DAFmap: Direct forest patrols from threats

#' download_GLAD
#' 
#' Creates a storage system for storing GLAD data on the local drive
#' then downloads the data into it.
#' It makes an effort to update the raster for the current year if necessary
#' At the beginning of a new year the last years data is archived
#' ... Note to self you still need to check this last bit. You should make sure this is the data
#'     for the full year.
#
#' 
#' @return  NULL
#' @export
#' @author Tom Swinfield
#' 
#' Created 17-02-21
#' 

download_GLAD<-function(){
  # vector from 2015 to today
  current_year<-year(today())
  years_avail<-rev(2016:current_year)
  
  #year<-years_avail[3]
  
  glad.files<-lapply(years_avail, function(year){
    year_regx<-paste("SEA_day_", year, ".*.tif$", sep="")
    glad_name<-list.files(path = "data/GLAD", pattern=year_regx, full.names = TRUE)
    if(length(glad_name)==0)
      glad_exists<-FALSE
    else
      glad_exists<-file.exists(pattern=glad_name)
    
    year_test<-year==current_year
    
    glad_link<-paste("http://glad.geog.umd.edu/alarm/SEA_day_", year, "n.tif", sep="")
    
    # For the current year update glad:
    if(glad_exists & year_test){
      # Check the date and test for fresh download:
      file_date<-unlist(regmatches(glad_name, gregexpr("[[:digit:]]+", glad_name)))
      file_date<-ymd(file_date)
      days_old <- as.numeric(today() - file_date)
      cat("Perhatian: data GLAD tahun ini sudah", days_old, "hari tua.\n")
      download_test<-select.list(c('Ya', 'Tidak'), preselect='Ya', title='Apakah Anda mau mengupdate GLAD?', graphics=TRUE)
      
      if(download_test=="Ya"){
        glad_name_new<-paste("data/GLAD/SEA_day_", gsub("-", "", today()), ".tif", sep="")
        download.file(glad_link, glad_name_new)
        if(glad_exists)
          file.remove(glad_name)
      }
    }
    
    # There is glad data but still as a temporary file from the previous year:
    if(glad_exists & !year_test){
    # Make sure the name is just the year
      file_date<-unlist(regmatches(glad_name, gregexpr("[[:digit:]]+", glad_name)))
      if(length(file_date)>4){
        glad_name_new<-paste("data/GLAD/SEA_day_", year, ".tif", sep="")
        download.file(glad_link, glad_name_new)
        if(glad_exists)
          file.remove(glad_name)
      }
    }
    
    # There is no glad data just download:  
    if(!glad_exists){
      if(year_test)
        glad_name_new<-paste("data/GLAD/SEA_day_", gsub("-", "", Sys.Date()), ".tif", sep="")
      else
        glad_name_new<-paste("data/GLAD/SEA_day_", year, ".tif", sep="")
      download.file(glad_link, glad_name_new)
    }
  })
  return(NULL)
}