dougal-software/etc/db/upgrades/upgrade25-v0.3.12-add-midnight-shots-procedure.sql

-- Fix not being able to edit a time-based event.
--
-- New schema version: 0.3.12
--
-- ATTENTION:
--
-- ENSURE YOU HAVE BACKED UP THE DATABASE BEFORE RUNNING THIS SCRIPT.
--
--
-- NOTE: This upgrade affects all schemas in the database.
-- NOTE: Each application starts a transaction, which must be committed
-- or rolled back.
--
-- This defines a midnight_shots view and a log_midnight_shots() procedure
-- (with some overloads). The view returns all points straddling midnight
-- UTC and belonging to the same sequence (so last shot of the day and
-- first shot of the next day).
--
-- The procedure inserts the corresponding events (optionally constrained
-- by an earliest and a latest date) in the event log, unless the events
-- already exist.
--
-- To apply, run as the dougal user:
--
-- psql <<EOF
-- \i $THIS_FILE
-- COMMIT;
-- EOF
--
-- NOTE: It can be applied multiple times without ill effect.
--

BEGIN;

CREATE OR REPLACE PROCEDURE pg_temp.show_notice (notice text) AS $$
BEGIN
	RAISE NOTICE '%', notice;
END;
$$ LANGUAGE plpgsql;

CREATE OR REPLACE PROCEDURE pg_temp.upgrade_survey_schema (schema_name text) AS $outer$
BEGIN

	RAISE NOTICE 'Updating schema %', schema_name;
	-- We need to set the search path because some of the trigger
	-- functions reference other tables in survey schemas assuming
	-- they are in the search path.
	EXECUTE format('SET search_path TO %I,public', schema_name);

	CREATE OR REPLACE VIEW midnight_shots AS
	WITH straddlers AS (
		-- Get sequence numbers straddling midnight UTC
		SELECT sequence
		FROM final_shots
		GROUP BY sequence
		HAVING min(date(tstamp)) != max(date(tstamp))
	),
	ts AS (
		-- Get earliest and latest timestamps for each day
		-- for each of the above sequences.
		-- This will return the timestamps for:
		-- FSP, LDSP, FDSP, LSP.
		SELECT
			fs.sequence,
			min(fs.tstamp) AS ts0,
			max(fs.tstamp) AS ts1
		FROM final_shots fs INNER JOIN straddlers USING (sequence)
		GROUP BY fs.sequence, (date(fs.tstamp))
		ORDER BY fs.sequence, date(fs.tstamp)
	),
	spts AS (
		-- Filter out FSP, LSP from the above.
		-- NOTE: This *should* in theory be able to cope with
		-- a sequence longer than 24 hours (so with more than
		-- one LDSP, FDSP) but that hasn't been tested.
		SELECT DISTINCT
			sequence,
			min(ts1) OVER (PARTITION BY sequence) ldsp,
			max(ts0) OVER (PARTITION BY sequence) fdsp
		FROM ts
		ORDER BY sequence
	), evt AS (
		SELECT
			fs.tstamp,
			fs.sequence,
			point,
			'Last shotpoint of the day' remarks,
			'{LDSP}'::text[] labels
		FROM final_shots fs
			INNER JOIN spts ON fs.sequence = spts.sequence AND fs.tstamp = spts.ldsp
		UNION SELECT
			fs.tstamp,
			fs.sequence,
			point,
			'First shotpoint of the day' remarks,
			'{FDSP}'::text[] labels
		FROM final_shots fs
			INNER JOIN spts ON fs.sequence = spts.sequence AND fs.tstamp = spts.fdsp
		ORDER BY tstamp
	)
	SELECT * FROM evt;


	CREATE OR REPLACE PROCEDURE log_midnight_shots (dt0 date, dt1 date)
	LANGUAGE sql
	AS $$
		INSERT INTO event_log (sequence, point, remarks, labels, meta)
		SELECT
			sequence, point, remarks, labels,
			'{"auto": true, "insertedBy": "log_midnight_shots"}'::jsonb
		FROM midnight_shots ms
		WHERE
			(dt0 IS NULL OR ms.tstamp >= dt0) AND
			(dt1 IS NULL OR ms.tstamp <= dt1) AND
			NOT EXISTS (
				SELECT 1
				FROM event_log el
				WHERE ms.sequence = el.sequence AND ms.point = el.point AND el.labels @> ms.labels
			);

		-- Delete any midnight shots that might have been inserted in the log
		-- but are no longer relevant according to the final_shots data.
		-- We operate on event_log, so the deletion is traceable.
		DELETE
		FROM event_log
		WHERE id IN (
			SELECT id
			FROM event_log el
				LEFT JOIN midnight_shots ms USING (sequence, point)
			WHERE
				'{LDSP,FDSP}'::text[] && el.labels -- &&: Do the arrays overlap?
				AND ms.sequence IS NULL
		);
	$$;

	COMMENT ON PROCEDURE log_midnight_shots (date, date)
		IS 'Add midnight shots between two dates dt0 and dt1 to the event_log, unless the events already exist.';


	CREATE OR REPLACE PROCEDURE log_midnight_shots (dt0 date)
	LANGUAGE sql
	AS $$
		CALL log_midnight_shots(dt0, NULL);
	$$;

	COMMENT ON PROCEDURE log_midnight_shots (date)
		IS 'Overload taking only a dt0 (adds events on that date or after).';

	CREATE OR REPLACE PROCEDURE log_midnight_shots ()
	LANGUAGE sql
	AS $$
		CALL log_midnight_shots(NULL, NULL);
	$$;

	COMMENT ON PROCEDURE log_midnight_shots ()
		IS 'Overload taking no arguments (adds all missing events).';

END;
$outer$ LANGUAGE plpgsql;

CREATE OR REPLACE PROCEDURE pg_temp.upgrade () AS $outer$
DECLARE
	row RECORD;
BEGIN

	FOR row IN
		SELECT schema_name FROM information_schema.schemata
		WHERE schema_name LIKE 'survey_%'
		ORDER BY schema_name
	LOOP
		CALL pg_temp.upgrade_survey_schema(row.schema_name);
	END LOOP;
END;
$outer$ LANGUAGE plpgsql;

CALL pg_temp.upgrade();

CALL pg_temp.show_notice('Cleaning up');
DROP PROCEDURE pg_temp.upgrade_survey_schema (schema_name text);
DROP PROCEDURE pg_temp.upgrade ();

CALL pg_temp.show_notice('Updating db_schema version');
INSERT INTO public.info VALUES ('version', '{"db_schema": "0.3.12"}')
ON CONFLICT (key) DO UPDATE
	SET value = public.info.value || '{"db_schema": "0.3.12"}' WHERE public.info.key = 'version';


CALL pg_temp.show_notice('All done. You may now run "COMMIT;" to persist the changes');
DROP PROCEDURE pg_temp.show_notice (notice text);

--
--NOTE Run `COMMIT;` now if all went well
--