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

const { predict } = require('generalFunctions');
const { buildPredictors } = require('../../src/prediction/predictors');

function makeCanonicalCurve() {
  // Canonical units already applied: pressure Pa, flow m3/s, power W,
  // x-axis is control %. Two pressure levels, monotonically rising y.
  return {
    nq: {
      100000: { x: [0, 50, 100], y: [0, 0.005, 0.01] },
      120000: { x: [0, 50, 100], y: [0, 0.006, 0.012] },
    },
    np: {
      100000: { x: [0, 50, 100], y: [0, 500, 1000] },
      120000: { x: [0, 50, 100], y: [0, 600, 1200] },
    },
  };
}

test('buildPredictors: returns three Predict instances', () => {
  const predictors = buildPredictors(makeCanonicalCurve());
  assert.ok(predictors.predictFlow instanceof predict);
  assert.ok(predictors.predictPower instanceof predict);
  assert.ok(predictors.predictCtrl instanceof predict);
});

test('buildPredictors: predictFlow yMax/yMin reflect input range', () => {
  const predictors = buildPredictors(makeCanonicalCurve());
  // After buildAllFxyCurves the fDimension is initialised to fValues.min.
  // currentFxyYMin/Max are the y-range at that pressure curve.
  assert.ok(Number.isFinite(predictors.predictFlow.currentFxyYMax));
  assert.ok(Number.isFinite(predictors.predictFlow.currentFxyYMin));
  assert.ok(predictors.predictFlow.currentFxyYMax > predictors.predictFlow.currentFxyYMin);
});

test('buildPredictors: predictCtrl is built from reversed nq (flow->ctrl mapping)', () => {
  const predictors = buildPredictors(makeCanonicalCurve());
  // predictCtrl's x-axis values must come from y-values in nq.
  // sanity-check via currentFxyXMax being in the flow range
  assert.ok(predictors.predictCtrl.currentFxyXMax <= 0.02, // flow range upper bound
    `expected predictCtrl xMax in flow-range, got ${predictors.predictCtrl.currentFxyXMax}`);
});

test('buildPredictors: throws when machineCurve is missing nq or np', () => {
  assert.throws(() => buildPredictors(null), /machineCurve\.nq and \.np are required/);
  assert.throws(() => buildPredictors({ nq: {} }), /required/);
});