Add regex docs to plugin.php page

plugin.php

@@ -1,26 +1,26 @@
-<?php
-/*
-Plugin Name: Better Yourls BlackList Domains
-Plugin URI: https://git.oldgate.org/Sophia/better-yourls-blacklist-domains
-Description: Plugin which disallows blacklisted domains and bans the submitter's IP address. GPL v3
-Version: 0.06
-Author: Sophia Atkinson
-Author URI: https://sophia.wtf
-Original Author: apelly
-Original Author URI: http://len.io
-*/
+    <?php
+    /*
+    Plugin Name: Better Yourls BlackList Domains
+    Plugin URI: https://git.oldgate.org/Sophia/better-yourls-blacklist-domains
+    Description: Plugin which disallows blacklisted domains and bans the submitter's IP address. GPL v3
+    Version: 0.06
+    Author: Sophia Atkinson
+    Author URI: https://sophia.wtf
+    Original Author: apelly
+    Original Author URI: http://len.io
+    */
 
-// No direct access
-if( !defined( 'YOURLS_ABSPATH' ) ) die();
+    // No direct access
+    if( !defined( 'YOURLS_ABSPATH' ) ) die();
 
-// Hook the custom function into the 'shunt_add_new_link' event
-yourls_add_filter( 'shunt_add_new_link', 'better_blacklist_domain_check' );
+    // Hook the custom function into the 'shunt_add_new_link' event
+    yourls_add_filter( 'shunt_add_new_link', 'better_blacklist_domain_check' );
 
-// Hook the admin page into the 'plugins_loaded' event
-yourls_add_action( 'plugins_loaded', 'better_blacklist_add_admin_page' );
+    // Hook the admin page into the 'plugins_loaded' event
+    yourls_add_action( 'plugins_loaded', 'better_blacklist_add_admin_page' );
 
-// Function to check if a domain is blacklisted
-function better_blacklist_domain_check( $shunt, $url ) {
+    // Function to check if a domain is blacklisted
+    function better_blacklist_domain_check( $shunt, $url ) {
         // Parse the URL and extract the host
         $parsed_url = parse_url( $url );
 
@@ -62,34 +62,34 @@ function better_blacklist_domain_check( $shunt, $url ) {
 
         // No match, allow the URL
         return $shunt;
-}
+    }
 
-// Return failure response for blacklisted URLs
-function blacklist_fail_response() {
+    // Return failure response for blacklisted URLs
+    function blacklist_fail_response() {
         return array(
             'status'  => 'fail',
             'code'    => 'error:url',
             'message' => 'This domain is blacklisted',
             'errorCode' => '403',
         );
-}
+    }
 
-// Add admin page to handle blacklist management
-function better_blacklist_add_admin_page() {
+    // Add admin page to handle blacklist management
+    function better_blacklist_add_admin_page() {
         yourls_register_plugin_page( 'better_blacklist_domain', 'Blacklist Domains', 'better_blacklist_admin_page' );
-}
+    }
 
-// Display the blacklist admin page
-function better_blacklist_admin_page() {
+    // Display the blacklist admin page
+    function better_blacklist_admin_page() {
         if ( $_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['action']) && $_POST['action'] === 'blacklist_domain' ) {
             better_blacklist_process_form();
         } else {
             better_blacklist_display_form();
         }
-}
+    }
 
-// Display the form to update the blacklist
-function better_blacklist_display_form() {
+    // Display the form to update the blacklist
+    function better_blacklist_display_form() {
         $nonce = yourls_create_nonce( 'blacklist_domain' );
         $blacklist_domains = yourls_get_option( 'better_blacklist_domain_list', 'Enter domain addresses here, one per line' );
 
@@ -103,14 +103,36 @@ function better_blacklist_display_form() {
             <input type="hidden" name="action" value="blacklist_domain" />
             <input type="hidden" name="nonce" value="$nonce" />
             <p>Enter domains to blacklist (one per line):</p>
-        <textarea class="blacklist-domains" cols="60" rows="15" name="blacklist_form">$blacklist_domains</textarea>
+
+            <details>
+                <summary>Advanced Usage (Regex)</summary>
+                <div>
+                    <p>
+                        You can use regular expressions (Regex) to define more complex patterns for blacklisting domains.<br> 
+                        To use Regex, enter your pattern between slashes (/).<br>
+                        
+                        For example, to block all subdomains of example.com, you could enter <code>/\.example\.com$/i</code>.<br>
+                        The <kbd>i</kbd> flag at the end makes the match case-insensitive. Usually you want to use this flag.
+                    </p>
+
+                    <p>
+                        <b>Further examples:</b><br>
+                        <code>/.*\.xxx$/i</code> - Blocks all domains ending with .xxx<br>
+                        <br>
+
+                        Be cautious when using Regex, as incorrect patterns can lead to unintended blocking of domains.<br>
+                        Always test your Regex patterns to ensure they work as expected.
+                    </p>
+                </div>
+            </details><br>
+            <textarea class="blacklist-domains" cols="60" rows="15" name="blacklist_form" placeholder="Example: block.example.com">$blacklist_domains</textarea>
             <p><input type="submit" value="Save" /></p>
         </form>
-HTML;
-}
+    HTML;
+    }
 
-// Process the blacklist form submission
-function better_blacklist_process_form() {
+    // Process the blacklist form submission
+    function better_blacklist_process_form() {
         // Verify nonce for security
         yourls_verify_nonce( 'blacklist_domain' );
 
@@ -133,4 +155,4 @@ function better_blacklist_process_form() {
             }
             echo "</ul>";
         }
-}
+    }