R/eyer-loading.R

In hejtmy/EyeR: Loading and preprocessing of eyetrakcer data

#' Loads data from a folder. Loads preprocessed events, gaze and fixations files
#'
#' @description eyer allows saving of preprocessed data with the function `eyer_save()`
#' this function then allows to load directly those prepared files into its structure. This function
#' returns NULL if there is no [name]_eyer_info.json file found in the directory.
#'
#' @param folder what directory should be searcher? Not recursive
#' @param name name of the files to find in case there are multiple saved eyer objects in the folder
#'
#' @return EyerObject with filled in data or NULL if no files are found
#' @export
#'
#' @examples
load_eyer_data <- function(folder, name = "", ...){
  obj <- EyerObject()
  #checks if there are already computed files
  ls_filepaths <- find_preprocessed_files(folder, name)
  #if (overrúide) delete_preprocessed_files(ls_filepaths)
  if(is.null(ls_filepaths$info)){
    warning("There are no info files of name ", name, " in folder", folder, "Returning NULL")
    return(NULL)
  }
  obj <- load_preprocessed_files(obj, ls_filepaths)
  return(obj)
}

#' returns filepaths of preprocessed fixations and events
#'
#' @param folder what directory to search in? Expects one fixation and one event to be present
#'
#' @return list with "fixations" and "events" fileds containing filepaths
#' @examples
find_preprocessed_files <- function(folder, name = ""){
  #actually search for it
  ls <- list()
  for(field in ALL_DATA_FIELDS){
    preprocessed_ptr <- paste0(name, "_eyer_", field)
    ls[[field]] <- find_file_or_null(folder, preprocessed_ptr)
  }
  info_ptr <- paste0(name, "_eyer_info.json")
  ls$info <- find_file_or_null(folder, info_ptr)
  return(ls)
}

#' @param folder where to look
#' @param ptr pattern to search for
#' @noRd
find_file_or_null <- function(folder, ptr, allow_multiples = FALSE){
  ptr <- paste("*", ptr, sep = "")
  filepath <- list.files(folder, pattern = ptr, full.names = TRUE)
  if(length(filepath) == 0) return(NULL)
  if(length(filepath) == 1) return(filepath)
  if(allow_multiples){
    return(filepath)
  } else {
    return(NULL)
  }
}

load_preprocessed_files <- function(obj, ls_filepaths){
  for(field in c("fixations", "gaze", "diameter", "events")){
    if(!is.null(ls_filepaths[[field]])){
      message("Loading preprocessed ", field, " log at ", ls_filepaths[[field]])
      obj$data[[field]] <- read.table(ls_filepaths[[field]], sep = ";", header = TRUE)
    }
  }
  if(!is.null(ls_filepaths$info)){
    message("Loading preprocessed info log ", ls_filepaths$gaze)
    obj$info <- jsonlite::read_json(ls_filepaths$info, simplifyVector = TRUE)
  }
  return(obj)
}

delete_preprocessed_files <- function(ls_filepaths){
  if(file.exists(ls_filepaths$fixations)) {
    message("Removing preprocessed fixations log ", ls_filepaths$fixations)
    file.remove(ls_filepaths$fixations)
  }
  if(file.exists(ls_filepaths$events)) {
    message("Removing preprocessed events log ", ls_filepaths$events)
    file.remove(ls_filepaths$events)
  }
}