Add more metadata elements

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/service/metadata/event.ex

@@ -1,9 +1,12 @@
 defimpl Mobilizon.Service.Metadata, for: Mobilizon.Events.Event do
   alias Phoenix.HTML
   alias Phoenix.HTML.Tag
+  alias Mobilizon.Actors.Actor
   alias Mobilizon.Addresses.Address
   alias Mobilizon.Events.{Event, EventOptions}
+  alias Mobilizon.Web.Endpoint
   alias Mobilizon.Web.JsonLD.ObjectView
+  alias Mobilizon.Web.Router.Helpers, as: Routes
 
   import Mobilizon.Service.Metadata.Utils,
     only: [process_description: 2, strip_tags: 1, datetime_to_string: 2, render_address: 1]
@@ -35,9 +38,64 @@ defimpl Mobilizon.Service.Metadata, for: Mobilizon.Events.Event do
           ]
       end
 
+    breadcrumbs =
+      if event.attributed_to do
+        [
+          %{
+            "@context" => "https://schema.org",
+            "@type" => "BreadcrumbList",
+            "itemListElement" => [
+              %{
+                "@type" => "ListItem",
+                "position" => 1,
+                "name" => Actor.display_name(event.attributed_to),
+                "item" =>
+                  Endpoint
+                  |> Routes.page_url(
+                    :actor,
+                    Actor.preferred_username_and_domain(event.attributed_to)
+                  )
+                  |> URI.decode()
+              },
+              %{
+                "@type" => "ListItem",
+                "position" => 2,
+                "name" => event.title
+              }
+            ]
+          }
+        ]
+      else
+        []
+      end
+
+    breadcrumbs =
+      breadcrumbs ++
+        [
+          %{
+            "@context" => "https://schema.org",
+            "@type" => "BreadcrumbList",
+            "itemListElement" => [
+              %{
+                "@type" => "ListItem",
+                "position" => 1,
+                "name" => "Events",
+                "item" => "#{Endpoint.url()}/search"
+              },
+              %{
+                "@type" => "ListItem",
+                "position" => 2,
+                "name" => event.title
+              }
+            ]
+          }
+        ]
+
     tags ++
       [
         Tag.tag(:meta, property: "twitter:card", content: "summary_large_image"),
+        ~s{<script type="application/ld+json">#{Jason.encode!(breadcrumbs)}</script>}
+        |> HTML.raw(),
         ~s{<script type="application/ld+json">#{json(event)}</script>} |> HTML.raw()
       ]
   end