'use strict';

const { BaseDomain, POSITIONS, statusBadge } = require('generalFunctions');

function cloneArray(values) {
  if (typeof structuredClone === 'function') return structuredClone(values);
  return Array.isArray(values) ? [...values] : values;
}

// Settler — secondary clarifier / sludge separator (Unit level).
// Splits influent into effluent, surplus sludge and return sludge based
// on a TSS mass balance. State updates come from an upstream reactor
// (stateChange → pull `getEffluent`) or operator-supplied influent via
// the `data.influent` command. The 3-port Fluent stream is produced by
// `getEffluent` and pushed onto Port 0 by the nodeClass.
class Settler extends BaseDomain {
  static name = 'settler';

  configure() {
    this.upstreamReactor = null;
    this.returnPump = null;

    this.F_in = 0;
    this.Cs_in = new Array(13).fill(0);
    this.C_TS = 2500;

    this.router
      .onRegister('measurement', (child) => this._connectMeasurement(child))
      .onRegister('reactor', (child) => this._connectReactor(child))
      .onRegister('machine', (child) => this._connectMachine(child));
  }

  // Three-stream output: effluent (inlet=0), surplus sludge (inlet=1),
  // return sludge (inlet=2). Downstream consumers (reactor inlets,
  // returnPump) read these by `payload.inlet`. F_s is clamped to F_in
  // to prevent negative effluent when X_TS_in/C_TS exceeds 1.
  get getEffluent() {
    const F_s = Math.min((this.F_in * this.Cs_in[12]) / this.C_TS, this.F_in);
    const F_eff = this.F_in - F_s;

    let F_sr = 0;
    if (this.returnPump) {
      F_sr = Math.min(
        this.returnPump.measurements.type('flow').variant('measured').position(POSITIONS.AT_EQUIPMENT).getCurrentValue(),
        F_s,
      );
    }
    const F_so = F_s - F_sr;

    const Cs_eff = cloneArray(this.Cs_in);
    if (F_s > 0) for (let i = 7; i <= 12; i++) Cs_eff[i] = 0;

    const Cs_s = cloneArray(this.Cs_in);
    if (F_s > 0) for (let i = 7; i <= 12; i++) Cs_s[i] = this.F_in * this.Cs_in[i] / F_s;

    const ts = Date.now();
    return [
      { topic: 'Fluent', payload: { inlet: 0, F: F_eff, C: Cs_eff }, timestamp: ts },
      { topic: 'Fluent', payload: { inlet: 1, F: F_so,  C: Cs_s },   timestamp: ts },
      { topic: 'Fluent', payload: { inlet: 2, F: F_sr,  C: Cs_s },   timestamp: ts },
    ];
  }

  _connectMeasurement(measurementChild) {
    const position = measurementChild.config.functionality.positionVsParent;
    const measurementType = measurementChild.config.asset.type;
    const eventName = `${measurementType}.measured.${String(position).toLowerCase()}`;

    measurementChild.measurements.emitter.on(eventName, (eventData) => {
      this.logger.debug(`${position} ${measurementType} from ${eventData.childName}: ${eventData.value} ${eventData.unit}`);
      this.measurements
        .type(measurementType)
        .variant('measured')
        .position(position)
        .value(eventData.value, eventData.timestamp, eventData.unit);
      this._updateMeasurement(measurementType, eventData.value, position, eventData);
    });
  }

  // Reactor → settler integration: the reactor pushes a `stateChange` event
  // on its own emitter (NOT measurements.emitter), so router.onMeasurement
  // can't subscribe — we wire the listener manually here, mirroring the
  // pre-refactor `_connectReactor`. The settler pulls `getEffluent` rather
  // than receiving it pushed; reactor.getEffluent may return an array or a
  // single envelope (the 2026-03-02 bug fix preserved both shapes).
  _connectReactor(reactorChild) {
    if (reactorChild.config.functionality.positionVsParent !== POSITIONS.UPSTREAM) {
      this.logger.warn('Reactor children of settlers should be upstream.');
    }
    this.upstreamReactor = reactorChild;

    reactorChild.emitter.on('stateChange', () => {
      this.logger.debug('State change of upstream reactor detected.');
      const raw = this.upstreamReactor.getEffluent;
      const effluent = Array.isArray(raw) ? raw[0] : raw;
      this.F_in = effluent.payload.F;
      this.Cs_in = effluent.payload.C;
      this.notifyOutputChanged();
    });
  }

  _connectMachine(machineChild) {
    if (machineChild.config.functionality.positionVsParent === POSITIONS.DOWNSTREAM) {
      machineChild.upstreamSource = this;
      this.returnPump = machineChild;
      return;
    }
    this.logger.warn('Failed to register machine child.');
  }

  _updateMeasurement(measurementType, value /*, _position, _context */) {
    switch (measurementType) {
      case 'quantity (tss)':
        this.C_TS = value;
        this.notifyOutputChanged();
        return;
      default:
        this.logger.error(`Type '${measurementType}' not recognized for measured update.`);
    }
  }

  // Telemetry snapshot for Port 1 (InfluxDB). Port 0 carries the 3-message
  // Fluent stream directly; this scalar view feeds dashboards.
  getOutput() {
    const streams = this.getEffluent;
    return {
      ...this.measurements.getFlattenedOutput?.(),
      F_in: this.F_in,
      C_TS: this.C_TS,
      F_eff: streams[0].payload.F,
      F_surplus: streams[1].payload.F,
      F_return: streams[2].payload.F,
    };
  }

  getStatusBadge() {
    if (this.F_in <= 0) return statusBadge.idle('no influent');
    const streams = this.getEffluent;
    const eff = streams[0].payload.F.toFixed(2);
    const sur = streams[1].payload.F.toFixed(2);
    return statusBadge.compose([`F_in=${this.F_in.toFixed(2)}`, `eff=${eff}`, `surplus=${sur}`], { fill: 'green', shape: 'dot' });
  }
}

module.exports = Settler;
module.exports.Settler = Settler;