Implement fader policies and pad sound state extraction for Ableton export

src/lib/exporters/ableton/faderPolicies.ts

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+import { FaderParam } from '../../../types/types';
+import type { AblTrack } from '../../transformers/ableton';
+
+export type FaderRenderStrategy = 'target' | 'note' | 'unsupported';
+export type FaderTargetScope = 'track' | 'pad';
+export type FaderSupportStatus = 'mapped' | 'research' | 'unsupported';
+
+export type FaderConversionContext = {
+  track: AblTrack;
+  groupMixer?: boolean;
+  valueOffset?: number;
+};
+
+export type FaderPolicy = {
+  defaultValue: number;
+  renderStrategy: FaderRenderStrategy;
+  targetScope: FaderTargetScope;
+  status: FaderSupportStatus;
+  toLive: (value: number, context: FaderConversionContext) => number;
+};
+
+const identity = (value: number) => value;
+
+export const FADER_POLICIES = {
+  [FaderParam.LVL]: {
+    defaultValue: 1,
+    renderStrategy: 'target',
+    targetScope: 'track',
+    status: 'mapped',
+    toLive: (value, context) =>
+      context.groupMixer ? value : context.track.volume * value,
+  },
+  [FaderParam.PTC]: {
+    defaultValue: 0.5,
+    renderStrategy: 'target',
+    targetScope: 'pad',
+    status: 'research',
+    toLive: (value, context) => (context.valueOffset ?? 0) + (value - 0.5) * 10,
+  },
+  [FaderParam.TIM]: {
+    defaultValue: 0.5,
+    renderStrategy: 'unsupported',
+    targetScope: 'pad',
+    status: 'unsupported',
+    toLive: identity,
+  },
+  [FaderParam.LPF]: {
+    defaultValue: 1,
+    renderStrategy: 'target',
+    targetScope: 'track',
+    status: 'research',
+    toLive: (value) => 20 + value * 0.9 * 115,
+  },
+  [FaderParam.HPF]: {
+    defaultValue: 0,
+    renderStrategy: 'target',
+    targetScope: 'track',
+    status: 'research',
+    toLive: (value) => 20 + value * 0.7 * 115,
+  },
+  [FaderParam.FX]: {
+    defaultValue: 0,
+    renderStrategy: 'target',
+    targetScope: 'track',
+    status: 'mapped',
+    toLive: identity,
+  },
+  [FaderParam.ATK]: {
+    defaultValue: 0,
+    renderStrategy: 'unsupported',
+    targetScope: 'pad',
+    status: 'research',
+    toLive: identity,
+  },
+  [FaderParam.REL]: {
+    defaultValue: 0,
+    renderStrategy: 'unsupported',
+    targetScope: 'pad',
+    status: 'research',
+    toLive: identity,
+  },
+  [FaderParam.PAN]: {
+    defaultValue: 0.5,
+    renderStrategy: 'target',
+    targetScope: 'track',
+    status: 'mapped',
+    toLive: (value) => (value - 0.5) * 2,
+  },
+  [FaderParam.TUNE]: {
+    defaultValue: 0.5,
+    renderStrategy: 'target',
+    targetScope: 'pad',
+    status: 'research',
+    toLive: (value) => Math.max(-0.5, Math.min(0.5, value - 0.5)) * 100,
+  },
+  [FaderParam.VEL]: {
+    defaultValue: 0,
+    renderStrategy: 'note',
+    targetScope: 'track',
+    status: 'research',
+    toLive: identity,
+  },
+  [FaderParam.MOD]: {
+    defaultValue: 0,
+    renderStrategy: 'target',
+    targetScope: 'pad',
+    status: 'research',
+    toLive: (value) => value / 20,
+  },
+} satisfies Record<FaderParam, FaderPolicy>;
+
+export function getFaderPolicy(parameter: FaderParam) {
+  return FADER_POLICIES[parameter];
+}
+
+export function getFaderDefaultValue(parameter: FaderParam) {
+  return getFaderPolicy(parameter).defaultValue;
+}
+
+export function convertGroupFaderValue(
+  parameter: FaderParam,
+  value: number,
+  context: FaderConversionContext,
+) {
+  return getFaderPolicy(parameter).toLive(value, context);
+}

src/lib/exporters/ableton/padSound.ts

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+import type { AblTrack } from '../../transformers/ableton';
+import { koEnvRangeToSeconds } from './utils';
+
+export type PadSoundState = {
+  amp: number;
+  pitch: number;
+  playMode: AblTrack['playMode'];
+  pan: number;
+  trimStart: number;
+  trimEnd: number;
+  envelope: {
+    attack: number;
+    release: number;
+  };
+  time: {
+    mode: AblTrack['timeStretch'];
+    bpm: number;
+    bars: number;
+  };
+  rootNote: number;
+  soundLength: number;
+};
+
+export type PadEnvelopeState = {
+  classicAttackMs: number;
+  classicReleaseMs: number;
+  oneShotFadeInMs: number;
+  oneShotFadeOutMs: number;
+};
+
+export function getPadSoundState(track: AblTrack): PadSoundState {
+  return {
+    amp: track.volume,
+    pitch: track.pitch,
+    playMode: track.playMode,
+    pan: track.pan,
+    trimStart: track.trimLeft,
+    trimEnd: track.trimRight,
+    envelope: {
+      attack: track.attack,
+      release: track.release,
+    },
+    time: {
+      mode: track.timeStretch,
+      bpm: track.timeStretchBpm,
+      bars: track.timeStretchBars,
+    },
+    rootNote: track.rootNote,
+    soundLength: track.soundLength,
+  };
+}
+
+export function getPadEnvelopeState(sound: PadSoundState): PadEnvelopeState {
+  return {
+    classicAttackMs:
+      koEnvRangeToSeconds(sound.envelope.attack, sound.soundLength) * 1000,
+    classicReleaseMs:
+      koEnvRangeToSeconds(sound.envelope.release, sound.soundLength) * 1000,
+    oneShotFadeInMs: 0,
+    oneShotFadeOutMs: 5,
+  };
+}