<?php

namespace IRI\Bundle\WikiTagBundle\Utils;

use IRI\Bundle\WikiTagBundle\Entity\Tag;

class WikiTagUtils

{

    // Constants

    private static $WIKIPEDIA_API_URL = "http://fr.wikipedia.org/w/api.php";

    private static $WIKIPEDIA_VERSION_PERMALINK_TEMPLATE = "http://fr.wikipedia.org/w/index.php?oldid=%s";

    private static $DBPEDIA_URI_TEMPLATE = "http://dbpedia.org/resource/%s";

    /**

     * Cleans the tag label

     */

    public static function normalizeTag($tag_label)

    {

        if(strlen($tag_label)==0){

            return $tag_label;

        }

        $tag_label = trim($tag_label);//tag.strip()

        $tag_label = str_replace("_", " ", $tag_label);//tag.replace("_", " ")

        $tag_label = preg_replace('/\s+/u', ' ', $tag_label);//" ".join(tag.split())

        $tag_label = ucfirst($tag_label);//tag[0].upper() + tag[1:]

        return $tag_label;

    }

    /**

     * Query wikipedia with a normalized label or a pageid

     * return an array with the form

     * array(

     *      'new_label'=>$new_label,

     *   	'alternative_label'=>$alternative_label,

     *   	'status'=>$status,

     *   	'wikipedia_url'=>$url,

     *      'wikipedia_alternative_url'=>$alternative_url,

     *   	'pageid'=>$pageid,

     *   	'alternative_pageid'=>$alternative_pageid,

     *   	'dbpedia_uri'=>$dbpedia_uri,

     *   	'revision_id'=> ,

     *   	'response'=> the original wikipedia json response

     *   	)

     *

     * @param string $tag_label_normalized

     * @param bigint $page_id

     * @return array

     */

    public static function getWikipediaInfo($tag_label_normalized, $page_id=null)

    {

        $params = array('action'=>'query', 'prop'=>'info|categories|langlinks', 'inprop'=>'url', 'lllimit'=>'500', 'cllimit'=>'500', 'rvprop'=>'ids', 'format'=>'json');

        if($tag_label_normalized!=null){

            $params['titles'] = urlencode($tag_label_normalized);

        }

        else if($page_id!=null){

            $params['pageids'] = $page_id;

        }

        else{

            return WikiTagUtils::returnNullResult(null);

        }

        $res = $ar[0];

        $original_response = $res;

        $pages = $ar[1];

        // If there 0 or more than 1 result, the query has failed

        if(count($pages)>1 || count($pages)==0){

            return WikiTagUtils::returnNullResult($res);

        }

        // get first result

        $page = reset($pages);

        // Unknow entry ?

        if(array_key_exists('missing', $page) || array_key_exists('invalid', $page)){

            return WikiTagUtils::returnNullResult($res);

        }

        // The entry exists, we get the datas.

        $url = array_key_exists('fullurl', $page) ? $page['fullurl'] : null;

        $pageid = array_key_exists('pageid', $page) ? $page['pageid'] : null;

        $new_label = array_key_exists('title', $page) ? $page['title'] : null;

        // We test the status (redirect first because a redirect has no categories key)

        if(array_key_exists('redirect', $page)){

            //return " REDIRECT";

            $status = Tag::$TAG_URL_STATUS_DICT["redirection"];

        }

        else if(WikiTagUtils::isHomonymy($page)){

            //return " HOMONYMY";

            $status = Tag::$TAG_URL_STATUS_DICT["homonyme"];

        }

        else{

            //return " MATCH";

            $status = Tag::$TAG_URL_STATUS_DICT["match"];

        }

        // In redirection, we have to get more datas by adding redirects=true to the params

        $alternative_label = null;

        $alternative_url = null;

        $alternative_pageid = null;

        if($status==Tag::$TAG_URL_STATUS_DICT["redirection"])

        {

            $params['redirects'] = "true";

            $ar = WikiTagUtils::requestWikipedia($params);

            $res = $ar[0];

            $pages = $ar[1];

            #we know that we have at least one answer

            if(count($pages)>1 || count($pages)==0){

                return WikiTagUtils::returnNullResult($res);

            }

            // get first result

            $page = reset($pages);

            $alternative_label = array_key_exists('title', $page) ? $page['title'] : null;

            $alternative_url = array_key_exists('fullurl', $page) ? $page['fullurl'] : null;

            $alternative_pageid = array_key_exists('pageid', $page) ? $page['pageid'] : null;

        }

        $revision_id = $page['lastrevid'];

        // process language to extract the english label

        $english_label = null;

        if($status==Tag::$TAG_URL_STATUS_DICT["match"] || $status==Tag::$TAG_URL_STATUS_DICT["redirection"]){

            if(array_key_exists("langlinks", $page)){

                foreach ($page["langlinks"] as $ar) {

                    if($ar["lang"]=="en"){

                        $english_label = $ar["*"];

                        break;

                    }

                }

            }

        }

        // We create the dbpedia uri.

        $dbpedia_uri = null;

        if($english_label!=null && strpos($english_label, '#')===false){

            $dbpedia_uri = WikiTagUtils::getDbpediaUri($english_label);

        }

        $wp_response = array(

            'new_label'=>$new_label,

        	'alternative_label'=>$alternative_label,

        	'status'=>$status,

        	'wikipedia_url'=>$url,

            'wikipedia_alternative_url'=>$alternative_url,

        	'pageid'=>$pageid,

        	'alternative_pageid'=>$alternative_pageid,

        	'dbpedia_uri'=>$dbpedia_uri,

        	'revision_id'=>$revision_id,

        	'response'=>$original_response);

        //return $url." <br/>RES =  ".$res/*." <br/>DUMP =  ".var_dump($pages)*/." <br/>COUNT =  ".count($pages)." <br/>page =  ".var_dump($page);

        return $wp_response;

    }

    /**

     * build and do the request to Wikipedia.

     *

     * @param array $params

     * @return array

     */

    private static function requestWikipedia($params)

    {

        $params_str = '';

        foreach ($params as $key => $value) {

            if ($params_str==''){

                $params_str = $key.'='.$value;

            }

            else{

                $params_str .= '&'.$key.'='.$value;

            }

        }

        $url = WikiTagUtils::$WIKIPEDIA_API_URL.'?'.$params_str;

        $ch = curl_init();

        curl_setopt($ch, CURLOPT_URL, $url);

        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

        curl_setopt($ch, CURLOPT_USERAGENT, 'http://www.iri.centrepompidou.fr');

        curl_setopt($ch, CURLOPT_TIMEOUT_MS, 5000);

        $res = curl_exec($ch);

        $curl_errno = curl_errno($ch);

        $curl_error = curl_error($ch);

        curl_close($ch);

        if ($curl_errno > 0) {

            throw new \Exception("Wikipedia request failed. cURLError #$curl_errno: $curl_error\n");

        }

        $val = json_decode($res, true);

        $pages = $val["query"]["pages"];

        return array($res, $pages);

    }

    /**

     * Returns tag with a null result, usually used after a failed request on Wikipedia

     */

    private static function returnNullResult($response)

    {

        return array('new_label'=>null, 'status'=>Tag::$TAG_URL_STATUS_DICT['null_result'], 'wikipedia_url'=>null, 'pageid'=>null, 'dbpedia_uri'=>null, 'revision_id'=>null, 'response'=>$response);

    }

    /**

     * Returns tag with a null result, usually used after a failed request on Wikipedia

     */

    private static function isHomonymy($page)

    {

        //$s = "";

        foreach ($page["categories"] as $ar) {

            //$s .= ", b : ".$ar." - title = ".$ar["title"].", strpos = ".strpos($ar["title"], 'Catégorie:Homonymie');

            // Strict test because false can be seen as "O".

            if(strpos($ar["title"], 'Catégorie:Homonymie')!==false || strpos($ar["title"], 'Category:Disambiguation')!==false){

                //$s .= "TRUE";

                return true;

            }

        }

        return false;

    }

    /**

     * Builds DbPedia URI

     */

    private static function getDbpediaUri($english_label)

    {

        return sprintf(WikiTagUtils::$DBPEDIA_URI_TEMPLATE, WikiTagUtils::urlize_for_wikipedia($english_label));

    }

    /**

     * URLencode label for wikipedia

     */

    private static function urlize_for_wikipedia($label){

        return urlencode(str_replace(" ", "_", $label));

    }

}