@spec execute(t()) ::
  {:event, new_state :: t(),
   BACnet.Protocol.NotificationParameters.ChangeOfStatusFlags.t()}
  | {:delayed_event | :no_event, new_state :: t()}

Calculates the new state for the current state and parameters. Prior to this function invocation, the state should have been updated with update/2, if any of the properties has changed.

:delayed_event helps identifying whether the algorithm needs to be called periodically in order to overcome the time_delay and trigger a state change. As soon as :event or :no_event is given as flag, it means the caller can go back to event orientated calling.

The status_flags field of the notifications parameters is updated from the state with the correct in_alarm state, however to ensure the Status Flags have an overall correct status, the user has to make sure all bits are correctly.

ASHRAE 135:

The conditions evaluated by this event algorithm are:

(a) If pCurrentState is NORMAL, and pMonitoredValue has a value of TRUE in any of its flags that also has a value of TRUE in the corresponding flag in pSelectedFlags for pTimeDelay, then indicate a transition to the OFFNORMAL event state.

(b) If pCurrentState is OFFNORMAL, and pMonitoredValue has none of its flags set to TRUE that also has a value of TRUE in the corresponding flag in the pSelectedFlags event parameter for pTimeDelayNormal, then indicate a transition to the NORMAL event state.

(c) If pCurrentState is OFFNORMAL, and the set of selected flags of pMonitoredValue that have a value of TRUE changes, then indicate a transition to the OFFNORMAL event state.

@spec new(
  BACnet.Protocol.StatusFlags.t(),
  BACnet.Protocol.ApplicationTags.Encoding.t() | nil,
  BACnet.Protocol.EventParameters.ChangeOfStatusFlags.t()
) :: t()

Creates a new algorithm state.

@spec update(t(), Keyword.t()) :: t()

Updates the state using the given parameters (monitored_value, parameters, present_value).