refactor(#74): Enhance function robustness and configurability

supabase/migrations/20241112214000_add_token_cleanup_function.sql

@@ -0,0 +1,34 @@
+-- Enable the "pg_cron" extension
+create extension pg_cron with schema pg_catalog;
+
+grant usage on schema cron to postgres;
+grant all privileges on all tables in schema cron to postgres;
+
+-- Create a function to delete expired tokens
+CREATE OR REPLACE FUNCTION delete_expired_tokens()
+RETURNS integer LANGUAGE plpgsql AS $$
+DECLARE
+  deletion_count integer;
+  expiry_interval interval := '24 hours'::interval;
+BEGIN
+  DELETE FROM account_deletion_requests
+  WHERE requested_at < NOW() - expiry_interval
+  RETURNING COUNT(*) INTO deletion_count;
+  RAISE NOTICE 'Deleted % expired token(s)', deletion_count;
+  RETURN deletion_count;
+END;
+$$;
+
+DO $$
+BEGIN
+  -- Schedule the function to run every hour
+  PERFORM cron.schedule(
+    'delete_expired_tokens',
+    '0 * * * *',
+    'SELECT delete_expired_tokens()'
+  );
+EXCEPTION WHEN OTHERS THEN
+  RAISE NOTICE 'Failed to schedule token cleanup: %', SQLERRM;
+  RAISE;
+END;
+$$;