CREATE OR REPLACE FUNCTION updatescores()
  RETURNS void AS
$BODY$DECLARE
	a float8;
	b float8;
	v float8;
	w float8;
	Al float8;
	Bl float8;
	Cl float8;
	C1 float8;
	C2 float8;
	C3 float8;
	c int4;
	d int4;
	e int4;
	x int4;
	y int4;
	z int4;
	i item%ROWTYPE;
BEGIN
	C1 := 0.5;
	C2 := 0.3 * 5;
	C3 := 0.2 * 5;

	SELECT AVG(val) INTO v FROM Values;
	SELECT COUNT(id) INTO x FROM Values;
	IF x < 2 THEN 
		x := 2; 
	END IF;
	SELECT COUNT(id) INTO y FROM Guesses;	
	SELECT AVG(val) INTO w FROM (SELECT val FROM Values ORDER BY val LIMIT (x + 1) % 2 + 1 OFFSET FLOOR(x / 2) - 1) as val;
	IF y < 2 THEN 
		y := 2; 
	END IF;
	SELECT SUM(views) INTO z FROM Items;
	IF z < 2 THEN 
		z := 2; 
	END IF;
	
	FOR i IN EXECUTE 'SELECT * FROM Items' LOOP					
		SELECT AVG(val) INTO a FROM Values WHERE item_id = i.id;
		SELECT COUNT(id) INTO c FROM Values WHERE item_id = i.id;
		SELECT AVG(val) INTO b FROM (SELECT val FROM Values WHERE item_id = i.id ORDER BY val LIMIT (c + 1) % 2 + 1 OFFSET FLOOR(c / 2) - 1) as val;		
		SELECT COUNT(id) INTO d FROM Guesses WHERE item_id = i.id;
		e := i.views;
		IF b IS NULL THEN
			b := 0;
		END IF;
		IF a IS NULL THEN
			a := 0;
		END IF;

		Al := LOG(x, (c + 1.0000000/x) );
		IF Al < 0 THEN Al := 0; END IF;
		Bl := LOG(y, (d + 1.0000000/y) );
		IF Bl < 0 THEN Bl := 0; END IF;
		Cl := LOG(z, (e + 1.0000000/z) );
		IF Cl < 0 THEN Cl := 0; END IF;	

		UPDATE Item SET score = C1 * ( (b * Al) + (v * (1 - Al) ) ) 
								+ ( (C2 * ( (a * Bl) + (w * (1 - Bl) ) ) ) / y) 
								+ ( (C3 * ( (a * Cl) + (w * (1 - Cl) ) ) ) / z) WHERE id = i.id;

		
	END LOOP;	
END;$BODY$
  LANGUAGE 'plpgsql' VOLATILE;