import { Transcript } from "./types.js";
export class YouTubeUtils {
/**
* Format time (convert seconds to readable format)
*/
static formatTime(seconds: number): string {
const hours = Math.floor(seconds / 3600);
const minutes = Math.floor((seconds % 3600) / 60);
const secs = Math.floor(seconds % 60);
const ms = Math.floor((seconds % 1) * 1000);
return `${hours.toString().padStart(2, "0")}:${minutes
.toString()
.padStart(2, "0")}:${secs.toString().padStart(2, "0")}.${ms
.toString()
.padStart(3, "0")}`;
}
/**
* Calculate total duration in seconds
*/
static calculateTotalDuration(items: Transcript[]): number {
return items.reduce(
(acc, item) => Math.max(acc, item.timestamp + item.duration),
0
);
}
/**
* Decode HTML entities
*/
static decodeHTML(text: string): string {
const entities: { [key: string]: string } = {
"&": "&",
"<": "<",
">": ">",
""": "\"",
"'": "'",
"'": "'",
"'": "'",
"/": "/",
"/": "/",
"/": "/",
" ": " ",
" ": " ",
};
return text.replace(/&[^;]+;/g, (match) => entities[match] || match).trim();
}
/**
* Normalize text formatting (punctuation and spaces)
*/
static normalizeText(text: string): string {
return text
.replace(/\n/g, " ")
.replace(/\s*\.\s*\.\s*/g, ". ") // Fix multiple dots
.replace(/\s*\.\s+/g, ". ") // Normalize spaces after dots
.replace(/\s+/g, " ") // Normalize spaces
.replace(/\s+([,.])/g, "$1") // Fix spaces before punctuation
.replace(/\s*\?\s*/g, "? ") // Normalize question marks
.replace(/\s*!\s*/g, "! ") // Normalize exclamation marks
.trim();
}
/**
* Format transcript text with optional paragraph breaks
*/
static formatTranscriptText(
transcripts: Transcript[],
options: {
enableParagraphs?: boolean;
timeGapThreshold?: number;
maxSentencesPerParagraph?: number;
} = {}
): string {
const {
enableParagraphs = false,
timeGapThreshold = 2,
maxSentencesPerParagraph = 5,
} = options;
const processedTranscripts = transcripts
.map((transcript) => this.decodeHTML(transcript.text))
.filter((text) => text.length > 0);
if (!enableParagraphs) {
return this.normalizeText(processedTranscripts.join(" "));
}
const paragraphs: string[] = [];
let currentParagraph: string[] = [];
let lastEndTime = 0;
for (const transcript of transcripts) {
const text = this.decodeHTML(transcript.text.trim());
if (!text) continue;
const timeGap = transcript.timestamp - lastEndTime;
const previousText = currentParagraph[currentParagraph.length - 1] || "";
const isTimeGap = timeGap > timeGapThreshold;
const isNewSentence = previousText.endsWith(".") && /^[A-Z]/.test(text);
const isParagraphFull =
currentParagraph.length >= maxSentencesPerParagraph;
const shouldStartNewParagraph =
isTimeGap || isNewSentence || isParagraphFull;
if (shouldStartNewParagraph && currentParagraph.length > 0) {
paragraphs.push(this.normalizeText(currentParagraph.join(" ")));
currentParagraph = [];
}
currentParagraph.push(text);
lastEndTime = transcript.timestamp + transcript.duration;
}
if (currentParagraph.length > 0) {
paragraphs.push(this.normalizeText(currentParagraph.join(" ")));
}
return paragraphs.join("\n\n");
}
}
