esphome:
  name: water-heater-template-test
host:
api:
logger:

globals:
  - id: global_away
    type: bool
    initial_value: "false"
  - id: global_is_on
    type: bool
    initial_value: "true"

water_heater:
  - platform: template
    id: test_boiler
    name: Test Boiler
    optimistic: true
    current_temperature: !lambda "return 45.0f;"
    target_temperature: !lambda "return 60.0f;"
    away: !lambda "return id(global_away);"
    is_on: !lambda "return id(global_is_on);"
    # Note: No mode lambda - we want optimistic mode changes to stick
    # A mode lambda would override mode changes in loop()
    supported_modes:
      - "off"
      - eco
      - gas
      - performance
    visual:
      min_temperature: 30.0
      max_temperature: 85.0
      target_temperature_step: 0.5
    set_action:
      - lambda: |-
          // Sync optimistic state back to globals so lambdas reflect the change
          id(global_away) = id(test_boiler).is_away();
          id(global_is_on) = id(test_boiler).is_on();