PrePaid

# A sensor that indicates how many prepaid units you have left

input_number:
  prepaid_units:
    name: Enter Prepaid Units from Meter
    min: 0
    max: 999
    step: 1
    unit_of_measurement: "kWh"
    mode: box
    icon: mdi:home-lightning-bolt-outline
  prepaid_units_left:
    name: Enter Prepaid Units Left
    min: -999
    max: 999
    step: 1
    unit_of_measurement: "kWh"
    icon: mdi:home-lightning-bolt-outline
  initial_grid_import:
    name: Initial Grid Import
    min: 0
    max: 99999
    step: 1
    unit_of_measurement: "kWh"
    icon: mdi:counter

# Input datetime to store the last update time
input_datetime:
  last_update:
    name: Last Update
    has_date: true
    has_time: true

# Template sensor to calculate remaining units
template:
  - sensor:
      - name: "Prepaid Units Left"
        icon: mdi:home-lightning-bolt-outline
        unit_of_measurement: "kWh"
        state: >
          {% set initial_import = states('input_number.initial_grid_import') | float %}
          {% set current_import = states('sensor.sunsynk_total_grid_import') | float %}
          {% set units = states('input_number.prepaid_units') | float %}
          {% set used_units = current_import - initial_import %}
          {{ (units - used_units) | round(2) }}
      - name: "Units Used Since Last Update"
        icon: mdi:flash
        unit_of_measurement: "kWh"
        state: >
          {% set initial_import = states('input_number.initial_grid_import') | float %}
          {% set current_import = states('sensor.sunsynk_total_grid_import') | float %}
          {{ (current_import - initial_import) | round(2) }}
      - name: "Last Update Date"
        icon: mdi:calendar
        state: >
          {{ states('input_datetime.last_update') }}

################################### scripts.yaml
script:
  update_prepaid_units:
    alias: Update Prepaid Units
    sequence:
      - service: input_number.set_value
        target:
          entity_id: input_number.prepaid_units
        data:
          value: "{{ states('input_number.prepaid_units') | float }}"
      - service: input_number.set_value
        target:
          entity_id: input_number.prepaid_units_left
        data:
          value: "{{ states('sensor.prepaid_units_left') | float }}"
      - service: input_number.set_value
        target:
          entity_id: input_number.initial_grid_import
        data:
          value: "{{ states('sensor.sunsynk_total_grid_import') | float }}"
      - service: input_datetime.set_datetime
        target:
          entity_id: input_datetime.last_update
        data:
          datetime: "{{ now().strftime('%Y-%m-%d %H:%M:%S') }}"
    mode: single