test_that("lonlat_to_cell returns a5_cell", {
  cell <- a5_lonlat_to_cell(-3.19, 55.95, resolution = 5)
  expect_s3_class(cell, "a5_cell")
  expect_length(cell, 1L)
})

test_that("round-trip lonlat -> cell -> lonlat is stable", {
  lon <- -3.19
  lat <- 55.95
  cell <- a5_lonlat_to_cell(lon, lat, resolution = 15)
  pt <- a5_cell_to_lonlat(cell)
  expect_equal(wk::wk_coords(pt)$x, lon, tolerance = 0.01)
  expect_equal(wk::wk_coords(pt)$y, lat, tolerance = 0.01)
})

test_that("vectorised indexing works", {
  lons <- c(-3.19, 0, 140)
  lats <- c(55.95, 0, 35.68)
  cells <- a5_lonlat_to_cell(lons, lats, resolution = 5)
  expect_length(cells, 3L)
  expect_s3_class(cells, "a5_cell")
})

test_that("NA handling in lonlat_to_cell", {
  cell <- a5_lonlat_to_cell(NA_real_, 55.95, resolution = 5)
  expect_true(is.na(cell[1]))

  cell2 <- a5_lonlat_to_cell(0, NA_real_, resolution = 5)
  expect_true(is.na(cell2[1]))

  cell3 <- a5_lonlat_to_cell(0, 0, resolution = NA_integer_)
  expect_true(is.na(cell3[1]))
})

test_that("cell_to_lonlat handles NA", {
  cells <- a5_cell(c("0800000000000006", NA))
  pts <- a5_cell_to_lonlat(cells)
  coords <- wk::wk_coords(pts)
  expect_false(is.na(coords$x[1]))
  expect_true(is.na(coords$x[2]))
})

test_that("cell_to_lonlat returns xy with longlat CRS", {
  cell <- a5_lonlat_to_cell(0, 0, resolution = 5)
  pt <- a5_cell_to_lonlat(cell)
  expect_s3_class(pt, "wk_xy")
  expect_identical(wk::wk_crs(pt), wk::wk_crs_longlat())
})

test_that("lonlat_to_cell rejects invalid resolution", {
  expect_error(a5_lonlat_to_cell(0, 0, resolution = 31), "resolution")
  expect_error(a5_lonlat_to_cell(0, 0, resolution = -1), "resolution")
})

test_that("cell_to_lonlat as_dataframe = TRUE returns a data frame", {
  cell <- a5_lonlat_to_cell(114.8, 4.1, resolution = 5)
  df <- a5_cell_to_lonlat(cell, as_dataframe = TRUE)
  expect_s3_class(df, "data.frame")
  expect_named(df, c("lon", "lat"))
  expect_true(df$lon >= -180 && df$lon <= 180)
})

test_that("cell_to_lonlat default wraps longitude to [-180, 180]", {
  cell <- a5_lonlat_to_cell(114.8, 4.1, resolution = 5)
  pt <- a5_cell_to_lonlat(cell)
  lon <- wk::wk_coords(pt)$x
  expect_true(lon >= -180 && lon <= 180)
})

test_that("cell_to_lonlat rejects the removed `normalise` argument", {
  cell <- a5_lonlat_to_cell(114.8, 4.1, resolution = 5)
  expect_error(
    a5_cell_to_lonlat(cell, normalise = TRUE),
    "unused argument"
  )
})