DROP TRIGGER IF EXISTS trigger_flag ON osm_housenumber_point;
DROP TRIGGER IF EXISTS trigger_refresh ON housenumber.updates;

-- etldoc: osm_housenumber_point -> osm_housenumber_point
CREATE OR REPLACE FUNCTION convert_housenumber_point() RETURNS VOID AS $$
BEGIN
  UPDATE osm_housenumber_point SET geometry=ST_PointOnSurface(geometry) WHERE ST_GeometryType(geometry) <> 'ST_Point';
END;
$$ LANGUAGE plpgsql;

SELECT convert_housenumber_point();

-- Handle updates

CREATE SCHEMA IF NOT EXISTS housenumber;

CREATE TABLE IF NOT EXISTS housenumber.updates(id serial primary key, t text, unique (t));
CREATE OR REPLACE FUNCTION housenumber.flag() RETURNS trigger AS $$
BEGIN
    INSERT INTO housenumber.updates(t) VALUES ('y')  ON CONFLICT(t) DO NOTHING;
    RETURN null;
END;    
$$ language plpgsql;

CREATE OR REPLACE FUNCTION housenumber.refresh() RETURNS trigger AS
  $BODY$
  BEGIN
    RAISE LOG 'Refresh housenumber';
    PERFORM convert_housenumber_point();
    DELETE FROM housenumber.updates;
    RETURN null;
  END;
  $BODY$
language plpgsql;

CREATE TRIGGER trigger_flag
    AFTER INSERT OR UPDATE OR DELETE ON osm_housenumber_point
    FOR EACH STATEMENT
    EXECUTE PROCEDURE housenumber.flag();

CREATE CONSTRAINT TRIGGER trigger_refresh
    AFTER INSERT ON housenumber.updates
    INITIALLY DEFERRED
    FOR EACH ROW
    EXECUTE PROCEDURE housenumber.refresh();