-- Knowledge Platform schema migration
-- Migration id: 0041_logical_document_availability
-- Dialect: postgres
-- Adds document-scoped availability without mutating source or physical index state.

ALTER TABLE "logical_documents"
  ADD COLUMN IF NOT EXISTS "enabled" BOOLEAN NOT NULL DEFAULT TRUE,
  ADD COLUMN IF NOT EXISTS "disabled_at" TIMESTAMP,
  ADD COLUMN IF NOT EXISTS "disabled_by_subject_id" VARCHAR(255);

ALTER TABLE "logical_documents"
  ADD CONSTRAINT "logical_documents_availability_ck"
  CHECK (
    ("enabled" AND "disabled_at" IS NULL AND "disabled_by_subject_id" IS NULL)
    OR (NOT "enabled" AND "disabled_at" IS NOT NULL AND "disabled_by_subject_id" IS NOT NULL)
  );