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

########## simple case ##########
file_out <- tempfile_nc()
yearmean("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(
    seq(83.5, 95.5, by = 3),
    seq(84.5, 96.5, by = 3),
    seq(85.5, 97.5, by = 3),
    seq(263.5, 275.5, by = 3),
    seq(264.5, 276.5, by = 3),
    seq(265.5, 277.5, by = 3),
    105.25, 108.25, 111.25, 83.5, 86.5, 106.25, 109.25, 112.25, 84.5, 87.5,
    107.25, 110.25, 113.25, 85.5, 88.5
  )
  expected <- aperm(array(expected_data, c(3, 5, 3)), c(1, 2, 3))

  expect_equivalent(actual, expected)
})

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::yearmean 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(149016, 157800, 166560)))
})

nc_close(file)

########## var does not exist #########
test_that("warning is shown if var does not exist", {
  file_out <- tempfile_nc()
  expect_warning(
    yearmean("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(
    yearmean("",
             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(
    yearmean(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(
    yearmean("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(
    yearmean("SIS",
             NULL,
             file_out),
    "Input filepath must be of length one and not NULL"
  )
})

########## output file already exists #########
test_that("error is thrown if output file already exists", {
  file_out <- tempfile_nc()
  cat("test\n", file = file_out)
  expect_error(
    yearmean("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(
    yearmean("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(
    yearmean("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