container Functions

--
-- Delete expired circulation bucket items for all users that have
-- a setting for patron.max_reading_list_interval.
--
DECLARE
    today        TIMESTAMP WITH TIME ZONE;
    threshold    TIMESTAMP WITH TIME ZONE;
	usr_setting  RECORD;
BEGIN
	SELECT date_trunc( 'day', now() ) INTO today;
	--
	FOR usr_setting in
		SELECT
			usr,
			value
		FROM
			actor.usr_setting
		WHERE
			name = 'patron.max_reading_list_interval'
	LOOP
		--
		-- Make sure the setting is a valid interval
		--
		BEGIN
			threshold := today - CAST( translate( usr_setting.value, '"', '' ) AS INTERVAL );
		EXCEPTION
			WHEN OTHERS THEN
				RAISE NOTICE 'Invalid setting patron.max_reading_list_interval for user %: ''%''',
					usr_setting.usr, usr_setting.value;
				CONTINUE;
		END;
		--
		--RAISE NOTICE 'User % threshold %', usr_setting.usr, threshold;
		--
    	DELETE FROM container.copy_bucket_item
    	WHERE
        	bucket IN
        	(
        	    SELECT
        	        id
        	    FROM
        	        container.copy_bucket
        	    WHERE
        	        owner = usr_setting.usr
        	        AND btype = 'circ_history'
        	)
        	AND create_time < threshold;
	END LOOP;
	--
END;

--
-- Delete old circulation bucket items for a specified user.
-- "Old" means older than the interval specified by a
-- user-level setting, if it is so specified.
--
DECLARE
    threshold TIMESTAMP WITH TIME ZONE;
BEGIN
	-- Sanity check
	IF ac_usr IS NULL THEN
		RETURN;
	END IF;
	-- Determine the threshold date that defines "old".  Subtract the
	-- interval from the system date, then truncate to midnight.
	SELECT
		date_trunc(
			'day',
			now() - CAST( translate( value, '"', '' ) AS INTERVAL )
		)
	INTO
		threshold
	FROM
		actor.usr_setting
	WHERE
		usr = ac_usr
		AND name = 'patron.max_reading_list_interval';
	--
	IF threshold is null THEN
		-- No interval defined; don't delete anything
		-- RAISE NOTICE 'No interval defined for user %', ac_usr;
		return;
	END IF;
	--
	-- RAISE NOTICE 'Date threshold: %', threshold;
	--
	-- Threshold found; do the delete
	delete from container.copy_bucket_item
	where
		bucket in
		(
			select
				id
			from
				container.copy_bucket
			where
				owner = ac_usr
				and btype = 'circ_history'
		)
		and create_time < threshold;
	--
	RETURN;
END;