-- Corrective migration: preserve the already applied 001-004 files.
BEGIN;
SET LOCAL lock_timeout = '10s';
SELECT pg_advisory_xact_lock(hashtextextended('mne:005_compatibility_guards',0));
DO $guard$
BEGIN
 IF to_regclass('mne.compatibility_controls') IS NULL THEN
  RAISE EXCEPTION '004 compatibility migration is required';
 END IF;
 IF EXISTS(SELECT 1 FROM mne.compatibility_controls WHERE capability='canonical_read' AND (enabled OR percentage<>0)) THEN
  RAISE EXCEPTION 'Canonical control is not disabled; explicit reconciliation required';
 END IF;
 IF EXISTS(SELECT 1 FROM pg_constraint WHERE conrelid='mne.compatibility_controls'::regclass AND conname='ck_mne_005_canonical_disabled') THEN
  IF (SELECT pg_get_constraintdef(oid) FROM pg_constraint WHERE conrelid='mne.compatibility_controls'::regclass AND conname='ck_mne_005_canonical_disabled')
   <> $$CHECK (((capability <> 'canonical_read'::text) OR ((NOT enabled) AND (percentage = 0))))$$ THEN
   RAISE EXCEPTION 'Unexpected canonical control constraint';
  END IF;
 ELSE
  ALTER TABLE mne.compatibility_controls ADD CONSTRAINT ck_mne_005_canonical_disabled
   CHECK (capability <> 'canonical_read' OR (NOT enabled AND percentage=0));
 END IF;
END $guard$;
COMMIT;