<?php
// partials/recent_static.php
// Cheap server-side prerender of recent blog/changelog items so users do
// not stare at "Loading…" while JS is still booting (and so the page is
// useful even when the fetch fails).

const RECENT_CACHE_TTL = 300; // 5 min

function _recent_cache_get(string $key, int $ttl, int $invalidate_before = 0) {
    $f = sys_get_temp_dir() . '/sillylaird_recent_' . $key . '.json';
    if (!is_file($f)) return null;
    $mt = filemtime($f);
    // Stale if older than TTL, or older than the upstream source mtime
    if ((time() - $mt) >= $ttl) return null;
    if ($invalidate_before > 0 && $mt < $invalidate_before) return null;
    $raw = @file_get_contents($f);
    if ($raw === false) return null;
    $data = json_decode($raw, true);
    return is_array($data) ? $data : null;
}

function _recent_changelog_source_mtime(): int {
    $latest = 0;
    foreach (glob(__DIR__ . '/../changelog/*-changelog.txt') ?: [] as $f) {
        $m = @filemtime($f);
        if ($m && $m > $latest) $latest = $m;
    }
    return $latest;
}

function _recent_cache_put(string $key, array $data): void {
    $f = sys_get_temp_dir() . '/sillylaird_recent_' . $key . '.json';
    @file_put_contents($f, json_encode($data), LOCK_EX);
}

// Last-resort fallback: return whatever is cached regardless of age, so an
// upstream hiccup never blanks the list (stale-on-error).
function _recent_cache_get_stale(string $key): ?array {
    $f = sys_get_temp_dir() . '/sillylaird_recent_' . $key . '.json';
    if (!is_file($f)) return null;
    $raw = @file_get_contents($f);
    if ($raw === false) return null;
    $data = json_decode($raw, true);
    return is_array($data) ? $data : null;
}

const BLOG_SQLITE = '/mnt/slab/blog.sillylaird.ca/blog.sqlite';

function _recent_fetch(string $url, float $timeout = 1.5): ?string {
    $ctx = stream_context_create(['http' => [
        'timeout' => $timeout,
        'ignore_errors' => true,
        'header' => "User-Agent: sillylaird-static-render/1.0\r\n",
    ]]);
    $body = @file_get_contents($url, false, $ctx);
    return $body === false ? null : $body;
}

function recent_blog_posts(int $limit = 2): array {
    // Invalidate cache when the blog DB changes so new posts show within the
    // window without waiting out the full TTL.
    $src_mtime = @filemtime(BLOG_SQLITE) ?: 0;
    $cached = _recent_cache_get('blog', RECENT_CACHE_TTL, $src_mtime);
    if ($cached !== null) return array_slice($cached, 0, $limit);

    // Blog runs on the same box; read its SQLite directly instead of an HTTP
    // round-trip to blog.sillylaird.ca (the old fetch blocked ~1.5s on every
    // cache miss and stalled when the blog vhost was slow/down).
    $posts = null;
    if (is_file(BLOG_SQLITE)) {
        try {
            $db = new PDO('sqlite:' . BLOG_SQLITE, null, null, [
                PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
                PDO::ATTR_TIMEOUT => 2,
            ]);
            $stmt = $db->query('SELECT title, path, year, month, day FROM posts ORDER BY id DESC');
            $posts = $stmt->fetchAll(PDO::FETCH_ASSOC);
        } catch (Throwable $e) {
            $posts = null;
        }
    }

    if (!is_array($posts)) {
        // DB unavailable — serve the last good list rather than blanking.
        $stale = _recent_cache_get_stale('blog');
        return $stale !== null ? array_slice($stale, 0, $limit) : [];
    }

    _recent_cache_put('blog', $posts);
    return array_slice($posts, 0, $limit);
}

function recent_changelog_entries(int $limit = 2): array {
    $cached = _recent_cache_get('changelog', RECENT_CACHE_TTL, _recent_changelog_source_mtime());
    if ($cached !== null) return array_slice($cached, 0, $limit);

    $html = _recent_fetch('https://www.sillylaird.ca/changelog/latest.php');
    if ($html === null) {
        $stale = _recent_cache_get_stale('changelog');
        return $stale !== null ? array_slice($stale, 0, $limit) : [];
    }

    $entries = [];
    $doc = new DOMDocument();
    libxml_use_internal_errors(true);
    if (!$doc->loadHTML('<?xml encoding="UTF-8">' . $html)) {
        libxml_clear_errors();
        $stale = _recent_cache_get_stale('changelog');
        return $stale !== null ? array_slice($stale, 0, $limit) : [];
    }
    libxml_clear_errors();
    $xp = new DOMXPath($doc);
    foreach ($xp->query('//div[contains(@class,"changelog-entry")]') as $node) {
        /** @var DOMElement $node */
        $title = '';
        foreach (['b', 'strong'] as $tag) {
            $el = $node->getElementsByTagName($tag)->item(0);
            if ($el) { $title = trim($el->textContent); break; }
        }
        $timeEl = $node->getElementsByTagName('time')->item(0);
        $iso  = $timeEl ? trim($timeEl->getAttribute('datetime')) : '';
        $when = $timeEl ? trim($timeEl->textContent) : '';

        $body = '';
        foreach ($xp->query('.//span[contains(@class,"text")]', $node) as $b) {
            $body = trim($b->textContent);
            break;
        }
        $entries[] = compact('title', 'iso', 'when', 'body');
    }

    _recent_cache_put('changelog', $entries);
    return array_slice($entries, 0, $limit);
}

function render_recent_blog(int $limit = 2): void {
    $posts = recent_blog_posts($limit);
    if (!$posts) {
        echo '<div class="muted">No posts to show right now.</div>';
        return;
    }
    $h = fn($s) => htmlspecialchars((string)$s, ENT_QUOTES, 'UTF-8');
    echo '<div><strong>Posts</strong> (<a href="https://blog.sillylaird.ca/">all</a>)</div>';
    echo '<ol class="recent-list">';
    foreach ($posts as $p) {
        $path = ltrim((string)($p['path'] ?? ''), '/');
        $iso  = sprintf('%04d-%02d-%02d', (int)($p['year'] ?? 0), (int)($p['month'] ?? 0), (int)($p['day'] ?? 0));
        $iso  = $iso === '0000-00-00' ? '' : $iso;
        echo '<li><a href="https://blog.sillylaird.ca/' . $h($path) . '">' . $h($p['title'] ?? 'Untitled') . '</a>';
        if ($iso) echo '<div class="muted"><time datetime="' . $h($iso) . '">' . $h($iso) . '</time></div>';
        echo '</li>';
    }
    echo '</ol>';
}

/** Latest changelog row for sidebar widgets (reads local TXT, no HTTP). */
function latest_changelog_entry(): ?array {
    static $entry = null;
    static $loaded = false;
    if ($loaded) return $entry;
    $loaded = true;

    $parser = __DIR__ . '/../changelog/api/parser.php';
    if (!is_file($parser)) return null;
    require_once $parser;

    $rows = get_changelog_entries(1);
    $entry = $rows[0] ?? null;
    return $entry;
}

function render_recent_changelog(int $limit = 2): void {
    $entries = recent_changelog_entries($limit);
    if (!$entries) {
        echo '<div class="muted">No entries to show right now.</div>';
        return;
    }
    $h = fn($s) => htmlspecialchars((string)$s, ENT_QUOTES, 'UTF-8');
    echo '<div><strong>Entries</strong> (<a href="https://www.sillylaird.ca/changelog/">all</a>)</div>';
    echo '<ol class="recent-list">';
    foreach ($entries as $e) {
        echo '<li>';
        if ($e['title']) echo '<strong>' . $h($e['title']) . '</strong>';
        if ($e['iso'] || $e['when']) {
            echo '<div class="muted"><time';
            if ($e['iso']) echo ' datetime="' . $h($e['iso']) . '"';
            echo '>' . $h($e['when'] ?: $e['iso']) . '</time></div>';
        }
        if ($e['body']) echo '<div>' . $h($e['body']) . '</div>';
        $yr = $e['iso'] ? substr((string)$e['iso'], 0, 4) : '';
        if ($yr) echo '<a class="changelog-more" href="https://www.sillylaird.ca/changelog/#year-' . $h($yr) . '">more (' . $h($yr) . ') &rarr;</a>';
        echo '</li>';
    }
    echo '</ol>';
}