prop/test/microwaveprop/radio_test.exs

defmodule Microwaveprop.RadioTest do
  use Microwaveprop.DataCase, async: true

  import Microwaveprop.AccountsFixtures

  alias Microwaveprop.Accounts.Scope
  alias Microwaveprop.Radio
  alias Microwaveprop.Radio.Contact

  defp create_contact(attrs \\ %{}) do
    default = %{
      station1: "W5XD",
      station2: "K5TR",
      qso_timestamp: ~U[2026-03-28 18:00:00Z],
      mode: "CW",
      band: Decimal.new("1296"),
      grid1: "EM12",
      grid2: "EM00",
      pos1: %{"lat" => 32.9, "lon" => -97.0},
      pos2: %{"lat" => 30.3, "lon" => -97.7},
      distance_km: Decimal.new("295")
    }

    merged = Map.merge(default, attrs)
    {user_id, changeset_attrs} = Map.pop(merged, :user_id)

    {:ok, contact} =
      %Contact{user_id: user_id}
      |> Contact.changeset(changeset_attrs)
      |> Repo.insert()

    contact
  end

  describe "list_contacts/1" do
    test "returns empty page when no QSOs exist" do
      result = Radio.list_contacts()

      assert result.entries == []
      assert result.page == 1
      assert result.total_pages == 1
      assert result.total_entries == 0
    end

    test "paginates 20 per page, ordered by qso_timestamp desc" do
      for i <- 1..25 do
        ts = DateTime.add(~U[2026-01-01 00:00:00Z], i * 3600, :second)
        create_contact(%{qso_timestamp: ts})
      end

      result = Radio.list_contacts()

      assert length(result.entries) == 20
      assert result.page == 1
      assert result.total_pages == 2
      assert result.total_entries == 25

      # Most recent first
      first = hd(result.entries)
      assert first.qso_timestamp == DateTime.add(~U[2026-01-01 00:00:00Z], 25 * 3600, :second)
    end

    test "returns second page" do
      for i <- 1..25 do
        ts = DateTime.add(~U[2026-01-01 00:00:00Z], i * 3600, :second)
        create_contact(%{qso_timestamp: ts})
      end

      result = Radio.list_contacts(page: 2)

      assert length(result.entries) == 5
      assert result.page == 2
      assert result.total_pages == 2
    end

    test "honors per_page option" do
      for i <- 1..25 do
        ts = DateTime.add(~U[2026-01-01 00:00:00Z], i * 3600, :second)
        create_contact(%{qso_timestamp: ts})
      end

      result = Radio.list_contacts(per_page: 50)

      assert length(result.entries) == 25
      assert result.total_pages == 1
    end

    test "clamps per_page to the maximum" do
      for i <- 1..3 do
        ts = DateTime.add(~U[2026-01-01 00:00:00Z], i * 3600, :second)
        create_contact(%{qso_timestamp: ts})
      end

      # 5000 is well above the 200 cap; should still return all 3 rows.
      result = Radio.list_contacts(per_page: 5000)
      assert length(result.entries) == 3
    end

    test "falls back to default when per_page is invalid" do
      for i <- 1..25 do
        ts = DateTime.add(~U[2026-01-01 00:00:00Z], i * 3600, :second)
        create_contact(%{qso_timestamp: ts})
      end

      result = Radio.list_contacts(per_page: 0)
      assert length(result.entries) == 20
    end
  end

  describe "list_contacts/1 sorting" do
    test "sorts by station1 ascending" do
      create_contact(%{station1: "ZZ9ZZ"})
      create_contact(%{station1: "AA1AA"})

      result = Radio.list_contacts(sort_by: :station1, sort_order: :asc)

      stations = Enum.map(result.entries, & &1.station1)
      assert stations == ["AA1AA", "ZZ9ZZ"]
    end

    test "sorts by distance_km descending" do
      create_contact(%{distance_km: Decimal.new("100"), station1: "A1A"})
      create_contact(%{distance_km: Decimal.new("500"), station1: "B2B"})

      result = Radio.list_contacts(sort_by: :distance_km, sort_order: :desc)

      distances = Enum.map(result.entries, & &1.distance_km)
      assert distances == [Decimal.new("500"), Decimal.new("100")]
    end

    test "invalid sort_by falls back to qso_timestamp desc" do
      early = create_contact(%{qso_timestamp: ~U[2026-01-01 00:00:00Z]})
      late = create_contact(%{qso_timestamp: ~U[2026-03-01 00:00:00Z]})

      result = Radio.list_contacts(sort_by: :bogus)

      ids = Enum.map(result.entries, & &1.id)
      assert ids == [late.id, early.id]
    end
  end

  describe "unprocessed_contacts/1" do
    test "returns QSOs where weather_queued is false and pos1 is not nil" do
      q1 = create_contact(%{station1: "W5XD", qso_timestamp: ~U[2026-03-28 12:00:00Z]})
      _q2 = create_contact(%{station1: "K5TR", pos1: nil, qso_timestamp: ~U[2026-03-28 13:00:00Z]})

      results = Radio.unprocessed_contacts()
      ids = Enum.map(results, & &1.id)
      assert q1.id in ids
    end

    test "excludes QSOs already marked as weather_status" do
      q = create_contact()
      Radio.mark_weather_queued!([q.id])

      assert Radio.unprocessed_contacts() == []
    end

    test "orders by qso_timestamp ascending" do
      q_late = create_contact(%{station1: "LATE", qso_timestamp: ~U[2026-03-28 20:00:00Z]})
      q_early = create_contact(%{station1: "EARLY", qso_timestamp: ~U[2026-03-28 10:00:00Z]})

      results = Radio.unprocessed_contacts()
      ids = Enum.map(results, & &1.id)
      assert ids == [q_early.id, q_late.id]
    end

    test "respects limit parameter" do
      for i <- 1..5 do
        ts = DateTime.add(~U[2026-01-01 00:00:00Z], i * 3600, :second)
        create_contact(%{qso_timestamp: ts})
      end

      assert length(Radio.unprocessed_contacts(3)) == 3
    end
  end

  describe "mark_weather_queued!/1" do
    test "sets weather_queued to true for given IDs" do
      q1 = create_contact(%{station1: "A1A"})
      q2 = create_contact(%{station1: "B2B"})

      Radio.mark_weather_queued!([q1.id, q2.id])

      assert Repo.get!(Contact, q1.id).weather_status == :queued
      assert Repo.get!(Contact, q2.id).weather_status == :queued
    end

    test "does not affect other QSOs" do
      q1 = create_contact(%{station1: "A1A"})
      q2 = create_contact(%{station1: "B2B"})

      Radio.mark_weather_queued!([q1.id])

      assert Repo.get!(Contact, q1.id).weather_status == :queued
      assert Repo.get!(Contact, q2.id).weather_status == :pending
    end

    test "handles empty list" do
      assert Radio.mark_weather_queued!([]) == {0, nil}
    end
  end

  describe "haversine_km/4" do
    test "calculates distance between two known points" do
      # Dallas to Austin ~roughly 295 km
      dist = Radio.haversine_km(32.9, -97.0, 30.3, -97.7)
      assert_in_delta dist, 295, 5
    end

    test "returns 0 for same point" do
      assert Radio.haversine_km(32.9, -97.0, 32.9, -97.0) == 0.0
    end

    test "uses the numerically stable atan2 form" do
      # Antipodal points sit on a 6371-km-radius sphere at exactly
      # π·r ≈ 20_015 km apart. Both haversine forms agree here, but
      # the asin form is fragile when `a` rounds to slightly above 1
      # (sqrt returns >1 and asin returns NaN). atan2 stays finite.
      dist = Radio.haversine_km(0.0, 0.0, 0.0, 180.0)
      assert_in_delta dist, 20_015, 1.0
    end
  end

  describe "backfill_distances/1" do
    test "calculates and stores distance for QSOs missing distance_km" do
      contact = create_contact(%{distance_km: nil})
      assert is_nil(contact.distance_km)

      Radio.backfill_distances([contact])

      updated = Repo.get!(Contact, contact.id)
      assert_in_delta Decimal.to_float(updated.distance_km), 295, 5
    end

    test "skips QSOs that already have a distance" do
      contact = create_contact(%{distance_km: Decimal.new("100")})

      Radio.backfill_distances([contact])

      updated = Repo.get!(Contact, contact.id)
      assert updated.distance_km == Decimal.new("100")
    end

    test "skips QSOs missing pos2" do
      contact = create_contact(%{distance_km: nil, pos2: nil})

      Radio.backfill_distances([contact])

      updated = Repo.get!(Contact, contact.id)
      assert is_nil(updated.distance_km)
    end
  end

  describe "get_contact!/1" do
    test "returns a QSO by ID" do
      contact = create_contact()

      found = Radio.get_contact!(contact.id)
      assert found.id == contact.id
      assert found.station1 == "W5XD"
    end

    test "raises Ecto.NoResultsError on bad ID" do
      assert_raise Ecto.NoResultsError, fn ->
        Radio.get_contact!(Ecto.UUID.generate())
      end
    end
  end

  describe "unprocessed_hrrr_contacts/1" do
    test "returns QSOs where hrrr_queued is false and pos1 is not nil" do
      q1 = create_contact(%{station1: "W5XD", qso_timestamp: ~U[2026-03-28 12:00:00Z]})
      _q2 = create_contact(%{station1: "K5TR", pos1: nil, qso_timestamp: ~U[2026-03-28 13:00:00Z]})

      results = Radio.unprocessed_hrrr_contacts()
      ids = Enum.map(results, & &1.id)
      assert q1.id in ids
    end

    test "excludes QSOs already marked as hrrr_status" do
      q = create_contact()
      Radio.mark_hrrr_queued!([q.id])

      assert Radio.unprocessed_hrrr_contacts() == []
    end

    test "orders by qso_timestamp ascending" do
      q_late = create_contact(%{station1: "LATE", qso_timestamp: ~U[2026-03-28 20:00:00Z]})
      q_early = create_contact(%{station1: "EARLY", qso_timestamp: ~U[2026-03-28 10:00:00Z]})

      results = Radio.unprocessed_hrrr_contacts()
      ids = Enum.map(results, & &1.id)
      assert ids == [q_early.id, q_late.id]
    end

    test "respects limit parameter" do
      for i <- 1..5 do
        ts = DateTime.add(~U[2026-01-01 00:00:00Z], i * 3600, :second)
        create_contact(%{qso_timestamp: ts})
      end

      assert length(Radio.unprocessed_hrrr_contacts(3)) == 3
    end
  end

  describe "mark_hrrr_queued!/1" do
    test "sets hrrr_queued to true for given IDs" do
      q1 = create_contact(%{station1: "A1A"})
      q2 = create_contact(%{station1: "B2B"})

      Radio.mark_hrrr_queued!([q1.id, q2.id])

      assert Repo.get!(Contact, q1.id).hrrr_status == :queued
      assert Repo.get!(Contact, q2.id).hrrr_status == :queued
    end

    test "does not affect other QSOs" do
      q1 = create_contact(%{station1: "A1A"})
      q2 = create_contact(%{station1: "B2B"})

      Radio.mark_hrrr_queued!([q1.id])

      assert Repo.get!(Contact, q1.id).hrrr_status == :queued
      assert Repo.get!(Contact, q2.id).hrrr_status == :pending
    end

    test "handles empty list" do
      assert Radio.mark_hrrr_queued!([]) == {0, nil}
    end
  end

  describe "unprocessed_terrain_contacts/1" do
    test "returns QSOs where terrain_queued is false and both pos1 and pos2 are not nil" do
      q1 = create_contact(%{station1: "W5XD", qso_timestamp: ~U[2026-03-28 12:00:00Z]})
      _q2 = create_contact(%{station1: "NOPOS1", pos1: nil, qso_timestamp: ~U[2026-03-28 13:00:00Z]})
      _q3 = create_contact(%{station1: "NOPOS2", pos2: nil, qso_timestamp: ~U[2026-03-28 14:00:00Z]})

      results = Radio.unprocessed_terrain_contacts()
      ids = Enum.map(results, & &1.id)
      assert q1.id in ids
      assert length(ids) == 1
    end

    test "excludes QSOs already marked as terrain_status" do
      q = create_contact()
      Radio.mark_terrain_queued!([q.id])

      assert Radio.unprocessed_terrain_contacts() == []
    end

    test "orders by qso_timestamp ascending" do
      q_late = create_contact(%{station1: "LATE", qso_timestamp: ~U[2026-03-28 20:00:00Z]})
      q_early = create_contact(%{station1: "EARLY", qso_timestamp: ~U[2026-03-28 10:00:00Z]})

      results = Radio.unprocessed_terrain_contacts()
      ids = Enum.map(results, & &1.id)
      assert ids == [q_early.id, q_late.id]
    end

    test "respects limit parameter" do
      for i <- 1..5 do
        ts = DateTime.add(~U[2026-01-01 00:00:00Z], i * 3600, :second)
        create_contact(%{qso_timestamp: ts})
      end

      assert length(Radio.unprocessed_terrain_contacts(3)) == 3
    end
  end

  describe "mark_terrain_queued!/1" do
    test "sets terrain_queued to true for given IDs" do
      q1 = create_contact(%{station1: "A1A"})
      q2 = create_contact(%{station1: "B2B"})

      Radio.mark_terrain_queued!([q1.id, q2.id])

      assert Repo.get!(Contact, q1.id).terrain_status == :queued
      assert Repo.get!(Contact, q2.id).terrain_status == :queued
    end

    test "does not affect other QSOs" do
      q1 = create_contact(%{station1: "A1A"})
      q2 = create_contact(%{station1: "B2B"})

      Radio.mark_terrain_queued!([q1.id])

      assert Repo.get!(Contact, q1.id).terrain_status == :queued
      assert Repo.get!(Contact, q2.id).terrain_status == :pending
    end

    test "handles empty list" do
      assert Radio.mark_terrain_queued!([]) == {0, nil}
    end
  end

  describe "contact_path_points/1" do
    test "returns pos1, midpoint, and pos2 when both positions exist" do
      contact =
        create_contact(%{
          pos1: %{"lat" => 32.9, "lon" => -97.0},
          pos2: %{"lat" => 30.3, "lon" => -97.7}
        })

      points = Radio.contact_path_points(contact)

      assert length(points) == 3
      [{lat1, lon1}, {mid_lat, mid_lon}, {lat2, lon2}] = points
      assert lat1 == 32.9
      assert lon1 == -97.0
      assert_in_delta mid_lat, 31.6, 0.01
      assert_in_delta mid_lon, -97.35, 0.01
      assert lat2 == 30.3
      assert lon2 == -97.7
    end

    test "returns only pos1 when pos2 is nil" do
      contact = create_contact(%{pos2: nil})

      points = Radio.contact_path_points(contact)

      assert points == [{32.9, -97.0}]
    end

    test "returns empty list when pos1 is nil" do
      contact = create_contact(%{pos1: nil})

      assert Radio.contact_path_points(contact) == []
    end

    test "handles lon key in position maps" do
      contact =
        create_contact(%{
          pos1: %{"lat" => 32.9, "lon" => -97.0},
          pos2: %{"lat" => 30.3, "lon" => -97.7}
        })

      points = Radio.contact_path_points(contact)
      assert length(points) == 3
    end

    test "computes a great-circle midpoint across the anti-meridian" do
      # Two stations on opposite sides of the 180° line. The arithmetic
      # mean of -179 and +179 lands at 0° (Greenwich) — clearly wrong;
      # the geodesic midpoint sits near the date line at ±180°.
      contact =
        create_contact(%{
          pos1: %{"lat" => 0.0, "lon" => 179.0},
          pos2: %{"lat" => 0.0, "lon" => -179.0}
        })

      [_, {mid_lat, mid_lon}, _] = Radio.contact_path_points(contact)

      assert_in_delta mid_lat, 0.0, 0.01
      assert abs(mid_lon) > 179.0
    end
  end

  describe "change_contact/2" do
    test "returns a submission changeset" do
      changeset = Radio.change_contact(%Contact{})
      assert %Ecto.Changeset{} = changeset
    end

    test "accepts attrs" do
      changeset = Radio.change_contact(%Contact{}, %{station1: "W5XD"})
      assert Ecto.Changeset.get_change(changeset, :station1) == "W5XD"
    end
  end

  describe "create_contact/1" do
    @valid_submission %{
      station1: "W5XD",
      station2: "K5TR",
      qso_timestamp: ~U[2026-03-28 18:00:00Z],
      mode: "CW",
      band: "1296",
      grid1: "EM12",
      grid2: "EM00",
      submitter_email: "test@example.com"
    }

    test "creates QSO with computed positions and distance" do
      assert {:ok, contact} = Radio.create_contact(@valid_submission)

      assert contact.station1 == "W5XD"
      assert contact.user_submitted == true
      assert contact.pos1["lat"]
      assert contact.pos1["lon"]
      assert contact.pos2["lat"]
      assert contact.pos2["lon"]
      assert contact.distance_km
    end

    test "computes correct position from grid" do
      assert {:ok, contact} = Radio.create_contact(@valid_submission)

      # EM12 center: lat = 4*10 - 90 + 1*1 + 0.5 = -48.5... wait
      # E=4, M=12 -> lon = 4*20 - 180 + 1*2 + 1 = -97, lat = 12*10 - 90 + 2*1 + 0.5 = 32.5
      assert_in_delta contact.pos1["lat"], 32.5, 0.1
      assert_in_delta contact.pos1["lon"], -97.0, 0.1
    end

    test "sets user_submitted to true" do
      assert {:ok, contact} = Radio.create_contact(@valid_submission)
      assert contact.user_submitted == true
    end

    test "returns error changeset for invalid data" do
      assert {:error, %Ecto.Changeset{}} = Radio.create_contact(%{})
    end

    test "returns error changeset for invalid grid" do
      attrs = Map.put(@valid_submission, :grid1, "ZZ99")
      assert {:error, changeset} = Radio.create_contact(attrs)
      assert errors_on(changeset).grid1
    end

    test "accepts authenticated submission without submitter_email" do
      # Regression: validate_user_or_email must see user_id, not just attrs.
      # Previously user_id was applied AFTER submission_changeset, so this
      # call returned `{:error, %Ecto.Changeset{errors: [submitter_email: ...]}}`
      # even though the user_id satisfies the ownership invariant.
      user = user_fixture()
      attrs = Map.delete(@valid_submission, :submitter_email)

      assert {:ok, contact} = Radio.create_contact(attrs, user.id)
      assert contact.user_id == user.id
      assert is_nil(contact.submitter_email)
    end
  end

  describe "list_contacts_for_user/1" do
    test "returns only contacts whose user_id matches the user" do
      user = user_fixture()
      other = user_fixture()

      owned =
        create_contact(%{station1: "W5OWN", user_id: user.id})

      _their =
        create_contact(%{station1: "W5THR", user_id: other.id})

      _anon = create_contact(%{station1: "W5ANO"})

      assert [found] = Radio.list_contacts_for_user(user)
      assert found.id == owned.id
    end

    test "orders newest first" do
      user = user_fixture()

      _old =
        create_contact(%{
          qso_timestamp: ~U[2020-01-01 00:00:00Z],
          user_id: user.id,
          station1: "W5OLD"
        })

      new =
        create_contact(%{
          qso_timestamp: ~U[2026-06-15 12:00:00Z],
          user_id: user.id,
          station1: "W5NEW"
        })

      assert [first, _] = Radio.list_contacts_for_user(user)
      assert first.id == new.id
    end

    test "returns an empty list when the user has submitted nothing" do
      user = user_fixture()
      assert Radio.list_contacts_for_user(user) == []
    end

    test "includes private contacts when the viewer is the owner" do
      user = user_fixture()
      private = create_contact(%{station1: "W5PRV", user_id: user.id, private: true})

      assert [found] = Radio.list_contacts_for_user(user, user)
      assert found.id == private.id
    end

    test "hides private contacts when the viewer is anonymous" do
      user = user_fixture()
      _private = create_contact(%{station1: "W5PRV", user_id: user.id, private: true})
      public = create_contact(%{station1: "W5PUB", user_id: user.id, private: false})

      assert [found] = Radio.list_contacts_for_user(user)
      assert found.id == public.id
    end

    test "hides private contacts from other authenticated viewers" do
      user = user_fixture()
      other = user_fixture()
      _private = create_contact(%{station1: "W5PRV", user_id: user.id, private: true})

      assert Radio.list_contacts_for_user(user, other) == []
    end

    test "includes private contacts when the viewer is an admin" do
      user = user_fixture()
      admin = user_fixture()
      admin = %{admin | is_admin: true}
      private = create_contact(%{station1: "W5PRV", user_id: user.id, private: true})

      assert [found] = Radio.list_contacts_for_user(user, admin)
      assert found.id == private.id
    end
  end

  describe "contact_map_payload/0 visibility" do
    test "excludes private contacts from the cached map payload" do
      _private = create_contact(%{station1: "W5PRV", private: true})
      public = create_contact(%{station1: "W5PUB", qso_timestamp: ~U[2026-03-28 19:00:00Z]})

      %{json: json, count: count} = Radio.contact_map_payload()

      assert count == 1
      decoded = json |> IO.iodata_to_binary() |> Jason.decode!()
      assert [[_, _, _, _, _, "W5PUB" | _]] = decoded
      refute to_string(IO.iodata_to_binary(json)) =~ "W5PRV"
      _ = public
    end
  end

  describe "can_view?/2" do
    test "public contact is viewable by anyone" do
      contact = create_contact(%{private: false})
      assert Radio.can_view?(contact, nil) == true
      assert Radio.can_view?(contact, %Scope{user: user_fixture()}) == true
    end

    test "private contact hidden from anonymous and non-owner" do
      owner = user_fixture()
      contact = create_contact(%{private: true, user_id: owner.id})
      assert Radio.can_view?(contact, nil) == false

      other = user_fixture()
      assert Radio.can_view?(contact, %Scope{user: other}) == false
    end

    test "private contact visible to owner and admin" do
      owner = user_fixture()
      admin = user_fixture() |> Ecto.Changeset.change(is_admin: true) |> Repo.update!()
      contact = create_contact(%{private: true, user_id: owner.id})

      assert Radio.can_view?(contact, %Scope{user: owner}) == true
      assert Radio.can_view?(contact, %Scope{user: admin}) == true
    end
  end

  describe "list_contacts/2 scope-aware visibility" do
    test "anonymous viewer sees only non-private" do
      _private = create_contact(%{station1: "W5PRV", private: true})
      public = create_contact(%{station1: "W5PUB", qso_timestamp: ~U[2026-03-28 19:00:00Z]})

      %{entries: entries} = Radio.list_contacts(scope: nil)
      assert Enum.map(entries, & &1.id) == [public.id]
    end

    test "owner sees their own private contacts" do
      owner = user_fixture()
      scope = %Scope{user: owner}
      private = create_contact(%{station1: "W5PRV", private: true, user_id: owner.id})
      public = create_contact(%{station1: "W5PUB", qso_timestamp: ~U[2026-03-28 19:00:00Z]})

      %{entries: entries} = Radio.list_contacts(scope: scope)
      ids = entries |> Enum.map(& &1.id) |> Enum.sort()
      assert Enum.sort([private.id, public.id]) == ids
    end

    test "admin sees all private contacts" do
      admin = user_fixture() |> Ecto.Changeset.change(is_admin: true) |> Repo.update!()
      scope = %Scope{user: admin}
      _other_user = user_fixture()
      private = create_contact(%{station1: "W5PRV", private: true})
      public = create_contact(%{station1: "W5PUB", qso_timestamp: ~U[2026-03-28 19:00:00Z]})

      %{entries: entries} = Radio.list_contacts(scope: scope)
      ids = entries |> Enum.map(& &1.id) |> Enum.sort()
      assert Enum.sort([private.id, public.id]) == ids
    end

    test "non-owning non-admin cannot see other users' private" do
      someone_else = user_fixture()
      viewer = user_fixture()
      scope = %Scope{user: viewer}
      _private = create_contact(%{station1: "W5PRV", private: true, user_id: someone_else.id})
      public = create_contact(%{station1: "W5PUB", qso_timestamp: ~U[2026-03-28 19:00:00Z]})

      %{entries: entries} = Radio.list_contacts(scope: scope)
      assert Enum.map(entries, & &1.id) == [public.id]
    end
  end

  describe "list_contacts_involving_callsign/1" do
    test "returns contacts where the callsign is station1" do
      match = create_contact(%{station1: "W5ISP", station2: "K5OTR"})
      _other = create_contact(%{station1: "W5OTH", station2: "K5OTR"})

      assert [found] = Radio.list_contacts_involving_callsign("W5ISP")
      assert found.id == match.id
    end

    test "returns contacts where the callsign is station2" do
      match = create_contact(%{station1: "W5OTH", station2: "W5ISP"})
      _other = create_contact(%{station1: "W5OTH", station2: "K5OTR"})

      assert [found] = Radio.list_contacts_involving_callsign("W5ISP")
      assert found.id == match.id
    end

    test "matching is case-insensitive" do
      match = create_contact(%{station1: "W5ISP", station2: "K5OTR"})

      assert [found] = Radio.list_contacts_involving_callsign("w5isp")
      assert found.id == match.id
    end

    test "orders newest first" do
      _old =
        create_contact(%{
          station1: "W5ISP",
          station2: "K5A",
          qso_timestamp: ~U[2020-01-01 00:00:00Z]
        })

      new =
        create_contact(%{
          station1: "K5B",
          station2: "W5ISP",
          qso_timestamp: ~U[2026-06-15 12:00:00Z]
        })

      assert [first, _] = Radio.list_contacts_involving_callsign("W5ISP")
      assert first.id == new.id
    end

    test "returns empty list when no contacts match" do
      create_contact(%{station1: "W5OTH", station2: "K5OTR"})

      assert Radio.list_contacts_involving_callsign("W5ISP") == []
    end

    test "returns empty list for blank or nil callsign" do
      assert Radio.list_contacts_involving_callsign("") == []
      assert Radio.list_contacts_involving_callsign(nil) == []
    end

    test "excludes private contacts" do
      _private = create_contact(%{station1: "W5ISP", station2: "K5OTR", private: true})
      visible = create_contact(%{station1: "W5ISP", station2: "K5OTR", qso_timestamp: ~U[2026-03-28 19:00:00Z]})

      assert [found] = Radio.list_contacts_involving_callsign("W5ISP")
      assert found.id == visible.id
    end

    test "caps the result at the 100 most recent contacts" do
      base = ~U[2020-01-01 00:00:00Z]

      for i <- 1..120 do
        create_contact(%{
          station1: "W5ISP",
          station2: "K5X#{i}",
          qso_timestamp: DateTime.add(base, i * 3600, :second)
        })
      end

      result = Radio.list_contacts_involving_callsign("W5ISP")

      assert length(result) == 100
      # The 100 newest by qso_timestamp correspond to i = 21..120; i=120 is newest.
      assert hd(result).station2 == "K5X120"
    end
  end
end