AverageCost returns the time-weighted average cost.

Duration returns the sum of all slot's durations.

IsFirst returns if the slot is the first slot in the plan.

New creates a price planner.

SlotAt returns the slot for the given time or an empty slot.

SlotHasSuccessor returns if the slot has an immediate successor.

Start returns the earliest slot's start time.

Planner plans a series of charging slots for a given (variable) tariff.