--$1 = id_zadania kliknietego (które chcemy przesunąć)
--$2 - numer zadania na ktore chcemy przesunąć nasze zadanie

DECLARE
numer_zadania_1 integer;
ilosc_zadan_1 integer;
id_nadzadania_1 integer;

id_zadania_2 integer;
ilosc_zadan_2 integer;
id_nadzadania_2 integer;

w_ktora_strone boolean;


BEGIN


SELECT numer
INTO numer_zadania_1
FROM zadania
WHERE id = $1;

SELECT id
INTO id_zadania_2
FROM zadania
WHERE numer = $2 AND id_projektu = (SELECT id_projektu FROM zadania WHERE id = $1);

SELECT id_nadzadania
INTO id_nadzadania_1
FROM zadania
WHERE id = $1;

SELECT id_nadzadania
INTO id_nadzadania_2
FROM zadania
WHERE id = id_zadania_2;

if(numer_zadania_1 > $2)
then
    w_ktora_strone = 0;
else
    w_ktora_strone = 1;
end if;


IF ( id_nadzadania_1 = id_nadzadania_2)
THEN
    IF w_ktora_strone = false
    THEN
        WITH RECURSIVE cte(id, id_nadzadania) AS (
            SELECT id, id_nadzadania FROM zadania WHERE id = $1
            UNION ALL
            SELECT z.id, z.id_nadzadania
            FROM zadania z
            INNER JOIN cte c ON c.id = z.id_nadzadania
        )
            SELECT count(id)
            INTO ilosc_zadan_1
            FROM cte;

        WITH RECURSIVE cte(id, id_nadzadania) AS (
            SELECT id, id_nadzadania FROM zadania WHERE id = id_zadania_2
            UNION ALL
            SELECT z.id, z.id_nadzadania
            FROM zadania z
            INNER JOIN cte c ON c.id = z.id_nadzadania
        )
            SELECT count(id)
            INTO ilosc_zadan_2
            FROM cte;


        WITH RECURSIVE cte(id, id_nadzadania) AS (
            SELECT id, id_nadzadania FROM zadania WHERE id = $1
            UNION ALL
            SELECT z.id, z.id_nadzadania
            FROM zadania z
            INNER JOIN cte c ON c.id = z.id_nadzadania
        )
            UPDATE zadania
            SET numer = numer - ilosc_zadan_2
            WHERE id IN (SELECT id FROM cte);

        WITH RECURSIVE cte(id, id_nadzadania) AS (
            SELECT id, id_nadzadania FROM zadania WHERE id = id_zadania_2
            UNION ALL
            SELECT z.id, z.id_nadzadania
            FROM zadania z
            INNER JOIN cte c ON c.id = z.id_nadzadania
        )
            UPDATE zadania
            SET numer = numer + ilosc_zadan_1
            WHERE id IN (SELECT id FROM cte);
    ELSE
            WITH RECURSIVE cte(id, id_nadzadania) AS (
            SELECT id, id_nadzadania FROM zadania WHERE id = $1
            UNION ALL
            SELECT z.id, z.id_nadzadania
            FROM zadania z
            INNER JOIN cte c ON c.id = z.id_nadzadania
        )
            SELECT count(id)
            INTO ilosc_zadan_1
            FROM cte;

        WITH RECURSIVE cte(id, id_nadzadania) AS (
            SELECT id, id_nadzadania FROM zadania WHERE id = id_zadania_2
            UNION ALL
            SELECT z.id, z.id_nadzadania
            FROM zadania z
            INNER JOIN cte c ON c.id = z.id_nadzadania
        )
            SELECT count(id)
            INTO ilosc_zadan_2
            FROM cte;


        WITH RECURSIVE cte(id, id_nadzadania) AS (
            SELECT id, id_nadzadania FROM zadania WHERE id = $1
            UNION ALL
            SELECT z.id, z.id_nadzadania
            FROM zadania z
            INNER JOIN cte c ON c.id = z.id_nadzadania
        )
            UPDATE zadania
            SET numer = numer + ilosc_zadan_2
            WHERE id IN (SELECT id FROM cte);

        WITH RECURSIVE cte(id, id_nadzadania) AS (
            SELECT id, id_nadzadania FROM zadania WHERE id = id_zadania_2
            UNION ALL
            SELECT z.id, z.id_nadzadania
            FROM zadania z
            INNER JOIN cte c ON c.id = z.id_nadzadania
        )
            UPDATE zadania
            SET numer = numer - ilosc_zadan_1
            WHERE id IN (SELECT id FROM cte);

    END IF;
END IF;
END;