-- Deploy tipus:ensure_role_exists to pg
-- requires: schema_auth
-- requires: user

begin;

set search_path to auth, public;

create or replace function ensure_role_exists() returns trigger as
$$
begin
    if not exists (select 1 from pg_roles where rolname = new.role) then
        raise foreign_key_violation using message = 'role not found: ' || new.role;
    end if;
    return new;
end;
$$
    language plpgsql;

comment on function ensure_role_exists() is
    'Makes sure that a role given to a user is a valid, existing role in the cluster.';

revoke execute on function ensure_role_exists() from public;

create trigger ensure_role_exists
    after insert or update
    on "user"
    for each row
execute procedure ensure_role_exists();

commit;