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import { newerRevision } from '@/shared/contracts/track.ts';
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import type { NowPlaying } from '@/shared/contracts/track.ts';
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import type { SessionState } from './session-state.ts';
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export function acceptMetadata(previous: NowPlaying | undefined, next: NowPlaying): NowPlaying {
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  return !previous || newerRevision(next.revision, previous.revision) ? next : previous;
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}
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/** Packets with a revision must match the current playback revision; legacy packets omit it. */
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export function matchesPlayback(revision: number | undefined, current?: NowPlaying): boolean {
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  return revision === undefined || revision === current?.revision;
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}
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export function playbackView(
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  state: Pick<SessionState, 'room' | 'nowPlaying' | 'telemetry' | 'paused'>,
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) {
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  const { nowPlaying, room, telemetry } = state;
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  // An explicit unknown track must not fall back to stale HTTP metadata.
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  const track = (nowPlaying ? nowPlaying.track : room.track) ?? undefined;
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  const currentSample = !nowPlaying || telemetry?.playbackRevision === nowPlaying.revision;
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  return {
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    track,
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    trackCount: nowPlaying?.trackCount ?? 1,
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    position: currentSample ? (telemetry?.positionMs ?? 0) : 0,
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    duration: track?.durationMs ?? (currentSample ? (telemetry?.durationMs ?? 0) : 0),
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    paused: state.paused ?? false,
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  };
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}