-- Student photo: a column for the stored path + a private storage bucket.

ALTER TABLE public.students ADD COLUMN IF NOT EXISTS photo_path TEXT;

INSERT INTO storage.buckets (id, name, public)
VALUES ('student-photos', 'student-photos', false)
ON CONFLICT (id) DO NOTHING;

-- Admins upload/replace/remove photos.
CREATE POLICY "student photos admin write" ON storage.objects FOR INSERT TO authenticated
  WITH CHECK (bucket_id = 'student-photos' AND public.current_user_has_role('admin'));
CREATE POLICY "student photos admin update" ON storage.objects FOR UPDATE TO authenticated
  USING (bucket_id = 'student-photos' AND public.current_user_has_role('admin'));
CREATE POLICY "student photos admin delete" ON storage.objects FOR DELETE TO authenticated
  USING (bucket_id = 'student-photos' AND public.current_user_has_role('admin'));

-- Read: admins, the student's teacher, or the student's parent.
-- Path convention is "<student_id>/<filename>", so folder[1] is the student id.
CREATE POLICY "student photos read" ON storage.objects FOR SELECT TO authenticated
  USING (
    bucket_id = 'student-photos' AND (
      public.current_user_has_role('admin')
      OR public.is_parent_of(((storage.foldername(name))[1])::uuid)
      OR public.teaches_student(((storage.foldername(name))[1])::uuid)
    )
  );