Add a plugin to show a banner on abandoned blogs (not ready yet)

archived-banner.css

+.archived-banner {
+  width: 100%;
+  text-align: center;
+  z-index: 99999;
+  position: relative;
+  display: block;
+}
+.archived-banner .archived-banner-text {
+  font-weight: 700;
+  padding: 10px 20px;
+}

archived-banner.js

+jQuery(document).ready(function() {
+    if (archivedBannerScriptParams.enabled) {
+        $('<div id="archived-banner" class="archived-banner"><div class="archived-banner-text"><span>'
+          + archivedBannerScriptParams.banner_text
+          + '</span></div>' + closeButton + '</div>')
+            .prependTo('body');
+    }
+});

archived-banner.php

+<?php
+/*
+ * Plugin Name: A/I - Archived Banner
+ * Description: Add a banner to archived blogs
+ * Version: 0.0.1
+ * Author: Autistici/Inventati
+ * Author URI: https://autistici.org
+ */
+
+/*
+ * This plugin adds a banner at the top of the page for
+ * abandoned websites.
+ */
+
+define('ARCHIVED_BANNER_VERSION', '0.0.1');
+
+function is_blog_abandoned() {
+  $last_post_date = date_create_from_format('Y-m-d H:i:s', get_lastpostdate());
+  $five_years = new DateInterval('P5Y');
+  $five_years_ago = new DateTime();
+  $five_years_ago->sub($five_years);
+
+  return ($last_post_date < $five_years_ago);
+}
+
+add_action('wp_enqueue_scripts', 'ai_archived_blog_banner');
+function ai_archived_blog_banner() {
+  $script_params = array(
+    "enabled" => true,
+    "banner_text" => "This blog is abandoned and is kept for archival purposes only."
+  );
+
+  wp_register_style('archived-banner-style', plugin_dir_url(__FILE__) . 'archived-banner.css', '', ARCHIVED_BANNER_VERSION);
+  wp_enqueue_style('archived-banner-style');
+  wp_register_script('archived-banner-script', plugin_dir_url( __FILE__ ) . 'archived-banner.js', array('jquery'), ARCHIVED_BANNER_VERSION);
+  wp_add_inline_script('archived-banner-script', 'const archivedBannerScriptParams = ' . wp_json_encode($script_params), 'before');
+  wp_enqueue_script('archived-banner-script');
+}