-- Tighten the published collectible invariant. Issuance is the only mutable
-- field and every committed upgrade advances it exactly once.

CREATE OR REPLACE FUNCTION public.telesrv_guard_collectible_revision() RETURNS trigger
    LANGUAGE plpgsql AS $$
BEGIN
    IF TG_OP = 'DELETE' THEN
        IF OLD.status = 'published' THEN
            RAISE EXCEPTION 'published collectible revision is immutable';
        END IF;
        RETURN OLD;
    END IF;

    IF OLD.status = 'published' THEN
        IF NEW.gift_id <> OLD.gift_id OR NEW.revision <> OLD.revision OR
           NEW.upgrade_stars <> OLD.upgrade_stars OR NEW.supply_total <> OLD.supply_total OR
           NEW.slug_prefix <> OLD.slug_prefix OR NEW.status <> OLD.status OR
           NEW.created_by <> OLD.created_by OR NEW.command_id <> OLD.command_id OR
           NEW.created_at <> OLD.created_at OR NEW.published_at <> OLD.published_at THEN
            RAISE EXCEPTION 'published collectible revision is immutable';
        END IF;
        IF NEW.issued <> OLD.issued + 1 THEN
            RAISE EXCEPTION 'published collectible issuance must advance exactly once';
        END IF;
    END IF;
    RETURN NEW;
END;
$$;