<?php

declare(strict_types=1);

define('BASE_PATH', realpath(__DIR__ . '/../'));

require_once BASE_PATH . '/src/auth.php';
require_once BASE_PATH . '/src/SiteSettings.php';
require_once BASE_PATH . '/config/config.php';
require_once BASE_PATH . '/src/ArticleManager.php';
require_once BASE_PATH . '/src/TrendingParser.php';

// ── Périodes supportées ───────────────────────────────────────────────────────

const TRENDING_PERIODS = [
    '10m' => ['seconds' => 600,      'label' => '10 dernières minutes'],
    '20m' => ['seconds' => 1200,     'label' => '20 dernières minutes'],
    '30m' => ['seconds' => 1800,     'label' => '30 dernières minutes'],
    '1h'  => ['seconds' => 3600,     'label' => 'dernière heure'],
    '8h'  => ['seconds' => 28800,    'label' => '8 dernières heures'],
    '1d'  => ['seconds' => 86400,    'label' => '24 dernières heures'],
    '7d'  => ['seconds' => 604800,   'label' => '7 derniers jours'],
    '14d' => ['seconds' => 1209600,  'label' => '14 derniers jours'],
    '30d' => ['seconds' => 2592000,  'label' => '30 derniers jours'],
    '1y'  => ['seconds' => 31536000, 'label' => 'dernière année'],
];

$period = $_GET['period'] ?? '1d';

if (!array_key_exists($period, TRENDING_PERIODS)) {
    http_response_code(400);
    header('Content-Type: text/plain; charset=UTF-8');
    echo 'Période invalide. Valeurs acceptées : ' . implode(', ', array_keys(TRENDING_PERIODS));
    exit;
}

$seconds  = TRENDING_PERIODS[$period]['seconds'];
$label    = TRENDING_PERIODS[$period]['label'];
$cutoff   = time() - $seconds;
$cacheTtl = max(60, min(28800, (int) ($seconds / 5)));

// ── Cache ─────────────────────────────────────────────────────────────────────

@mkdir(DATA_PATH . '/_cache', 0755, true);
$cacheFile = DATA_PATH . '/_cache/trending_' . $period . '.json';
$topPaths  = null;

if (file_exists($cacheFile) && (time() - filemtime($cacheFile)) < $cacheTtl) {
    $topPaths = json_decode((string) file_get_contents($cacheFile), true) ?: null;
}

if ($topPaths === null) {
    $parser   = new TrendingParser('/var/log/apache2', apacheAccessLog());
    $topPaths = $parser->top($cutoff, 50);
    @file_put_contents($cacheFile, json_encode($topPaths));
}

// ── Index slug → article (publiés, non privés) ────────────────────────────────

$articleManager = new ArticleManager(DATA_PATH);
$now            = time();
$privateCats    = $articleManager->getPrivateCategories();
$slugIndex      = [];

foreach ($articleManager->getAll(publishedOnly: true) as $a) {
    if (strtotime((string) ($a['published_at'] ?? '')) > $now) {
        continue;
    }
    $cat = trim($a['category'] ?? '');
    if ($cat !== '' && in_array($cat, $privateCats, true)) {
        continue;
    }
    $slugIndex[$a['slug']] = $a;
}

// ── Construction des items ────────────────────────────────────────────────────

$base  = rtrim(APP_URL, '/');
$items = [];

foreach ($topPaths as $path => $visitors) {
    if (!preg_match('#^/post/([^/]+)$#', $path, $m)) {
        continue;
    }
    $slug    = rawurldecode($m[1]);
    $article = $slugIndex[$slug] ?? null;
    if ($article === null) {
        continue;
    }
    $items[] = ['article' => $article, 'visitors' => (int) $visitors];
    if (count($items) >= 50) {
        break;
    }
}

// ── Réponse RSS ───────────────────────────────────────────────────────────────

header('Content-Type: application/rss+xml; charset=UTF-8');
header('X-Content-Type-Options: nosniff');
header('Cache-Control: public, max-age=' . $cacheTtl);

$feedTitle = htmlspecialchars(siteTitle() . ' — Tendances (' . $label . ')', ENT_XML1);
$feedUrl   = htmlspecialchars($base . '/trending?period=' . rawurlencode($period), ENT_XML1);
$baseXml   = htmlspecialchars($base, ENT_XML1);
$buildDate = htmlspecialchars(date(DATE_RSS));
$descXml   = htmlspecialchars('Top 50 articles par visiteurs uniques — ' . $label, ENT_XML1);
$langXml   = htmlspecialchars(siteLang(), ENT_XML1);

echo '<?xml version="1.0" encoding="UTF-8"?>' . "\n";
?>
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
  <channel>
    <title><?= $feedTitle ?></title>
    <link><?= $baseXml ?></link>
    <description><?= $descXml ?></description>
    <language><?= $langXml ?></language>
    <lastBuildDate><?= $buildDate ?></lastBuildDate>
    <atom:link href="<?= $feedUrl ?>" rel="self" type="application/rss+xml"/>
<?php foreach ($items as ['article' => $a, 'visitors' => $v]):
    $link    = htmlspecialchars($base . '/post/' . rawurlencode($a['slug']), ENT_XML1);
    $pubDate = htmlspecialchars(date(DATE_RSS, (int) strtotime((string) ($a['published_at'] ?? $a['created_at'] ?? ''))));
    $title   = htmlspecialchars(($a['title'] ?? ''), ENT_XML1);
    $plural  = $v > 1 ? 's' : '';
    $desc    = htmlspecialchars($title . ' — ' . $v . ' visiteur' . $plural . ' unique' . $plural . ' (' . $label . ')', ENT_XML1);
?>
    <item>
      <title><?= $title ?> (<?= $v ?> visiteur<?= $plural ?>)</title>
      <link><?= $link ?></link>
      <description><?= $desc ?></description>
      <pubDate><?= $pubDate ?></pubDate>
      <guid isPermaLink="true"><?= $link ?></guid>
    </item>
<?php endforeach; ?>
  </channel>
</rss>