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

const Machine = require('../../src/specificClass');
const { makeMachineConfig, makeStateConfig, makeChildMeasurement } = require('../helpers/factories');

test('registerChild listens to measurement events and stores measured pressure', async () => {
  const machine = new Machine(makeMachineConfig(), makeStateConfig());
  const child = makeChildMeasurement({ positionVsParent: 'downstream', type: 'pressure', unit: 'mbar' });

  machine.registerChild(child, 'measurement');

  child.measurements
    .type('pressure')
    .variant('measured')
    .position('downstream')
    .value(123, Date.now(), 'mbar');

  const stored = machine.measurements
    .type('pressure')
    .variant('measured')
    .position('downstream')
    .getCurrentValue('mbar');

  assert.equal(typeof stored, 'number');
  assert.equal(Math.round(stored), 123);
});

test('registerChild deduplicates listeners on re-registration', async () => {
  const machine = new Machine(makeMachineConfig(), makeStateConfig());
  const child = makeChildMeasurement({ id: 'pt-dup', positionVsParent: 'downstream', type: 'pressure', unit: 'mbar' });
  const eventName = 'pressure.measured.downstream';

  let handlerCalls = 0;
  const originalUpdatePressure = machine.updateMeasuredPressure.bind(machine);
  machine.updateMeasuredPressure = (...args) => {
    handlerCalls += 1;
    return originalUpdatePressure(...args);
  };

  machine.registerChild(child, 'measurement');
  machine.registerChild(child, 'measurement');

  assert.equal(child.measurements.emitter.listenerCount(eventName), 1);

  child.measurements
    .type('pressure')
    .variant('measured')
    .position('downstream')
    .value(321, Date.now(), 'mbar');

  assert.equal(handlerCalls, 1);
});