blueprint:
  name: Bathroom Fan Manager
  description: >
    Turns fan on with bathroom lights (after optional delay), keeps it on while any light is on, and turns it off after all lights are off and a timeout.
  domain: automation
  input:
    fan:
      name: Fan Entity
      selector:
        entity:
          domain: fan

    lights:
      name: Bathroom Light Entities
      selector:
        entity:
          domain: light
          multiple: true

    delay_before_fan_on:
      name: Delay Before Turning Fan On
      description: Time to wait after any light turns on before turning on the fan.
      default: 0
      selector:
        number:
          min: 0
          max: 300
          unit_of_measurement: seconds

    time_fan_stays_on_after_lights_off:
      name: Time Fan Stays On After All Lights Are Off
      description: Time to keep the fan running after all lights are off.
      default: 300
      selector:
        number:
          min: 0
          max: 3600
          unit_of_measurement: seconds

mode: restart

trigger:
  - platform: state
    entity_id: !input lights
    to:
      - "on"
      - "off"

variables:
  fan_entity: !input fan
  lights: !input lights

action:
  - choose:
      - conditions:
          - condition: template
            value_template: >
              {{ expand(lights) | selectattr('state', 'eq', 'on') | list | count > 0 }}
        sequence:
          - delay:
              seconds: !input delay_before_fan_on
          - service: fan.turn_on
            target:
              entity_id: "{{ fan_entity }}"
      - conditions:
          - condition: template
            value_template: >
              {{ expand(lights) | selectattr('state', 'eq', 'on') | list | count == 0 }}
        sequence:
          - delay:
              seconds: !input time_fan_stays_on_after_lights_off
          - condition: template
            value_template: >
              {{ expand(lights) | selectattr('state', 'eq', 'on') | list | count == 0 }}
          - service: fan.turn_off
            target:
              entity_id: "{{ fan_entity }}"