defmodule Microwaveprop.Weather.Era5BatchClientTest do
  use Microwaveprop.DataCase, async: true

  alias Microwaveprop.Weather.Era5BatchClient
  alias Microwaveprop.Weather.Era5Profile

  describe "tile_for_point/2" do
    test "floors positive coordinates to a 2° lattice" do
      assert {32, 96} = Era5BatchClient.tile_for_point(32.75, 97.5)
      assert {32, 96} = Era5BatchClient.tile_for_point(33.99, 97.99)
      assert {34, 98} = Era5BatchClient.tile_for_point(34.0, 98.0)
    end

    test "floors negative longitudes toward -infinity" do
      assert {32, -98} = Era5BatchClient.tile_for_point(32.75, -97.25)
      assert {32, -98} = Era5BatchClient.tile_for_point(33.0, -97.01)
      assert {32, -100} = Era5BatchClient.tile_for_point(33.0, -99.0)
    end

    test "floors negative latitudes toward -infinity" do
      assert {-2, 0} = Era5BatchClient.tile_for_point(-1.25, 0.5)
      assert {-34, -60} = Era5BatchClient.tile_for_point(-33.5, -59.5)
    end

    test "edges land on the tile to the right/north" do
      # 30.0 exactly → tile 30 (south/west edge)
      assert {30, 96} = Era5BatchClient.tile_for_point(30.0, 97.5)
    end
  end

  describe "fetch_month_into_db/1 idempotency" do
    test "returns {:ok, 0} when the month-tile already has any profile" do
      # Seed one profile inside the 2014-03, tile (32, -98) window.
      %Era5Profile{}
      |> Era5Profile.changeset(%{
        lat: 32.5,
        lon: -97.25,
        valid_time: ~U[2014-03-15 12:00:00Z],
        profile: []
      })
      |> Repo.insert!()

      # No CDS API key configured in tests → if the cache check fails, the
      # function would return an ERA5_CDS_API_KEY error. {:ok, 0} means the
      # short-circuit path was taken.
      assert {:ok, 0} =
               Era5BatchClient.fetch_month_into_db(%{
                 year: 2014,
                 month: 3,
                 tile_lat: 32,
                 tile_lon: -98
               })
    end

    test "a profile outside the tile window does not count as cached" do
      # This profile is in tile (30, -100), not (32, -98).
      %Era5Profile{}
      |> Era5Profile.changeset(%{
        lat: 30.5,
        lon: -99.25,
        valid_time: ~U[2014-03-15 12:00:00Z],
        profile: []
      })
      |> Repo.insert!()

      # The (32, -98) tile is still uncached, so fetch_month_into_db tries
      # to reach CDS and fails with missing API key, which bubbles up
      # (rather than :ok, 0).
      assert {:error, _} =
               Era5BatchClient.fetch_month_into_db(%{
                 year: 2014,
                 month: 3,
                 tile_lat: 32,
                 tile_lon: -98
               })
    end
  end
end