From 448d3636a173423a7f23231a1bfc890bab38e1ba Mon Sep 17 00:00:00 2001
From: Graham McIntire <graham@mcintire.me>
Date: Sat, 25 Apr 2026 16:15:36 -0500
Subject: [PATCH] feat(rover): Oban worker enriches station elevation
 post-insert

---
 .../workers/station_elevation_worker.ex       | 43 +++++++++++++++++
 .../workers/station_elevation_worker_test.exs | 47 +++++++++++++++++++
 .../microwaveprop_web/live/skewt_svg_test.exs |  2 +-
 3 files changed, 91 insertions(+), 1 deletion(-)
 create mode 100644 lib/microwaveprop/workers/station_elevation_worker.ex
 create mode 100644 test/microwaveprop/workers/station_elevation_worker_test.exs

diff --git a/lib/microwaveprop/workers/station_elevation_worker.ex b/lib/microwaveprop/workers/station_elevation_worker.ex
new file mode 100644
index 00000000..cd8f4c88
--- /dev/null
+++ b/lib/microwaveprop/workers/station_elevation_worker.ex
@@ -0,0 +1,43 @@
+defmodule Microwaveprop.Workers.StationElevationWorker do
+  @moduledoc """
+  Oban worker that enriches a `FixedStation` row with its SRTM
+  elevation. Enqueued from `Microwaveprop.Rover.create_station/2`
+  whenever the user-supplied attrs leave `elevation_m` nil.
+
+  A missing tile or a void value is non-fatal — the row simply stays
+  with `elevation_m = nil`. The worker also no-ops if the station has
+  been deleted between enqueue and execution.
+  """
+  use Oban.Worker, queue: :terrain, max_attempts: 3
+
+  alias Microwaveprop.Repo
+  alias Microwaveprop.Rover.FixedStation
+  alias Microwaveprop.Terrain.Srtm
+
+  @impl Oban.Worker
+  def perform(%Oban.Job{args: %{"id" => id}}) do
+    case Repo.get(FixedStation, id) do
+      nil ->
+        :ok
+
+      station ->
+        update_elevation(station)
+    end
+  end
+
+  defp update_elevation(station) do
+    tiles_dir = Application.get_env(:microwaveprop, :srtm_tiles_dir, "/data/srtm")
+
+    case Srtm.lookup(station.lat, station.lon, tiles_dir) do
+      {:ok, elev} ->
+        station
+        |> Ecto.Changeset.change(elevation_m: elev)
+        |> Repo.update()
+
+        :ok
+
+      {:error, _} ->
+        :ok
+    end
+  end
+end
diff --git a/test/microwaveprop/workers/station_elevation_worker_test.exs b/test/microwaveprop/workers/station_elevation_worker_test.exs
new file mode 100644
index 00000000..63ec0a4c
--- /dev/null
+++ b/test/microwaveprop/workers/station_elevation_worker_test.exs
@@ -0,0 +1,47 @@
+defmodule Microwaveprop.Workers.StationElevationWorkerTest do
+  use Microwaveprop.DataCase, async: false
+
+  import Microwaveprop.AccountsFixtures
+
+  alias Microwaveprop.Rover
+  alias Microwaveprop.Rover.FixedStation
+  alias Microwaveprop.Workers.StationElevationWorker
+
+  setup do
+    tmp = Path.join(System.tmp_dir!(), "station_elev_#{System.unique_integer([:positive])}")
+    File.mkdir_p!(tmp)
+    prev = Application.get_env(:microwaveprop, :srtm_tiles_dir)
+    Application.put_env(:microwaveprop, :srtm_tiles_dir, tmp)
+
+    on_exit(fn ->
+      File.rm_rf!(tmp)
+
+      if prev do
+        Application.put_env(:microwaveprop, :srtm_tiles_dir, prev)
+      else
+        Application.delete_env(:microwaveprop, :srtm_tiles_dir)
+      end
+    end)
+
+    :ok
+  end
+
+  describe "perform/1" do
+    test "returns :ok and leaves elevation nil when SRTM tile is missing" do
+      user = user_fixture()
+      {:ok, station} = Rover.create_station(user, %{callsign: "W5LUA", lat: 33.0, lon: -96.0})
+
+      assert :ok = StationElevationWorker.perform(%Oban.Job{args: %{"id" => station.id}})
+
+      reloaded = Repo.get!(FixedStation, station.id)
+      assert reloaded.elevation_m == nil
+    end
+
+    test "returns :ok when station id no longer exists" do
+      assert :ok =
+               StationElevationWorker.perform(%Oban.Job{
+                 args: %{"id" => Ecto.UUID.generate()}
+               })
+    end
+  end
+end
diff --git a/test/microwaveprop_web/live/skewt_svg_test.exs b/test/microwaveprop_web/live/skewt_svg_test.exs
index 01ab3303..dcc6bfe4 100644
--- a/test/microwaveprop_web/live/skewt_svg_test.exs
+++ b/test/microwaveprop_web/live/skewt_svg_test.exs
@@ -16,7 +16,7 @@ defmodule MicrowavepropWeb.SkewtSvgTest do
     test "produces a valid <svg> root with the expected viewBox" do
       svg = @profile |> SkewtSvg.render() |> IO.iodata_to_binary()
 
-      assert svg =~ ~r|<svg[^>]*viewBox="0 0 720 640"|
+      assert svg =~ ~r|<svg[^>]*viewBox="0 0 820 640"|
       assert String.ends_with?(svg, "</svg>")
     end