Hola, me llamo Navaja Suiza. Te hago de todo

-- It generates a valid ticket with the desired packets.
-- It makes sure the code generated is unique among the active tickets
CREATE OR REPLACE FUNCTION generate_ticket_packets(packages_ids int[],
                                                   TYPE text,
                                                   transaction_id text DEFAULT NULL::text,
                                                   _account text DEFAULT NULL::text)
    RETURNS TABLE (ticket_id int, ticket_code text) AS $generate_ticket_packets$

    #variable_conflict use_variable
    DECLARE _rec RECORD;
    DECLARE _packages_id int;
    DECLARE _groups_id int;
    DECLARE _services_id int;
    DECLARE c refcursor;
    BEGIN

        SELECT create_unique_barcode() INTO ticket_code;

        INSERT INTO tickets(code, TYPE) VALUES (ticket_code, TYPE) RETURNING id INTO ticket_id;

        FOREACH _packages_id IN ARRAY packages_ids
        LOOP
            SELECT packets_id, duration FROM packages WHERE id = _packages_id INTO _rec;
            SELECT groups_id INTO _groups_id FROM packets WHERE id = _rec.packets_id;
            OPEN c FOR SELECT services_id FROM packets_have_services WHERE packets_id = _rec.packets_id;
            LOOP
                FETCH c INTO _services_id;
                EXIT WHEN NOT FOUND;
                INSERT INTO tickets_have_services(tickets_id, services_id, groups_id, duration) VALUES (ticket_id, _services_id, _groups_id, _rec.duration);
            END LOOP;
            CLOSE c;
        END LOOP;

        IF transaction_id IS NOT NULL THEN
            UPDATE purchasing_transactions
            SET ticket_code = ticket_code,
                transaction_type = CASE WHEN transaction_type = 'PURCHASE_FREE' THEN 'PURCHASE_FREE' ELSE 'PURCHASE_COMMIT' END,
                account = CASE WHEN _account = NULL::text THEN '{}'::jsonb ELSE _account::jsonb END
            WHERE pasat_transaction_id = transaction_id;
        END IF;
        RETURN NEXT;

    END;
$generate_ticket_packets$ LANGUAGE plpgsql;