uid: jag_rules:bayesian_sensor_calculation
label: Bayesian Sensor Calculation
description: Recalculate the probability of a bayesian sensor event when some input changes
configDescriptions:
  - name: sensorgroup
    type: TEXT
    context: item
    label: Bayesian Group
    required: true
    description: Group item configured with the BayesianSensor metadata
triggers:
  - id: "1"
    configuration:
      groupName: "{{sensorgroup}}"
    type: core.GroupStateChangeTrigger
conditions: []
actions:
  - inputs: {}
    id: "2"
    configuration:
      type: application/javascript;version=ECMAScript-2021
      script: >
        /*

        This Script provides functions for the sensor control system.

        */


        //Initialize

        var runtime = require('@runtime');

        var logger = Java.type('org.slf4j.LoggerFactory').getLogger('org.openhab.rule.bayesianSensor');

        var ZonedDateTime = Java.type("java.time.ZonedDateTime");

        var Duration = Java.type("java.time.Duration");

        logger.info('Bayesian Sensor - Recalculating')


        //Access MetadataRegistry

        var FrameworkUtil = Java.type('org.osgi.framework.FrameworkUtil');

        this.ScriptHandler = Java.type("org.openhab.core.automation.module.script.rulesupport.shared.ScriptedHandler");

        var _bundle = FrameworkUtil.getBundle(ScriptHandler.class);

        var bundle_context = _bundle.getBundleContext();

        var MetadataRegistry_Ref = bundle_context.getServiceReference('org.openhab.core.items.MetadataRegistry');

        var MetadataRegistry = bundle_context.getService(MetadataRegistry_Ref);

        var MetadataKey = Java.type('org.openhab.core.items.MetadataKey');


        //Bayesian Probability Calculation

        function updatePrior (updPrior, updPTrue, updPFalse, updItem) {
            var numerator = updPTrue * updPrior;
            var denominator = numerator + updPFalse * (1 - updPrior);
            logger.info(updItem + ': ' + updPrior.toString() + ' -> ' + (numerator / denominator).toString());
            return numerator / denominator;
        }


        //Find All Bayesian Sensor Groups for Event Item

        var parentGroups = items.getItem(event.itemName).groupNames;

        var sensorGroups = parentGroups.filter(x => items.getItem(x).tags.includes('Bayesian Sensor'));


        //Read BayesianSensor MetaData and Iterate Through Sensors for Each Impacted Sensor Group

        for (var sensorGroup of sensorGroups) {
          var metaList = MetadataRegistry.get(new MetadataKey('BayesianSensor',sensorGroup));
          if (!metaList || !metaList.configuration) {
            logger.info(['Bayesian metadata not configured for ',sensorGroup].join(''));
          } else {
            var sensorConfig = metaList['configuration'];
            var sensorList = sensorConfig.sensors;
            var prior = sensorConfig.prior || 0.5;
              for (var checkItem in sensorList) {
                if (sensorList[checkItem].decay) {
                  var now = ZonedDateTime.now();
                  var changedTime = items.getItem(sensorList[checkItem].decay.timestamp || checkItem + '_TS').rawState.getZonedDateTime();
                  var decayTime = Duration.between(changedTime,now).toMinutes();
                  var numSteps = Math.floor(decayTime / (sensorList[checkItem].decay.timeStep || 5));
                  var probTrue = Math.max((sensorList[checkItem].decay.decayMin || .6),sensorList[checkItem].pTrue - (numSteps * sensorList[checkItem].decay.decayStep));
                } else {
                  var probTrue = sensorList[checkItem].pTrue;
                }
                switch (sensorList[checkItem].testType) {
                  case 'gt':
                    if (runtime.items[checkItem] > sensorList[checkItem].testState) {
                      prior = updatePrior(prior, probTrue,sensorList[checkItem].pFalse,checkItem);
                    }
                    break;
                  case 'lt':
                    if (runtime.items[checkItem] < sensorList[checkItem].testState) {
                      prior = updatePrior(prior, probTrue,sensorList[checkItem].pFalse,checkItem);
                    }
                    break;
                  case 'bt':
                    if ((sensorList[checkItem].testState[0] > runtime.items[checkItem]) && (runtime.items[checkItem] > sensorList[checkItem].testState[1])) {
                      prior = updatePrior(prior, probTrue,sensorList[checkItem].pFalse,checkItem);
                    }
                    break;
                  case 'neq':
                    if (runtime.items[checkItem].toString() != sensorList[checkItem].testState) {
                      prior = updatePrior(prior, probTrue,sensorList[checkItem].pFalse,checkItem);
                    }
                    break;
                  case 'list':
                    if (sensorList[checkItem].testState.contains(runtime.items[checkItem])) {
                      prior = updatePrior(prior, probTrue,sensorList[checkItem].pFalse,checkItem);
                    }
                    break;
                  default:
                    if (runtime.items[checkItem].toString() == sensorList[checkItem].testState) {
                      prior = updatePrior(prior, probTrue,sensorList[checkItem].pFalse,checkItem);
                    }
                    break;
                }
              }
            if (sensorConfig.posterior) runtime.events.postUpdate(sensorConfig.posterior,prior.toString());
            runtime.events.sendCommand(sensorConfig.proxy,(prior >= sensorConfig.threshold) ? (sensorConfig.trueState || 'ON') : (sensorConfig.falseState || 'OFF'));
            logger.info([sensorGroup + ' new probability of ',prior, (prior >= sensorConfig.threshold) ? ' is over ' : 'is under ', sensorConfig.threshold].join(''));
          }
        }
    type: script.ScriptAction