#' @include Forecaster.R
#'
#' Persistence Forecaster
#'
#' Return the last centered (similar) day curve.
#' Inherits \code{\link{Forecaster}}
#'
PersistenceForecaster = R6::R6Class("PersistenceForecaster",
	inherit = Forecaster,

	public = list(
		predictShape = function(data, today, memory, horizon, ...)
		{
			# Return centered last (similar) day curve, avoiding NAs until memory is run
			first_day = max(1, today-memory)
			same_day = ifelse(hasArg("same_day"), list(...)$same_day, TRUE)
			# If 'same_day', get the last known future of similar day: -7 + 1 == -6
			index = today - ifelse(same_day,6,0)
			repeat
			{
				{
					last_serie = data$getCenteredSerie(index)[1:horizon]
					index = index - ifelse(same_day,7,1)
				};
				if (!any(is.na(last_serie)))
					return (last_serie);
				if (index < first_day)
					return (NA)
			}
		}
	)
)