Clear notifications when subscription is removed

lib/philomena/channels.ex

@@ -12,6 +12,7 @@ defmodule Philomena.Channels do
   alias Philomena.Tags
 
   use Philomena.Subscriptions,
+    on_delete: :clear_channel_notification,
     id_name: :channel_id
 
   @doc """

lib/philomena/galleries.ex

@@ -19,6 +19,7 @@ defmodule Philomena.Galleries do
   alias Philomena.Images
 
   use Philomena.Subscriptions,
+    on_delete: :clear_gallery_notification,
     id_name: :gallery_id
 
   @doc """

lib/philomena/images.ex

@@ -39,6 +39,7 @@ defmodule Philomena.Images do
   alias Philomena.Users.User
 
   use Philomena.Subscriptions,
+    on_delete: :clear_image_notification,
     id_name: :image_id
 
   @doc """

lib/philomena/subscriptions.ex

@@ -25,6 +25,18 @@ defmodule Philomena.Subscriptions do
     # For Philomena.Images, this yields :image_id
     field_name = Keyword.fetch!(opts, :id_name)
 
+    # Deletion callback
+    on_delete =
+      case Keyword.get(opts, :on_delete) do
+        nil ->
+          []
+
+        callback when is_atom(callback) ->
+          quote do
+            apply(__MODULE__, unquote(callback), [object, user])
+          end
+      end
+
     # For Philomena.Images, this yields Philomena.Images.Subscription
     subscription_module = Module.concat(__CALLER__.module, Subscription)
 
@@ -100,6 +112,8 @@ defmodule Philomena.Subscriptions do
 
       """
       def delete_subscription(object, user) do
+        unquote(on_delete)
+
         Philomena.Subscriptions.delete_subscription(
           unquote(subscription_module),
           unquote(field_name),

lib/philomena/topics.ex

@@ -14,6 +14,7 @@ defmodule Philomena.Topics do
   alias Philomena.NotificationWorker
 
   use Philomena.Subscriptions,
+    on_delete: :clear_topic_notification,
     id_name: :topic_id
 
   @doc """

lib/philomena_web/templates/notification/_topic.html.slime

@@ -18,6 +18,3 @@
 .flex.flex--centered.flex--no-wrap
   a.button.button--separate-right title="Delete" href=~p"/forums/#{forum}/topics/#{topic}/read" data-method="post" data-remote="true" data-click-hideparent=".notification"
     i.fa.fa-trash
-
-  a.button title="Unsubscribe" href=~p"/forums/#{forum}/subscription" data-method="delete" data-remote="true" data-click-hideparent=".notification"
-    i.fa.fa-bell-slash