prop/test/microwaveprop/propagation/profiles_file_test.exs

defmodule Microwaveprop.Propagation.ProfilesFileTest do
  # async: false — tests mutate the global Application env to redirect
  # the scores dir to a private tmp tree.
  use ExUnit.Case, async: false

  alias Microwaveprop.Propagation.ProfilesFile

  setup do
    dir =
      Path.join(
        System.tmp_dir!(),
        "profiles_file_test_#{System.unique_integer([:positive])}"
      )

    File.mkdir_p!(dir)

    prev = Application.get_env(:microwaveprop, :propagation_scores_dir)
    Application.put_env(:microwaveprop, :propagation_scores_dir, dir)

    on_exit(fn ->
      File.rm_rf!(dir)

      if prev do
        Application.put_env(:microwaveprop, :propagation_scores_dir, prev)
      else
        Application.delete_env(:microwaveprop, :propagation_scores_dir)
      end
    end)

    %{dir: dir}
  end

  describe "path_for/1" do
    test "nests under base_dir/profiles/<iso>.etf.gz", %{dir: dir} do
      assert ProfilesFile.path_for(~U[2026-04-14 18:00:00Z]) ==
               Path.join([dir, "profiles", "2026-04-14T18:00:00Z.etf.gz"])
    end
  end

  describe "read/1" do
    test "returns the full grid_data map round-tripped through ETF" do
      valid_time = ~U[2026-04-14 18:00:00Z]

      grid_data = %{
        {32.75, -97.125} => %{surface_temp_c: 25.0, surface_dewpoint_c: 15.0},
        {33.0, -97.0} => %{surface_temp_c: 26.0}
      }

      ProfilesFile.write!(valid_time, grid_data)

      assert {:ok, round_tripped} = ProfilesFile.read(valid_time)
      assert round_tripped[{32.75, -97.125}][:surface_temp_c] == 25.0
      assert round_tripped[{33.0, -97.0}][:surface_temp_c] == 26.0
    end

    test "returns :enoent when no file exists" do
      assert ProfilesFile.read(~U[2026-04-14 18:00:00Z]) == {:error, :enoent}
    end
  end

  describe "latest_valid_time/0" do
    test "returns the most recent persisted valid_time" do
      assert ProfilesFile.latest_valid_time() == nil

      for vt <- [~U[2026-04-14 10:00:00Z], ~U[2026-04-14 18:00:00Z], ~U[2026-04-14 14:00:00Z]] do
        ProfilesFile.write!(vt, %{{25.0, -125.0} => %{surface_temp_c: 1.0}})
      end

      assert ProfilesFile.latest_valid_time() == ~U[2026-04-14 18:00:00Z]
    end
  end

  describe "write!/2 + read_point/3" do
    test "round-trips a point and snaps lat/lon to the 0.125° grid" do
      valid_time = ~U[2026-04-14 18:00:00Z]

      grid_data = %{
        {32.75, -97.125} => %{surface_temp_c: 25.0, surface_dewpoint_c: 15.0, wind_u: 3.0, wind_v: -1.0},
        {25.0, -125.0} => %{surface_temp_c: 10.0}
      }

      ProfilesFile.write!(valid_time, grid_data)

      # Exact match
      assert %{surface_temp_c: 25.0, wind_u: 3.0} =
               ProfilesFile.read_point(valid_time, 32.75, -97.125)

      # Nudged within snap tolerance still resolves to the same cell
      assert %{surface_temp_c: 25.0} =
               ProfilesFile.read_point(valid_time, 32.7, -97.1)

      # A point with no stored profile returns nil
      assert ProfilesFile.read_point(valid_time, 40.0, -80.0) == nil
    end

    test "returns nil for a missing valid_time" do
      assert ProfilesFile.read_point(~U[2026-04-14 18:00:00Z], 32.75, -97.125) == nil
    end
  end

  describe "prune_older_than/1" do
    test "deletes files with valid_time strictly before the cutoff" do
      old = ~U[2026-04-14 10:00:00Z]
      keep = ~U[2026-04-14 18:00:00Z]

      ProfilesFile.write!(old, %{{25.0, -125.0} => %{surface_temp_c: 1.0}})
      ProfilesFile.write!(keep, %{{25.0, -125.0} => %{surface_temp_c: 2.0}})

      assert 1 == ProfilesFile.prune_older_than(~U[2026-04-14 12:00:00Z])
      assert ProfilesFile.read_point(old, 25.0, -125.0) == nil
      assert %{surface_temp_c: 2.0} = ProfilesFile.read_point(keep, 25.0, -125.0)
    end
  end

  describe "retain_window/2" do
    test "keeps only files whose valid_time is inside [run_time, run_time + max_fh * 3600]" do
      run_time = ~U[2026-04-14 18:00:00Z]

      inside_f00 = ~U[2026-04-14 18:00:00Z]
      inside_f10 = ~U[2026-04-15 04:00:00Z]
      after_window = ~U[2026-04-15 13:00:00Z]
      before_window = ~U[2026-04-14 10:00:00Z]

      for vt <- [inside_f00, inside_f10, after_window, before_window] do
        ProfilesFile.write!(vt, %{{25.0, -125.0} => %{surface_temp_c: 1.0}})
      end

      assert 2 == ProfilesFile.retain_window(run_time, 18)
      assert %{surface_temp_c: 1.0} = ProfilesFile.read_point(inside_f00, 25.0, -125.0)
      assert %{surface_temp_c: 1.0} = ProfilesFile.read_point(inside_f10, 25.0, -125.0)
      assert ProfilesFile.read_point(after_window, 25.0, -125.0) == nil
      assert ProfilesFile.read_point(before_window, 25.0, -125.0) == nil
    end
  end
end