refactor: pattern-match InfoLive.Show path parsing + add tests

- parse_path_element_with_link splits its fat `if`/or-chain into three
  focused helpers: linkable_callsign?/1 (regex + alias check),
  path_alias?/1 (four String.starts_with guards), and
  classify_path_element/2 (link vs. text dispatched on the boolean).
- display_for_element/2 chooses the callsign form with/without the
  asterisk via two function heads instead of an inline `if`.

Adds 7 tests covering the parse_path_with_links/1 public API — plain
callsigns, heard-via asterisk preservation, non-linkable aliases
(WIDE/TRACE/RELAY/TCPIP), q-constructs, whitespace trimming, and mixed
paths.

lib/aprsme_web/live/info_live/show.ex

@@ -599,24 +599,35 @@ defmodule AprsmeWeb.InfoLive.Show do
 
   defp parse_path_element_with_link(element) do
     element = String.trim(element)
-
-    # Check if it's a callsign (with or without SSID)
-    if Regex.match?(~r/^[A-Z0-9]{1,6}(-\d{1,2})?(\*)?$/, element) and
-         not String.starts_with?(element, "WIDE") and
-         not String.starts_with?(element, "TRACE") and
-         not String.starts_with?(element, "RELAY") and
-         not String.starts_with?(element, "TCPIP") and
-         not String.starts_with?(element, "q") do
-      # Remove asterisk if present (indicates the packet was digipeated through this station)
-      callsign = String.replace(element, "*", "")
-      display = if String.ends_with?(element, "*"), do: "#{callsign}*", else: callsign
-      {:link, callsign, display}
-    else
-      # Not a linkable callsign, just return as text
-      {:text, element, element}
-    end
+    classify_path_element(linkable_callsign?(element), element)
   end
 
+  # Only real callsigns (not digipeater aliases or q-constructs) become links.
+  defp linkable_callsign?(element) do
+    Regex.match?(~r/^[A-Z0-9]{1,6}(-\d{1,2})?(\*)?$/, element) and
+      not path_alias?(element)
+  end
+
+  defp path_alias?(element) do
+    String.starts_with?(element, "WIDE") or
+      String.starts_with?(element, "TRACE") or
+      String.starts_with?(element, "RELAY") or
+      String.starts_with?(element, "TCPIP") or
+      String.starts_with?(element, "q")
+  end
+
+  # Strip the trailing `*` from the canonical callsign while preserving it
+  # in the display string so the UI still shows "was-heard-via" markers.
+  defp classify_path_element(true, element) do
+    callsign = String.replace(element, "*", "")
+    {:link, callsign, display_for_element(String.ends_with?(element, "*"), callsign)}
+  end
+
+  defp classify_path_element(false, element), do: {:text, element, element}
+
+  defp display_for_element(true, callsign), do: "#{callsign}*"
+  defp display_for_element(false, callsign), do: callsign
+
   defp decode_path_element(element) do
     element = String.trim(element)
 

test/aprsme_web/live/info_live/show_helpers_test.exs

@@ -99,4 +99,47 @@ defmodule AprsmeWeb.InfoLive.ShowHelpersTest do
       assert d > 0
     end
   end
+
+  describe "parse_path_with_links/1" do
+    test "returns empty list for non-binary input" do
+      assert Show.parse_path_with_links(nil) == []
+      assert Show.parse_path_with_links("") == []
+      assert Show.parse_path_with_links(123) == []
+    end
+
+    test "splits on commas and links plain callsigns" do
+      result = Show.parse_path_with_links("K5ABC-1,W1XYZ")
+      assert [{:link, "K5ABC-1", "K5ABC-1"}, {:link, "W1XYZ", "W1XYZ"}] = result
+    end
+
+    test "preserves the heard-via asterisk in the display text" do
+      assert [{:link, "K5ABC", "K5ABC*"}] = Show.parse_path_with_links("K5ABC*")
+    end
+
+    test "does not link WIDE/TRACE/RELAY/TCPIP path aliases" do
+      assert [{:text, "WIDE1-1", "WIDE1-1"}] = Show.parse_path_with_links("WIDE1-1")
+      assert [{:text, "TRACE3-3", "TRACE3-3"}] = Show.parse_path_with_links("TRACE3-3")
+      assert [{:text, "RELAY", "RELAY"}] = Show.parse_path_with_links("RELAY")
+      assert [{:text, "TCPIP*", "TCPIP*"}] = Show.parse_path_with_links("TCPIP*")
+    end
+
+    test "does not link q-constructs" do
+      assert [{:text, "qAC", "qAC"}] = Show.parse_path_with_links("qAC")
+      assert [{:text, "qAR", "qAR"}] = Show.parse_path_with_links("qAR")
+    end
+
+    test "trims whitespace before linking" do
+      assert [{:link, "K5ABC", "K5ABC"}] = Show.parse_path_with_links(" K5ABC ")
+    end
+
+    test "mixes links and text in a single path" do
+      result = Show.parse_path_with_links("K5ABC*,WIDE1-1,W1XYZ")
+
+      assert [
+               {:link, "K5ABC", "K5ABC*"},
+               {:text, "WIDE1-1", "WIDE1-1"},
+               {:link, "W1XYZ", "W1XYZ"}
+             ] = result
+    end
+  end
 end