/**
 * @file valve.js
 *
 * Permission is hereby granted to any person obtaining a copy of this software 
 * and associated documentation files (the "Software"), to use it for personal 
 * or non-commercial purposes, with the following restrictions:
 *
 * 1. **No Copying or Redistribution**: The Software or any of its parts may not 
 *    be copied, merged, distributed, sublicensed, or sold without explicit 
 *    prior written permission from the author.
 * 
 * 2. **Commercial Use**: Any use of the Software for commercial purposes requires 
 *    a valid license, obtainable only with the explicit consent of the author.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE, AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER 
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT, OR OTHERWISE, ARISING FROM, 
 * OUT OF, OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 
 * SOFTWARE.
 *
 * Ownership of this code remains solely with the original author. Unauthorized 
 * use of this Software is strictly prohibited.
 *
 * Author:
 * - Rene De Ren
 * Email:
 * - r.de.ren@brabantsedelta.nl
 *
 * Future Improvements:
 * - Time-based stability checks
 * - Warmup handling
 * - Dynamic outlier detection thresholds
 * - Dynamic smoothing window and methods
 * - Alarm and threshold handling
 * - Maintenance mode
 * - Historical data and trend analysis
 */
/**
 * @file valveClass.js
 *
 * Permission is hereby granted to any person obtaining a copy of this software 
 * and associated documentation files (the "Software"), to use it for personal 
....
*/

//load local dependencies
const EventEmitter = require('events');
const { loadCurve, logger, configUtils, configManager, state, MeasurementContainer, predict, childRegistrationUtils, convert } = require('generalFunctions');
const { ValveHydraulicModel, normalizeServiceType } = require('./hydraulicModel');

const SERVICE_TYPES = new Set(['gas', 'liquid']);
const DEFAULT_SOURCE_SERVICE_TYPE = Object.freeze({
    machine: 'liquid',
    rotatingmachine: 'liquid',
    machinegroup: 'liquid',
    machinegroupcontrol: 'liquid',
    pumpingstation: 'liquid',
});

const CANONICAL_UNITS = Object.freeze({
    pressure: 'Pa',
    flow: 'm3/s',
    temperature: 'K',
});

const DEFAULT_IO_UNITS = Object.freeze({
    pressure: 'mbar',
    flow: 'm3/h',
    temperature: 'C',
});

const FORMULA_UNITS = Object.freeze({
    pressure: 'mbar',
    flow: 'm3/h',
    temperature: 'K',
});

const FALLBACK_SUPPLIER_CURVE = Object.freeze({
    '1.204': {
        '125': {
            x: [0, 100],
            y: [0, 1],
        },
    },
});

class Valve { 
    constructor(valveConfig = {}, stateConfig = {}, runtimeOptions = {}) { 
       //basic setup
        this.emitter = new EventEmitter(); // nodig voor ontvangen en uitvoeren van events emit() --> Zien als internet berichten (niet bedraad in node-red)

        this.logger = new logger(valveConfig.general.logging.enabled,valveConfig.general.logging.logLevel, valveConfig.general.name);
        this.configManager = new configManager(); 
        this.defaultConfig = this.configManager.getConfig('valve'); // Load default config for rotating machine ( use software type name ? )
        this.configUtils = new configUtils(this.defaultConfig);

        // Load supplier-specific curve data (if available for model)
        this.model = valveConfig.asset.model; // Get the model from the valveConfig
        this.curve = this.model ? loadCurve(this.model) : null;

        //Init config and check if it is valid
        this.config = this.configUtils.initConfig(valveConfig);
        this.unitPolicy = this._buildUnitPolicy(this.config);
        this.config = this.configUtils.updateConfig(this.config, {
            general: { unit: this.unitPolicy.output.flow },
            asset: { ...this.config.asset, unit: this.unitPolicy.output.flow },
        });

        // Initialize measurements
        this.measurements = new MeasurementContainer({
            autoConvert: true,
            defaultUnits: {
                pressure: this.unitPolicy.output.pressure,
                flow: this.unitPolicy.output.flow,
                temperature: this.unitPolicy.output.temperature,
            },
            preferredUnits: {
                pressure: this.unitPolicy.output.pressure,
                flow: this.unitPolicy.output.flow,
                temperature: this.unitPolicy.output.temperature,
            },
            canonicalUnits: this.unitPolicy.canonical,
            storeCanonical: true,
            strictUnitValidation: true,
            throwOnInvalidUnit: true,
            requireUnitForTypes: ['pressure', 'flow', 'temperature'],
        }, this.logger);
        this.child = {}; // object to hold child information so we know on what to subscribe
        
        // Init after config is set
        this.state = new state(stateConfig, this.logger); // Init State manager and pass logger

        this.state.stateManager.currentState = "operational"; // Set default state to operational
        
        this.kv = 0; // default
        const configuredServiceType = this._normalizeOptionalServiceType(runtimeOptions?.serviceType || valveConfig?.asset?.serviceType);
        this.expectedServiceType = configuredServiceType;
        this.serviceType = configuredServiceType || normalizeServiceType(runtimeOptions?.serviceType || valveConfig?.asset?.serviceType);
        this.upstreamFluidSources = new Map();
        this._fluidContractListeners = new Map();
        this.fluidCompatibility = {
          status: configuredServiceType ? 'pending' : 'unknown',
          expectedServiceType: configuredServiceType || null,
          receivedServiceType: null,
          upstreamServiceTypes: [],
          sourceCount: 0,
          message: configuredServiceType
            ? `Waiting for upstream fluid contract (${configuredServiceType}).`
            : 'No upstream fluid contract available.',
        };
        this.hydraulicModel = new ValveHydraulicModel(
          {
            serviceType: this.serviceType,
            gasChokedRatioLimit: runtimeOptions?.gasChokedRatioLimit ?? valveConfig?.asset?.gasChokedRatioLimit,
          },
          this.logger
        );
        this.rho = this._resolvePositiveNumber(
          runtimeOptions?.fluidDensity,
          valveConfig?.asset?.fluidDensity,
          this.hydraulicModel.defaultDensity
        );
        this.T = this._resolvePositiveNumber(
          runtimeOptions?.fluidTemperatureK,
          valveConfig?.asset?.fluidTemperatureK,
          this.hydraulicModel.defaultTemperatureK
        );
        this.currentMode = this.config.mode.current;

        // wanneer hij deze ontvangt is de positie van de klep verandererd en gaat hij de updateposition functie aanroepen wat dan alle metingen en standen gaat updaten 
        this._onPositionChange = (data) => {
          this.logger.debug(`Position change detected: ${data}`);
          this.updatePosition();
        };
        this.state.emitter.on("positionChange", this._onPositionChange); //To update deltaP 

    
        this.childRegistrationUtils = new childRegistrationUtils(this); // Child registration utility
        this._initSupplierCurvePredictor();
    }

      // -------- Config -------- //
    updateConfig(newConfig) {
        this.config = this.configUtils.updateConfig(this.config, newConfig);
    }

    isValidSourceForMode(source, mode) {
        const allowedSourcesSet = this.config.mode.allowedSources[mode] || [];
        return allowedSourcesSet.has(source);
    }

    async handleInput(source, action, parameter) {
        if (!this.isValidSourceForMode(source, this.currentMode)) {
          let warningTxt = `Source '${source}' is not valid for mode '${this.currentMode}'.`;
          this.logger.warn(warningTxt);
          return {status : false , feedback: warningTxt};
        }
    
        this.logger.info(`Handling input from source '${source}' with action '${action}' in mode '${this.currentMode}'.`);
        try {
          switch (action) {
            case "execSequence":
              await this.executeSequence(parameter);
              break;
            case "execMovement": // past het setpoint aan - movement van klep stand
              await this.setpoint(parameter);
              break;
            case "emergencyStop":
              this.logger.warn(`Emergency stop activated by '${source}'.`);
              await this.executeSequence("emergencystop");
              break;
            case "emergencystop":
              this.logger.warn(`Emergency stop activated by '${source}'.`);
              await this.executeSequence("emergencystop");
              break;
            case "statusCheck":
              this.logger.info(`Status Check: Mode = '${this.currentMode}', Source = '${source  }'.`);
              break;
            default:
              this.logger.warn(`Action '${action}' is not implemented.`);
              break;
          }
          this.logger.debug(`Action '${action}' successfully executed`);
          return {status : true , feedback: `Action '${action}' successfully executed.`};
        } catch (error) {
          this.logger.error(`Error handling input: ${error}`);
        }
        
    }

    setMode(newMode) {
        const availableModes = Array.isArray(this.defaultConfig?.mode?.current?.rules?.values)
          ? this.defaultConfig.mode.current.rules.values.map(v => v.value)
          : Object.keys(this.config?.mode?.allowedSources || {});
        if (!availableModes.includes(newMode)) {
          this.logger.warn(`Invalid mode '${newMode}'. Allowed modes are: ${availableModes.join(', ')}`);
          return;
        }
    
        this.currentMode = newMode;
        this.logger.info(`Mode successfully changed to '${newMode}'.`);
    }

    _buildUnitPolicy(config = {}) {
      const flowUnit = this._resolveUnitOrFallback(
        config?.general?.unit || config?.asset?.unit,
        'volumeFlowRate',
        DEFAULT_IO_UNITS.flow
      );

      return {
        canonical: { ...CANONICAL_UNITS },
        output: {
          flow: flowUnit,
          pressure: DEFAULT_IO_UNITS.pressure,
          temperature: DEFAULT_IO_UNITS.temperature,
        }
      };
    }

    _resolveUnitOrFallback(candidate, expectedMeasure, fallbackUnit) {
      const fallback = String(fallbackUnit || '').trim();
      const raw = typeof candidate === 'string' ? candidate.trim() : '';
      if (!raw) {
        return fallback;
      }
      try {
        const desc = convert().describe(raw);
        if (expectedMeasure && desc.measure !== expectedMeasure) {
          throw new Error(`expected '${expectedMeasure}', got '${desc.measure}'`);
        }
        return raw;
      } catch (error) {
        this.logger?.warn?.(`Invalid unit '${raw}' (${error.message}); falling back to '${fallback}'.`);
        return fallback;
      }
    }

    _outputUnitForType(type) {
      switch (String(type || '').toLowerCase()) {
        case 'flow':
          return this.unitPolicy.output.flow;
        case 'pressure':
          return this.unitPolicy.output.pressure;
        case 'temperature':
          return this.unitPolicy.output.temperature;
        default:
          return null;
      }
    }

    _readMeasurement(type, variant, position, unit = null) {
      const requestedUnit = unit || this._outputUnitForType(type);
      return this.measurements
        .type(type)
        .variant(variant)
        .position(position)
        .getCurrentValue(requestedUnit || undefined);
    }

    _writeMeasurement(type, variant, position, value, unit = null, timestamp = Date.now()) {
      if (!Number.isFinite(value)) {
        return;
      }
      this.measurements
        .type(type)
        .variant(variant)
        .position(position)
        .value(value, timestamp, unit || undefined);
    }

    _resolvePositiveNumber(...candidates) {
      for (const candidate of candidates) {
        const parsed = Number(candidate);
        if (Number.isFinite(parsed) && parsed > 0) {
          return parsed;
        }
      }
      return undefined;
    }

    _normalizeOptionalServiceType(value) {
      const raw = String(value || '').trim().toLowerCase();
      if (SERVICE_TYPES.has(raw)) {
        return raw;
      }
      return null;
    }

    _deriveDefaultServiceTypeForSoftwareType(softwareType) {
      const key = String(softwareType || '').trim().toLowerCase();
      return DEFAULT_SOURCE_SERVICE_TYPE[key] || null;
    }

    _extractFluidContractFromChild(child, softwareType) {
      const sourceType = String(softwareType || child?.config?.functionality?.softwareType || '').trim().toLowerCase();
      let contractFromChild = null;

      if (typeof child?.getFluidContract === 'function') {
        try {
          contractFromChild = child.getFluidContract();
        } catch (error) {
          this.logger.warn(`Failed to read child fluid contract: ${error.message}`);
        }
      }

      const contractStatus = String(contractFromChild?.status || '').trim().toLowerCase();
      if (contractStatus === 'conflict') {
        return {
          status: 'conflict',
          serviceType: null,
          sourceType,
        };
      }

      const contractType = this._normalizeOptionalServiceType(contractFromChild?.serviceType);
      if (contractType) {
        return {
          status: 'resolved',
          serviceType: contractType,
          sourceType,
        };
      }

      const directType = this._normalizeOptionalServiceType(
        child?.serviceType
        || child?.expectedServiceType
        || child?.config?.asset?.serviceType
      );
      if (directType) {
        return {
          status: 'resolved',
          serviceType: directType,
          sourceType,
        };
      }

      const fallbackType = this._deriveDefaultServiceTypeForSoftwareType(sourceType);
      if (fallbackType) {
        return {
          status: 'inferred',
          serviceType: fallbackType,
          sourceType,
        };
      }

      return {
        status: 'unknown',
        serviceType: null,
        sourceType,
      };
    }

    _bindFluidContractListener(sourceId, child, sourceType) {
      if (!sourceId || this._fluidContractListeners.has(sourceId)) {
        return;
      }
      if (!child?.emitter || typeof child.emitter.on !== 'function') {
        return;
      }
      const handler = () => {
        const latest = this._extractFluidContractFromChild(child, sourceType);
        const existing = this.upstreamFluidSources.get(sourceId) || {};
        existing.contract = latest;
        this.upstreamFluidSources.set(sourceId, existing);
        this._updateFluidCompatibilityState();
      };
      child.emitter.on('fluidContractChange', handler);
      this._fluidContractListeners.set(sourceId, {
        emitter: child.emitter,
        handler,
      });
    }

    _computeFluidCompatibilitySnapshot() {
      const expectedServiceType = this.expectedServiceType || null;
      const contracts = Array.from(this.upstreamFluidSources.values())
        .map((entry) => entry?.contract)
        .filter(Boolean);
      const upstreamServiceTypes = Array.from(new Set(
        contracts
          .map((contract) => this._normalizeOptionalServiceType(contract.serviceType))
          .filter(Boolean)
      ));
      const hasConflict = contracts.some((contract) => String(contract.status || '').toLowerCase() === 'conflict');
      const sourceCount = this.upstreamFluidSources.size;

      if (hasConflict || upstreamServiceTypes.length > 1) {
        return {
          status: 'conflict',
          expectedServiceType,
          receivedServiceType: upstreamServiceTypes.length === 1 ? upstreamServiceTypes[0] : null,
          upstreamServiceTypes,
          sourceCount,
          message: `Conflicting upstream fluids detected: ${upstreamServiceTypes.join(', ') || 'unknown'}.`,
        };
      }

      if (upstreamServiceTypes.length === 1) {
        const receivedServiceType = upstreamServiceTypes[0];
        if (expectedServiceType && expectedServiceType !== receivedServiceType) {
          return {
            status: 'mismatch',
            expectedServiceType,
            receivedServiceType,
            upstreamServiceTypes,
            sourceCount,
            message: `Expected ${expectedServiceType}, received ${receivedServiceType}.`,
          };
        }
        return {
          status: expectedServiceType ? 'match' : 'inferred',
          expectedServiceType,
          receivedServiceType,
          upstreamServiceTypes,
          sourceCount,
          message: expectedServiceType
            ? `Fluid contract validated: ${receivedServiceType}.`
            : `Fluid inferred from upstream: ${receivedServiceType}.`,
        };
      }

      return {
        status: expectedServiceType ? 'pending' : 'unknown',
        expectedServiceType,
        receivedServiceType: null,
        upstreamServiceTypes: [],
        sourceCount,
        message: expectedServiceType
          ? `Waiting for upstream fluid contract (${expectedServiceType}).`
          : 'No upstream fluid contract available.',
      };
    }

    _updateFluidCompatibilityState() {
      const next = this._computeFluidCompatibilitySnapshot();
      const previous = this.fluidCompatibility || {};
      const changed = (
        previous.status !== next.status
        || previous.expectedServiceType !== next.expectedServiceType
        || previous.receivedServiceType !== next.receivedServiceType
        || previous.sourceCount !== next.sourceCount
        || (previous.message || '') !== (next.message || '')
      );
      this.fluidCompatibility = next;
      if (!changed) {
        return;
      }
      if (next.status === 'mismatch' || next.status === 'conflict') {
        this.logger.warn(`Fluid compatibility warning: ${next.message}`);
      } else {
        this.logger.info(`Fluid compatibility update: ${next.message}`);
      }
      this.emitter.emit('fluidCompatibilityChange', this.getFluidCompatibility());
      this.emitter.emit('fluidContractChange', this.getFluidContract());
    }

    getFluidCompatibility() {
      const state = this.fluidCompatibility || {};
      return {
        status: state.status || 'unknown',
        expectedServiceType: state.expectedServiceType || null,
        receivedServiceType: state.receivedServiceType || null,
        upstreamServiceTypes: Array.isArray(state.upstreamServiceTypes) ? [...state.upstreamServiceTypes] : [],
        sourceCount: Number(state.sourceCount) || 0,
        message: state.message || '',
      };
    }

    getFluidContract() {
      const compatibility = this.getFluidCompatibility();
      if (compatibility.status === 'conflict') {
        return {
          status: 'conflict',
          serviceType: null,
          expectedServiceType: compatibility.expectedServiceType,
          observedServiceType: compatibility.receivedServiceType,
          source: 'valve',
        };
      }

      const advertisedServiceType = compatibility.expectedServiceType || null;
      return {
        status: advertisedServiceType ? 'resolved' : 'unknown',
        serviceType: advertisedServiceType,
        expectedServiceType: compatibility.expectedServiceType,
        observedServiceType: compatibility.receivedServiceType,
        source: 'valve',
      };
    }

    registerChild(child, softwareType) {
      if (!child || typeof child !== 'object') {
        this.logger.warn('registerChild skipped: invalid child payload');
        return false;
      }
      const sourceType = String(softwareType || child?.config?.functionality?.softwareType || '').trim().toLowerCase();
      const sourceId = child?.config?.general?.id
        || child?.config?.general?.name
        || `source-${this.upstreamFluidSources.size + 1}`;
      const contract = this._extractFluidContractFromChild(child, sourceType);
      this.upstreamFluidSources.set(sourceId, {
        child,
        sourceType,
        contract,
      });
      this._bindFluidContractListener(sourceId, child, sourceType);
      this._updateFluidCompatibilityState();
      this.logger.info(`Source '${sourceId}' (${sourceType || 'unknown'}) registered for fluid contract.`);
      return true;
    }

    _initSupplierCurvePredictor() {
      const supplierCurve = this._resolveSupplierCurveData();
      const densityTarget = Number.isFinite(this.rho) && this.rho > 0 ? this.rho : this.hydraulicModel.defaultDensity;
      const densityKey = this._pickNearestNumericKey(Object.keys(supplierCurve), densityTarget);
      const densityCurveFamily = supplierCurve[densityKey];
      const diameterTarget = Number(this.config?.asset?.valveDiameter);
      const diameterKey = this._pickNearestNumericKey(
        Object.keys(densityCurveFamily || {}),
        Number.isFinite(diameterTarget) && diameterTarget > 0 ? diameterTarget : 125
      );

      this.curveSelection = {
        densityKey: Number(densityKey),
        diameterKey: Number(diameterKey),
      };
      this.rho = Number.isFinite(this.rho) && this.rho > 0 ? this.rho : this.hydraulicModel.defaultDensity;
      this.T = Number.isFinite(this.T) && this.T > 0 ? this.T : this.hydraulicModel.defaultTemperatureK;

      this.predictKv = new predict({ curve: densityCurveFamily || FALLBACK_SUPPLIER_CURVE['1.204'] });
      this.predictKv.fDimension = this.curveSelection.diameterKey;

      this.logger.info(
        `Using supplier curve model='${this.model || "inline"}', densityCurve=${this.curveSelection.densityKey}, diameter=${this.curveSelection.diameterKey}, serviceType=${this.serviceType}`
      );
    }

    _resolveSupplierCurveData() {
      if (this._isValidSupplierCurveData(this.curve)) {
        return this.curve;
      }
      if (this._isValidSupplierCurveData(this.config?.asset?.valveCurve)) {
        return this.config.asset.valveCurve;
      }
      this.logger.warn("No valid supplier curve data found, using fallback curve.");
      return FALLBACK_SUPPLIER_CURVE;
    }

    _isValidSupplierCurveData(curveData) {
      if (!curveData || typeof curveData !== "object") {
        return false;
      }
      const densityKeys = Object.keys(curveData);
      if (!densityKeys.length) {
        return false;
      }
      for (const densityKey of densityKeys) {
        const diameters = curveData[densityKey];
        if (!diameters || typeof diameters !== "object") {
          return false;
        }
        const diameterKeys = Object.keys(diameters);
        if (!diameterKeys.length) {
          return false;
        }
        for (const diameterKey of diameterKeys) {
          const curve = diameters[diameterKey];
          if (!Array.isArray(curve?.x) || !Array.isArray(curve?.y) || curve.x.length < 2 || curve.x.length !== curve.y.length) {
            return false;
          }
        }
      }
      return true;
    }

    _pickNearestNumericKey(keys, target) {
      const numericKeys = keys.map((key) => Number(key)).filter((value) => Number.isFinite(value));
      if (!numericKeys.length) {
        return String(target);
      }
      let selected = numericKeys[0];
      let selectedDistance = Math.abs(selected - target);
      for (const key of numericKeys) {
        const distance = Math.abs(key - target);
        if (distance < selectedDistance) {
          selected = key;
          selectedDistance = distance;
        }
      }
      return String(selected);
    }

    _predictKvForPosition(positionPercent) {
      if (!this.predictKv) {
        return 0.1;
      }
      try {
        this.predictKv.fDimension = this.curveSelection?.diameterKey || this.predictKv.fDimension;
        const kv = Number(this.predictKv.y(positionPercent));
        if (!Number.isFinite(kv)) {
          return 0.1;
        }
        return Math.max(0.1, kv);
      } catch (error) {
        this.logger.warn(`Failed to predict Kv for position=${positionPercent}: ${error.message}`);
        return 0.1;
      }
    }

    // -------- Sequence Handlers -------- //  
  async executeSequence(sequenceName) {

    const sequence = this.config.sequences[sequenceName];

    if (!sequence || sequence.size === 0) {
      this.logger.warn(`Sequence '${sequenceName}' not defined.`);
      return;
    }

    if (this.state.getCurrentState() == "operational" && sequenceName == "shutdown") {
      this.logger.info(`Machine will ramp down to position 0 before performing ${sequenceName} sequence`);
      await this.setpoint(0);
    }

    this.logger.info(` --------- Executing sequence: ${sequenceName} -------------`);

    for (const state of sequence) {
      try {
        await this.state.transitionToState(state);
        // Update measurements after state change

      } catch (error) {
        this.logger.error(`Error during sequence '${sequenceName}': ${error}`);
        break; // Exit sequence execution on error
      }
    }
    }

    async setpoint(setpoint) {

    try {
      // Validate setpoint
      if (typeof setpoint !== 'number' || setpoint < 0) {
        throw new Error("Invalid setpoint: Setpoint must be a non-negative number.");
      }

      // Move to the desired setpoint
      await this.state.moveTo(setpoint);

    } catch (error) {
      this.logger.error(`Error setting setpoint: ${error}`);
    }
  }

  updatePressure(variant,value,position,unit = this.unitPolicy.output.pressure) {
    if( value === null || value === undefined) {
      this.logger.warn(`Received null or undefined value for pressure update. Variant: ${variant}, Position: ${position}`);
      return;
    }
    this.logger.debug(`Updating pressure: variant=${variant}, value=${value}, position=${position}`);

    switch (variant) {
      case ("measured"): {
        // put value in measurements container
        this._writeMeasurement("pressure", "measured", position, Number(value), unit);
        // get latest downstream pressure measurement
        const measuredDownStreamP = this._readMeasurement("pressure", "measured", "downstream", FORMULA_UNITS.pressure);
        const measuredFlow = this._readMeasurement("flow", "measured", "downstream", FORMULA_UNITS.flow);
        const predictedFlow = this._readMeasurement("flow", "predicted", "downstream", FORMULA_UNITS.flow);
        const activeFlow = Number.isFinite(predictedFlow) ? predictedFlow : measuredFlow;
        // update predicted flow measurement
        this.updateDeltaPKlep(activeFlow,this.kv,measuredDownStreamP,this.rho,this.T);
        break;
      }

      case ("predicted"): {
        // put value in measurements container
        this._writeMeasurement("pressure", "predicted", position, Number(value), unit);
        const predictedDownStreamP = this._readMeasurement("pressure", "predicted", "downstream", FORMULA_UNITS.pressure);
        const measuredFlowFromPred = this._readMeasurement("flow", "measured", "downstream", FORMULA_UNITS.flow);
        const predictedFlowFromPred = this._readMeasurement("flow", "predicted", "downstream", FORMULA_UNITS.flow);
        const activeFlowFromPred = Number.isFinite(predictedFlowFromPred) ? predictedFlowFromPred : measuredFlowFromPred;
        this.updateDeltaPKlep(activeFlowFromPred,this.kv,predictedDownStreamP,this.rho,this.T);
        break;
      }

      default:
        this.logger.warn(`Unrecognized variant '${variant}' for flow update.`);
        break;
    }
  }

  updateMeasurement(variant, subType, value, position, unit) {
    this.logger.debug(`---------------------- updating ${subType} ------------------ `);
    switch (subType) {
      case "pressure":
        // Update pressure measurement
        this.updatePressure(variant,value,position, unit || this.unitPolicy.output.pressure);
        break;
      case "flow":
        this.updateFlow(variant,value,position, unit || this.unitPolicy.output.flow);
        break;
      case "power":
        // Update power measurement
        break;
      default:
        this.logger.error(`Type '${subType}' not recognized for measured update.`);
        return;
    }
  }

  // NOTE: q in m3/h (normalized basis), downstreamP in mbar(g), temp in K
  updateDeltaPKlep(q,kv,downstreamP,rho,temp){
      const result = this.hydraulicModel.calculateDeltaPMbar({
        qM3h: q,
        kv,
        downstreamGaugeMbar: downstreamP,
        rho,
        tempK: temp,
      });
      if (!result || !Number.isFinite(result.deltaPMbar)) {
        return;
      }

      const deltaP = result.deltaPMbar;
      this.deltaPKlep = deltaP;
      this.hydraulicDiagnostics = result.details || null;

      this._writeMeasurement("pressure", "predicted", "delta", deltaP, this.unitPolicy.output.pressure);
      this.logger.info('DeltaP updated to: ' + deltaP);

      this.emitter.emit('deltaPChange', deltaP); // Emit event to notify valveGroupController of deltaP change
      this.logger.info('DeltaPChange emitted to valveGroupController');
  }

     
  // Als er een nieuwe flow door de klep komt doordat de machines harder zijn gaan werken, dan update deze functie dit ook in de valve attributes en measurements
  updateFlow(variant,value,position,unit = this.unitPolicy.output.flow) {
    if( value === null || value === undefined) {
      this.logger.warn(`Received null or undefined value for flow update. Variant: ${variant}, Position: ${position}`);
      return;
    }
    this.logger.debug(`Updating flow: variant=${variant}, value=${value}, position=${position}`);

    switch (variant) {
      case ("measured"): {
        // put value in measurements container
        this._writeMeasurement("flow", "measured", position, Number(value), unit);
        // get latest downstream pressure measurement
        const measuredDownStreamP = this._readMeasurement("pressure", "measured", "downstream", FORMULA_UNITS.pressure);
        const measuredFlow = this._readMeasurement("flow", "measured", position, FORMULA_UNITS.flow);
        // update predicted flow measurement
        this.updateDeltaPKlep(measuredFlow,this.kv,measuredDownStreamP,this.rho,this.T);
        break;
      }

      case ("predicted"): {
        // put value in measurements container
        this._writeMeasurement("flow", "predicted", position, Number(value), unit);
        const predictedDownStreamP = this._readMeasurement("pressure", "measured", "downstream", FORMULA_UNITS.pressure);
        const predictedFlow = this._readMeasurement("flow", "predicted", position, FORMULA_UNITS.flow);
        this.updateDeltaPKlep(predictedFlow,this.kv,predictedDownStreamP,this.rho,this.T);
        break;
      }

      default:
        this.logger.warn(`Unrecognized variant '${variant}' for flow update.`);
        break;
    }
  }

  updatePosition() { //update alle parameters nadat er een verandering is geweest in stand van klep
    if (this.state.getCurrentState() == "operational" || this.state.getCurrentState() == "accelerating" || this.state.getCurrentState() == "decelerating") {
      
      this.logger.debug('Calculating new deltaP');
      const currentPosition = this.state.getCurrentPosition();
      const measuredFlow = this._readMeasurement("flow", "measured", "downstream", FORMULA_UNITS.flow);
      const predictedFlow = this._readMeasurement("flow", "predicted", "downstream", FORMULA_UNITS.flow);
      const currentFlow = Number.isFinite(predictedFlow) ? predictedFlow : measuredFlow;
      
      const downstreamP = this._readMeasurement("pressure", "measured", "downstream", FORMULA_UNITS.pressure);
      const x = currentPosition; // dit is de positie van de klep waarvoor we delta P willen berekenen
      const y = this._predictKvForPosition(x); // haal de waarde van kv op uit de supplierscurve

      this.kv = y; //update de kv waarde in de valve class
      this.logger.debug(`Kv value for position valve ${x} is ${this.kv}`); // log de waarde van kv
  
      this.updateDeltaPKlep(currentFlow,this.kv,downstreamP,this.rho,this.T); //update deltaP

    }
  }

  showCurve() {
    return {
      model: this.model || null,
      serviceType: this.serviceType,
      expectedServiceType: this.expectedServiceType,
      gasChokedRatioLimit: this.hydraulicModel?.gasChokedRatioLimit,
      selectedDensity: this.curveSelection?.densityKey ?? null,
      selectedDiameter: this.curveSelection?.diameterKey ?? null,
      curve: this.predictKv?.currentFxyCurve?.[this.predictKv?.fDimension] || null,
      hydraulics: this.hydraulicDiagnostics || null,
    };
  }

  destroy() {
    if (this._onPositionChange && this.state?.emitter?.off) {
      this.state.emitter.off("positionChange", this._onPositionChange);
    }
    for (const { emitter, handler } of this._fluidContractListeners.values()) {
      if (typeof emitter?.off === 'function') {
        emitter.off('fluidContractChange', handler);
      } else if (typeof emitter?.removeListener === 'function') {
        emitter.removeListener('fluidContractChange', handler);
      }
    }
    this._fluidContractListeners.clear();
  }
	
  getOutput() { 

    // Improved output object generation
    const output = {};
    //build the output object
    Object.entries(this.measurements.measurements || {}).forEach(([type, variants]) => {
      Object.entries(variants || {}).forEach(([variant, positions]) => {
        Object.keys(positions || {}).forEach((position) => {
          const value = this._readMeasurement(type, variant, position, this._outputUnitForType(type));
          if (value != null) {
            output[`${position}_${variant}_${type}`] = value;
          }
        });
      });
    });

    //fill in the rest of the output object
    output["state"] = this.state.getCurrentState();
    output["percentageOpen"] = this.state.getCurrentPosition();
    output["moveTimeleft"] = this.state.getMoveTimeLeft();
    output["mode"] = this.currentMode;

    //this.logger.debug(`Output: ${JSON.stringify(output)}`);

    return output;
  }

}

module.exports = Valve;