feat: add send_trail_line_for_tracked_callsign function

- Filters packets by tracked callsign and time threshold
- Sorts packets chronologically by received_at
- Pushes show_trail_line event with coordinates
- Returns socket unchanged when no packets found

lib/aprsme_web/live/map_live/display_manager.ex

@@ -74,6 +74,56 @@ defmodule AprsmeWeb.MapLive.DisplayManager do
     end
   end
 
+  @doc """
+  Send trail line data for tracked callsign.
+  Connects all position points chronologically, regardless of distance.
+  """
+  @spec send_trail_line_for_tracked_callsign(Socket.t()) :: Socket.t()
+  def send_trail_line_for_tracked_callsign(socket) do
+    callsign = socket.assigns.tracked_callsign
+    threshold = socket.assigns.packet_age_threshold
+
+    packets =
+      socket.assigns.visible_packets
+      |> Map.values()
+      |> Enum.filter(fn packet ->
+        sender = Map.get(packet, :sender) || Map.get(packet, "sender")
+        received_at = Map.get(packet, :received_at) || Map.get(packet, "received_at")
+
+        String.upcase(sender) == String.upcase(callsign) &&
+          DateTime.compare(received_at, threshold) != :lt
+      end)
+      |> Enum.sort_by(
+        fn packet ->
+          received_at = Map.get(packet, :received_at) || Map.get(packet, "received_at")
+          DateTime.to_unix(received_at, :microsecond)
+        end,
+        :asc
+      )
+
+    if Enum.empty?(packets) do
+      socket
+    else
+      points =
+        Enum.map(packets, fn packet ->
+          lat = Map.get(packet, :lat) || Map.get(packet, "lat")
+          lon = Map.get(packet, :lon) || Map.get(packet, "lon")
+          received_at = Map.get(packet, :received_at) || Map.get(packet, "received_at")
+
+          %{
+            lat: Aprsme.EncodingUtils.to_float(lat) || 0.0,
+            lng: Aprsme.EncodingUtils.to_float(lon) || 0.0,
+            timestamp: DateTime.to_iso8601(received_at)
+          }
+        end)
+
+      LiveView.push_event(socket, "show_trail_line", %{
+        callsign: callsign,
+        points: points
+      })
+    end
+  end
+
   @doc """
   Send heat map data for filtered packets.
   """

test/aprsme_web/live/map_live/display_manager_test.exs

@@ -0,0 +1,136 @@
+defmodule AprsmeWeb.MapLive.DisplayManagerTest do
+  use Aprsme.DataCase, async: true
+
+  alias AprsmeWeb.MapLive.DisplayManager
+
+  setup do
+    # Create a basic socket mock for testing
+    socket = %Phoenix.LiveView.Socket{
+      assigns: %{
+        visible_packets: %{},
+        tracked_callsign: nil,
+        packet_age_threshold: nil,
+        map_bounds: nil,
+        map_zoom: 10,
+        historical_packets: %{}
+      },
+      private: %{live_temp: %{}}
+    }
+
+    {:ok, socket: socket}
+  end
+
+  describe "send_trail_line_for_tracked_callsign/1" do
+    test "pushes trail line event with sorted points", %{socket: socket} do
+      packet1 = %{
+        id: "1",
+        sender: "W5ISP-9",
+        lat: 30.123,
+        lon: -97.456,
+        received_at: ~U[2024-01-01 10:00:00Z]
+      }
+
+      packet2 = %{
+        id: "2",
+        sender: "W5ISP-9",
+        lat: 30.124,
+        lon: -97.457,
+        received_at: ~U[2024-01-01 10:05:00Z]
+      }
+
+      packet3 = %{
+        id: "3",
+        sender: "W5ISP-9",
+        lat: 30.125,
+        lon: -97.458,
+        received_at: ~U[2024-01-01 10:10:00Z]
+      }
+
+      visible_packets = %{"W5ISP-9:1" => packet1, "W5ISP-9:2" => packet2, "W5ISP-9:3" => packet3}
+
+      socket =
+        Map.put(socket, :assigns, %{
+          socket.assigns
+          | visible_packets: visible_packets,
+            tracked_callsign: "W5ISP-9",
+            packet_age_threshold: ~U[2024-01-01 09:00:00Z]
+        })
+
+      result_socket = DisplayManager.send_trail_line_for_tracked_callsign(socket)
+
+      push_events = get_in(result_socket.private, [:live_temp, :push_events]) || []
+      assert length(push_events) == 1
+
+      [[event_name, event_data]] = push_events
+      assert event_name == "show_trail_line"
+
+      assert event_data == %{
+               callsign: "W5ISP-9",
+               points: [
+                 %{lat: 30.123, lng: -97.456, timestamp: "2024-01-01T10:00:00Z"},
+                 %{lat: 30.124, lng: -97.457, timestamp: "2024-01-01T10:05:00Z"},
+                 %{lat: 30.125, lng: -97.458, timestamp: "2024-01-01T10:10:00Z"}
+               ]
+             }
+    end
+
+    test "filters by packet age threshold", %{socket: socket} do
+      packet1 = %{
+        id: "1",
+        sender: "W5ISP-9",
+        lat: 30.123,
+        lon: -97.456,
+        received_at: ~U[2024-01-01 09:00:00Z]
+      }
+
+      # Too old
+      packet2 = %{
+        id: "2",
+        sender: "W5ISP-9",
+        lat: 30.124,
+        lon: -97.457,
+        received_at: ~U[2024-01-01 10:05:00Z]
+      }
+
+      # Within threshold
+
+      visible_packets = %{"W5ISP-9:1" => packet1, "W5ISP-9:2" => packet2}
+
+      socket =
+        Map.put(socket, :assigns, %{
+          socket.assigns
+          | visible_packets: visible_packets,
+            tracked_callsign: "W5ISP-9",
+            packet_age_threshold: ~U[2024-01-01 10:00:00Z]
+        })
+
+      result_socket = DisplayManager.send_trail_line_for_tracked_callsign(socket)
+
+      push_events = get_in(result_socket.private, [:live_temp, :push_events]) || []
+      assert length(push_events) == 1
+
+      [[event_name, event_data]] = push_events
+      assert event_name == "show_trail_line"
+
+      assert event_data == %{
+               callsign: "W5ISP-9",
+               points: [%{lat: 30.124, lng: -97.457, timestamp: "2024-01-01T10:05:00Z"}]
+             }
+    end
+
+    test "returns socket unchanged when no packets", %{socket: socket} do
+      socket =
+        Map.put(socket, :assigns, %{
+          socket.assigns
+          | visible_packets: %{},
+            tracked_callsign: "W5ISP-9",
+            packet_age_threshold: ~U[2024-01-01 10:00:00Z]
+        })
+
+      result_socket = DisplayManager.send_trail_line_for_tracked_callsign(socket)
+
+      push_events = get_in(result_socket.private, [:live_temp, :push_events]) || []
+      assert push_events == []
+    end
+  end
+end