import { empty } from '../constants';
import floor     from '../floor';

const ALPHABET = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';

type Options = {
    /** The alphabet to use */
    alphabet?: string;
};

export function numberToLetter(n: number, { alphabet = ALPHABET }: Options = {}): string {
    const base              = alphabet.length;
    const letters: string[] = [];

    do {
        --n;
        letters.unshift(alphabet[n % base]);
        n = floor(n / base, { tolerance: 0.005 });
    } while(n > 0);

    return letters.join(empty);
}

export default numberToLetter;