-- Catalog row timestamps for dev/prod harmonize (last-write-wins merge).
-- Idempotent: safe to re-run on existing databases.

CREATE OR REPLACE FUNCTION sync_touch_updated_at()
RETURNS TRIGGER AS $$
BEGIN
  NEW.updated_at = now();
  RETURN NEW;
END;
$$ LANGUAGE plpgsql;

DO $$
DECLARE
  tbl TEXT;
BEGIN
  FOREACH tbl IN ARRAY ARRAY[
    'historical_eras',
    'art_movements',
    'artists',
    'artist_periods',
    'paintings',
    'painting_influences',
    'painting_influence_sources',
    'painting_annotations',
    'tour_stops'
  ]
  LOOP
    -- Skip tables not created yet (e.g. tour_stops before migrate-tours.sql).
    IF to_regclass(format('public.%I', tbl)) IS NULL THEN
      CONTINUE;
    END IF;

    EXECUTE format(
      'ALTER TABLE %I ADD COLUMN IF NOT EXISTS updated_at TIMESTAMPTZ NOT NULL DEFAULT now()',
      tbl
    );

    EXECUTE format('DROP TRIGGER IF EXISTS %I ON %I', tbl || '_updated_at', tbl);
    EXECUTE format(
      'CREATE TRIGGER %I BEFORE UPDATE ON %I FOR EACH ROW EXECUTE PROCEDURE sync_touch_updated_at()',
      tbl || '_updated_at',
      tbl
    );
  END LOOP;
END $$;