postgresql rookie needs help with system catalog

I am trying to come up with a query of the system catalog tables to give me
the same info as the psql command "\d tablename"

so far I have come up with the following query
1 SELECT
2 a.attname as "Column",
3 pg_catalog.format_type(a.atttypid, a.atttypmod) as "Datatype"
4 FROM
5 pg_catalog.pg_attribute a
6 WHERE
7 a.attnum > 0
8 AND NOT a.attisdropped
9 AND a.attrelid = (
10 SELECT c.oid
11 FROM pg_catalog.pg_class c
12 LEFT JOIN pg_catalog.pg_namespace n ON n.oid =
c.relnamespace
13 WHERE c.relname = 'laptop'
14 AND pg_catalog.pg_table_is_visible(c.oid)
15 );

which yields the following result

Column | Datatype
---------------+------------------------
id | integer
name | character varying(250)
price | double precision
purchase_date | date
(4 rows)

But how do I get the Collation and Nullable and Default values displayed by
the "psql \d" command ?

Thanks.
--

Barrry Kimelman
Winnipeg, Manitoba, Canada