-- +goose Up
-- Ранжировщик волны v2 (docs/recommendations.md#6.3): признаки кандидата в момент показа — для обучения
-- LightGBM на исходах показов (wave_impressions.outcome); артефакт модели хранится в model_versions.
CREATE TABLE rec_impression_features (
  wave_session_id uuid NOT NULL REFERENCES wave_sessions(id) ON DELETE CASCADE,
  track_id        uuid NOT NULL,
  features        real[] NOT NULL,
  served_at       timestamptz NOT NULL DEFAULT now(),
  PRIMARY KEY (wave_session_id, track_id)
);
CREATE INDEX rec_impression_features_served_idx ON rec_impression_features (served_at);

ALTER TABLE model_versions ADD COLUMN artifact text;

-- +goose Down
ALTER TABLE model_versions DROP COLUMN artifact;
DROP TABLE rec_impression_features;