feat: coordinate adaptive audio intent

src/audio/journey-music-state.ts

@@ -1,25 +1,56 @@
-import type { AudioJourneyState } from '@/audio/types';
+import type { SectionId } from '@/content/types';
+import type {
+  AudioJourneyState,
+  ChapterIntent,
+  DriveEnergySample,
+  MusicMood,
+} from '@/audio/types';
 
 const JOURNEY_MUSIC = Object.freeze({
-  start: { bias: 'open', entryPhrase: 0 },
-  profile: { bias: 'open', entryPhrase: 1 },
-  experience: { bias: 'shadow', entryPhrase: 2 },
-  infrastructure: { bias: 'shadow', entryPhrase: 3 },
-  'selected-builds': { bias: 'lift', entryPhrase: 4 },
-  'additional-work': { bias: 'lift', entryPhrase: 5 },
-  toolkit: { bias: 'resolve', entryPhrase: 6 },
-  contact: { bias: 'resolve', entryPhrase: 7 },
-} as const);
+  start: { mood: 'open', entryPhrase: 0 },
+  profile: { mood: 'open', entryPhrase: 1 },
+  experience: { mood: 'shadow', entryPhrase: 2 },
+  infrastructure: { mood: 'shadow', entryPhrase: 3 },
+  'selected-builds': { mood: 'lift', entryPhrase: 4 },
+  'additional-work': { mood: 'lift', entryPhrase: 5 },
+  toolkit: { mood: 'resolve', entryPhrase: 6 },
+  contact: { mood: 'resolve', entryPhrase: 7 },
+} as const satisfies Readonly<Record<
+  SectionId,
+  { readonly mood: MusicMood; readonly entryPhrase: number }
+>>);
+
+export function resolveChapterIntent(
+  sectionId: SectionId,
+  generation = 0,
+): ChapterIntent {
+  const chapter = JOURNEY_MUSIC[sectionId];
+  return Object.freeze({
+    sectionId,
+    mood: chapter.mood,
+    atStart: sectionId === 'start',
+    entryPhrase: chapter.entryPhrase,
+    generation: Math.max(0, Math.trunc(generation)),
+  });
+}
+
+export const DEFAULT_CHAPTER_INTENT = resolveChapterIntent('start');
+export const DEFAULT_DRIVE_ENERGY = Object.freeze({
+  energy: 0,
+  source: 'idle',
+} as const satisfies DriveEnergySample);
 
 export function resolveJourneyMusicState(sectionId: string, intensity = 0): AudioJourneyState {
-  const chapter = Object.hasOwn(JOURNEY_MUSIC, sectionId)
-    ? JOURNEY_MUSIC[sectionId as keyof typeof JOURNEY_MUSIC]
-    : JOURNEY_MUSIC.start;
+  const canonicalId = Object.hasOwn(JOURNEY_MUSIC, sectionId)
+    ? sectionId as SectionId
+    : 'start';
+  const chapter = resolveChapterIntent(canonicalId);
   const finiteIntensity = Number.isFinite(intensity) ? intensity : 0;
   return Object.freeze({
-    ...chapter,
     atStart: sectionId === 'start',
     intensity: Math.min(1, Math.max(0, finiteIntensity)),
+    bias: chapter.mood,
+    entryPhrase: chapter.entryPhrase,
   });
 }