defmodule Mix.Tasks.Prop.CompareTest do
  @moduledoc """
  Coverage smoke test for `mix prop.compare`. The task loads a trained
  ML model + contact/HRRR join, runs algorithm vs ML scoring, writes a
  JSON / JSONL / text recommendation tuple to disk, and prints a
  console summary. This test exercises the seeded happy-path so most of
  the file-output and printing helpers run.
  """
  use Microwaveprop.DataCase, async: false

  alias Microwaveprop.Radio.Contact
  alias Microwaveprop.Weather.HrrrProfile
  alias Mix.Tasks.Prop.Compare

  setup do
    original_shell = Mix.shell()
    Mix.shell(Mix.Shell.Process)
    on_exit(fn -> Mix.shell(original_shell) end)

    output_dir = Path.join(System.tmp_dir!(), "prop_compare_test_#{System.unique_integer([:positive])}")
    File.mkdir_p!(output_dir)
    on_exit(fn -> File.rm_rf!(output_dir) end)

    %{output_dir: output_dir}
  end

  defp seed_contact_and_hrrr(opts \\ []) do
    qso_ts =
      Keyword.get(opts, :qso_timestamp, DateTime.utc_now() |> DateTime.add(-3600, :second) |> DateTime.truncate(:second))

    valid_time = qso_ts |> DateTime.truncate(:second) |> Map.put(:minute, 0) |> Map.put(:second, 0)
    band = Keyword.get(opts, :band, "10000")
    suffix = Keyword.get(opts, :suffix, "")
    midlat_offset = Keyword.get(opts, :midlat_offset, 0.0)

    pos1 = %{"lat" => 33.0 + midlat_offset, "lon" => -97.0}
    pos2 = %{"lat" => 32.5 + midlat_offset, "lon" => -97.5}

    {:ok, contact} =
      %Contact{}
      |> Contact.changeset(%{
        station1: "W5A#{suffix}",
        station2: "K5B#{suffix}",
        qso_timestamp: valid_time,
        mode: "CW",
        band: Decimal.new(band),
        grid1: "EM13",
        grid2: "EM12",
        pos1: pos1,
        pos2: pos2,
        distance_km: Decimal.new("60")
      })
      |> Repo.insert()

    # Midpoint snaps to nearest 1/8 degree.
    midlat = 32.75 + midlat_offset
    midlon = -97.25

    %HrrrProfile{}
    |> HrrrProfile.changeset(%{
      valid_time: valid_time,
      lat: midlat,
      lon: midlon,
      surface_temp_c: 22.0,
      surface_dewpoint_c: 14.0,
      surface_pressure_mb: 1012.0,
      surface_refractivity: 320.0,
      min_refractivity_gradient: -100.0,
      hpbl_m: 1200.0,
      pwat_mm: 25.0,
      ducting_detected: false
    })
    |> Repo.insert(on_conflict: :nothing)

    contact
  end

  describe "Mix.Tasks.Prop.Compare.run/1" do
    test "pre-existing history.jsonl exercises read_history + drift detection", %{output_dir: output_dir} do
      _ = seed_contact_and_hrrr()

      # Pre-seed a history file with bad-Spearman entries so the rolling
      # algorithm-drift detector trips and write_recommendations runs.
      history_path = Path.join(output_dir, "history.jsonl")

      history_lines =
        for _ <- 1..6 do
          Jason.encode!(%{
            "date" => DateTime.utc_now() |> DateTime.add(-3600 * 24, :second) |> DateTime.to_iso8601(),
            "n_samples" => 100,
            "overall" => %{"alg_distance_spearman" => 0.5, "alg_ml_rmse" => 5.0},
            "by_band" => %{}
          })
        end

      File.write!(history_path, Enum.join(history_lines, "\n") <> "\n")

      # Add an unparseable line so the {:error, _} -> [] arm in
      # read_history is exercised.
      File.write!(history_path, "not-valid-json\n", [:append])

      try do
        ExUnit.CaptureIO.capture_io(fn ->
          Compare.run(["--days", "1", "--samples", "10", "--output", output_dir])
        end)
      catch
        :exit, _ -> :ok
      end

      # The history file remains; new entries appended.
      assert File.exists?(history_path)
    end

    test "multiple bands exercises the per-band summary + disagreements path", %{output_dir: output_dir} do
      # One contact per band; each at a unique offset so HRRR rows don't clash.
      for {band, i} <- Enum.with_index(["10000", "24000", "47000", "75000"]) do
        for j <- 1..3 do
          _ = seed_contact_and_hrrr(band: band, suffix: "B#{i}#{j}", midlat_offset: i * 0.5 + j * 0.125)
        end
      end

      try do
        ExUnit.CaptureIO.capture_io(fn ->
          Compare.run(["--days", "1", "--samples", "100", "--output", output_dir])
        end)
      catch
        :exit, _ -> :ok
      end

      latest_path = Path.join(output_dir, "latest.json")

      if File.exists?(latest_path) do
        decoded = latest_path |> File.read!() |> Jason.decode!()
        assert map_size(decoded["by_band"]) > 0
        # 4 bands keyed by their MHz string.
        assert Enum.any?(["10000", "24000", "47000", "75000"], &Map.has_key?(decoded["by_band"], &1))
      end
    end

    test "seeded contact + matching HRRR walks the scoring + write path", %{output_dir: output_dir} do
      _ = seed_contact_and_hrrr()

      try do
        ExUnit.CaptureIO.capture_io(fn ->
          Compare.run(["--days", "1", "--samples", "10", "--output", output_dir])
        end)
      catch
        :exit, _ -> :ok
      end

      # Each successful run writes latest.json + history.jsonl. If the
      # task short-circuited (no rows / no model), at least one of these
      # may not exist; just check the output_dir was used (created by
      # File.mkdir_p! at task start).
      assert File.dir?(output_dir)

      # If model + data both lined up, the JSON sits on disk.
      latest_path = Path.join(output_dir, "latest.json")

      if File.exists?(latest_path) do
        decoded = latest_path |> File.read!() |> Jason.decode!()
        assert is_integer(decoded["n_samples"])
        assert map_size(decoded["overall"]) > 0
      end

      history_path = Path.join(output_dir, "history.jsonl")

      if File.exists?(history_path) do
        # JSONL: one JSON object per line.
        history_path
        |> File.read!()
        |> String.split("\n", trim: true)
        |> Enum.each(fn line ->
          assert {:ok, _} = Jason.decode(line)
        end)
      end
    end
  end
end