client/posts: improve form behavior when saving

- Disable and enable the form
- Notify about success in the sidebar
- Notify about errors in the sidebar rather than using a native alert

client/js/controllers/post_controller.js

@@ -101,7 +101,7 @@ class PostController {
     }
 
     _evtPostEdit(e) {
-        // TODO: disable form
+        this._view.sidebarControl.disableForm();
         const post = e.detail.post;
         if (e.detail.tags !== undefined) {
             post.tags = e.detail.tags;
@@ -123,11 +123,12 @@ class PostController {
         }
         post.save()
             .then(() => {
+                this._view.sidebarControl.showSuccess('Post saved.');
+                this._view.sidebarControl.enableForm();
                 misc.disableExitConfirmation();
-                // TODO: enable form
             }, errorMessage => {
-                window.alert(errorMessage);
-                // TODO: enable form
+                this._view.sidebarControl.showError(errorMessage);
+                this._view.sidebarControl.enableForm();
             });
     }
 

client/js/controls/post_edit_sidebar_control.js

@@ -144,6 +144,22 @@ class PostEditSidebarControl extends events.EventTarget {
         return this._formNode.querySelector(
             '.post-thumbnail .dropper-container');
     }
+
+    enableForm() {
+        views.enableForm(this._formNode);
+    }
+
+    disableForm() {
+        views.disableForm(this._formNode);
+    }
+
+    showSuccess(message) {
+        views.showSuccess(this._hostNode, message);
+    }
+
+    showError(message) {
+        views.showError(this._hostNode, message);
+    }
 };
 
 module.exports = PostEditSidebarControl;