Add API to join and leave an event

lib/mobilizon_web/resolvers/event.ex

@@ -4,7 +4,7 @@ defmodule MobilizonWeb.Resolvers.Event do
   """
   alias Mobilizon.Service.ActivityPub
   alias Mobilizon.Activity
-  alias Mobilizon.Events.Event
+  alias Mobilizon.Events.{Event, Participant}
   alias Mobilizon.Actors.User
 
   # We limit the max number of events that can be retrieved
@@ -43,6 +43,78 @@ defmodule MobilizonWeb.Resolvers.Event do
     {:ok, Mobilizon.Events.list_participants_for_event(uuid, 1, 10)}
   end
 
+  @doc """
+  Join an event for an actor
+  """
+  def actor_join_event(
+        _parent,
+        %{actor_id: actor_id, event_id: event_id},
+        %{
+          context: %{
+            current_user: user
+          }
+        }
+      ) do
+    with {:is_owned, true, actor} <- User.owns_actor(user, actor_id),
+         {:ok, %Event{} = event} <- Mobilizon.Events.get_event(event_id),
+         {:error, :participant_not_found} <- Mobilizon.Events.get_participant(event_id, actor_id),
+         role <- Mobilizon.Events.get_default_participant_role(event),
+         {:ok, participant} <-
+           Mobilizon.Events.create_participant(%{
+             role: role,
+             event_id: event.id,
+             actor_id: actor.id
+           }),
+         participant <-
+           Map.put(participant, :event, event)
+           |> Map.put(:actor, actor) do
+      {:ok, participant}
+    else
+      {:is_owned, false} ->
+        {:error, "Actor id is not owned by authenticated user"}
+
+      {:error, :event_not_found} ->
+        {:error, "Event id not found"}
+
+      {:ok, %Participant{}} ->
+        {:error, "You are already a participant of this event"}
+    end
+  end
+
+  def actor_join_event(_parent, _args, _resolution) do
+    {:error, "You need to be logged-in to join an event"}
+  end
+
+  @doc """
+  Leave an event for an actor
+  """
+  def actor_leave_event(
+        _parent,
+        %{actor_id: actor_id, event_id: event_id},
+        %{
+          context: %{
+            current_user: user
+          }
+        }
+      ) do
+    with {:is_owned, true, _} <- User.owns_actor(user, actor_id),
+         {:ok, %Participant{} = participant} <-
+           Mobilizon.Events.get_participant(event_id, actor_id),
+         {:ok, _} <- Mobilizon.Events.delete_participant(participant) do
+      {:ok, %{event: %{id: event_id}, actor: %{id: actor_id}}}
+    else
+      {:is_owned, false} ->
+        {:error, "Actor id is not owned by authenticated user"}
+
+      {:error, :participant_not_found} ->
+        {:error, "Participant not found"}
+    end
+  end
+
+  def actor_leave_event(_parent, _args, _resolution) do
+    {:error, "You need to be logged-in to leave an event"}
+  end
+
   @doc """
   Search events by title
   """
@@ -103,7 +175,7 @@ defmodule MobilizonWeb.Resolvers.Event do
         context: %{current_user: user}
       }) do
     with {:ok, %Event{} = event} <- Mobilizon.Events.get_event(event_id),
-         {:is_owned, true} <- User.owns_actor(user, actor_id),
+         {:is_owned, true, _} <- User.owns_actor(user, actor_id),
          {:event_can_be_managed, true} <- Event.can_event_be_managed_by(event, actor_id),
          event <- Mobilizon.Events.delete_event!(event) do
       {:ok, %{id: event.id}}

lib/mobilizon_web/resolvers/group.ex

@@ -82,7 +82,7 @@ defmodule MobilizonWeb.Resolvers.Group do
         }
       ) do
     with {:ok, %Actor{} = group} <- Actors.find_group_by_actor_id(group_id),
-         {:is_owned, true} <- User.owns_actor(user, actor_id),
+         {:is_owned, true, _} <- User.owns_actor(user, actor_id),
          {:ok, %Member{} = member} <- Member.get_member(actor_id, group.id),
          {:is_admin, true} <- Member.is_administrator(member),
          group <- Actors.delete_group!(group) do