R/AirFireWRF.R

In MazamaScience/AirFireWRF: Utilities for working with WRF atmospheric model data

#' @docType package
#' @name AirFireWRF
#' @title Utilities for working with WRF model output
#' @description A suite of utility functions providing functions commonly
#' required for working with WRF model output in R.
NULL

# ----- Internal Package State -------------------------------------------------

AirFireWRFEnv <- new.env(parent = emptyenv())
AirFireWRFEnv$dataDir <- NULL

# ----- Data Directory Configuration -------------------------------------------

#' @docType data
#' @keywords environment
#' @name WRFDataDir
#' @title Directory for modeling data
#' @format Absolute path string.
#' @description This package maintains an internal directory location which
#' users can set using \code{setWRFDataDir()}. All package functions use this
#' directory whenever datasets are created or loaded.
#'
#' The default setting when the package is loaded is \code{getwd()}.
#' @seealso \link{getWRFDataDir}
#' @seealso \link{setWRFDataDir}
NULL

#' @export
#' @title Get package data directory
#' @description Returns the package data directory where model data is located.
#' @return Absolute path string.
#' @seealso \link{WRFDataDir}
#' @seealso \link{setWRFDataDir}

getWRFDataDir <- function() {
  if ( is.null(AirFireWRFEnv$dataDir) ) {
    stop(paste0(
      "No data directory found. ",
      "Please set a data directory with setWRFDataDir('~/Data/WRF')"
    ), call. = FALSE)
  } else {
    return(AirFireWRFEnv$dataDir)
  }
}

#' @export
#' @title Set package data directory
#' @param dataDir directory where model datasets are located
#' @description Sets the package data directory where model data is located.
#' If the directory does not exist, it will be created.
#' @return Silently returns previous value of data directory.
#' @seealso \link{WRFDataDir}
#' @seealso \link{getWRFDataDir}

setWRFDataDir <- function(dataDir) {
  old <- AirFireWRFEnv$dataDir
  dataDir <- path.expand(dataDir)
  tryCatch({
    if (!file.exists(dataDir)) dir.create(dataDir)
    AirFireWRFEnv$dataDir <- dataDir
  }, warning = function(warn) {
    warning("Invalid path name.")
  }, error   = function(err) {
    stop(paste0("Error in setWRFDataDir(", dataDir, ")."))
  })
  return(invisible(old))
}

#' @keywords internal
#' @title Remove package data directory
#' @description Resets the package data directory to NULL. Used for internal
#' testing.
#' @return Silently returns previous value of data directory.
#' @seealso WRFDataDir
#' @seealso getWRFDataDir
#' @seealso setWRFDataDir

removeWRFDataDir <- function() {
  old <- AirFireWRFEnv$dataDir
  AirFireWRFEnv$dataDir <- NULL
}