SET search_path TO atlas, public;

-- 素材保留审计关系，删除后释放内容摘要，重新上传会创建独立素材和对象路径。
ALTER TABLE media_assets ADD COLUMN deleted_at TIMESTAMPTZ;
ALTER TABLE media_assets ADD COLUMN deleted_checksum_sha256 TEXT;
ALTER TABLE media_assets ALTER COLUMN checksum_sha256 DROP NOT NULL;
ALTER TABLE media_assets ADD CONSTRAINT media_assets_deletion_shape
    CHECK ((deleted_at IS NULL AND checksum_sha256 IS NOT NULL)
        OR (deleted_at IS NOT NULL AND checksum_sha256 IS NULL));
ALTER TABLE collection_asset_transfers ADD COLUMN deleted_at TIMESTAMPTZ;

CREATE TABLE product_image_deletions (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    workspace_id UUID NOT NULL,
    product_id UUID NOT NULL,
    asset_id UUID,
    collection_image_id UUID,
    status TEXT NOT NULL DEFAULT 'queued' CHECK (status IN ('queued', 'succeeded', 'failed')),
    objects JSONB NOT NULL DEFAULT '[]',
    error_code TEXT,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    completed_at TIMESTAMPTZ,
    FOREIGN KEY (workspace_id, product_id) REFERENCES products(workspace_id, id) ON DELETE RESTRICT,
    FOREIGN KEY (workspace_id, asset_id) REFERENCES media_assets(workspace_id, id) ON DELETE RESTRICT,
    FOREIGN KEY (collection_image_id) REFERENCES collection_asset_transfers(id) ON DELETE RESTRICT,
    UNIQUE (workspace_id, id),
    UNIQUE (workspace_id, asset_id),
    UNIQUE (workspace_id, collection_image_id),
    CHECK (asset_id IS NOT NULL OR collection_image_id IS NOT NULL)
);
ALTER TABLE product_image_deletions ENABLE ROW LEVEL SECURITY;
ALTER TABLE product_image_deletions FORCE ROW LEVEL SECURITY;
CREATE POLICY workspace_isolation ON product_image_deletions
    USING (workspace_id = app_current_workspace_id()) WITH CHECK (workspace_id = app_current_workspace_id());
ALTER TABLE collection_asset_transfers ADD CONSTRAINT collection_asset_transfers_product_identity UNIQUE (workspace_id, id, product_id);
ALTER TABLE product_image_deletions ADD CONSTRAINT product_image_deletions_collection_scope
    FOREIGN KEY (workspace_id, collection_image_id, product_id) REFERENCES collection_asset_transfers(workspace_id, id, product_id);

-- 引用写入锁定素材，与删除事务的排他锁串行；历史引用保留，但不能重新选择已删除素材。
CREATE FUNCTION reject_deleted_media_reference() RETURNS trigger LANGUAGE plpgsql SET search_path = atlas, public AS $$
DECLARE column_name TEXT; asset UUID; removed TIMESTAMPTZ;
BEGIN
    FOREACH column_name IN ARRAY TG_ARGV LOOP
        FOR asset IN SELECT value::uuid FROM jsonb_array_elements_text(
            CASE WHEN jsonb_typeof(to_jsonb(NEW)->column_name) = 'array' THEN to_jsonb(NEW)->column_name
            ELSE jsonb_build_array(to_jsonb(NEW)->column_name) END) value WHERE value IS NOT NULL LOOP
            SELECT deleted_at INTO removed FROM media_assets WHERE id = asset FOR KEY SHARE;
            IF removed IS NOT NULL THEN RAISE EXCEPTION 'media asset has been deleted' USING ERRCODE = '23514'; END IF;
        END LOOP;
    END LOOP;
    RETURN NEW;
END $$;
DO $$ DECLARE rel RECORD; BEGIN
    FOR rel IN SELECT c.conrelid::regclass AS tab, a.attname AS col
        FROM pg_constraint c JOIN pg_attribute a ON a.attrelid = c.conrelid AND a.attnum = ANY(c.conkey)
        WHERE c.contype = 'f' AND c.confrelid = 'atlas.media_assets'::regclass
          AND a.attname <> 'workspace_id' AND c.conrelid <> 'atlas.product_image_deletions'::regclass LOOP
        EXECUTE format('CREATE TRIGGER %I BEFORE INSERT OR UPDATE OF %I ON %s FOR EACH ROW EXECUTE FUNCTION reject_deleted_media_reference(%L)',
            'guard_deleted_' || rel.col, rel.col, rel.tab, rel.col);
    END LOOP;
END $$;
CREATE TRIGGER guard_deleted_ai_references BEFORE INSERT OR UPDATE OF reference_asset_ids ON media_ai_edits
    FOR EACH ROW EXECUTE FUNCTION reject_deleted_media_reference('reference_asset_ids');