distinct_random.yaml

blueprint:
  name: Distinct Random
  description: >
    Creates a sensor which holds a random value from the referenced
    input_select. When the sensor receives the DISTINCT_UPDATE event, a new
    random value will be chosen. The random value will be distinct, meaning that
    a duplicate will not be returned until all options are exhaused.

    For Example if an Input Select has items: a, b, c
    On creation the template might contain `a`, then after a refresh it might
    contain `b`, and then finally `c`. Once the list has been exhausted, the
    "seen" values will be reset and it will be possible to return a, b, c again.

    The DISTINCT_UPDATE event must contain `name: "<sensor name>"` for the event
    to match.
  domain: template
  input:
    reference_entity:
      name: Input select
      description: The input_select to use as the source of options.
      selector:
        entity:
          domain: input_select
    sensor_name:
      name: Sensor Name
      description: The name of the new distinct random sensor to create.
variables:
  reference_entity: !input reference_entity
  sensor_name: !input sensor_name
trigger:
  # Recalculate the state if an option was removed.
  - trigger: state
    entity_id: "{{ reference_entity }}"
    attribute: options
  # Ideally we would use homeassistant.update_entity
  # but it's not available for trigger templates.
  # So we define a new event that needs to be fired.
  - trigger: event
    event_type: DISTINCT_UPDATE
    event_data:
      name: "{{ sensor_name }}"
  # Causes the template to render when first created.
  - trigger: event
    event_type: event_template_reloaded
sensor:
  - name: "{{ sensor_name }}"
    state: >
      {% set seen = (state_attr(this.entity_id, 'seen') | default([], true)) %}
      {% if trigger.platform == "event" and trigger.event.type == "DISTINCT_UPDATE" %}
        {% set seen = seen + ([states(this.entity_id)] | reject('eq', 'unknown') | list ) %}
      {% endif %}
      {% set available = (state_attr(reference_entity, "options") | reject("in", seen) | list) %}
      {% if available %}
        {{ available | random }}
      {% else %}
        {{ state_attr(this.entity_id, 'seen') | random }}
      {% endif %}
    attributes:
      trigger: >
        {{ trigger | pprint}}
      seen: >
        {% set seen = (state_attr(this.entity_id, 'seen') | default([], true)) %}
        {% if trigger.platform == "event" and trigger.event.type == "DISTINCT_UPDATE" %}
          {% set seen = seen + ([states(this.entity_id)] | reject('eq', 'unknown') | list ) %}
        {% endif %}
        {% set available = (state_attr(reference_entity, "options") | reject("in", seen) | list) %}
        {% if available %}
          {{ seen }}
        {% else %}
          {{ [] }}
        {% endif %}