'use strict';

const { test } = require('node:test');
const assert = require('node:assert/strict');
const lib = require('../index.js');

test('mass balance closes for steady-state pass-through', () => {
  const r = lib.assertMassBalance({ inflowKgPerS: 10, outflowKgPerS: 10 });
  assert.equal(r.ok, true);
  assert.equal(r.residualKgPerS, 0);
});

test('mass balance reports residual when leaking', () => {
  const r = lib.assertMassBalance({ inflowKgPerS: 10, outflowKgPerS: 9.5 });
  assert.equal(r.ok, false);
  assert.equal(Math.round(r.residualKgPerS * 1000), 500);
});

test('hydraulic balance: ΔP = pumpHead - friction - static', () => {
  const r = lib.assertHydraulicBalance({
    headerSuctionPa: 0,
    headerDischargePa: 90000,
    pumpHeadPa: 100000,
    frictionPa: 8000,
    staticHeadPa: 2000,
  });
  assert.equal(r.ok, true);
});

test('hydraulic power Q·H / η — within 0.5% relative tolerance', () => {
  const Q = 0.03;
  const H = 100000;
  const eta = 0.65;
  const shaft = (Q * H) / eta;
  const r = lib.assertHydraulicPower({ flowM3PerS: Q, headPa: H, shaftPowerW: shaft, efficiency: eta });
  assert.equal(r.ok, true);
});

test('hydraulic power flags eta=0', () => {
  const r = lib.assertHydraulicPower({ flowM3PerS: 0.03, headPa: 100000, shaftPowerW: 5000, efficiency: 0 });
  assert.equal(r.ok, false);
});

test('OTR check uses standard KLa formula', () => {
  const kla = 0.002;
  const cs = 9.0;
  const c = 2.0;
  const V = 20;
  const otr = kla * (cs - c) * V / 1e6;
  const r = lib.assertOxygenTransfer({ klaPerS: kla, csMgPerL: cs, cMgPerL: c, volumeM3: V, otrKgPerS: otr });
  assert.equal(r.ok, true);
});

test('energy balance: heat-in + work-in = heat-out + work-out + accumulation', () => {
  const r = lib.assertEnergyBalance({ heatInW: 1000, workInW: 200, heatOutW: 700, workOutW: 400, accumulationW: 100 });
  assert.equal(r.ok, true);
});