const test = require('node:test');
const assert = require('node:assert/strict');

const { ValveHydraulicModel } = require('../../src/hydraulicModel');

test('hydraulic model gas branch keeps existing formula when not choked', () => {
  const model = new ValveHydraulicModel({ serviceType: 'gas', gasChokedRatioLimit: 0.9 });
  const result = model.calculateDeltaPMbar({
    qM3h: 36,
    kv: 10,
    downstreamGaugeMbar: 500,
    rho: 1.204,
    tempK: 293.15,
  });

  const p2AbsBar = (500 / 1000) + 1.01325;
  const expectedDeltaPMbar = ((36 ** 2 * 1.204 * 293.15) / (514 ** 2 * 10 ** 2 * p2AbsBar)) * 1000;

  assert.ok(result);
  assert.ok(Math.abs(result.deltaPMbar - expectedDeltaPMbar) < 0.05, `expected ${expectedDeltaPMbar}, got ${result.deltaPMbar}`);
  assert.equal(result.details.isChoked, false);
});

test('hydraulic model gas branch applies choked-flow cap', () => {
  const model = new ValveHydraulicModel({ serviceType: 'gas', gasChokedRatioLimit: 0.2 });
  const result = model.calculateDeltaPMbar({
    qM3h: 1000,
    kv: 1,
    downstreamGaugeMbar: 500,
    rho: 1.204,
    tempK: 293.15,
  });

  const p2AbsBar = (500 / 1000) + 1.01325;
  const expectedCappedDeltaPMbar = p2AbsBar * 0.2 * 1000;

  assert.ok(result);
  assert.equal(result.details.isChoked, true);
  assert.ok(Math.abs(result.deltaPMbar - expectedCappedDeltaPMbar) < 0.0001, `expected ${expectedCappedDeltaPMbar}, got ${result.deltaPMbar}`);
});

test('hydraulic model liquid branch uses liquid Kv equation', () => {
  const model = new ValveHydraulicModel({ serviceType: 'liquid' });
  const result = model.calculateDeltaPMbar({
    qM3h: 100,
    kv: 50,
    downstreamGaugeMbar: 500,
    rho: 998,
    tempK: 293.15,
  });

  const expectedDeltaPMbar = (((100 / 50) ** 2) * (998 / 1000)) * 1000;

  assert.ok(result);
  assert.equal(result.details.isChoked, false);
  assert.ok(Math.abs(result.deltaPMbar - expectedDeltaPMbar) < 0.0001, `expected ${expectedDeltaPMbar}, got ${result.deltaPMbar}`);
});