feat: more robust host config

lib/elixir_auth_google.ex

@@ -25,12 +25,22 @@ defmodule ElixirAuthGoogle do
   `get_baseurl_from_conn/1` derives the base URL from the conn struct
   """
   @spec get_baseurl_from_conn(conn) :: String.t()
-  def get_baseurl_from_conn(%{host: h, port: p}) when h == "localhost" do
-    "http://#{h}:#{p}"
+  def get_baseurl_from_conn(%{host: h, port: p, scheme: s}) when p != 80 do
+    "#{Atom.to_string(s)}://#{h}:#{p}"
   end
 
-  def get_baseurl_from_conn(%{host: h}) do
-    "https://#{h}"
+  def get_baseurl_from_conn(%{host: h, scheme: s}) do
+    "#{Atom.to_string(s)}://#{h}"
+  end
+
+  def get_baseurl_from_conn(%{host: h} = conn) do
+    scheme =
+      case h do
+        "localhost" -> :http
+        _ -> :https
+      end
+
+    get_baseurl_from_conn(Map.put(conn, :scheme, scheme))
   end
 
   @doc """

test/elixir_auth_google_test.exs

@@ -5,24 +5,56 @@ defmodule ElixirAuthGoogleTest do
 
   import Mock
 
-  test "get_baseurl_from_conn(conn) detects the URL based on conn.host" do
+  test "get_baseurl_from_conn(conn) detects the URL based on conn.host HTTP" do
     conn = %{
       host: "localhost",
-      port: 4000
+      port: 4000,
+      scheme: :http
     }
 
     assert ElixirAuthGoogle.get_baseurl_from_conn(conn) == "http://localhost:4000"
   end
 
-  test "get_baseurl_from_conn(conn) detects the URL for production" do
+  test "get_baseurl_from_conn(conn) detects the URL based on conn.host HTTPS" do
+    conn = %{
+      host: "localhost",
+      port: 4000,
+      scheme: :https
+    }
+
+    assert ElixirAuthGoogle.get_baseurl_from_conn(conn) == "https://localhost:4000"
+  end
+
+  test "get_baseurl_from_conn(conn) detects the URL for production HTTPS" do
     conn = %{
       host: "dwyl.com",
-      port: 80
+      port: 80,
+      scheme: :https
     }
 
     assert ElixirAuthGoogle.get_baseurl_from_conn(conn) == "https://dwyl.com"
   end
 
+  test "get_baseurl_from_conn(conn) detects the URL for production HTTP" do
+    conn = %{
+      host: "dwyl.com",
+      port: 80,
+      scheme: :http
+    }
+
+    assert ElixirAuthGoogle.get_baseurl_from_conn(conn) == "http://dwyl.com"
+  end
+
+  test "get_baseurl_from_conn(conn) detects the URL for production HTTPS, non-standard port" do
+    conn = %{
+      host: "dwyl.com",
+      port: 8080,
+      scheme: :https
+    }
+
+    assert ElixirAuthGoogle.get_baseurl_from_conn(conn) == "https://dwyl.com:8080"
+  end
+
   test "get Google login url" do
     conn = %{
       host: "localhost",