CREATE TABLE computer_file_poll_scopes (
    computer_id TEXT NOT NULL REFERENCES computers(id) ON DELETE CASCADE,
    provider_ref TEXT NOT NULL,
    generation INTEGER NOT NULL CHECK(generation > 0),
    bot_id TEXT NOT NULL REFERENCES bots(id) ON DELETE CASCADE,
    last_polled TIMESTAMPTZ NOT NULL DEFAULT '-infinity',
    lease_token TEXT,
    lease_until TIMESTAMPTZ,
    PRIMARY KEY(computer_id,provider_ref,generation,bot_id)
);
CREATE INDEX computer_file_poll_order ON computer_file_poll_scopes(computer_id,provider_ref,generation,last_polled,bot_id);
INSERT INTO computer_file_poll_scopes(computer_id,provider_ref,generation,bot_id)
SELECT DISTINCT computer_id,provider_ref,generation,bot_id FROM computer_file_dispatches;
-- Queue admission is atomic with the durable dispatch identity, including callers
-- on older API versions during a rolling upgrade.
CREATE FUNCTION enqueue_file_poll_scope() RETURNS trigger LANGUAGE plpgsql AS $$
BEGIN
    INSERT INTO computer_file_poll_scopes(computer_id,provider_ref,generation,bot_id)
    VALUES (NEW.computer_id,NEW.provider_ref,NEW.generation,NEW.bot_id)
    ON CONFLICT DO NOTHING;
    RETURN NEW;
END;
$$;
CREATE TRIGGER enqueue_file_poll_scope AFTER INSERT ON computer_file_dispatches
FOR EACH ROW EXECUTE FUNCTION enqueue_file_poll_scope();
CREATE UNIQUE INDEX computer_file_poll_lease ON computer_file_poll_scopes(lease_token) WHERE lease_token IS NOT NULL;