Dynamic travel time

transport:
  template:
    - sensor:
        - name: dynamic travel time
          unique_id: 08420e6f28e54d45b49de95436047abf
          state: >-
            {# PARAMETERS TO BE CHANGED #}
            {% set calendar = 'calendar.jacob_lindvig_gmail_com' %}
            {% set work_keyword = 'Arbejde' %}
            {% set travel_sensor = 'sensor.waze_travel_time_arbejde' %}
            {% set off_state = 'off' %}
            {% set time_before = 300 %}

            {# EXTRACTIONS OF VARIABLES #}
            {# EXTRACT DATE AND TIME OF WORK #}
            {% set work_datetime_str = state_attr(calendar, 'start_time') %}
            {# EXTRACT THE DATE OF WORK #}
            {% set work_date_str = work_datetime_str.split(' ')[0] %}
            {# EXTRACT TODAYS DATE AS STRING #}
            {% set today_date_str = (now() ~ '').split(' ')[0] %}

            {# MAGIC BELOW #}
            {# IS THE EVENT TODAY AND IS IT MARKED WITH THE KEYWORD #}
            {% if work_date_str == today_date_str and is_state_attr(calendar, 'message', work_keyword) %}
              {# CALCULATE THE DEPATURE TIME AND OUTPUT IT AS HH:MM #}
              {{
                (
                  (work_datetime_str | as_timestamp()) -
                  time_before -
                  (( states(travel_sensor) | float ) * 60)
                ) | timestamp_custom('%H:%M')
              }}
            {% else %}
              {{ off_state }}
            {% endif %}