Refactor member view by using presenter

- Create MemberPresenter alongside with GroupMemberPresenter and ProjectMemberPresenter
- Make Member model Presentable
- Move action_member_permission from MembersHelper into the MemberPresenter
- Added rspec using double, separate specs for GroupMemberPresenter and ProjectMemberPresenter

Fixes #28004.

Signed-off-by: Rémy Coutable <remy@rymai.me>

3 files changed, 70 insertions, 0 deletions

diff --git a/app/presenters/group_member_presenter.rb b/app/presenters/group_member_presenter.rb
new file mode 100644
index 00000000000..8f53dfa105e
--- /dev/null
+++ b/app/presenters/group_member_presenter.rb
@@ -0,0 +1,15 @@
+class GroupMemberPresenter < MemberPresenter
+  private
+
+  def admin_member_permission
+    :admin_group_member
+  end
+
+  def update_member_permission
+    :update_group_member
+  end
+
+  def destroy_member_permission
+    :destroy_group_member
+  end
+end
diff --git a/app/presenters/member_presenter.rb b/app/presenters/member_presenter.rb
new file mode 100644
index 00000000000..a8732226018
--- /dev/null
+++ b/app/presenters/member_presenter.rb
@@ -0,0 +1,40 @@
+class MemberPresenter < Gitlab::View::Presenter::Delegated
+  include Gitlab::Allowable
+
+  presents :member
+
+  def can_resend_invite?
+    invite? &&
+      can?(current_user, admin_member_permission, source)
+  end
+
+  def can_update?
+    can?(current_user, update_member_permission, member)
+  end
+
+  def cannot_update?
+    !can_update?
+  end
+
+  def can_remove?
+    can?(current_user, destroy_member_permission, member)
+  end
+
+  def can_approve?
+    request? && can_update?
+  end
+
+  private
+
+  def admin_member_permission
+    raise NotImplementedError
+  end
+
+  def update_member_permission
+    raise NotImplementedError
+  end
+
+  def destroy_member_permission
+    raise NotImplementedError
+  end
+end
diff --git a/app/presenters/project_member_presenter.rb b/app/presenters/project_member_presenter.rb
new file mode 100644
index 00000000000..7f42d2b70df
--- /dev/null
+++ b/app/presenters/project_member_presenter.rb
@@ -0,0 +1,15 @@
+class ProjectMemberPresenter < MemberPresenter
+  private
+
+  def admin_member_permission
+    :admin_project_member
+  end
+
+  def update_member_permission
+    :update_project_member
+  end
+
+  def destroy_member_permission
+    :destroy_project_member
+  end
+end