test_that("a5_cell_to_arrow returns uint64 array", {
  skip_if_not_installed("arrow")
  cells <- a5_lonlat_to_cell(c(-3.19, 135, -60), c(55.95, 0, 45), 10)
  arr <- a5_cell_to_arrow(cells)
  expect_s3_class(arr, "Array")
  expect_equal(arr$type$ToString(), "uint64")
  expect_equal(arr$length(), 3L)
})

test_that("a5_cell_from_arrow rejects non-uint64", {
  skip_if_not_installed("arrow")
  arr <- arrow::Array$create(1:3, type = arrow::int32())
  expect_error(a5_cell_from_arrow(arr), "uint64")
})

test_that("round-trip a5_cell -> arrow -> a5_cell is lossless", {
  skip_if_not_installed("arrow")
  # Include cells with bit 63 set (origin >= 6) — these exceed 2^53
  cells <- a5_lonlat_to_cell(
    c(-3.19, 135, -60, 0, 179),
    c(55.95, 0, 45, 0, -89),
    resolution = 10
  )
  arr <- a5_cell_to_arrow(cells)
  back <- a5_cell_from_arrow(arr)
  expect_equal(format(back), format(cells))
})

test_that("round-trip preserves cells across all origins", {
  skip_if_not_installed("arrow")
  # Systematically test points that hit different icosahedron faces
  lons <- seq(-180, 170, by = 30)
  lats <- rep(c(-45, 0, 45), length.out = length(lons))
  cells <- a5_lonlat_to_cell(lons, lats, resolution = 15)
  arr <- a5_cell_to_arrow(cells)
  back <- a5_cell_from_arrow(arr)
  expect_equal(format(back), format(cells))
})

test_that("NA round-trips through arrow", {
  skip_if_not_installed("arrow")
  cells <- a5_cell(c("0800000000000006", NA, "633e000000000000"))
  arr <- a5_cell_to_arrow(cells)
  expect_true(arr$IsNull(1))
  expect_false(arr$IsNull(0))
  back <- a5_cell_from_arrow(arr)
  expect_equal(format(back), format(cells))
  expect_true(is.na(back[2]))
})

test_that("a5_cell_from_arrow handles ChunkedArray", {
  skip_if_not_installed("arrow")
  cells <- a5_lonlat_to_cell(c(0, 135), c(0, 0), 10)
  arr <- a5_cell_to_arrow(cells)
  chunked <- arrow::chunked_array(arr, arr)
  back <- a5_cell_from_arrow(chunked)
  expect_length(back, 4L)
  expect_equal(format(back), rep(format(cells), 2))
})

test_that("parquet round-trip is lossless", {
  skip_if_not_installed("arrow")
  cells <- a5_lonlat_to_cell(
    c(-3.19, 135, -60, 0, 179),
    c(55.95, 0, 45, 0, -89),
    resolution = 10
  )

  tf <- tempfile(fileext = ".parquet")
  on.exit(unlink(tf))

  # Write
  tbl <- arrow::arrow_table(cell_id = a5_cell_to_arrow(cells))
  arrow::write_parquet(tbl, tf)

  # Read
  back_tbl <- arrow::read_parquet(tf, as_data_frame = FALSE)
  back_cells <- a5_cell_from_arrow(back_tbl$column(0))
  expect_equal(format(back_cells), format(cells))
})

test_that("high resolution survives parquet round-trip", {
  skip_if_not_installed("arrow")
  # High resolution uses many bits of the u64
  cells <- a5_lonlat_to_cell(c(-60, 135, 0), c(45, 0, 0), resolution = 20)
  arr <- a5_cell_to_arrow(cells)
  back <- a5_cell_from_arrow(arr)
  expect_equal(format(back), format(cells))
  expect_true(all(a5_get_resolution(back) == 20L))
})

test_that("resolution 29 round-trips through arrow (vectorised)", {
  skip_if_not_installed("arrow")
  # res 29 uses nearly every bit of the u64 — precision stress test
  # (res 30 has an upstream bug in the a5 crate)
  lons <- seq(-180, 170, by = 10)
  lats <- rep(c(-80, -40, 0, 40, 80), length.out = length(lons))
  cells <- a5_lonlat_to_cell(lons, lats, resolution = 29)
  expect_true(all(a5_get_resolution(cells) == 29L))
  arr <- a5_cell_to_arrow(cells)
  back <- a5_cell_from_arrow(arr)
  expect_equal(format(back), format(cells))
})