Non-JSON MQTT state with three possible options

1

I have a device which is controlled via MQTT. It is very simple and has only two topics:

  • aromadiffuser/command with values press for switch on and press_long for switch off
  • aromadiffuser/state where 3 possible values: on, off and error (in case low level of water).

I want to have a switch in HA which will be show an error in case of error or current state of the device. And I need to have an ability to enabling and disabling it from HA with the same switch.

I am trying to implement it with this code:

switch:
  - platform: template
    switches:
      aromadiffuser:
        friendly_name: Aromadiffuser
        value_template: '{{ value }}'
        payload_on: "on"
        payload_off: "off"
        turn_on:
          service: mqtt.publish
          data:
            topic: "aromadiffuser/command"
            payload: "press"
        turn_off:
          service: mqtt.publish
          data:
            topic: "aromadiffuser/command"
            payload: "press_long"

As I see it’s able to enable or disable the device but it doesn’t show any state of the device. How can I handle non-JSON state with 3 options?