-- Drop old event tables.
--
-- New schema version: 0.3.1
--
-- 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 completes the migration from the old event logging mechanism by
-- DROPPING THE OLD DATABASE OBJECTS, MAKING THE MIGRATION IRREVERSIBLE,
-- other than by restoring from backup and manually transferring any new
-- data that may have been created in the meanwhile.
--
-- To apply, run as the dougal user:
--
-- psql <<EOF
-- \i $THIS_FILE
-- COMMIT;
-- EOF
--
-- NOTE: It can take a while if run on a large database.
-- NOTE: It can be applied multiple times without ill effect.
-- NOTE: This will lock the database while the transaction is active.
--
-- WARNING: Applying this upgrade drops the old tables. Ensure that you
-- have migrated the data first.
--
-- NOTE: This is a patch version change so it does not require a
-- backend restart.

BEGIN;

CREATE OR REPLACE PROCEDURE 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 $$
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);

	DROP FUNCTION IF EXISTS
		label_in_sequence(integer,text), reset_events_serials();

	DROP VIEW IF EXISTS
		events_midnight_shot, events_seq_timed, events_labels, "events";

	DROP TABLE IF EXISTS
		events_seq_labels, events_timed_labels, events_timed_seq, events_seq, events_timed;

	DROP SEQUENCE IF EXISTS
		events_seq_id_seq, events_timed_id_seq;

END;
$$ LANGUAGE plpgsql;

CREATE OR REPLACE PROCEDURE pg_temp.upgrade_database () AS $$
DECLARE
	row RECORD;
BEGIN
	FOR row IN
		SELECT schema_name FROM information_schema.schemata
		WHERE schema_name LIKE 'survey_%'
		ORDER BY schema_name
	LOOP
		CALL pg_temp.upgrade_survey_schema(row.schema_name);
	END LOOP;
END;
$$ LANGUAGE plpgsql;

CALL pg_temp.upgrade_database();

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

CALL show_notice('Updating db_schema version');
INSERT INTO public.info VALUES ('version', '{"db_schema": "0.3.1"}')
ON CONFLICT (key) DO UPDATE
	SET value = public.info.value || '{"db_schema": "0.3.1"}' WHERE public.info.key = 'version';


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

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