset($names['fr'])) ? $names['fr'] : ((isset($names['en'])) ? $names['en'] : $firstVal);

    }

    /**

     * Check viaf id format

     */

    private function checkViafIdFormat($viafid) {

        return ctype_digit($viafid);

    }

    /**

     * Get name from Viaf id

     * @param string $id The id to resolve. Can be an url starting with http://viaf.org/viaf/

     * @return a string with the name

     */

    public function getName($id) {

        $viafid = $id;

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

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

        }

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

        if(!$this->checkViafIdFormat($viafid)) {

            throw new ViafResolverException("ViafId not in correct format", 400);

        }

        $that = $this;

        return Cache::remember("viaf:$viafid", config('corpusparole.viaf_cache_expiration'), function() use ($that, $viafid)  {

            return $that->queryName($viafid);

        });

    }

    /**

     * 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://viaf.org/viaf/

     */

    public function getNames(array $ids) {

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

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

        }

        return array_combine($ids, array_map([$this,'getName'], $ids));

    }

}