uid: rules_tools:meter
label: Meter Reading
description: Keeps a sum from a counting meter Item that can randomly be reset back to zero.
configDescriptions:
  - name: meter
    type: TEXT
    context: item
    filterCriteria:
      - name: type
        value: Number
    label: Meter Item
    required: true
    description: Item that holds the meter readings.
  - name: total
    type: TEXT
    context: item
    filterCriteria:
      - name: type
        value: Number
    label: Total Item
    required: true
    description: Item that holds the running total.
triggers:
  - id: "1"
    configuration:
      itemName: "{{meter}}"
    type: core.ItemStateChangeTrigger
conditions:
  - inputs: {}
    id: "2"
    configuration:
      type: application/javascript;version=ECMAScript-2021
      script: "!items.getItem(event.itemName).isUninitialized;"
    type: script.ScriptCondition
actions:
  - inputs: {}
    id: "3"
    configuration:
      type: application/javascript;version=ECMAScript-2021
      script: >-
        var totalItem = items.getItem('{{total}}');

        var reading = event.itemState.floatValue();

        var lastReading = (event.oldItemState.toString() == 'NULL' || event.oldItemState.toString() == 'UNDEF') ? reading  : event.oldItemState.floatValue();

        var currTotal = (totalItem.isUninitialized) ? 0 : totalItem.rawState.floatValue();


        // If the device counter was reset, use the current reading as the delta

        var delta = (reading < lastReading) ? reading : (reading - lastReading);


        totalItem.postUpdate((currTotal + delta).toString());
    type: script.ScriptAction