-- PR8 rollback SQL (manual, only safe BEFORE any project has >1 mentor)
-- Reverses 20260522155652_multi_mentor_per_team

-- MentorChangeRequest: drop new table + enum
DROP TABLE IF EXISTS "MentorChangeRequest";
DROP TYPE IF EXISTS "MentorChangeRequestStatus";

-- MentorFile: drop projectId scope + restore mentorAssignmentId as required Cascade
ALTER TABLE "MentorFile" DROP CONSTRAINT IF EXISTS "MentorFile_projectId_fkey";
DROP INDEX IF EXISTS "MentorFile_projectId_idx";
ALTER TABLE "MentorFile" DROP COLUMN IF EXISTS "projectId";
-- Restoring NOT NULL is safe only if no rows have NULL mentorAssignmentId (true unless multi-mentor assignments were dropped post-migration)
ALTER TABLE "MentorFile" ALTER COLUMN "mentorAssignmentId" SET NOT NULL;
ALTER TABLE "MentorFile" DROP CONSTRAINT IF EXISTS "MentorFile_mentorAssignmentId_fkey";
ALTER TABLE "MentorFile" ADD CONSTRAINT "MentorFile_mentorAssignmentId_fkey"
  FOREIGN KEY ("mentorAssignmentId") REFERENCES "MentorAssignment"("id") ON DELETE CASCADE ON UPDATE CASCADE;

-- MentorAssignment: restore projectId @unique + drop new fields
DROP INDEX IF EXISTS "MentorAssignment_projectId_mentorId_key";
DROP INDEX IF EXISTS "MentorAssignment_projectId_idx";
ALTER TABLE "MentorAssignment" DROP COLUMN IF EXISTS "notificationSentAt";
-- Re-adding UNIQUE will FAIL if any project has >1 mentor (intended safety signal)
ALTER TABLE "MentorAssignment" ADD CONSTRAINT "MentorAssignment_projectId_key" UNIQUE ("projectId");
