-- M4a: outbound ListenBrainz scrobble worker.
-- Per-user LB config (plaintext token; users rotate via /settings if leaked).
-- scrobble_queue is a work list, not a log: successfully-sent rows are
-- DELETEd by the worker (the canonical record stays in play_events.scrobbled_at
-- via M2's column). Only `pending` and `failed` states exist.

ALTER TABLE users
    ADD COLUMN listenbrainz_token   TEXT NULL,
    ADD COLUMN listenbrainz_enabled BOOLEAN NOT NULL DEFAULT FALSE;

CREATE TABLE scrobble_queue (
    id               uuid        PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id          uuid        NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    play_event_id    uuid        NOT NULL REFERENCES play_events(id) ON DELETE CASCADE,
    status           TEXT        NOT NULL CHECK (status IN ('pending', 'failed')),
    attempts         INTEGER     NOT NULL DEFAULT 0,
    next_attempt_at  timestamptz NOT NULL DEFAULT now(),
    last_error       TEXT        NULL,
    enqueued_at      timestamptz NOT NULL DEFAULT now(),
    UNIQUE (play_event_id)
);

-- Hot path for the worker's per-tick query.
CREATE INDEX scrobble_queue_pending_idx
    ON scrobble_queue (next_attempt_at)
    WHERE status = 'pending';