'use strict';

const { MeasurementContainer } = require('generalFunctions');

/**
 * VirtualPressureChildren — builds two dashboard-sim children backed
 * by their own MeasurementContainer (upstream + downstream). Children
 * are signed as belonging to a parent machine via `setParentRef`.
 *
 * Extracted from rotatingMachine specificClass._initVirtualPressureChildren.
 */

const DEFAULT_IDS = {
  upstream: 'dashboard-sim-upstream',
  downstream: 'dashboard-sim-downstream',
};

class VirtualPressureChildren {
  /**
   * @param {object} opts
   *   - logger: pass-through to MeasurementContainer
   *   - unitPolicy: { canonical, output }
   *   - parentRef: object to use as parent for setParentRef (optional)
   *   - ids: override the default { upstream, downstream } id pair (optional)
   */
  constructor({ logger, unitPolicy, parentRef = null, ids = DEFAULT_IDS } = {}) {
    this.logger = logger || { warn() {}, debug() {} };
    this.unitPolicy = unitPolicy;
    this.parentRef = parentRef;
    this.ids = { ...DEFAULT_IDS, ...(ids || {}) };
  }

  /**
   * @returns {{ upstream: VirtualChild, downstream: VirtualChild }}
   *   Each child = { config: { general, functionality, asset }, measurements }.
   */
  build() {
    return {
      upstream: this._createChild('upstream'),
      downstream: this._createChild('downstream'),
    };
  }

  _createChild(position) {
    const id = this.ids[position];
    const name = `dashboard-sim-${position}`;
    const measurements = new MeasurementContainer({
      autoConvert: true,
      defaultUnits: this._unitMap('output'),
      preferredUnits: this._unitMap('output'),
      canonicalUnits: this.unitPolicy?.canonical,
      storeCanonical: true,
      strictUnitValidation: true,
      throwOnInvalidUnit: true,
      requireUnitForTypes: ['pressure'],
    }, this.logger);

    if (typeof measurements.setChildId === 'function') measurements.setChildId(id);
    if (typeof measurements.setChildName === 'function') measurements.setChildName(name);
    if (this.parentRef && typeof measurements.setParentRef === 'function') {
      measurements.setParentRef(this.parentRef);
    }

    return {
      config: {
        general: { id, name },
        functionality: {
          softwareType: 'measurement',
          positionVsParent: position,
        },
        asset: {
          type: 'pressure',
          unit: this.unitPolicy?.output?.pressure,
        },
      },
      measurements,
    };
  }

  _unitMap(section) {
    const src = this.unitPolicy?.[section] || {};
    return {
      pressure: src.pressure,
      flow: src.flow,
      power: src.power,
      temperature: src.temperature,
    };
  }
}

VirtualPressureChildren.DEFAULT_IDS = DEFAULT_IDS;
module.exports = VirtualPressureChildren;