Reduce cyclomatic complexity in weather callsign view

Simplify timestamp comparison and weather value formatting:
- Extract compare_timestamps with pattern matching for different types
- Remove duplicate formatter code (was a bug)
- Extract format_string_value and format_numeric_value helpers

Co-Authored-By: Graham <noreply@anthropic.com>

lib/aprsme_web/live/weather_live/callsign_view.ex

@@ -92,38 +92,35 @@ defmodule AprsmeWeb.WeatherLive.CallsignView do
   defp should_update_weather?(nil, _new_packet), do: true
 
   defp should_update_weather?(current_packet, new_packet) do
-    # Only update if the new packet is actually newer
-    # Handle both atom and string keys
     new_received_at = Map.get(new_packet, :received_at) || Map.get(new_packet, "received_at")
     current_received_at = Map.get(current_packet, :received_at) || Map.get(current_packet, "received_at")
 
-    case {new_received_at, current_received_at} do
+    compare_timestamps(new_received_at, current_received_at)
-      {nil, _} ->
+  end
-        false
 
-      {_, nil} ->
+  defp compare_timestamps(nil, _), do: false
-        true
+  defp compare_timestamps(_, nil), do: true
 
-      {new_time, current_time} when is_binary(new_time) and is_binary(current_time) ->
+  defp compare_timestamps(new_time, current_time) when is_binary(new_time) and is_binary(current_time) do
     new_time > current_time
+  end
 
-      {new_time, current_time} when is_binary(new_time) ->
+  defp compare_timestamps(new_time, current_time) when is_binary(new_time) do
-        # Parse string timestamp and compare
     case DateTime.from_iso8601(new_time <> "Z") do
       {:ok, new_dt, _} -> DateTime.after?(new_dt, current_time)
       _ -> false
     end
+  end
 
-      {new_time, current_time} when is_binary(current_time) ->
+  defp compare_timestamps(new_time, current_time) when is_binary(current_time) do
-        # Parse string timestamp and compare
     case DateTime.from_iso8601(current_time <> "Z") do
       {:ok, current_dt, _} -> DateTime.after?(new_time, current_dt)
       _ -> true
     end
-
-      {new_time, current_time} ->
-        DateTime.after?(new_time, current_time)
   end
+
+  defp compare_timestamps(new_time, current_time) do
+    DateTime.after?(new_time, current_time)
   end
 
   defp update_weather_data(socket) do
@@ -246,22 +243,18 @@ defmodule AprsmeWeb.WeatherLive.CallsignView do
     value = PacketUtils.get_weather_field(packet, key)
 
     case value do
-      "N/A" ->
+      v when v == "N/A" or is_nil(v) ->
-        nil
-
-      nil ->
         nil
 
       value when is_binary(value) ->
-        case @weather_formatters[key] do
+        format_string_value(value, key, locale)
-          {formatter, separator} ->
-            {converted_value, unit} = formatter.(value, locale)
-            "#{converted_value}#{separator}#{unit}"
 
-          nil ->
+      value when is_number(value) ->
-            "#{value}"
+        format_numeric_value(value, key, locale)
+    end
   end
 
+  defp format_string_value(value, key, locale) do
     case @weather_formatters[key] do
       {formatter, separator} ->
         case Float.parse(value) do
@@ -276,8 +269,9 @@ defmodule AprsmeWeb.WeatherLive.CallsignView do
       nil ->
         "#{value}"
     end
+  end
 
-      value when is_number(value) ->
+  defp format_numeric_value(value, key, locale) do
     case @weather_formatters[key] do
       {formatter, separator} ->
         {converted_value, unit} = formatter.(value, locale)
@@ -287,5 +281,4 @@ defmodule AprsmeWeb.WeatherLive.CallsignView do
         "#{value}"
     end
   end
-  end
 end