codec-bytes/base32

import {toObject, inverse} from '@iterable-iterator/mapping';
import {enumerate} from '@iterable-iterator/zip';

const variants = {
    // Standard ``base32''
    RFC4648: {
        alphabet: 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567',
        padding: '=',
    },

    // Also RFC4648 (used by NSEC3)
    // ``encoded data maintains its sort order when the encoded data is compared bit-wise''
    base32hex: {
        alphabet: '0123456789ABCDEFGHIJKLMNOPQRSTUV',
        padding: '=',
    },

    // ``easier for human use and more compact''
    'z-base-32': {
        alphabet: 'ybndrfg8ejkmcpqxot1uwisza345h769',
        padding: false,
    },

    // It excludes the letters I, L, and O to avoid confusion with digits. It
    // also excludes the letter U to reduce the likelihood of accidental
    // obscenity.
    // See http://www.crockford.com/wrmg/base32.html
    crockford: {
        alphabet: '0123456789ABCDEFGHJKMNPQRSTVWXYZ',
        padding: false,
        index: {
            0: 0,
            o: 0,
            O: 0,
            1: 1,
            i: 1,
            I: 1,
            l: 1,
            L: 1,
            2: 2,
            3: 3,
            4: 4,
            5: 5,
            6: 6,
            7: 7,
            8: 8,
            9: 9,
            a: 10,
            A: 10,
            b: 11,
            B: 11,
            c: 12,
            C: 12,
            d: 13,
            D: 13,
            e: 14,
            E: 14,
            f: 15,
            F: 15,
            g: 16,
            G: 16,
            h: 17,
            H: 17,
            j: 18,
            J: 18,
            k: 19,
            K: 19,
            m: 20,
            M: 20,
            n: 21,
            N: 21,
            p: 22,
            P: 22,
            q: 23,
            Q: 23,
            r: 24,
            R: 24,
            s: 25,
            S: 25,
            t: 26,
            T: 26,
            v: 27,
            V: 27,
            w: 28,
            W: 28,
            x: 29,
            X: 29,
            y: 30,
            Y: 30,
            z: 31,
            Z: 31,
        },
    },
};

for (const variant in variants) {
    if (variants[variant].index) continue;
    variants[variant].index = toObject(
        inverse(enumerate(variants[variant].alphabet)),
    );
}

// eslint-disable-next-line no-multi-assign
variants.default = variants.base32 = variants.RFC3548 = variants.RFC4648;
variants.RFC2938 = variants.base32hex;
variants.Crockford = variants.crockford;

export default variants;