add event controls to topic edit

assets/javascripts/discourse/connectors/edit-topic/topic-controls-event.hbs

@@ -0,0 +1,3 @@
+{{#if showEventControls}}
+  {{add-event-controls event=buffered.event category=buffered.category noText=site.mobileView}}
+{{/if}}

assets/javascripts/discourse/connectors/edit-topic/topic-controls-event.js.es6

@@ -0,0 +1,21 @@
+import { getOwner } from 'discourse-common/lib/get-owner';
+import Category from 'discourse/models/category';
+
+export default {
+  setupComponent(attrs, component) {
+    const buffered = this.get('buffered');
+    const user = Discourse.User.current();
+    const showEventControls = (category) => {
+      return category.events_enabled && (
+        user.staff ||
+        user.trust_level >= category.events_min_trust_to_create
+      );
+    }
+    component.set('showEventControls', showEventControls(buffered.get('category')))
+    buffered.addObserver('category_id', () => {
+      if (this._state === 'destroying') return;
+      let category = Category.findById(this.get('buffered.category_id'));
+      component.set('showEventControls', showEventControls(category));
+    })
+  }
+}