// OG tags for sharing a specific timeline event via /timeline/?event=ID
add_action('wp_head', function(){
    if (!is_page()) return;
    // limit to timeline page to avoid side effects
    $is_timeline = false;
    $obj = get_queried_object();
    if ($obj && !empty($obj->post_name)) {
        $is_timeline = ($obj->post_name === 'timeline');
    }
    if (!$is_timeline) return;
    $eid = isset($_GET['event']) ? intval($_GET['event']) : (isset($_GET['event_id']) ? intval($_GET['event_id']) : 0);
    if ($eid <= 0) return;
    global $wpdb;
    $tbl = $wpdb->prefix . 'sh_timeline_events';
    $ev = $wpdb->get_row($wpdb->prepare("SELECT * FROM {$tbl} WHERE id = %d LIMIT 1", $eid));
    if (!$ev) return;
    if (!empty($ev->event_id)) {
        $orig = $wpdb->get_row($wpdb->prepare("SELECT * FROM {$tbl} WHERE id = %d LIMIT 1", intval($ev->event_id)));
        if ($orig) { $ev = $orig; }
    }
    $title = !empty($ev->title) ? wp_strip_all_tags($ev->title) : 'Δημοσίευση';
    $desc = !empty($ev->description) ? wp_strip_all_tags($ev->description) : '';
    $img = '';
    if (!empty($ev->event_image_id)) {
        $img = wp_get_attachment_image_url(intval($ev->event_image_id), 'large');
        if (function_exists('sh_maybe_private_media_url')) { $img = sh_maybe_private_media_url($img); }
    }
    // Absolute og:url pointing to sharable query URL (hash is ignored by crawlers)
    $og_url = add_query_arg('event', $eid, home_url('/timeline/'));
    // Output minimal OG/Twitter tags only when image/title available
    echo "\n";
    echo '<meta property="og:type" content="article" />' . "\n";
    echo '<meta property="og:url" content="' . esc_url($og_url) . '" />' . "\n";
    echo '<meta property="og:title" content="' . esc_attr($title) . '" />' . "\n";
    if ($desc) { echo '<meta property="og:description" content="' . esc_attr(wp_trim_words($desc, 40, '…')) . '" />' . "\n"; }
    if ($img) {
        echo '<meta property="og:image" content="' . esc_url($img) . '" />' . "\n";
        echo '<meta name="twitter:card" content="summary_large_image" />' . "\n";
        echo '<meta name="twitter:image" content="' . esc_url($img) . '" />' . "\n";
    }
}, 1);