headsetcontrol-battery-widget/package/contents/ui/main.qml

import QtQuick 2.0
import QtQuick.Layouts 1.3
import org.kde.plasma.plasmoid 2.0
import org.kde.plasma.core 2.0 as PlasmaCore

Item {
  id: main

  property int pollingrate: Plasmoid.configuration.pollingrate
  property int batteryPercent: -2

  PlasmaCore.DataSource {
    id: hsSource
    engine: "executable"
    connectedSources: ["headsetcontrol -bc"]
    interval: pollingrate * 1e3
    onNewData: {
      if(data['exit_code'] > 0)
        return console.log('error lol');
      batteryPercent = data['stdout'];
    }
  }

  Plasmoid.preferredRepresentation: Plasmoid.compactRepresentation

  Plasmoid.compactRepresentation: Item {
    Layout.minimumWidth: units.iconSizes.medium

    Image {
      anchors.fill: parent
      smooth: true
      fillMode: Image.PreserveAspectFit
      source: batteryIcon()
      Plasmoid.toolTipMainText: "battery level: " + batteryLevel()
      Plasmoid.toolTipSubText: "polling rate: " + pollingrate + " seconds"
    }

    function batteryIcon() {
      let iconName = "battery_100"
      if(batteryPercent == -1) // charging
        iconName = "battery_charging"
      else if(batteryPercent == -2) // not connected
        iconName = "battery_nc";
      else if(batteryPercent > 80)
        iconName = "battery_100";
      else if(batteryPercent > 60)
        iconName = "battery_80";
      else if(batteryPercent > 40)
        iconName = "battery_60";
      else if(batteryPercent > 20)
        iconName = "battery_40";
      else
        iconName = "battery_20";
      return "../icons/" + iconName + ".png";
    }

    function batteryLevel() {
      if(batteryPercent == -1)
        return "charging";
      else if(batteryPercent == -2)
        return "not connected";
      else
        return batteryPercent + "%";
    }
  }
}