uid: prosenb:offline_things_display
label: Offline Things display
description: Queries all Things about offline state and displays the offline ones.
configDescriptions:
  - name: PARENT_ITEM
    label: Parent item
    description: Online items for Things will be created under this item. It must be of type `Group`.
    type: TEXT
    context: item
    required: true
  - name: IGNORE_THINGS_ITEM
    label: Ignored Things item
    description: Create a tag on this item for each Thing to be ignore.
    type: TEXT
    context: item
    required: false
  - name: THINGS_ONLINE_ITEM
    label: Things online item
    description: This items shows if any Thing is offline. It is `on` when all Things are online and `off` otherwise. It must be of type `Switch` or `Group`. If it's `Group`, the  `Members Base Type`  must be set to `Switch`.
    type: TEXT
    context: item
    required: false
  - name: ITEM_LIST_WIDGET
    label: Online items list widget
    description: The list widget of the items representing the online state of Things.
    type: TEXT
    required: false
    defaultValue: oh-label-item
triggers:
  - id: "1"
    label: A Thing Changes Status
    description: Triggers when any Thing changes status
    configuration:
      types: ThingStatusInfoChangedEvent
      payload: ""
      topic: openhab/things/**
      source: ""
    type: core.GenericEventTrigger
conditions: []
actions:
  - inputs: {}
    id: "1"
    configuration:
      type: application/javascript;version=ECMAScript-2021
      script: >-
        /* global Java, event, items, actions */
        (function () {
          // Arguments
          const parentItemName = '{{PARENT_ITEM}}';
          const ignoreThingsItemName = '{{IGNORE_THINGS_ITEM}}';
          const thingsOnlineItemName = '{{THINGS_ONLINE_ITEM}}';
          const itemListWidget = '{{ITEM_LIST_WIDGET}}';

          const parentItem = items.getItem(parentItemName, true);
          const ignoreThingsItem = items.getItem(ignoreThingsItemName, true);
          const thingsOnlineItem = items.getItem(thingsOnlineItemName, true);

          if (parentItem == null) {
            console.info("parentItem not found, stop rule.")
            return;
          }

          var notProcessedThingOnlineItems = parentItem.members;

          var atLeastOneOffline = false;
          things.getThings().forEach(thing => {
            const onlineItemName = generateOnlineItemName(thing);
            // remove this item from notProcessedThingOnlineItems
            notProcessedThingOnlineItems = notProcessedThingOnlineItems.filter(item => item.name !== onlineItemName);

            if (ignoreThingsItem != null && ignoreThingsItem.tags.includes(thing.uid)) {
              if (items.getItem(onlineItemName, true) != null) {
                items.removeItem(onlineItemName);
                console.info("OfflineThingsDisplay", "ignored, remove onlineItem: " + onlineItemName);
              }
            } else if (thing.status == "OFFLINE") {
              atLeastOneOffline = true;
              var onlineItem = items.getItem(onlineItemName, true);
              if (onlineItem == null) {
                console.info("OfflineThingsDisplay", "add onlineItem: " + onlineItemName);
                addItem(onlineItemName, thing.label);
                onlineItem = items.getItem(onlineItemName);
              }
              if (onlineItem.state == "ON") {
                console.info("OfflineThingsDisplay", "offline: " + onlineItemName);
              }
              onlineItem.sendCommandIfDifferent("OFF");
              replaceMetadata(onlineItem, "widgetOrder", "1");
            } else { // ONLINE
              const onlineItem = items.getItem(onlineItemName, true);
              if (onlineItem != null) {
                if (onlineItem.state == "OFF") {
                  console.info("OfflineThingsDisplay", "online: " + onlineItemName);
                }
                onlineItem.sendCommandIfDifferent("ON");
                replaceMetadata(onlineItem, "widgetOrder", "100");
              }
            }
          });

          if (thingsOnlineItem != null) {
            if (atLeastOneOffline) {
              thingsOnlineItem.sendCommandIfDifferent("OFF");
            } else {
              thingsOnlineItem.sendCommandIfDifferent("ON");
            }
          }

          // remove ThingOnlineItems that related to deleted Things
          notProcessedThingOnlineItems.forEach(item => {
            if (item.tags.find(tag => tag == "ThingOnlineItem") == null) {
              console.debug("Not removed item " + item.name
                           + " because it does not have the tag ThingOnlineItem but: " + item.tags);
            } else if (item.groupNames.length > 1) {
              console.debug("Not removed item " + item.name
                           + " because it is also in other groups: " + item.groupNames);
            } else {
              items.removeItem(item.name);
              console.info("Removed item: " + item.name);
            }
          });

          function addItem(name, label) {
            items.addItem({
              type: 'Switch',
              name: name,
              label: label,
              groups: [parentItemName],
              tags: ['Point', 'ThingOnlineItem'],
              metadata: {
                listWidget: itemListWidget,
                stateDescription: {
                  config: {
                    readOnly: true
                  }
                }
              }
            });
          }
          function generateOnlineItemName(thing) {
            const newName = 'Online_' + thing.uid;
            return newName.replaceAll(":", "_").replaceAll("-", "_");
          }
          function replaceMetadata(item, namespace, value) {
            // OPENHAB_JS_VERSION before 4.5.0 are null
            if (utils.OPENHAB_JS_VERSION == null) {
              item.upsertMetadataValue(namespace, value);
            } else {
              item.replaceMetadata(namespace, value);
            }
          }
        })()

    type: script.ScriptAction