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

const { makeMeasurementInstance } = require('../helpers/factories');

/**
 * Tests for the calibration / stability / repeatability primitives. These
 * methods interact with the stored window from the smoothing pipeline, so
 * each test seeds storedValues explicitly.
 */

test("isStable returns false with fewer than 2 samples", () => {
  const m = makeMeasurementInstance();
  m.storedValues = [];
  assert.equal(m.isStable(), false); // current implementation returns false (not object) at <2 samples
});

test("isStable reports stability and stdDev for a flat window", () => {
  const m = makeMeasurementInstance();
  m.storedValues = [10, 10, 10, 10, 10];
  const { isStable, stdDev } = m.isStable();
  assert.equal(isStable, true);
  assert.equal(stdDev, 0);
});

test("evaluateRepeatability returns stdDev when conditions are met", () => {
  const m = makeMeasurementInstance({
    smoothing: { smoothWindow: 5, smoothMethod: 'mean' },
  });
  m.storedValues = [10, 10, 10, 10, 10];
  const rep = m.evaluateRepeatability();
  assert.equal(rep, 0);
});

test("evaluateRepeatability refuses when smoothing is disabled", () => {
  const m = makeMeasurementInstance({
    smoothing: { smoothWindow: 5, smoothMethod: 'none' },
  });
  m.storedValues = [10, 10, 10, 10, 10];
  assert.equal(m.evaluateRepeatability(), null);
});

test("evaluateRepeatability refuses with insufficient samples", () => {
  const m = makeMeasurementInstance({
    smoothing: { smoothWindow: 5, smoothMethod: 'mean' },
  });
  m.storedValues = [10];
  assert.equal(m.evaluateRepeatability(), null);
});

test("calibrate sets offset when input is stable and scaling enabled", () => {
  const m = makeMeasurementInstance({
    scaling: { enabled: true, inputMin: 4, inputMax: 20, absMin: 0, absMax: 100, offset: 0 },
    smoothing: { smoothWindow: 5, smoothMethod: 'mean' },
  });
  // Stable window fed through calculateInput so outputAbs reflects the
  // pipeline (important because calibrate uses outputAbs for its delta).
  [3, 3, 3, 3, 3].forEach((v) => m.calculateInput(v));
  const outputBefore = m.outputAbs;
  m.calibrate();
  // Offset should now be inputMin - outputAbs(before).
  assert.equal(m.config.scaling.offset, 4 - outputBefore);
});

test("calibrate aborts when input is not stable", () => {
  const m = makeMeasurementInstance({
    scaling: { enabled: true, inputMin: 0, inputMax: 100, absMin: 0, absMax: 10, offset: 0 },
    smoothing: { smoothWindow: 5, smoothMethod: 'mean' },
  });
  // Cheat: populate storedValues with clearly non-stable data. calibrate
  // calls isStable() -> stdDev > threshold -> warn + no offset change.
  m.storedValues = [0, 100, 0, 100, 0];
  const offsetBefore = m.config.scaling.offset;
  m.calibrate();
  assert.equal(m.config.scaling.offset, offsetBefore);
});

test("calibrate uses absMin when scaling is disabled", () => {
  const m = makeMeasurementInstance({
    scaling: { enabled: false, inputMin: 0, inputMax: 1, absMin: 5, absMax: 10, offset: 0 },
    smoothing: { smoothWindow: 5, smoothMethod: 'mean' },
  });
  [5, 5, 5, 5, 5].forEach((v) => m.calculateInput(v));
  const out = m.outputAbs;
  m.calibrate();
  assert.equal(m.config.scaling.offset, 5 - out);
});

test("toggleSimulation flips the simulation flag", () => {
  const m = makeMeasurementInstance({ simulation: { enabled: false } });
  m.toggleSimulation();
  assert.equal(m.config.simulation.enabled, true);
  m.toggleSimulation();
  assert.equal(m.config.simulation.enabled, false);
});

test("tick runs simulateInput when simulation is enabled", async () => {
  const m = makeMeasurementInstance({
    scaling: { enabled: false, inputMin: 0, inputMax: 1, absMin: 0, absMax: 100, offset: 0 },
    smoothing: { smoothWindow: 1, smoothMethod: 'none' },
    simulation: { enabled: true },
  });
  const before = m.inputValue;
  await m.tick();
  await m.tick();
  await m.tick();
  // Simulated input must drift from its initial state.
  assert.notEqual(m.inputValue, before);
});

test("tick is a no-op on inputValue when simulation is disabled", async () => {
  const m = makeMeasurementInstance({
    scaling: { enabled: false, inputMin: 0, inputMax: 1, absMin: 0, absMax: 100, offset: 0 },
    smoothing: { smoothWindow: 1, smoothMethod: 'none' },
    simulation: { enabled: false },
  });
  m.inputValue = 42;
  await m.tick();
  await m.tick();
  assert.equal(m.inputValue, 42);
});