data_dir <- file.path("..", "testdata")
tempfile_nc <- function() {
  tempfile_helper("cmsaf.regres_")
}

########## simple case ##########
file_out <- tempfile_nc()
cmsaf.regres("SIS",
        file.path(data_dir, "ex_year.nc"),
        file_out)
file <- nc_open(file_out)

test_that("data is correct", {
  actual <- ncvar_get(file, "SIS")
  expected_data <- c(
    1.9401544,1.9401544,1.9401544,
    1.3227799,1.3227799,1.9401544,
    1.9401544,1.9401544,1.3227799,
    1.3227799,1.9401544,1.9401544,
    1.9401544,1.3227799,1.3227799
  )
  expected <- array(expected_data, c(5,3))
  expect_equivalent(actual, expected, tolerance = 1e-6)
})

test_that("attributes are correct", {
  actual <- ncatt_get(file, "lon", "units")$value
  expect_equal(actual, "degrees_east")

  actual <- ncatt_get(file, "lon", "long_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "standard_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "axis")$value
  expect_equal(actual, "X")

  actual <- ncatt_get(file, "lat", "units")$value
  expect_equal(actual, "degrees_north")

  actual <- ncatt_get(file, "lat", "long_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "standard_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "axis")$value
  expect_equal(actual, "Y")

  actual <- ncatt_get(file, "time", "units")$value
  expect_equal(actual, "hours since 1983-01-01 00:00:00")

  actual <- ncatt_get(file, "time", "long_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "standard_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "calendar")$value
  expect_equal(actual, "standard")

  actual <- ncatt_get(file, "SIS", "standard_name")$value
  expect_equal(actual, "SIS_standard")

  actual <- ncatt_get(file, "SIS", "long_name")$value
  expect_equal(actual, "Surface Incoming Shortwave Radiation")

  actual <- ncatt_get(file, "SIS", "units")$value
  expect_equal(actual, "W m-2")

  actual <- ncatt_get(file, "SIS", "_FillValue")$value
  expect_equal(actual, -999)

  actual <- ncatt_get(file, "SIS", "cmsaf_info")$value
  expect_equal(actual, "cmsafops::cmsaf.regres for variable SIS")

  global_attr <- ncatt_get(file, 0)
  expect_equal(length(global_attr), 1)

  actual <- names(global_attr[1])
  expect_equal(actual, "Info")

  actual <- global_attr[[1]]
  expect_equal(actual, "Created with the CM SAF R Toolbox.")
})

# test_that("coordinates are correct", {
#   actual <- ncvar_get(file, "lon")
#   expect_identical(actual, array(seq(5, 6, by = 0.5)))
# 
#   actual <- ncvar_get(file, "lat")
#   expect_identical(actual, array(seq(45, 47, by = 0.5)))
# 
#   #actual <- ncvar_get(file, "time")
#   #expect_equal(actual, array(c(166560)))
# })
# 
# nc_close(file)
# 
# ########## var does not exist #########
# test_that("warning is shown if var does not exist", {
#   file_out <- tempfile_nc()
#   expect_warning(
#     cmsaf.regres("someVariable",
#             file.path(data_dir, "ex_year.nc"),
#             file_out),
#     "Variable 'someVariable' not found. Variable 'SIS' will be used instead.")
# })
# 
# ########## var is empty #########
# test_that("warning is shown if var is empty", {
#   file_out <- tempfile_nc()
#   expect_warning(
#     cmsaf.regres("",
#             file.path(data_dir, "ex_year.nc"),
#             file_out),
#     "Variable '' not found. Variable 'SIS' will be used instead.")
# })
# 
# ########## var is NULL #########
# test_that("error is thrown if var is NULL", {
#   file_out <- tempfile_nc()
#   expect_error(
#     cmsaf.regres(NULL,
#             file.path(data_dir, "ex_year.nc"),
#             file_out),
#     "variable must not be NULL"
#   )
# })
# 
# ########## input file does not exist #########
# test_that("error is thrown if input file does not exist", {
#   file_out <- tempfile_nc()
#   expect_error(
#     cmsaf.regres("SIS",
#             file.path(data_dir, "ex_doesNotExist.nc"),
#             file_out),
#     "Input file does not exist")
# })
# 
# ########## input filename is NULL #########
# test_that("error is thrown if input file is NULL", {
#   file_out <- tempfile_nc()
#   expect_error(
#     cmsaf.regres("SIS",
#             NULL,
#             file_out),
#     "Input filepath must be of length one and not NULL"
#   )
# })
# 
# ########## output file already exists #########
# test_that("no error is thrown if output file already exists", {
#   file_out <- tempfile_nc()
#   cat("test\n", file = file_out)
#   expect_error(
#     cmsaf.regres("SIS",
#             file.path(data_dir, "ex_year.nc"),
#             file_out),
#     paste0("File '",
#            file_out,
#            "' already exists. Specify 'overwrite = TRUE' if you want to overwrite it."),
#     fixed = TRUE)
# })
# 
# ########## output file already exists (overwrite = TRUE) #########
# test_that("no error is thrown if overwrite = TRUE", {
#   file_out <- tempfile_nc()
#   cat("test\n", file = file_out)
#   expect_error(
#     cmsaf.regres("SIS",
#             file.path(data_dir, "ex_year.nc"),
#             file_out,
#             overwrite = TRUE),
#     NA)
# })
# 
# ########## output file is NULL #########
# test_that("error is thrown if output file is NULL", {
#   expect_error(
#     cmsaf.regres("SIS",
#             file.path(data_dir, "ex_year.nc"),
#             NULL),
#     "Output filepath must be of length one and not NULL"
#   )
# })
# 
# #TODO add test case where input data is weird somehow