minstrel/internal/db/migrations/0005_events.up.sql

-- Listening telemetry: play_sessions, play_events, skip_events.
-- The table is named play_sessions (not sessions — that table already
-- exists from migration 0004 and holds HTTP auth sessions). Listening
-- sessions are an entirely separate concept.
--
-- session_vector_at_play is nullable: plays are recorded before the
-- recommendation engine fills it.

CREATE TABLE play_sessions (
    id              uuid        PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id         uuid        NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    started_at      timestamptz NOT NULL,
    ended_at        timestamptz,
    last_event_at   timestamptz NOT NULL,
    track_count     integer     NOT NULL DEFAULT 0,
    client_id       text
);
CREATE INDEX play_sessions_user_last_event_idx ON play_sessions (user_id, last_event_at DESC);

CREATE TABLE play_events (
    id                       uuid             PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id                  uuid             NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    track_id                 uuid             NOT NULL REFERENCES tracks(id) ON DELETE CASCADE,
    session_id               uuid             NOT NULL REFERENCES play_sessions(id) ON DELETE CASCADE,
    started_at               timestamptz      NOT NULL,
    ended_at                 timestamptz,
    duration_played_ms       integer,
    completion_ratio         double precision,
    was_skipped              boolean          NOT NULL DEFAULT false,
    client_id                text,
    session_vector_at_play   jsonb,
    scrobbled_at             timestamptz
);
CREATE INDEX play_events_user_started_idx ON play_events (user_id, started_at DESC);
CREATE INDEX play_events_user_track_idx   ON play_events (user_id, track_id);

CREATE TABLE skip_events (
    id           uuid        PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id      uuid        NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    track_id     uuid        NOT NULL REFERENCES tracks(id) ON DELETE CASCADE,
    session_id   uuid        NOT NULL REFERENCES play_sessions(id) ON DELETE CASCADE,
    skipped_at   timestamptz NOT NULL,
    position_ms  integer     NOT NULL
);
CREATE INDEX skip_events_user_skipped_idx ON skip_events (user_id, skipped_at DESC);