Cost calculation for Octopus Flexi tariff (Spain)

[goncal]

Hi!

Thanks a lot for the excellent work in this integration. I have put together some code to estimate the charges corresponding to the Octopus Flexi tariff (Spanish market). I'm adding it below, just in case someone else finds it useful and/or you want to share it in your wiki.
In order for it to work, one needs to set up two instances of the "Workday" integration:

• binary_sensor.workday_sensor: configured for working days in Spain, offset 0 (today)
• binary_sensor.workday_sensor_tomorrow: configured for working days in Spain, offset 1 (tomorrow)
  These are needed in order to accurately take into account whether today or tomorrow are official holidays (or week-ends).
  The calculation includes taxes, both IVA (21%) and the tax on electricity (3.8%).

Best regards,
Gonçal
OctopusFlexiES.txt