/**
 * registerChild adapter for rotatingMachine. Custom because:
 *   - virtual + real pressure children share the upstream/downstream
 *     position slots; real ones must be tracked for the preference order
 *   - re-registration of the same child must dedup the emitter listener
 *   - non-measurement softwareTypes are no-ops (Machine has no children
 *     other than measurement nodes today)
 */

'use strict';

function registerMeasurementChild(host, child, softwareType) {
  const swType = softwareType || child?.config?.functionality?.softwareType || 'measurement';
  host.logger.debug(`Setting up child event for softwaretype ${swType}`);
  if (swType !== 'measurement') return;

  const position = String(child.config.functionality.positionVsParent || 'atEquipment').toLowerCase();
  const measurementType = child.config.asset.type;
  const childId = child.config?.general?.id || `${measurementType}-${position}-unknown`;
  const isVirtual = Object.values(host.virtualPressureChildIds).includes(childId);
  if (measurementType === 'pressure' && !isVirtual) host.realPressureChildIds[position]?.add(childId);

  const eventName = `${measurementType}.measured.${position}`;
  const key = `${childId}:${eventName}`;
  const existing = host.childMeasurementListeners.get(key);
  if (existing) {
    if (typeof existing.emitter.off === 'function') existing.emitter.off(existing.eventName, existing.handler);
    else if (typeof existing.emitter.removeListener === 'function') existing.emitter.removeListener(existing.eventName, existing.handler);
  }
  const handler = (eventData) => {
    host.logger.debug(`🔄 ${position} ${measurementType} from ${eventData.childName}: ${eventData.value} ${eventData.unit}`);
    host._callMeasurementHandler(measurementType, eventData.value, position, eventData);
  };
  child.measurements.emitter.on(eventName, handler);
  host.childMeasurementListeners.set(key, { emitter: child.measurements.emitter, eventName, handler });
}

function detachAllListeners(host) {
  if (!host.childMeasurementListeners) return;
  for (const [, e] of host.childMeasurementListeners) {
    if (typeof e.emitter?.off === 'function') e.emitter.off(e.eventName, e.handler);
    else if (typeof e.emitter?.removeListener === 'function') e.emitter.removeListener(e.eventName, e.handler);
  }
  host.childMeasurementListeners.clear();
}

module.exports = { registerMeasurementChild, detachAllListeners };