add duplicate and deleted handling

lib/philomena_web/controllers/image_controller.ex

@@ -12,7 +12,7 @@ defmodule PhilomenaWeb.ImageController do
   alias Philomena.Repo
   import Ecto.Query
 
-  plug :load_and_authorize_resource, model: Image, only: :show, preload: [:tags, user: [awards: :badge]]
+  plug :load_image
 
   plug PhilomenaWeb.FilterBannedUsersPlug when action in [:new, :create]
   plug PhilomenaWeb.UserAttributionPlug when action in [:create]
@@ -135,4 +135,30 @@ defmodule PhilomenaWeb.ImageController do
 
     {user_galleries, image_galleries}
   end
+
+  defp load_image(conn, _opts) do
+    id = conn.params["id"]
+
+    image =
+      Image
+      |> where(id: ^id)
+      |> preload([:tags, :deleter, user: [awards: :badge]])
+      |> Repo.one()
+
+    cond do
+      is_nil(image) ->
+        PhilomenaWeb.NotFoundPlug.call(conn)
+
+      not is_nil(image.duplicate_id) and not Canada.Can.can?(conn, :show, image) ->
+        conn
+        |> put_flash(:info, "The image you were looking for has been marked a duplicate of the image below")
+        |> redirect(to: Routes.image_path(conn, :show, image.duplicate_id))
+
+      image.hidden_from_users ->
+        render(conn, "deleted.html", image: image)
+
+      true ->
+        assign(conn, :image, image)
+    end
+  end
 end

lib/philomena_web/templates/image/deleted.html.slime

@@ -0,0 +1,23 @@
+.walloftext
+  .block.block--fixed.block--warning
+    h1 This image has been deleted
+    p
+      ' Reason:
+      strong
+        = @image.deletion_reason || "Unknown (likely deleted in error). Please contact a moderator."
+
+    = if can?(@conn, :undelete, @image) do
+      p
+        strong> Spoilers!
+        ' Done by:
+        strong = deleter(@image)
+  p
+    ' If you originally uploaded the file previously located here, please don't re-upload it -
+    => link "contact us", to: "/pages/contact"
+    ' if you feel this was in error and we'll talk! We're only human, and mistakes happen.
+  p
+    ' Here's the
+    => link "tagging guidelines", to: "/pages/tags"
+    ' and
+    = link "rules of the site", to: "/pages/rules"
+    ' . Other useful links can be found at the bottom of the page.

lib/philomena_web/views/image_view.ex

@@ -144,6 +144,9 @@ defmodule PhilomenaWeb.ImageView do
     render PhilomenaWeb.TagView, "_tags_row.html", conn: conn, tags: tags
   end
 
+  def deleter(%{deleter: %{name: name}}), do: name
+  def deleter(_image), do: "System"
+
   defp thumb_format("svg", _name), do: "png"
   defp thumb_format(_, :rendered), do: "png"
   defp thumb_format(format, _name), do: format