multi-downloader-nx_mirror/modules/module.vttconvert.ts

// vtt loader
export type Record = {
	text?: string;
	time_start?: string;
	time_end?: string;
	ext_param?: unknown;
};
export type NullRecord = Record | null;

function loadVtt(vttStr: string) {
	const rx = /^([\d:.]*) --> ([\d:.]*)\s?(.*?)\s*$/;
	const lines = vttStr.replace(/\r?\n/g, '\n').split('\n');
	const data: Record[] = [];
	let lineBuf: string[] = [],
		record: NullRecord = null;
	// check  lines
	for (const l of lines) {
		const m = l.match(rx);
		if (m) {
			if (lineBuf.length > 0) {
				lineBuf.pop();
			}
			if (record !== null) {
				record.text = lineBuf.join('\n');
				data.push(record);
			}
			record = {
				time_start: m[1],
				time_end: m[2],
				ext_param: m[3]
					.split(' ')
					.map((x) => x.split(':'))
					.reduce((p: any, c: any) => (p[c[0]] = c[1]) && p, {})
			};
			lineBuf = [];
			continue;
		}
		lineBuf.push(l);
	}
	if (record !== null) {
		if (lineBuf[lineBuf.length - 1] === '') {
			lineBuf.pop();
		}
		record.text = lineBuf.join('\n');
		data.push(record);
	}
	return data;
}

// ass specific
function convertToAss(vttStr: string, lang: string, fontSize: number, fontName?: string) {
	let ass = [
		'\ufeff[Script Info]',
		`Title: ${lang}`,
		'ScriptType: v4.00+',
		'PlayResX: 1280',
		'PlayResY: 720',
		'WrapStyle: 0',
		'ScaledBorderAndShadow: yes',
		'',
		'[V4+ Styles]',
		'Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, ' +
			'Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, ' +
			'BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding',
		`Style: Main,${fontName || 'Noto Sans'},${fontSize},&H00FFFFFF,&H000000FF,&H00020713,&H00000000,0,0,0,0,100,100,0,0,1,3,0,2,10,10,10,1`,
		`Style: MainTop,${fontName || 'Noto Sans'},${fontSize},&H00FFFFFF,&H000000FF,&H00020713,&H00000000,0,0,0,0,100,100,0,0,1,3,0,8,10,10,10,1`,
		'',
		'[Events]',
		'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text'
	];

	const vttData = loadVtt(vttStr);
	for (const l of vttData) {
		const line = convertToAssLine(l, 'Main');
		ass = ass.concat(line);
	}

	return ass.join('\r\n') + '\r\n';
}

function convertToAssLine(l: Record, style: string) {
	const start = convertTime(l.time_start as string);
	const end = convertTime(l.time_end as string);
	const text = convertToAssText(l.text as string);

	// debugger
	if ((l.ext_param as any).line === '7%') {
		style = 'MainTop';
	}

	if ((l.ext_param as any).line === '10%') {
		style = 'MainTop';
	}

	return `Dialogue: 0,${start},${end},${style},,0,0,0,,${text}`;
}

function convertToAssText(text: string) {
	text = text
		.replace(/\r/g, '')
		.replace(/\n/g, '\\N')
		.replace(/\\N +/g, '\\N')
		.replace(/ +\\N/g, '\\N')
		.replace(/(\\N)+/g, '\\N')
		.replace(/<b[^>]*>([^<]*)<\/b>/g, '{\\b1}$1{\\b0}')
		.replace(/<i[^>]*>([^<]*)<\/i>/g, '{\\i1}$1{\\i0}')
		.replace(/<u[^>]*>([^<]*)<\/u>/g, '{\\u1}$1{\\u0}')
		.replace(/&lt;/g, '<')
		.replace(/&gt;/g, '>')
		.replace(/&amp;/g, '&')
		.replace(/<[^>]>/g, '')
		.replace(/\\N$/, '')
		.replace(/ +$/, '');
	return text;
}

// srt specific
function convertToSrt(vttStr: string) {
	let srt: string[] = [],
		srtLineIdx = 0;

	const vttData = loadVtt(vttStr);
	for (const l of vttData) {
		srtLineIdx++;
		const line = convertToSrtLine(l, srtLineIdx);
		srt = srt.concat(line);
	}

	return srt.join('\r\n') + '\r\n';
}

function convertToSrtLine(l: Record, idx: number): string {
	const bom = idx == 1 ? '\ufeff' : '';
	const start = convertTime(l.time_start as string, true);
	const end = convertTime(l.time_end as string, true);
	const text = l.text;
	return `${bom}${idx}\r\n${start} --> ${end}\r\n${text}\r\n`;
}

// time parser
function convertTime(time: string, srtFormat = false) {
	const mTime = time.match(/([\d:]*)\.?(\d*)/);
	if (!mTime) {
		return srtFormat ? '00:00:00,000' : '0:00:00.00';
	}
	return toSubsTime(mTime[0], srtFormat);
}

function toSubsTime(str: string, srtFormat: boolean): string {
	const n: string[] = [],
		x: (string | number)[] = str.split(/[:.]/).map((x) => Number(x));
	let sx;

	const msLen = srtFormat ? 3 : 2;
	const hLen = srtFormat ? 2 : 1;

	x[3] = '0.' + ('' + x[3]).padStart(3, '0');
	sx = (x[0] as number) * 60 * 60 + (x[1] as number) * 60 + (x[2] as number) + Number(x[3]);
	sx = sx.toFixed(msLen).split('.');

	n.unshift(padTimeNum(srtFormat ? ',' : '.', sx[1], msLen));
	sx = Number(sx[0]);

	n.unshift(padTimeNum(':', sx % 60, 2));
	n.unshift(padTimeNum(':', Math.floor(sx / 60) % 60, 2));
	n.unshift(padTimeNum('', Math.floor(sx / 3600) % 60, hLen));

	return n.join('');
}

function padTimeNum(sep: string, input: string | number, pad: number) {
	return sep + ('' + input).padStart(pad, '0');
}

// export module
const _default = (vttStr: string, toSrt: boolean, lang = 'English', fontSize: number, fontName?: string) => {
	const convert = toSrt ? convertToSrt : convertToAss;
	return convert(vttStr, lang, fontSize, fontName);
};
export default _default;