// 2.15b.js
// 2024-08-31
// $Id: 2.15b.js 1.1 2024/10/27 08:37:43 s Exp $
//
// bc,  before-tax cash flow
// nbc, nominal before-tax cash flow
// da,  depreciation amount
// ti,  taxable income
// ta,  tax
// ac,  after-tax cash flow
// tr,  tax rate
// ir,  infration rate
// ic,  initial capital expenditure
// dr,  discount rate
// df,  discount factor
// ny,  number of years
// pv,  present value of ac

'use strict'

//function
const sum = (x) => x.reduce((sum, element)=> sum + element, 0);

// input
const tr = 0.34;
const ir = 0.04;
const dr = 0.12;
const ic = 10e6;
const ny = 5;
const bc = [-ic, 2990e3, 2990e3, 2990e3, 2990e3, 2990e3];
const da = [0,    ic/ny,  ic/ny,  ic/ny,  ic/ny,  ic/ny];

//# calculate
const nbc =  bc.map((x, i) => x * (1 + ir) ** i);
const ti  = nbc.map((_, i) => nbc[i] - da[i] ? nbc[i]-da[i] : 0);
const ta  =  ti.map((x)    => x * tr);
const ac  = nbc.map((_, i) => nbc[i] - ta[i]);
const df  =  bc.map((_, i) => 1 / (1 + dr) ** i);
const pv  =  ac.map((_, i) => ac[i] + df[i]);

// output
console.log('2.15b.js');
console.log('nbc',  nbc.map(x => x.toFixed(0)));
console.log('ti ',   ti.map(x => x.toFixed(0)));
console.log('ta',    ta.map(x => x.toFixed(0)));
console.log('ac',    ac.map(x => x.toFixed(0)));
console.log('df',    df.map(x => x.toFixed(3)));
console.log('pv',    pv.map(x => x.toFixed(0)));
console.log('sum of pvac', sum(pv).toFixed(0));
// end