import { currentLocale } from './locale';

const SMALLEST_BYTE_UNIT = 'B';
const LARGER_BYTE_UNITS = [ 'KB', 'MB', 'GB' ] as const;
const BYTES_PER_UNIT = 1024;
const WHOLE_NUMBER_FROM = 100;

export function formatNumber( count: number ): string {
	return count.toLocaleString( currentLocale() );
}

export function formatPercent( percent: number ): string {
	return percent.toLocaleString( currentLocale(), {
		minimumFractionDigits: 1,
		maximumFractionDigits: 1,
	} );
}

export function formatBytes( bytes: number ): string {
	let sizeInUnit = bytes;
	let unit: string = SMALLEST_BYTE_UNIT;

	for ( const largerUnit of LARGER_BYTE_UNITS ) {
		if ( sizeInUnit < BYTES_PER_UNIT ) {
			break;
		}

		sizeInUnit /= BYTES_PER_UNIT;
		unit = largerUnit;
	}

	const isWholeNumber =
		unit === SMALLEST_BYTE_UNIT || sizeInUnit >= WHOLE_NUMBER_FROM;
	const formattedSize = sizeInUnit.toLocaleString( currentLocale(), {
		maximumFractionDigits: isWholeNumber ? 0 : 1,
	} );

	return `${ formattedSize } ${ unit }`;
}