Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 | 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 130x 130x 130x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 145x 145x 145x 145x 145x 152x 152x 152x 152x 152x 25x 25x 25x 25x 25x 25x 5x 5x 152x 7x 7x 7x 127x 120x 120x 120x 120x 120x 120x 120x 152x 152x 150x 152x 152x 152x 152x 152x 152x 11x 11x 9x 9x 9x 3x 3x 3x 3x 3x 3x 9x 11x 11x 11x 1x 1x 152x 139x 139x 139x 139x 139x 139x 139x 139x 139x 152x 145x 34x 34x 28x 28x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 34x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x | import { AUDIO_MANIFEST_MAP } from './audioManifest'
import { getClipMeta } from './audioClipRegistry'
import { computeClipHash, resolveCanonicalText } from './clipHash'
export type SubtitleAnchor = 'top' | 'bottom'
export interface TtsAudioManagerConfig {
volume: number
enabled: boolean
subtitleDurationMultiplier: number
/** Bottom offset in pixels for subtitle positioning (default 64). */
subtitleBottomOffset: number
/** Anchor subtitles to top or bottom of viewport (default 'bottom'). */
subtitleAnchor: SubtitleAnchor
/** Audio playback speed multiplier (default 1). Pitch is preserved. */
playbackRate: number
}
export interface ManagerSnapshot {
isPlaying: boolean
isEnabled: boolean
volume: number
subtitleText: string | null
subtitleDurationMultiplier: number
subtitleDurationMs: number
/** Bottom offset in pixels for subtitle positioning. */
subtitleBottomOffset: number
/** Anchor subtitles to top or bottom of viewport. */
subtitleAnchor: SubtitleAnchor
/** Last TTS error message (e.g. API failures). Cleared on next successful speak(). */
lastError: string | null
}
/** Locale -> fallback text map (BCP 47 keys). */
export type TtsSay = Record<string, string>
export interface TtsConfig {
tone?: string
say?: TtsSay
/** Voice sources prepended to the global chain for this specific call. */
prependChain?: VoiceSource[]
}
/**
* A segment in a TTS sequence.
* - `string` -> explicit clip ID
* - `{ clipId: string, ... }` -> explicit clip ID with per-segment config
* - `{ say: TtsSay, tone?: string }` -> hash-based (clip ID computed from content)
*/
export type TtsSegment =
| string
| ({ clipId: string } & Partial<TtsConfig>)
| { say: TtsSay; tone?: string }
function hasExplicitClipId(seg: object): seg is { clipId: string } & Partial<TtsConfig> {
return 'clipId' in seg && typeof (seg as Record<string, unknown>).clipId === 'string'
}
export type TtsInput = TtsSegment | TtsSegment[]
export interface CollectedClip {
clipId: string
say: TtsSay
tone: string
playCount: number
firstSeen: Date
lastSeen: Date
}
export type { VoiceSourceData } from './voiceSource'
import type { VoiceSourceData } from './voiceSource'
import {
type VoiceSource,
PregeneratedVoice,
CustomVoice,
GenerateVoice,
hydrateVoiceChain,
} from './voiceSource'
type Listener = () => void
type ChainAttemptOutcome = 'no-clip' | 'play-error' | 'unavailable' | 'skipped'
interface ChainAttempt {
source: VoiceSource
outcome: ChainAttemptOutcome
}
/** Resolved segment ready for playback. */
interface ResolvedSegment {
clipId: string
fallbackText: string
tone: string
prependChain?: VoiceSource[]
}
const INTER_SEGMENT_GAP_MS = 80
export class TtsAudioManager {
private listeners = new Set<Listener>()
private collection = new Map<string, CollectedClip>()
private _isPlaying = false
private _isEnabled = false
private _volume = 0.8
private _playbackRate = 1
private _subtitleDurationMultiplier = 1
private _currentSubtitleDurationMs = 0
private _subtitleBottomOffset = 64
private _subtitleAnchor: SubtitleAnchor = 'bottom'
// Voice chain: ordered fallback list for playback
private _voiceChain: VoiceSource[] = []
// Pre-generated clip IDs: voice name -> set of clip IDs with mp3s on disk
private _pregenClipIds = new Map<string, Set<string>>()
// Currently playing Audio element (for mp3 playback)
private _currentAudio: HTMLAudioElement | null = null
// Duration (ms) of the currently playing audio clip, set from loadedmetadata
private _currentAudioDurationMs: number | null = null
// Preloaded Audio element for the next expected speak() call.
// Set by preloadForSpeak(), consumed by playMp3() for instant playback.
private _preloadedAudio: { url: string; audio: HTMLAudioElement } | null = null
// Pending seek: if set, playMp3() applies this seek after audio starts.
// Set by seekNextAudio(), consumed (cleared) by playMp3().
private _pendingSeekMs: number | null = null
// Sequence cancellation flag
private _sequenceCancelled = false
// Monotonically increasing speak call ID for stale detection
private _speakSeq = 0
private _activeSpeakId = 0
// Subtitle display state
private _subtitleText: string | null = null
private _subtitleTimer: ReturnType<typeof setTimeout> | null = null
private _subtitleResolve: (() => void) | null = null
// Last error from TTS generation/playback (surfaced to admin/debug UI)
private _lastError: string | null = null
// Cached snapshot for useSyncExternalStore -- must be referentially stable
private _cachedSnapshot: ManagerSnapshot = {
isPlaying: false,
isEnabled: false,
volume: 0.8,
subtitleText: null,
subtitleDurationMultiplier: 1,
subtitleDurationMs: 0,
subtitleBottomOffset: 64,
subtitleAnchor: 'bottom',
lastError: null,
}
// -- Configuration --
configure(config: Partial<TtsAudioManagerConfig>): void {
let changed = false
if (config.volume !== undefined) {
this._volume = Math.max(0, Math.min(1, config.volume))
changed = true
}
if (config.enabled !== undefined) {
const wasEnabled = this._isEnabled
this._isEnabled = config.enabled
changed = true
if (wasEnabled && !config.enabled) {
this.stop()
}
}
if (config.subtitleDurationMultiplier !== undefined) {
this._subtitleDurationMultiplier = config.subtitleDurationMultiplier
changed = true
// Restart the active subtitle timer so the new speed takes effect immediately
if (this._subtitleText && this._subtitleResolve) {
if (this._subtitleTimer) clearTimeout(this._subtitleTimer)
const newMs = this.estimateReadingTimeMs(this._subtitleText)
this._currentSubtitleDurationMs = newMs
const resolve = this._subtitleResolve
this._subtitleTimer = setTimeout(() => {
this._subtitleResolve = null
resolve()
}, newMs)
}
}
if (config.subtitleBottomOffset !== undefined) {
this._subtitleBottomOffset = config.subtitleBottomOffset
changed = true
}
if (config.subtitleAnchor !== undefined) {
this._subtitleAnchor = config.subtitleAnchor
changed = true
}
if (config.playbackRate !== undefined) {
this._playbackRate = Math.max(0.25, Math.min(4, config.playbackRate))
// Apply to currently playing audio element immediately
if (this._currentAudio) {
this._currentAudio.playbackRate = this._playbackRate
this._currentAudio.preservesPitch = true
}
changed = true
}
if (changed) this.notify()
}
// -- Voice Chain --
/**
* Load the pre-generated clip manifest for the given voice chain.
* Fetches from the manifest endpoint to populate `_pregenClipIds`.
*/
async loadPregenManifest(voiceChainData: VoiceSourceData[]): Promise<void> {
this._voiceChain = hydrateVoiceChain(voiceChainData)
const diskVoices = this._voiceChain
.filter(
(s): s is PregeneratedVoice | CustomVoice =>
s instanceof PregeneratedVoice || s instanceof CustomVoice
)
.map((s) => s.name)
if (diskVoices.length === 0) return
try {
const res = await fetch(`/api/audio/collected-clips/manifest?voices=${diskVoices.join(',')}`)
if (!res.ok) return
const data: { clipIdsByVoice: Record<string, string[]> } = await res.json()
for (const [voice, ids] of Object.entries(data.clipIdsByVoice)) {
this._pregenClipIds.set(voice, new Set(ids))
}
} catch {
// Non-fatal -- fall back to browser TTS
}
}
// -- Runtime Collection --
register(input: TtsInput, config?: TtsConfig): void {
const segments = Array.isArray(input) ? input : [input]
const topTone = config?.tone ?? ''
const topSay = config?.say
for (const seg of segments) {
let clipId: string
let segSay: TtsSay | undefined
let segTone: string | undefined
if (typeof seg === 'string') {
clipId = seg
// Look up per-clip text from the static registry so it overrides
// any sentence-level topSay (e.g. when an array of clip IDs is
// registered alongside a full-sentence say map).
const meta = getClipMeta(clipId)
if (meta) {
segSay = { en: meta.text }
}
} else if (hasExplicitClipId(seg)) {
clipId = seg.clipId
segSay = seg.say
segTone = seg.tone
} else {
// Hash-based segment: compute clip ID from content
segSay = seg.say
segTone = seg.tone
const effectiveSay: TtsSay = { ...topSay, ...segSay }
const effectiveTone = segTone ?? topTone
clipId = computeClipHash(effectiveSay, effectiveTone)
}
if (!clipId) continue
const effectiveTone = segTone ?? topTone
// Merge: top-level say, then segment say (segment wins)
const effectiveSay: TtsSay = { ...topSay, ...segSay }
const existing = this.collection.get(clipId)
if (existing) {
// Clobber detection for explicit IDs: warn if canonical text changed
if (typeof seg === 'string' || (typeof seg === 'object' && hasExplicitClipId(seg))) {
const oldCanonical = resolveCanonicalText(existing.say)
const newCanonical = resolveCanonicalText(effectiveSay)
if (oldCanonical && newCanonical && oldCanonical !== newCanonical) {
console.warn(
`[TTS] Clip "${clipId}" re-registered with different text: ` +
`"${oldCanonical}" → "${newCanonical}". ` +
`Consider using hash-based IDs: useTTS({ say: { en: '...' }, tone: '...' })`
)
}
}
// Merge say maps across calls
Object.assign(existing.say, effectiveSay)
if (effectiveTone && !existing.tone) {
existing.tone = effectiveTone
}
} else {
this.collection.set(clipId, {
clipId,
say: effectiveSay,
tone: effectiveTone,
playCount: 0,
firstSeen: new Date(),
lastSeen: new Date(),
})
}
}
}
getCollection(): CollectedClip[] {
return Array.from(this.collection.values())
}
/**
* Flush played clips to the server.
*
* By default uses `sendBeacon` (fire-and-forget, safe during page unload).
* Pass `{ awaitResponse: true }` to use `fetch` so the caller can await
* the server's response before proceeding (e.g. before generation).
*/
async flush(options?: { awaitResponse?: boolean }): Promise<void> {
const clips = this.getCollection().filter((c) => c.playCount > 0)
if (clips.length === 0) return
const payload = clips.map((c) => ({
clipId: c.clipId,
say: c.say,
tone: c.tone,
playCount: c.playCount,
}))
const body = JSON.stringify({ clips: payload })
if (options?.awaitResponse) {
// Awaitable path — caller needs the data committed before continuing
try {
await fetch('/api/audio/collected-clips', {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body,
})
} catch {
// Best-effort -- don't throw during cleanup
}
return
}
// Fire-and-forget path — safe during page unload
if (typeof navigator !== 'undefined' && navigator.sendBeacon) {
navigator.sendBeacon(
'/api/audio/collected-clips',
new Blob([body], { type: 'application/json' })
)
} else {
try {
await fetch('/api/audio/collected-clips', {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body,
})
} catch {
// Best-effort -- don't throw during cleanup
}
}
}
// -- Audio duration (for adaptive animation timing) --
/**
* Duration (ms) of the currently playing audio clip.
* Reads directly from the live Audio element when available (immune to
* speak()'s cached field reset race). Falls back to the cached value
* from loadedmetadata for edge cases.
* Returns null when no audio is playing or duration is unknown.
*/
getCurrentAudioDurationMs(): number | null {
const audio = this._currentAudio
if (audio && audio.readyState >= 1) {
const d = audio.duration
if (isFinite(d) && d > 0) return d * 1000
}
return this._currentAudioDurationMs
}
/**
* Request that the next audio clip starts playback from `timeMs` into
* the clip rather than from the beginning. Consumed (cleared) by
* playMp3() once applied. Use before calling speak() to resume
* mid-sentence after a scrub.
*/
seekNextAudio(timeMs: number): void {
this._pendingSeekMs = timeMs > 0 ? timeMs : null
}
/**
* Preload audio for an upcoming speak() call so it starts instantly.
*
* Resolves the input through the voice chain and, if a pre-generated mp3
* is available, creates an Audio element with `preload='auto'` to start
* fetching in the background. When speak() is later called for the same
* clip, playMp3() uses the already-buffered element — zero load latency.
*
* No-op when audio is disabled or when the clip requires generation /
* browser TTS / subtitle-only playback.
*/
preloadForSpeak(input: TtsInput, config?: TtsConfig): void {
if (!this._isEnabled) return
const segments = Array.isArray(input) ? input : [input]
if (segments.length !== 1) return
const resolved = this.resolveSegment(segments[0], config)
for (const source of this._voiceChain) {
if (source instanceof PregeneratedVoice || source instanceof CustomVoice) {
const clipIds = this._pregenClipIds.get(source.name)
if (clipIds?.has(resolved.clipId)) {
const url = `/api/audio/clips/${encodeURIComponent(source.name)}/${encodeURIComponent(resolved.clipId)}`
if (this._preloadedAudio?.url === url) return // already preloading
if (this._preloadedAudio) this._preloadedAudio.audio.src = ''
const audio = new Audio(url)
audio.preload = 'auto'
audio.volume = this._volume
this._preloadedAudio = { url, audio }
return
}
}
}
}
// -- Playback --
/**
* Play an mp3 file from a URL.
* Returns true if playback completed, false on error.
*/
private playMp3(url: string): Promise<boolean> {
return new Promise<boolean>((resolve) => {
// Pause any orphaned audio element before creating a new one
if (this._currentAudio) {
this._currentAudio.pause()
this._currentAudio = null
}
// Use preloaded element if available — instant playback, no network wait
let audio: HTMLAudioElement
if (this._preloadedAudio?.url === url) {
audio = this._preloadedAudio.audio
this._preloadedAudio = null
} else {
audio = new Audio(url)
}
audio.volume = this._volume
audio.playbackRate = this._playbackRate
audio.preservesPitch = true
this._currentAudio = audio
// Expose audio duration for adaptive animation timing
audio.addEventListener('loadedmetadata', () => {
if (this._currentAudio === audio) {
this._currentAudioDurationMs = audio.duration * 1000
}
})
// For preloaded elements, metadata is already available
if (audio.readyState >= 1 && this._currentAudio === audio) {
this._currentAudioDurationMs = audio.duration * 1000
}
// Only clear _currentAudio if it's still THIS element — a newer
// speak() call may have already overwritten it with a different one.
const clearIfOwned = () => {
if (this._currentAudio === audio) this._currentAudio = null
}
audio.onended = () => {
clearIfOwned()
resolve(true)
}
audio.onerror = () => {
clearIfOwned()
resolve(false)
}
audio.play().catch(() => {
clearIfOwned()
resolve(false)
})
// Apply pending seek (set by seekNextAudio) — works even before
// the audio is fully loaded; the browser buffers and seeks.
if (this._pendingSeekMs !== null) {
const seekSec = this._pendingSeekMs / 1000
this._pendingSeekMs = null
// If metadata is already loaded, seek immediately
if (audio.readyState >= 1 && isFinite(audio.duration)) {
audio.currentTime = Math.min(seekSec, audio.duration)
} else {
// Wait for metadata then seek
audio.addEventListener(
'loadedmetadata',
() => {
if (this._currentAudio === audio && isFinite(audio.duration)) {
audio.currentTime = Math.min(seekSec, audio.duration)
}
},
{ once: true }
)
}
}
})
}
/**
* Resolve BCP 47 locale from a TtsSay map using navigator.languages.
*/
private resolveSay(say: TtsSay | undefined): string | undefined {
if (!say) return undefined
const keys = Object.keys(say)
if (keys.length === 0) return undefined
if (typeof navigator !== 'undefined' && navigator.languages) {
for (const locale of navigator.languages) {
// Exact match
if (say[locale] !== undefined) return say[locale]
// Language-only prefix: en-US -> en
const langOnly = locale.split('-')[0]
if (say[langOnly] !== undefined) return say[langOnly]
}
}
// Fall back to first available key
return say[keys[0]]
}
/**
* Resolve a single segment into playback-ready form.
*/
private resolveSegment(seg: TtsSegment, topConfig?: TtsConfig): ResolvedSegment {
let clipId: string
let segSay: TtsSay | undefined
let segTone: string | undefined
if (typeof seg === 'string') {
const meta = getClipMeta(seg)
if (meta) {
clipId = seg
segSay = { en: meta.text }
} else {
// Not a registered clip — treat as text to be spoken.
// Hash it to produce a safe, short clipId instead of using
// the raw string (which can exceed filesystem name limits).
segSay = { en: seg }
segTone = topConfig?.tone ?? ''
clipId = computeClipHash(segSay, segTone)
}
} else if (hasExplicitClipId(seg)) {
clipId = seg.clipId
segSay = seg.say
segTone = seg.tone
} else {
// Hash-based segment
segSay = seg.say
segTone = seg.tone
const effectiveSay: TtsSay = { ...topConfig?.say, ...segSay }
const effectiveTone = segTone ?? topConfig?.tone ?? ''
clipId = computeClipHash(effectiveSay, effectiveTone)
}
const effectiveTone = segTone ?? topConfig?.tone ?? ''
const effectiveSay: TtsSay = { ...topConfig?.say, ...segSay }
// Resolve fallback text: manifest entry .text > resolveSay() > clipId
const manifestEntry = AUDIO_MANIFEST_MAP[clipId]
const fallbackText = manifestEntry?.text ?? this.resolveSay(effectiveSay) ?? clipId
return { clipId, fallbackText, tone: effectiveTone, prependChain: topConfig?.prependChain }
}
/** Check if this speak call has been superseded by a newer one. */
private _isStale(speakId: number): boolean {
return speakId !== this._activeSpeakId
}
/**
* Try playing a single resolved segment via the voice chain.
* Returns true if something played, false if chain exhausted.
*/
private async playOneSegment(resolved: ResolvedSegment, speakId: number): Promise<boolean> {
if (this._isStale(speakId)) return false
// When a per-call prependChain is present, insert a GenerateVoice
// after the prepended sources so that on-demand generation fires
// for the character voice before the global chain's cached voices.
const effectiveChain = resolved.prependChain?.length
? [...resolved.prependChain, new GenerateVoice(), ...this._voiceChain]
: this._voiceChain
const log: ChainAttempt[] = []
if (effectiveChain.length > 0) {
for (let i = 0; i < effectiveChain.length; i++) {
if (this._isStale(speakId)) return false
const source = effectiveChain[i]
if (source instanceof PregeneratedVoice || source instanceof CustomVoice) {
const clipIds = this._pregenClipIds.get(source.name)
const hasClip = clipIds?.has(resolved.clipId) ?? false
if (hasClip) {
const url = `/api/audio/clips/${encodeURIComponent(source.name)}/${encodeURIComponent(resolved.clipId)}`
const ok = await this.playMp3(url)
if (this._isStale(speakId)) return false
if (ok) return true
log.push({ source, outcome: 'play-error' })
} else {
log.push({ source, outcome: 'no-clip' })
}
} else if (source.type === 'browser-tts') {
const ok = await this.speakBrowserTts(resolved.fallbackText)
if (this._isStale(speakId)) return false
if (ok) return true
log.push({ source, outcome: 'unavailable' })
} else if (source.type === 'subtitle') {
const readingMs = this.estimateReadingTimeMs(resolved.fallbackText)
this._subtitleText = resolved.fallbackText
this._currentSubtitleDurationMs = readingMs
this.notify()
await new Promise<void>((resolve) => {
this._subtitleResolve = resolve
this._subtitleTimer = setTimeout(() => {
this._subtitleResolve = null
resolve()
}, readingMs)
})
this._subtitleText = null
this._subtitleTimer = null
this._subtitleResolve = null
this._currentSubtitleDurationMs = 0
this.notify()
return !this._isStale(speakId)
} else if (source.type === 'generate') {
const missed = log
.filter((a) => a.outcome === 'no-clip' && a.source.canGenerate())
.map((a) => a.source)
if (missed.length > 0) {
const [primary, ...others] = missed
const ok = await this.generateAndPlay(primary, resolved, speakId)
if (this._isStale(speakId)) return false
if (ok) {
if (others.length > 0) {
this.generateInBackground(others, resolved)
}
return true
}
log.push({ source, outcome: 'play-error' })
} else {
log.push({ source, outcome: 'skipped' })
}
}
}
return false
}
// No voice chain -- fall back to browser TTS
if (this._isStale(speakId)) return false
return await this.speakBrowserTts(resolved.fallbackText)
}
/**
* Play a sequence of resolved segments with inter-segment gaps.
*/
private async playSequence(segments: ResolvedSegment[], speakId: number): Promise<void> {
this._isPlaying = true
this._sequenceCancelled = false
this.notify()
for (let i = 0; i < segments.length; i++) {
if (this._isStale(speakId)) break
await this.playOneSegment(segments[i], speakId)
// Inter-segment gap (skip after last segment)
if (i < segments.length - 1 && !this._isStale(speakId)) {
await new Promise<void>((resolve) => setTimeout(resolve, INTER_SEGMENT_GAP_MS))
}
}
this.setPlaying(false)
}
async speak(input: TtsInput, config?: TtsConfig): Promise<void> {
this.register(input, config)
const speakId = ++this._speakSeq
this._activeSpeakId = speakId
if (!this._isEnabled) return
const segments = Array.isArray(input) ? input : [input]
if (segments.length === 0) return
const resolved = segments.map((seg) => this.resolveSegment(seg, config))
// Increment play counts
for (const r of resolved) {
const entry = this.collection.get(r.clipId)
if (entry) {
entry.playCount++
entry.lastSeen = new Date()
}
}
// Cancel any in-flight playback before starting new speech.
this._sequenceCancelled = true
this._currentAudioDurationMs = null
if (this._subtitleTimer) {
clearTimeout(this._subtitleTimer)
this._subtitleTimer = null
}
if (this._subtitleResolve) {
this._subtitleResolve()
this._subtitleResolve = null
}
this._subtitleText = null
if (this._currentAudio) {
this._currentAudio.pause()
this._currentAudio = null
}
// If browser TTS is active from a previous speak() call, cancel it
// and wait a frame. Chrome silently drops speechSynthesis.speak() if
// cancel() was called in the same synchronous frame, so the delay is
// required to ensure the subsequent speak() is not swallowed.
if (
typeof window !== 'undefined' &&
'speechSynthesis' in window &&
(speechSynthesis.speaking || speechSynthesis.pending)
) {
speechSynthesis.cancel()
this._activeUtterances.clear()
await new Promise<void>((r) => setTimeout(r, 50))
}
if (resolved.length === 1) {
this.setPlaying(true)
await this.playOneSegment(resolved[0], speakId)
if (!this._isStale(speakId)) this.setPlaying(false)
} else {
await this.playSequence(resolved, speakId)
}
}
/**
* Speak using browser SpeechSynthesis.
* Returns true if successful, false if unavailable or errored.
*/
private speakBrowserTts(text: string): Promise<boolean> {
if (typeof window === 'undefined' || !('speechSynthesis' in window)) {
return Promise.resolve(false)
}
// Fast-fail when no active user gesture
if (navigator.userActivation && !navigator.userActivation.isActive) {
return Promise.resolve(false)
}
const voices = speechSynthesis.getVoices()
if (voices.length === 0) {
return Promise.resolve(false)
}
return new Promise<boolean>((resolve) => {
let settled = false
const settle = (value: boolean) => {
if (settled) return
settled = true
clearTimeout(safetyTimeout)
clearTimeout(startTimeout)
resolve(value)
}
// Safety timeout — if browser hangs, don't block the UI forever
const safetyTimeout = setTimeout(() => {
speechSynthesis.cancel()
this._activeUtterances.delete(utterance)
settle(false)
}, 10_000)
// Start detection — if speaking hasn't started after 1.5s, it silently failed
const startTimeout = setTimeout(() => {
if (!speechSynthesis.speaking && !speechSynthesis.pending) {
speechSynthesis.cancel()
this._activeUtterances.delete(utterance)
settle(false)
}
}, 1500)
const utterance = new SpeechSynthesisUtterance(text)
utterance.volume = this._volume
utterance.rate = 0.9 * this._playbackRate
utterance.onend = () => {
this._activeUtterances.delete(utterance)
settle(true)
}
utterance.onerror = () => {
this._activeUtterances.delete(utterance)
settle(false)
}
this._activeUtterances.add(utterance)
speechSynthesis.speak(utterance)
})
}
// Prevent GC of in-flight utterances — Chrome may corrupt the speech
// queue if a queued SpeechSynthesisUtterance is garbage-collected.
private _activeUtterances = new Set<SpeechSynthesisUtterance>()
/**
* Generate a clip on-demand via the voice's `generate()` method and play it.
* On success, also adds the clip to the pregen cache so future
* playback hits the pregenerated path directly.
*/
private async generateAndPlay(
source: VoiceSource,
resolved: ResolvedSegment,
speakId: number
): Promise<boolean> {
let blobUrl: string | null = null
try {
const blob = await source.generate(resolved.clipId, resolved.fallbackText, resolved.tone)
if (this._isStale(speakId)) return false
if (!blob) {
const voiceName =
source instanceof PregeneratedVoice || source instanceof CustomVoice
? source.name
: source.type
this._lastError = `[TTS] Generation returned empty response (voice: ${voiceName}, clip: ${resolved.clipId})`
console.error(this._lastError)
this.notify()
return false
}
blobUrl = URL.createObjectURL(blob)
const ok = await this.playMp3(blobUrl)
if (this._isStale(speakId)) return false
if (ok) {
// Clear error on success
if (this._lastError) {
this._lastError = null
this.notify()
}
if (source instanceof PregeneratedVoice || source instanceof CustomVoice) {
this.addToPregenCache(source.name, resolved.clipId)
}
}
return ok
} catch (err) {
const msg = err instanceof Error ? err.message : String(err)
this._lastError = `[TTS] generateAndPlay error: ${msg}`
console.error(this._lastError)
this.notify()
return false
} finally {
if (blobUrl) URL.revokeObjectURL(blobUrl)
}
}
/**
* Fire-and-forget generation for additional voices that were missed.
* On success, adds the clip to the pregen cache for future playback.
*/
private generateInBackground(sources: VoiceSource[], resolved: ResolvedSegment): void {
for (const source of sources) {
source
.generate(resolved.clipId, resolved.fallbackText, resolved.tone)
.then((blob) => {
if (blob && (source instanceof PregeneratedVoice || source instanceof CustomVoice)) {
this.addToPregenCache(source.name, resolved.clipId)
}
})
.catch(() => {
// Silent — background generation is best-effort
})
}
}
private addToPregenCache(voice: string, clipId: string): void {
let ids = this._pregenClipIds.get(voice)
if (!ids) {
ids = new Set()
this._pregenClipIds.set(voice, ids)
}
ids.add(clipId)
}
stop(): void {
// Invalidate any in-flight speak call so its chain stops
this._activeSpeakId = -1
// Cancel any running sequence
this._sequenceCancelled = true
this._currentAudioDurationMs = null
this._pendingSeekMs = null
// Stop any playing mp3
if (this._currentAudio) {
this._currentAudio.pause()
this._currentAudio = null
}
// Stop browser TTS
if (typeof window !== 'undefined' && 'speechSynthesis' in window) {
speechSynthesis.cancel()
}
this._activeUtterances.clear()
// Clear subtitle display
if (this._subtitleTimer) {
clearTimeout(this._subtitleTimer)
this._subtitleTimer = null
}
if (this._subtitleResolve) {
this._subtitleResolve()
this._subtitleResolve = null
}
this._subtitleText = null
// Clear preloaded audio
if (this._preloadedAudio) {
this._preloadedAudio.audio.src = ''
this._preloadedAudio = null
}
if (this._isPlaying) {
this.setPlaying(false)
}
}
// -- React integration: useSyncExternalStore --
subscribe = (listener: Listener): (() => void) => {
this.listeners.add(listener)
return () => {
this.listeners.delete(listener)
}
}
getSnapshot = (): ManagerSnapshot => {
return this._cachedSnapshot
}
// -- Introspection (for admin tools) --
/**
* Return per-voice clip availability for the current voice chain.
* Read-only — mirrors what `playOneSegment` checks internally.
*/
getClipAvailability(clipId: string): Array<{ source: VoiceSourceData; hasClip: boolean }> {
return this._voiceChain.map((source) => ({
source: source.toJSON(),
hasClip:
source instanceof PregeneratedVoice || source instanceof CustomVoice
? (this._pregenClipIds.get(source.name)?.has(clipId) ?? false)
: true, // browser-tts, subtitle, generate are always "available"
}))
}
/**
* Dismiss the current subtitle early, advancing to the next segment.
*/
dismissSubtitle(): void {
if (this._subtitleTimer) {
clearTimeout(this._subtitleTimer)
this._subtitleTimer = null
}
if (this._subtitleResolve) {
this._subtitleResolve()
this._subtitleResolve = null
}
}
// -- Cleanup --
dispose(): void {
this.stop()
}
// -- Private --
private setPlaying(playing: boolean): void {
if (this._isPlaying !== playing) {
this._isPlaying = playing
this.notify()
}
}
private estimateReadingTimeMs(text: string): number {
const words = text.trim().split(/\s+/).length
const baseMs = (words / 200) * 60_000
return Math.max(1500, baseMs * this._subtitleDurationMultiplier)
}
private notify(): void {
// Rebuild cached snapshot so useSyncExternalStore sees a new reference
this._cachedSnapshot = {
isPlaying: this._isPlaying,
isEnabled: this._isEnabled,
volume: this._volume,
subtitleText: this._subtitleText,
subtitleDurationMultiplier: this._subtitleDurationMultiplier,
subtitleDurationMs: this._currentSubtitleDurationMs,
subtitleBottomOffset: this._subtitleBottomOffset,
subtitleAnchor: this._subtitleAnchor,
lastError: this._lastError,
}
for (const listener of this.listeners) {
listener()
}
}
}
|