factumovil/cc.js

Utilities for Bolivian invoice generation

function verhoeff(num, times)
{
    d = [
        [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
        [1, 2, 3, 4, 0, 6, 7, 8, 9, 5],
        [2, 3, 4, 0, 1, 7, 8, 9, 5, 6],
        [3, 4, 0, 1, 2, 8, 9, 5, 6, 7],
        [4, 0, 1, 2, 3, 9, 5, 6, 7, 8],
        [5, 9, 8, 7, 6, 0, 4, 3, 2, 1],
        [6, 5, 9, 8, 7, 1, 0, 4, 3, 2],
        [7, 6, 5, 9, 8, 2, 1, 0, 4, 3],
        [8, 7, 6, 5, 9, 3, 2, 1, 0, 4],
        [9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
    ]
    p = [
        [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
        [1, 5, 7, 6, 2, 8, 3, 0, 9, 4],
        [5, 8, 0, 3, 7, 9, 6, 1, 4, 2],
        [8, 9, 1, 6, 0, 4, 3, 5, 2, 7],
        [9, 4, 5, 3, 1, 2, 6, 8, 7, 0],
        [4, 2, 8, 6, 5, 7, 3, 9, 0, 1],
        [2, 7, 9, 3, 8, 0, 6, 4, 1, 5],
        [7, 0, 4, 6, 9, 1, 3, 2, 5, 8]
    ]
    inv = [0, 4, 3, 2, 1, 5, 6, 7, 8, 9]
    for (;times > 0; times--) {
        c = 0
        for (i = num.length-1; i >= 0; i--){
            c = d[c][p[((num.length - i) % 8)][num[i]]]
        }
        num += inv[c]
    }
    return num
}

function arc4(msg, key)
{
    state = []
    for (i=0; i<256; i++) {
        state[i] = i
    }
    j = 0
    for (i=0; i<256; i++) {
        j = (j + state[i] + key[i % key.length].charCodeAt(0)) % 256
        temp = state[i]
        state[i] = state[j]
        state[j] = temp
    }
    x = 0, y = 0
    output = ""
    for (i=0; i<msg.length; i++) {
        x = (x + 1) % 256
        y = (state[x] + y) % 256
        temp = state[x]
        state[x] = state[y]
        state[y] = temp
        output += ("0" + (msg[i].charCodeAt(0) ^ state[(state[x] + state[y]) % 256]).toString(16)).slice(-2)
    }
    return output.toUpperCase();
}

function base64(number) {
    result = ""
    dic = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz+/"
    while (number > 0) {
        result = dic[number % 64] + result
        number = Math.floor(number / 64)
    }
    return result
}

function controlCode(auth, number, nit, date, total, key) {
    code = ""
    number = verhoeff(number, 2)
    nit = verhoeff(nit, 2)
    date = verhoeff(date, 2)
    total = verhoeff(total, 2)
    vf = verhoeff("" + (
        parseInt(number) +
        parseInt(nit) +
        parseInt(date) +
        parseInt(total))
    , 5).slice(-5)

    input = [auth, number, nit, date, total]
    idx = 0;
    for (i=0; i<5; i++) {
        code += input[i] + key.substring(idx, idx+1+parseInt(vf[i]))
        idx += 1+parseInt(vf[i])
    }
    code = arc4(code, key + vf)

    final_sum = 0
    total_sum = 0
    partial_sum = [0,0,0,0,0]
    for (i=0; i<code.length; i++) {
        partial_sum[i%5] += code[i].charCodeAt(0)
        total_sum += code[i].charCodeAt(0)
    }
    for (i=0; i<5; i++) {
        final_sum += Math.floor((total_sum * partial_sum[i]) / (1 + parseInt(vf[i])))
    }

    code = arc4(base64(final_sum), key + vf).match(/.{2}/g).join("-")

    return code
}