enable syncthing only if necessary

roles/syncthing/tasks/main.yml

@@ -10,17 +10,22 @@
   template:
     src: "{{ role_path }}/templates/config.xml.j2"
     dest: ~/.config/syncthing/config.xml
+  register: config
 - name: Copy Syncthing private key
   copy:
     src: "{{ role_path }}/files/key.pem"
     dest: ~/.config/syncthing/key.pem
+  register: private_key
 - name: Copy Syncthing certificate
   copy:
     src: "{{ role_path }}/files/cert.pem"
     dest: ~/.config/syncthing/cert.pem
+  register: certificate
 - name: Enable Syncthing
   become: true
   systemd:
     enabled: true
     name: "syncthing@{{ ansible_user_id }}"
-    state: restarted
+    state: "{{ state }}"
+  vars:
+    state: "{{ 'restarted' if config.changed or private_key.changed or certificate.changed else 'started' }}"