Add ability to delete a group

lib/mobilizon/actors/actors.ex

@@ -242,6 +242,13 @@ defmodule Mobilizon.Actors do
     |> Repo.insert()
   end
 
+  @doc """
+  Delete a group
+  """
+  def delete_group!(%Actor{type: :Group} = group) do
+    Repo.delete!(group)
+  end
+
   alias Mobilizon.Actors.User
 
   @doc """
@@ -551,6 +558,16 @@ defmodule Mobilizon.Actors do
     end
   end
 
+  @doc """
+  Find a group by its actor id
+  """
+  def find_group_by_actor_id(actor_id) do
+    case Repo.get_by(Actor, id: actor_id, type: :Group) do
+      nil -> {:error, :group_not_found}
+      actor -> {:ok, actor}
+    end
+  end
+
   @doc """
   Authenticate user
   """

lib/mobilizon/actors/member.ex

@@ -6,6 +6,7 @@ defmodule Mobilizon.Actors.Member do
   import Ecto.Changeset
   alias Mobilizon.Actors.Member
   alias Mobilizon.Actors.Actor
+  alias Mobilizon.Repo
 
   schema "members" do
     field(:approved, :boolean, default: true)
@@ -24,4 +25,22 @@ defmodule Mobilizon.Actors.Member do
     |> validate_required([:parent_id, :actor_id])
     |> unique_constraint(:parent_id, name: :members_actor_parent_unique_index)
   end
+
+  @doc """
+  Gets a single member of an actor (for example a group)
+  """
+  def get_member(actor_id, parent_id) do
+    case Repo.get_by(Member, actor_id: actor_id, parent_id: parent_id) do
+      nil -> {:error, :member_not_found}
+      member -> {:ok, member}
+    end
+  end
+
+  def is_administrator(%Member{role: 2} = member) do
+    {:is_admin, true}
+  end
+
+  def is_administrator(%Member{}) do
+    {:is_admin, false}
+  end
 end

lib/mobilizon/actors/user.ex

@@ -144,4 +144,16 @@ defmodule Mobilizon.Actors.User do
   def is_confirmed(%User{} = user) do
     {:ok, user}
   end
+
+  def owns_actor(%User{default_actor_id: default_actor_id} = user, %Actor{id: actor_id})
+      when default_actor_id == actor_id do
+    {:is_owned, true}
+  end
+
+  def owns_actor(%User{actors: actors} = user, actor_id) do
+    case Enum.any?(actors, fn a -> a.id == actor_id end) do
+      true -> {:is_owned, true}
+      _ -> {:is_owned, false}
+    end
+  end
 end

lib/mobilizon_web/resolvers/group.ex

@@ -3,7 +3,7 @@ defmodule MobilizonWeb.Resolvers.Group do
   Handles the group-related GraphQL calls
   """
   alias Mobilizon.Actors
-  alias Mobilizon.Actors.{Actor}
+  alias Mobilizon.Actors.{Actor, User, Member}
   alias Mobilizon.Service.ActivityPub
   alias Mobilizon.Activity
   require Logger
@@ -68,4 +68,41 @@ defmodule MobilizonWeb.Resolvers.Group do
   def create_group(_parent, _args, _resolution) do
     {:error, "You need to be logged-in to create a group"}
   end
+
+  @doc """
+  Delete an existing group
+  """
+  def delete_group(
+        _parent,
+        %{group_id: group_id, actor_id: actor_id},
+        %{
+          context: %{
+            current_user: user
+          }
+        }
+      ) do
+    with {:ok, %Actor{} = group} <- Actors.find_group_by_actor_id(group_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
+      {:ok, %{id: group.id}}
+    else
+      {:error, :group_not_found} ->
+        {:error, "Group with preferred username not found"}
+
+      {:is_owned, false} ->
+        {:error, "Actor id is not owned by authenticated user"}
+
+      {:error, :member_not_found} ->
+        {:error, "Actor id is not a member of this group"}
+
+      {:is_admin, false} ->
+        {:error, "User is not an administrator of the selected group"}
+    end
+  end
+
+  def delete_group(_parent, _args, _resolution) do
+    {:error, "You need to be logged-in to delete a group"}
+  end
 end

lib/mobilizon_web/schema.ex

@@ -20,6 +20,11 @@ defmodule MobilizonWeb.Schema do
 
   alias MobilizonWeb.Resolvers
 
+  @desc "A struct containing the id of the deleted object"
+  object :deleted_object do
+    field(:id, :integer)
+  end
+
   @desc "A JWT and the associated user ID"
   object :login do
     field(:token, non_null(:string), description: "A JWT Token for this session")
@@ -301,6 +306,14 @@ defmodule MobilizonWeb.Schema do
       resolve(&Resolvers.Group.create_group/3)
     end
 
+    @desc "Delete a group"
+    field :delete_group, :deleted_object do
+      arg(:group_id, non_null(:integer))
+      arg(:actor_id, non_null(:integer))
+
+      resolve(&Resolvers.Group.delete_group/3)
+    end
+
     # @desc "Upload a picture"
     # field :upload_picture, :picture do
     #   arg(:file, non_null(:upload))

priv/repo/migrations/20190125143718_group_delete_members_cascade.exs

@@ -0,0 +1,13 @@
+defmodule Mobilizon.Repo.Migrations.GroupDeleteMembersCascade do
+  use Ecto.Migration
+
+  def change do
+    drop constraint(:members, "members_account_id_fkey")
+    drop constraint(:members, "members_parent_id_fkey")
+
+    alter table(:members) do
+      modify :actor_id, references(:actors, on_delete: :delete_all)
+      modify :parent_id, references(:actors, on_delete: :delete_all)
+    end
+  end
+end

test/mobilizon_web/resolvers/group_resolver_test.exs

@@ -114,5 +114,36 @@ defmodule MobilizonWeb.Resolvers.GroupResolverTest do
       assert hd(json_response(res, 200)["errors"])["message"] ==
                "Group with name #{@non_existent_username} not found"
     end
+
+    test "delete_group/3 deletes a group", %{conn: conn, user: user, actor: actor} do
+      group = insert(:group)
+      insert(:member, parent: group, actor: actor, role: 2)
+
+      mutation = """
+          mutation {
+            deleteGroup(
+              actor_id: #{actor.id},
+              group_id: #{group.id}
+            ) {
+                id
+              }
+            }
+      """
+
+      res =
+        conn
+        |> auth_conn(user)
+        |> post("/api", AbsintheHelpers.mutation_skeleton(mutation))
+
+      assert json_response(res, 200)["errors"] == nil
+      assert json_response(res, 200)["data"]["deleteGroup"]["id"] == group.id
+
+      res =
+        conn
+        |> auth_conn(user)
+        |> post("/api", AbsintheHelpers.mutation_skeleton(mutation))
+
+      assert hd(json_response(res, 200)["errors"])["message"] =~ "not found"
+    end
   end
 end

test/support/factory.ex

@@ -148,7 +148,8 @@ defmodule Mobilizon.Factory do
   def member_factory do
     %Mobilizon.Actors.Member{
       parent: build(:actor),
-      actor: build(:actor)
+      actor: build(:actor),
+      role: 0
     }
   end
 end