/**
 * node class.js
 *
 * Encapsulates all node logic in a reusable class. In future updates we can split this into multiple generic classes and use the config to specifiy which ones to use.
 * This allows us to keep the Node-RED node clean and focused on wiring up the UI and event handlers.
 */
const { outputUtils, configManager, convert } = require('generalFunctions');
const Specific = require("./specificClass");

class nodeClass {
  /**
   * Create a Node.
   * @param {object} uiConfig - Node-RED node configuration.
   * @param {object} RED    - Node-RED runtime API.
   */
  constructor(uiConfig, RED, nodeInstance, nameOfNode) {

    // Preserve RED reference for HTTP endpoints if needed
    this.node = nodeInstance; // This is the Node-RED node instance, we can use this to send messages and update status
    this.RED = RED; // This is the Node-RED runtime API, we can use this to create endpoints if needed
    this.name = nameOfNode; // This is the name of the node, it should match the file name and the node type in Node-RED
    this.source = null; // Will hold the specific class instance
    this.config = null; // Will hold the merged configuration
    this._pressureInitWarned = false;

    // Load default & UI config
    this._loadConfig(uiConfig,this.node);

    // Instantiate core class
    this._setupSpecificClass(uiConfig);

    // Wire up event and lifecycle handlers
    this._bindEvents();
    this._registerChild();
    this._startTickLoop();
    this._attachInputHandler();
    this._attachCloseHandler();
  }

  /**
   * Load and merge default config with user-defined settings.
   * @param {object} uiConfig - Raw config from Node-RED UI.
   */
  _loadConfig(uiConfig,node) {
    const cfgMgr = new configManager();
    const resolvedAssetUuid = uiConfig.assetUuid || uiConfig.uuid || null;
    const resolvedAssetTagCode = uiConfig.assetTagCode || uiConfig.assetTagNumber || null;
    const flowUnit = this._resolveUnitOrFallback(uiConfig.unit, 'volumeFlowRate', 'm3/h', 'flow');
    const curveUnits = {
      pressure: this._resolveUnitOrFallback(uiConfig.curvePressureUnit, 'pressure', 'mbar', 'curve pressure'),
      flow: this._resolveUnitOrFallback(uiConfig.curveFlowUnit || flowUnit, 'volumeFlowRate', flowUnit, 'curve flow'),
      power: this._resolveUnitOrFallback(uiConfig.curvePowerUnit, 'power', 'kW', 'curve power'),
      control: this._resolveControlUnitOrFallback(uiConfig.curveControlUnit, '%'),
    };

    // Build config: base sections + rotatingMachine-specific domain config
    this.config = cfgMgr.buildConfig(this.name, uiConfig, node.id, {
      flowNumber: uiConfig.flowNumber
    });

    // Override asset with rotatingMachine-specific fields
    this.config.asset = {
      ...this.config.asset,
      uuid: resolvedAssetUuid,
      tagCode: resolvedAssetTagCode,
      tagNumber: uiConfig.assetTagNumber || null,
      unit: flowUnit,
      curveUnits
    };

    // Ensure general unit uses resolved flow unit
    this.config.general.unit = flowUnit;

    // Utility for formatting outputs
    this._output = new outputUtils();
  }

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

  _resolveControlUnitOrFallback(candidate, fallback = '%') {
    const raw = typeof candidate === 'string' ? candidate.trim() : '';
    return raw || fallback;
  }

  /**
   * Instantiate the core Measurement logic and store as source.
   */
  _setupSpecificClass(uiConfig) {
    const machineConfig = this.config;

    // need extra state for this
    const stateConfig = {
        general: {
          logging: {
            enabled: machineConfig.general.logging.enabled,
            logLevel: machineConfig.general.logging.logLevel
          }
        },
        movement: {
          speed: Number(uiConfig.speed),
          mode: uiConfig.movementMode
        },
        time: {
          starting: Number(uiConfig.startup),
          warmingup: Number(uiConfig.warmup),
          stopping: Number(uiConfig.shutdown),
          coolingdown: Number(uiConfig.cooldown)
        }
      };

    this.source = new Specific(machineConfig, stateConfig);

    //store in node 
    this.node.source = this.source; // Store the source in the node instance for easy access
  
  }

  /**
   * Bind events to Node-RED status updates. Using internal emitter. --> REMOVE LATER WE NEED ONLY COMPLETE CHILDS AND THEN CHECK FOR UPDATES
   */
  _bindEvents() {

  }

  _updateNodeStatus() {
    const m = this.source;
    try {
          const mode = m.currentMode;
          const state = m.state.getCurrentState();
          const requiresPressurePrediction = ["operational", "warmingup", "accelerating", "decelerating"].includes(state);
          const pressureStatus = typeof m.getPressureInitializationStatus === "function"
            ? m.getPressureInitializationStatus()
            : { initialized: true };

          if (requiresPressurePrediction && !pressureStatus.initialized) {
            if (!this._pressureInitWarned) {
              this.node.warn("Pressure input is not initialized (upstream/downstream missing). Predictions are using minimum pressure.");
              this._pressureInitWarned = true;
            }
            return { fill: "yellow", shape: "ring", text: `${mode}: pressure not initialized` };
          }

          if (pressureStatus.initialized) {
            this._pressureInitWarned = false;
          }
          const flowUnit = m?.config?.general?.unit || 'm3/h';
          const flow = Math.round(m.measurements.type("flow").variant("predicted").position('downstream').getCurrentValue(flowUnit));
          const power = Math.round(m.measurements.type("power").variant("predicted").position('atEquipment').getCurrentValue('kW'));
          let symbolState;
          switch(state){
            case "off":
              symbolState = "⬛";
              break;
            case "idle":
              symbolState = "⏸️";
              break;
            case "operational":
              symbolState = "⏵️";
              break;
            case "starting":
              symbolState = "⏯️";
              break;
            case "warmingup":
              symbolState = "🔄";
              break;
            case "accelerating":
              symbolState = "⏩";
              break;
            case "stopping":
              symbolState = "⏹️";
              break;
            case "coolingdown":
              symbolState = "❄️";
              break;
            case "decelerating":
              symbolState = "⏪";
              break;
            case "maintenance":
              symbolState = "🔧";
              break;
          }
          const position = m.state.getCurrentPosition();
          const roundedPosition = Math.round(position * 100) / 100;

          let status;
          switch (state) {
            case "off":
              status = { fill: "red", shape: "dot", text: `${mode}: OFF` };
              break;
            case "idle":
              status = { fill: "blue", shape: "dot", text: `${mode}: ${symbolState}` };
              break;
            case "operational":
                status = { fill: "green", shape: "dot", text: `${mode}: ${symbolState} | ${roundedPosition}% | 💨${flow}${flowUnit} | ⚡${power}kW` };
              break;
            case "starting":
              status = { fill: "yellow", shape: "dot", text: `${mode}: ${symbolState}` };
              break;
            case "warmingup":
              status = { fill: "green", shape: "dot", text: `${mode}: ${symbolState} | ${roundedPosition}% | 💨${flow}${flowUnit} | ⚡${power}kW` };
              break;
            case "accelerating":
              status = { fill: "yellow", shape: "dot", text: `${mode}: ${symbolState} | ${roundedPosition}%| 💨${flow}${flowUnit} | ⚡${power}kW` };
              break;
            case "stopping":
              status = { fill: "yellow", shape: "dot", text: `${mode}: ${symbolState}` };
              break;
            case "coolingdown":
              status = { fill: "yellow", shape: "dot", text: `${mode}: ${symbolState}` };
              break;
            case "decelerating":
              status = { fill: "yellow", shape: "dot", text: `${mode}: ${symbolState} - ${roundedPosition}% | 💨${flow}${flowUnit} | ⚡${power}kW` };
              break;
            default:
              status = { fill: "grey", shape: "dot", text: `${mode}: ${symbolState}` };
          }
          return status;
        } catch (error) {
          this.node.error("Error in updateNodeStatus: " + error.message);
          return { fill: "red", shape: "ring", text: "Status Error" };
        }
      }
  /**
   * Register this node as a child upstream and downstream.
   * Delayed to avoid Node-RED startup race conditions.
   */
  _registerChild() {
    setTimeout(() => {
      this.node.send([
        null,
        null,
        { topic: 'registerChild', payload: this.node.id, positionVsParent: this.config?.functionality?.positionVsParent || 'atEquipment' },
      ]);
    }, 100);
  }

  /**
   * Start the periodic tick loop.
   */
  _startTickLoop() {
    this._startupTimeout = setTimeout(() => {
      this._startupTimeout = null;
      this._tickInterval = setInterval(() => this._tick(), 1000);

      // Update node status on nodered screen every second
      this._statusInterval = setInterval(() => {
        const status = this._updateNodeStatus();
        this.node.status(status);
      }, 1000);

    }, 1000);
  }

  /**
   * Execute a single tick: update measurement, format and send outputs.
   */
  _tick() {
    //this.source.tick();

    const raw = this.source.getOutput();
    const processMsg = this._output.formatMsg(raw, this.source.config, 'process');
    const influxMsg  = this._output.formatMsg(raw, this.source.config, 'influxdb');

    // Send only updated outputs on ports 0 & 1
    this.node.send([processMsg, influxMsg, null]);
  }

  /**
   * Attach the node's input handler, routing control messages to the class.
   */
  _attachInputHandler() {
    this.node.on('input', async (msg, send, done) => {
      const m = this.source;
      const nodeSend = typeof send === 'function' ? send : (outMsg) => this.node.send(outMsg);

      try {
        switch(msg.topic) {
            case 'registerChild': {
              const childId = msg.payload;
              const childObj = this.RED.nodes.getNode(childId);
              if (!childObj || !childObj.source) {
                this.node.warn(`registerChild failed: child '${childId}' not found or has no source`);
                break;
              }
              m.childRegistrationUtils.registerChild(childObj.source ,msg.positionVsParent);
              break;
            }
            case 'setMode':
              m.setMode(msg.payload);
              break;
            case 'execSequence': {
              const { source, action, parameter } = msg.payload;
              await m.handleInput(source, action, parameter);
              break;
            }
            case 'execMovement': {
              const { source: mvSource, action: mvAction, setpoint } = msg.payload;
              await m.handleInput(mvSource, mvAction, Number(setpoint));
              break;
            }
            case 'flowMovement': {
              const { source: fmSource, action: fmAction, setpoint: fmSetpoint } = msg.payload;
              await m.handleInput(fmSource, fmAction, Number(fmSetpoint));
              break;
            }
            case 'emergencystop': {
              const { source: esSource, action: esAction } = msg.payload;
              await m.handleInput(esSource, esAction);
              break;
            }
            case 'simulateMeasurement':
              {
                const payload = msg.payload || {};
                const type = String(payload.type || '').toLowerCase();
                const position = payload.position || 'atEquipment';
                const value = Number(payload.value);
                const unit = typeof payload.unit === 'string' ? payload.unit.trim() : '';
                const supportedTypes = new Set(['pressure', 'flow', 'temperature', 'power']);
                const context = {
                  timestamp: payload.timestamp || Date.now(),
                  unit,
                  childName: 'dashboard-sim',
                  childId: 'dashboard-sim',
                };

                if (!Number.isFinite(value)) {
                  this.node.warn('simulateMeasurement payload.value must be a finite number');
                  break;
                }

                if (!supportedTypes.has(type)) {
                  this.node.warn(`Unsupported simulateMeasurement type: ${type}`);
                  break;
                }

                if (!unit) {
                  this.node.warn('simulateMeasurement payload.unit is required');
                  break;
                }

                if (typeof m.isUnitValidForType === 'function' && !m.isUnitValidForType(type, unit)) {
                  this.node.warn(`simulateMeasurement payload.unit '${unit}' is invalid for type '${type}'`);
                  break;
                }

                switch (type) {
                  case 'pressure':
                    if (typeof m.updateSimulatedMeasurement === "function") {
                      m.updateSimulatedMeasurement(type, position, value, context);
                    } else {
                      m.updateMeasuredPressure(value, position, context);
                    }
                    break;
                  case 'flow':
                    m.updateMeasuredFlow(value, position, context);
                    break;
                  case 'temperature':
                    m.updateMeasuredTemperature(value, position, context);
                    break;
                  case 'power':
                    m.updateMeasuredPower(value, position, context);
                    break;
                }
              }
              break;
            case 'showWorkingCurves':
              nodeSend([{ ...msg, topic : "showWorkingCurves" , payload: m.showWorkingCurves() }, null, null]);
              break;
            case 'CoG':
              nodeSend([{ ...msg, topic : "showCoG" , payload: m.showCoG() }, null, null]);
              break;
          }
        if (typeof done === 'function') done();
      } catch (error) {
        if (typeof done === 'function') {
          done(error);
        } else {
          this.node.error(error, msg);
        }
      }
    });
  }

  /**
   * Clean up timers and intervals when Node-RED stops the node.
   */
  _attachCloseHandler() {
    this.node.on('close', (done) => {
      clearTimeout(this._startupTimeout);
      clearInterval(this._tickInterval);
      clearInterval(this._statusInterval);

      // Clean up child measurement listeners
      const m = this.source;
      if (m?.childMeasurementListeners) {
        for (const [, entry] of m.childMeasurementListeners) {
          if (typeof entry.emitter?.off === 'function') {
            entry.emitter.off(entry.eventName, entry.handler);
          } else if (typeof entry.emitter?.removeListener === 'function') {
            entry.emitter.removeListener(entry.eventName, entry.handler);
          }
        }
        m.childMeasurementListeners.clear();
      }

      // Clean up state emitter listeners
      if (m?.state?.emitter) {
        m.state.emitter.removeAllListeners();
      }

      if (typeof done === 'function') done();
    });
  }
}

module.exports = nodeClass;