--- /dev/null
+<?php
+/*
+ * Name: invidious
+ * Description: Replaces links to youtube.com to an invidious instance in all displays of postings on a node.
+ * Version: 0.1
+ * Author: Matthias Ebers <@feb@loma.ml>
+ *
+ */
+
+use Friendica\App;
+use Friendica\Core\Hook;
+use Friendica\Core\Renderer;
+use Friendica\DI;
+
+function invidious_install()
+{
+ Hook::register('prepare_body_final', 'addon/invidious/invidious.php', 'invidious_render');
+}
+
+/* Handle the send data from the admin settings
+ */
+function invidious_addon_admin_post()
+{
+ DI::config()->set('invidious', 'server', rtrim(trim($_POST['invidiousserver']), '/'));
+}
+
+/* Hook into the admin settings to let the admin choose an
+ * invidious server to use for the replacement.
+ */
+function invidious_addon_admin(string &$o)
+{
+ $invidiousserver = DI::config()->get('invidious', 'server');
+ $t = Renderer::getMarkupTemplate('admin.tpl', 'addon/invidious/');
+ $o = Renderer::replaceMacros($t, [
+ '$settingdescription' => DI::l10n()->t('Which Invidious server shall be used for the replacements in the post bodies? Use the URL with servername and protocol. See %s for a list of available public Invidious servers.', 'https://redirect.invidious.io'),
+ '$invidiousserver' => ['invidiousserver', DI::l10n()->t('Invidious server'), $invidiousserver, 'https://example.com'],
+ '$submit' => DI::l10n()->t('Save Settings'),
+ ]);
+}
+
+/*
+ * replace "youtube.com" with the chosen Invidious instance
+ */
+function invidious_render(array &$b)
+{
+ // this needs to be a system setting
+ $replaced = false;
+ $invidious = DI::config()->get('invidious', 'server', 'https://invidio.us');
+ if (strstr($b['html'], 'https://www.youtube.com')) {
+ $b['html'] = str_replace('https://www.youtube.com', $invidious, $b['html']);
+ $replaced = true;
+ }
+ if (strstr($b['html'], 'https://youtube.com')) {
+ $b['html'] = str_replace('https://youtube.com', $invidious, $b['html']);
+ $replaced = true;
+ }
+ if (strstr($b['html'], 'https://youtu.be')) {
+ $b['html'] = str_replace('https://youtu.be', $invidious, $b['html']);
+ $replaced = true;
+ }
+ if ($replaced) {
+ $b['html'] .= '<hr><p><small>' . DI::l10n()->t('(Invidious addon enabled: YouTube links via %s)', $invidious) . '</small></p>';
+ }
+}