minstrel/web/src/lib/api/normalization.ts

import { api, apiFetch } from './client';

// Loudness normalization preference (M464 #4998). One per user, stored on
// the server so the web player, the Android app and casts agree.
export type NormalizationMode = 'off' | 'auto' | 'track' | 'album';
export type NormalizationTarget = -18 | -16 | -14;
export type NormalizationBoost = 'headroom' | 'limiter';

export type NormalizationPrefs = {
  mode: NormalizationMode;
  target_lufs: NormalizationTarget;
  boost: NormalizationBoost;
};

// Must match library.DefaultNormalizationPrefs on the server.
export const DEFAULT_NORMALIZATION: NormalizationPrefs = {
  mode: 'auto',
  target_lufs: -18,
  boost: 'headroom'
};

export const NORMALIZATION_MODES: NormalizationMode[] = ['off', 'auto', 'track', 'album'];
export const NORMALIZATION_TARGETS: NormalizationTarget[] = [-18, -16, -14];

export function isNormalizationPrefs(v: unknown): v is NormalizationPrefs {
  if (typeof v !== 'object' || v === null) return false;
  const p = v as Record<string, unknown>;
  return (
    NORMALIZATION_MODES.includes(p.mode as NormalizationMode) &&
    NORMALIZATION_TARGETS.includes(p.target_lufs as NormalizationTarget) &&
    (p.boost === 'headroom' || p.boost === 'limiter')
  );
}

export function getNormalization(): Promise<NormalizationPrefs> {
  return api.get<NormalizationPrefs>('/api/me/normalization');
}

// The whole preference is sent every time; the server keeps the last write.
export function putNormalization(p: NormalizationPrefs): Promise<NormalizationPrefs> {
  return api.put<NormalizationPrefs>('/api/me/normalization', p);
}

// Per-track gains (#4997): dB to the -18 LUFS ReplayGain reference and linear
// peaks. A field is absent until the server has measured it.
export type ReplayGain = {
  track_gain?: number;
  track_peak?: number;
  album_gain?: number;
  album_peak?: number;
};

/**
 * Gains for up to 200 tracks; an id missing from items has none yet. Given
 * a deadline: the player waits on it, and a request that never answers
 * would leave those tracks unleveled for the rest of the session.
 */
export function getReplayGain(ids: string[]): Promise<{ items: Record<string, ReplayGain> }> {
  return apiFetch(`/api/tracks/replay-gain?ids=${ids.map(encodeURIComponent).join(',')}`, {
    signal: AbortSignal.timeout(10_000)
  }) as Promise<{ items: Record<string, ReplayGain> }>;
}