Arjun PatelandGitHub
a8a0b7db1b
* wip * wip * wip * format * wip(mobile): lint and format * cleanup * nits * nits * idiomatic react * nit * format all root files
50 lines
1.5 KiB
TypeScript
50 lines
1.5 KiB
TypeScript
import { useMemo } from 'react';
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import type { Transcript } from '@/api/types';
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type Sentence = Transcript['paragraphs'][number]['sentences'][number];
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interface TranscriptPlaybackState {
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/** The sentence currently being spoken, or null if between sentences */
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activeSentence: Sentence | null;
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/** Index of the active word within the transcript's flat words array */
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activeWordIndex: number | null;
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}
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export function useTranscriptPlayback(
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transcript: Transcript | undefined,
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currentTime: number,
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): TranscriptPlaybackState {
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return useMemo(() => {
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if (!transcript) return { activeSentence: null, activeWordIndex: null };
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// Find the active sentence across all paragraphs
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let activeSentence: Sentence | null = null;
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for (const paragraph of transcript.paragraphs) {
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const sentence = paragraph.sentences.find(
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(s) => currentTime >= s.start && currentTime <= s.end,
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);
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if (sentence) {
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activeSentence = sentence;
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break;
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}
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}
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// Binary search for active word
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const words = transcript.words;
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let activeWordIndex: number | null = null;
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let lo = 0;
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let hi = words.length - 1;
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while (lo <= hi) {
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const mid = (lo + hi) >>> 1;
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if (currentTime < words[mid].start) hi = mid - 1;
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else if (currentTime > words[mid].end) lo = mid + 1;
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else {
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activeWordIndex = mid;
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break;
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}
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}
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return { activeSentence, activeWordIndex };
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}, [transcript, currentTime]);
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}
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