download_saga <- function(surl) {
  # Downloads a saga windows x64 binary from sourceforge
  saga_zipdir <- file.path(tempdir(), tools::file_path_sans_ext(basename(surl)))
  dir.create(saga_zipdir, showWarnings = FALSE)

  err <- tryCatch(
    {
      download.file(
        url = surl,
        destfile = tempfile(tmpdir = saga_zipdir, fileext = ".zip"),
        quiet = TRUE
      )

      unzip(
        zipfile = list.files(saga_zipdir, full.names = TRUE),
        exdir = saga_zipdir
      )
    },
    error = function(e) {
      return(NULL)
    }
  )

  if (!is.null(err)) {
    saga_bin <- file.path(
      list.dirs(path = saga_zipdir, recursive = FALSE),
      "saga_cmd.exe"
    )
  } else {
    saga_bin <- NULL
  }

  return(saga_bin)
}


testthat::test_that("initiation of SAGA-GIS 2.3.1", {
  testthat::skip_on_cran()
  testthat::skip_if_not(
    Sys.info()["sysname"] == "Windows" &
      Sys.info()["machine"] == "x86-64"
  )

  saga_url <-
    "https://sourceforge.net/projects/saga-gis/files/SAGA%20-%202/SAGA%202.3.1/saga_2.3.1_x64.zip"
  saga_bin <- download_saga(saga_url)

  if (!is.null(saga_bin)) {
    saga <- saga_gis(saga_bin)
    testthat::expect_false(is.null(saga))
    testthat::expect_gt(length(saga), 0)
    testthat::expect_s4_class(
      saga$grid_calculus$random_terrain(iterations = 1, radius = 1),
      "SpatRaster"
    )
    unlink(dirname(saga_bin), recursive = TRUE)
  }
})


testthat::test_that("initiation of SAGA-GIS 6.0.0", {
  testthat::skip_on_cran()
  testthat::skip_if_not(
    Sys.info()["sysname"] == "Windows" &
      Sys.info()["machine"] == "x86-64"
  )

  saga_url <-
    "https://sourceforge.net/projects/saga-gis/files/SAGA%20-%206/SAGA%20-%206.0.0/saga-6.0.0_x64.zip"
  saga_bin <- download_saga(saga_url)

  if (!is.null(saga_bin)) {
    saga <- saga_gis(saga_bin)
    testthat::expect_false(is.null(saga))
    testthat::expect_gt(length(saga), 0)
    testthat::expect_s4_class(
      saga$grid_calculus$random_terrain(iterations = 1, radius = 1),
      "SpatRaster"
    )
    unlink(dirname(saga_bin), recursive = TRUE)
  }
})


testthat::test_that("initiation of SAGA-GIS 7.0.0", {
  testthat::skip_on_cran()
  testthat::skip_if_not(
    Sys.info()["sysname"] == "Windows" &
      Sys.info()["machine"] == "x86-64"
  )

  saga_url <-
    "https://sourceforge.net/projects/saga-gis/files/SAGA%20-%207/SAGA%20-%207.0.0/saga-7.0.0_x64.zip"
  saga_bin <- download_saga(saga_url)

  if (!is.null(saga_bin)) {
    saga <- saga_gis(saga_bin)
    testthat::expect_false(is.null(saga))
    testthat::expect_gt(length(saga), 0)
    testthat::expect_s4_class(
      saga$grid_calculus$random_terrain(iterations = 1, radius = 1),
      "SpatRaster"
    )
    unlink(dirname(saga_bin), recursive = TRUE)
  }
})


testthat::test_that("initiation of SAGA-GIS 7.4.0", {
  testthat::skip_on_cran()
  testthat::skip_if_not(
    Sys.info()["sysname"] == "Windows" &
      Sys.info()["machine"] == "x86-64"
  )

  saga_url <-
    "https://sourceforge.net/projects/saga-gis/files/SAGA%20-%207/SAGA%20-%207.4.0/saga-7.4.0_x64.zip"
  saga_bin <- download_saga(saga_url)

  if (!is.null(saga_bin)) {
    saga <- saga_gis(saga_bin)
    testthat::expect_false(is.null(saga))
    testthat::expect_gt(length(saga), 0)
    testthat::expect_s4_class(
      saga$grid_calculus$random_terrain(iterations = 1, radius = 1),
      "SpatRaster"
    )
    unlink(dirname(saga_bin), recursive = TRUE)
  }
})


testthat::test_that("initiation of SAGA-GIS 8.0.1", {
  testthat::skip_on_cran()
  testthat::skip_if_not(
    Sys.info()["sysname"] == "Windows" &
      Sys.info()["machine"] == "x86-64"
  )

  saga_url <-
    "https://sourceforge.net/projects/saga-gis/files/SAGA%20-%208/SAGA%20-%208.0.1/saga-8.0.1_x64.zip"
  saga_bin <- download_saga(saga_url)

  if (!is.null(saga_bin)) {
    saga <- saga_gis(saga_bin)
    testthat::expect_false(is.null(saga))
    testthat::expect_gt(length(saga), 0)
    testthat::expect_s4_class(
      saga$grid_calculus$random_terrain(iterations = 1, radius = 1),
      "SpatRaster"
    )
    unlink(dirname(saga_bin), recursive = TRUE)
  }
})

testthat::test_that("initiation of SAGA-GIS 9.0.1", {
  testthat::skip_on_cran()
  testthat::skip_if_not(
    Sys.info()["sysname"] == "Windows" &
      Sys.info()["machine"] == "x86-64"
  )
  
  saga_url <-
    "https://sourceforge.net/projects/saga-gis/files/SAGA%20-%209/SAGA%20-%209.0.1/saga-9.0.1_x64.zip"
  saga_bin <- download_saga(saga_url)
  
  if (!is.null(saga_bin)) {
    saga <- saga_gis(saga_bin)
    testthat::expect_false(is.null(saga))
    testthat::expect_gt(length(saga), 0)
    testthat::expect_s4_class(
      saga$grid_calculus$random_terrain(iterations = 1, radius = 1),
      "SpatRaster"
    )
    unlink(dirname(saga_bin), recursive = TRUE)
  }
})