MDL-72720 repository: Implement enable_plugin() method

This one was tricky because it works slightly different and requires
a repository instance will be created if it doesn't exist.
For now I've implemented the easiest approach because it's not
possible to create instances (some extra parameters should be added
to the method in order to support it).

admin/repository.php

@@ -183,23 +183,15 @@ function repository_action_url($repository) {
     if (!confirm_sesskey()) {
         print_error('confirmsesskeybad', '', $baseurl);
     }
-    $repositorytype = repository::get_type_by_typename($repository);
-    if (empty($repositorytype)) {
-        print_error('invalidplugin', 'repository', '', $repository);
-    }
-    $repositorytype->update_visibility(true);
-    core_plugin_manager::reset_caches();
+    $class = \core_plugin_manager::resolve_plugininfo_class('repository');
+    $class::enable_plugin($repository, true);
     $return = true;
 } else if ($action == 'hide') {
     if (!confirm_sesskey()) {
         print_error('confirmsesskeybad', '', $baseurl);
     }
-    $repositorytype = repository::get_type_by_typename($repository);
-    if (empty($repositorytype)) {
-        print_error('invalidplugin', 'repository', '', $repository);
-    }
-    $repositorytype->update_visibility(false);
-    core_plugin_manager::reset_caches();
+    $class = \core_plugin_manager::resolve_plugininfo_class('repository');
+    $class::enable_plugin($repository, false);
     $return = true;
 } else if ($action == 'delete') {
     $repositorytype = repository::get_type_by_typename($repository);

lib/classes/plugininfo/repository.php

@@ -40,6 +40,32 @@ public static function get_enabled_plugins() {
         return $DB->get_records_menu('repository', null, 'type ASC', 'type, type AS val');
     }
 
+    public static function enable_plugin(string $pluginname, int $enabled): bool {
+        global $DB;
+
+        $haschanged = false;
+        $repositorytype = \repository::get_type_by_typename($pluginname);
+        if (empty($repositorytype)) {
+            throw new \moodle_exception('invalidplugin', 'repository', '', $pluginname);
+        }
+
+        // The visibility will be only changed if the repository exists in database. Otherwise, this method won't do anything.
+        if ($plugin = $DB->get_record('repository', ['type' => $pluginname])) {
+            $oldvalue = $plugin->visible;
+            // Only set visibility if it's different from the current value.
+            if ($oldvalue != $enabled) {
+                $haschanged = true;
+                $repositorytype->update_visibility($enabled);
+
+                // Include this information into config changes table.
+                add_to_config_log('repository_visibility', $oldvalue, $enabled, $pluginname);
+                \core_plugin_manager::reset_caches();
+            }
+        }
+
+        return $haschanged;
+    }
+
     public function get_settings_section_name() {
         return 'repositorysettings'.$this->name;
     }