crypto-keygen-suite/keyGen/keygenerators/gs1keygenerator.js

Key generation utilities for cryptographic operations. YES I RENAMED IT. SIX STATE PROTOCOL!!! See its folder for all <3

import fs from 'fs';

function calculateCheckDigit(gtin) {
    const digits = gtin.split('').map(Number);
    const sum = digits.slice(0, -1).reduce((acc, digit, index) => {
        // GS1 standard weighting: from right to left,
        // odd positions = 3, even positions = 1,
        // your original logic with index % 2 works here
        return acc + (index % 2 === 0 ? digit : digit * 3);
    }, 0);
    return (10 - (sum % 10)) % 10;
}

const lengths = {
    'GTIN8': 7,
    'GTIN12': 11,
    'GTIN13': 12,
    'GTIN14': 13,
    'GSIN': 16,
    'SSCC': 17,
    'GLN': 12,
    'GRAI': 13,
    'GIAI': 16,
    'GSRN': 16,
    'GDTI': 16,
    'GINC': 17
};

function generateGS1Key(format) {
    const keyFormat = format.toUpperCase().replace(/-/g, '');
    const length = lengths[keyFormat];
    if (!length) {
        throw new Error(`Invalid format '${format}' specified.`);
    }

    let key = '';
    for (let i = 0; i < length; i++) {
        key += Math.floor(Math.random() * 10).toString();
    }

    const checkDigit = calculateCheckDigit(key + '0');
    return key + checkDigit;
}

// CLI argument parsing
const args = process.argv.slice(2);
let format = '';
let count = 1;
let outputFile = null;

if (args.includes('--help') || args.length === 0) {
    console.log(`
Usage:
  node gs1gen.js --format <FORMAT> [--count <number>] [--output <file>]

Options:
  --format   One of: GTIN-8, GTIN-12, GTIN-13, GTIN-14, GSIN, SSCC, GLN, GRAI, GIAI, GSRN, GDTI, GINC
  --count    Number of keys to generate         (default: 1)
  --output   Save generated keys to a file
  --help     Show this help message
`);
    process.exit(0);
}

// Parse args manually
for (let i = 0; i < args.length; i++) {
    const key = args[i];
    const value = args[i + 1];

    if (key === '--format') format = value;
    if (key === '--count') count = parseInt(value) || 1;
    if (key === '--output') outputFile = value;
}

if (!format) {
    console.error('Error: --format is required.');
    process.exit(1);
}

// Generate keys
try {
    const keys = Array.from({ length: count }, () => generateGS1Key(format));

    if (outputFile) {
        const lines = keys.map(key => `${format} key: ${key}`);
        fs.writeFileSync(outputFile, lines.join('\n'), 'utf-8');
        console.log(`Saved ${count} ${format} key(s) to ${outputFile}`);
    } else {
        keys.forEach((key, idx) => {
            console.log(`Generated ${format} [${idx + 1}]: ${key}`);
        });
    }
} catch (err) {
    console.error('Error:', err.message);
    process.exit(1);
}