Home Assistant NFC check-in/out for a Shelly plug energy (session tracking)

shelly-checkin.yaml

blueprint:
  name: NFC Session Tracker - Shared Desk
  description: Tracks energy per person with cumulative history
  domain: automation
  
  input:
    tag_id:
      name: NFC tag_id
      selector:
        text:
    
    energy_entity:
      name: Shelly cumulative energy (kWh)
      selector:
        entity:
          domain: sensor
    
    power_entity:
      name: Shelly power (W) - for power-off reset
      selector:
        entity:
          domain: sensor
    
    person_name:
      name: Person identifier (for logging)
      selector:
        text:
    
    person_cumulative_entity:
      name: input_number for person's total energy
      selector:
        entity:
          domain: input_number
    
    # Shared entities
    checked_in_boolean:
      name: input_boolean "checked in"
      selector:
        entity:
          domain: input_boolean
    
    active_person_input:
      name: input_text "active person"
      selector:
        entity:
          domain: input_text
    
    session_start_energy:
      name: input_number "session start energy"
      selector:
        entity:
          domain: input_number
    
    delta_sensor:
      name: Template sensor for current delta
      selector:
        entity:
          domain: sensor
    
    power_off_below:
      name: Power-off threshold (W)
      default: 1
      selector:
        number:
          min: 0
          max: 10000
          step: 0.1
    
    power_off_duration_minutes:
      name: Power-off duration (minutes)
      default: 2
      selector:
        number:
          min: 0
          max: 60
          step: 1

trigger:
  - platform: tag
    tag_id: !input tag_id
  
  - platform: numeric_state
    entity_id: !input power_entity
    below: !input power_off_below
    for:
      minutes: !input power_off_duration_minutes

variables:
  is_nfc_scan: "{{ trigger.platform == 'tag' }}"
  scanned_person: !input person_name
  current_person: "{{ states(active_person_input) }}"
  is_same_person: "{{ is_state(checked_in_boolean, 'on') and current_person == scanned_person }}"
  session_delta: "{{ states(delta_sensor) | float(0) }}"
  person_total_entity: !input person_cumulative_entity
  current_total: "{{ states(person_total_entity) | float(0) }}"

action:
  - choose:
      # NFC tag scan
      - conditions:
          - condition: template
            value_template: "{{ is_nfc_scan }}"
        sequence:
          - choose:
              # Same person scans => CHECKOUT
              - conditions:
                  - condition: template
                    value_template: "{{ is_same_person }}"
                sequence:
                  # Add session delta to cumulative total
                  - service: input_number.set_value
                    target:
                      entity_id: "{{ person_total_entity }}"
                    data:
                      value: "{{ current_total + session_delta }}"
                  
                  # Log to logbook with history
                  - service: logbook.log
                    data:
                      name: "Energy Tracking"
                      message: "{{ scanned_person }} checked out. Session: {{ session_delta | round(3) }} kWh, Total: {{ (current_total + session_delta) | round(3) }} kWh"
                  
                  # Reset session state
                  - service: input_boolean.turn_off
                    target:
                      entity_id: !input checked_in_boolean
                  - service: input_text.set_value
                    target:
                      entity_id: !input active_person_input
                    data:
                      value: ""
                  - service: input_number.set_value
                    target:
                      entity_id: !input session_start_energy
                    data:
                      value: 0
              
              # Different person or first check-in => CHECK-IN
              - conditions: []
                sequence:
                  # If someone was already checked in, auto-checkout
                  - if: "{{ is_state(checked_in_boolean, 'on') }}"
                    then:
                      - variables:
                          prev_person: "{{ current_person }}"
                          # Would need the previous person's entity as input... 
                          # For now, just log
                      - service: logbook.log
                        data:
                          name: "Energy Tracking"
                          message: "Auto-checkout: {{ current_person }}. Session: {{ session_delta | round(3) }} kWh"
                  
                  # Check in new person
                  - service: input_boolean.turn_on
                    target:
                      entity_id: !input checked_in_boolean
                  - service: input_text.set_value
                    target:
                      entity_id: !input active_person_input
                    data:
                      value: "{{ scanned_person }}"
                  - service: input_number.set_value
                    target:
                      entity_id: !input session_start_energy
                    data:
                      value: "{{ states(energy_entity) | float(0) }}"
                  
                  - service: logbook.log
                    data:
                      name: "Energy Tracking"
                      message: "{{ scanned_person }} checked in"
      
      # Power-off reset
      - conditions:
          - condition: template
            value_template: "{{ not is_nfc_scan }}"
          - condition: state
            entity_id: !input checked_in_boolean
            state: "on"
        sequence:
          - variables:
              person_at_reset: "{{ current_person }}"
          
          # Optionally log partial session if needed
          - service: logbook.log
            data:
              name: "Energy Tracking"
              message: "Power-off detected. {{ person_at_reset }} session reset (partial delta: {{ session_delta | round(3) }} kWh)"
          
          # Clear session
          - service: input_boolean.turn_off
            target:
              entity_id: !input checked_in_boolean
          - service: input_text.set_value
            target:
              entity_id: !input active_person_input
            data:
              value: ""
          - service: input_number.set_value
            target:
              entity_id: !input session_start_energy
            data:
              value: 0