<?php
require __DIR__ . '/common.php';

/**
 * Proxy/cache du flux RSS WordPress natif de silly.be (articles complets
 * dans content:encoded, categories, 10 derniers articles). On le re-sert
 * sous notre domaine pour garder une URL stable et on corrige atom:link
 * rel="self" (il pointe sinon vers silly.be) pour le validateur W3C.
 *
 * WordPress limite le flux a 10 articles (reglage du site, non modifiable
 * d'ici) mais accepte ?paged=N : on concatene NEWS_PAGES pages pour
 * obtenir jusqu'a 50 articles.
 */
const NEWS_FEED_URL = 'https://www.silly.be/actualites/feed/';
const NEWS_PAGES = 5; // 5 x 10 = 50 articles
const SELF_URL = 'https://sillycone-village.be/silly-rss/actualites.php';

function build_news_feed(): string
{
    $raw = http_get(NEWS_FEED_URL, ['Accept: application/rss+xml, application/xml']);

    $doc = new DOMDocument();
    if (!@$doc->loadXML($raw)) {
        throw new RuntimeException('Flux WordPress illisible (XML invalide)');
    }

    $xpath = new DOMXPath($doc);
    $xpath->registerNamespace('atom', 'http://www.w3.org/2005/Atom');
    $selfLinks = $xpath->query('/rss/channel/atom:link[@rel="self"]');
    if ($selfLinks->length === 0) {
        throw new RuntimeException('Reponse inattendue : pas un flux RSS');
    }
    foreach ($selfLinks as $selfLink) {
        $selfLink->setAttribute('href', SELF_URL);
    }

    // WordPress emet <sy:updatePeriod>\n\thourly\t</sy:updatePeriod> : on retire
    // les blancs parasites autour des valeurs.
    $xpath->registerNamespace('sy', 'http://purl.org/rss/1.0/modules/syndication/');
    foreach ($xpath->query('/rss/channel/sy:*') as $node) {
        $node->textContent = trim($node->textContent);
    }

    // Pages suivantes : un echec (ou une page vide) arrete simplement la
    // pagination, la premiere page suffit a servir un flux valide.
    $channel = $xpath->query('/rss/channel')->item(0);
    $seen = [];
    foreach ($xpath->query('/rss/channel/item/guid') as $g) {
        $seen[trim($g->textContent)] = true;
    }
    for ($page = 2; $page <= NEWS_PAGES; $page++) {
        try {
            $more = new DOMDocument();
            $raw = http_get(NEWS_FEED_URL . '?paged=' . $page, ['Accept: application/rss+xml, application/xml']);
            if (!@$more->loadXML($raw)) {
                break;
            }
        } catch (Throwable $e) {
            break;
        }
        $added = 0;
        $moreXpath = new DOMXPath($more);
        foreach ($moreXpath->query('/rss/channel/item') as $item) {
            // Le tri de WordPress n'est pas stable entre articles de meme
            // date : on dedoublonne par guid aux jonctions de pages.
            $guid = trim($moreXpath->evaluate('string(guid)', $item));
            if ($guid === '' || isset($seen[$guid])) {
                continue;
            }
            $seen[$guid] = true;
            $channel->appendChild($doc->importNode($item, true));
            $added++;
        }
        if ($added === 0) {
            break;
        }
    }

    return $doc->saveXML();
}

serve_cached_feed('actualites', 'build_news_feed');