From e2c5cb815a2a74fb5f008d2ab8c1632990fcd917 Mon Sep 17 00:00:00 2001
From: Matt de Courcelle <mjdecour@gmail.com>
Date: Mon, 18 May 2026 12:06:31 -0500
Subject: [PATCH] feat(:segmented_button_group): add count prop per segment
 (Wave 3.7 Class C extension)

Adds optional count badge per segment to the canonical :segmented_button_group
widget, addressing comp-fidelity gap EX-6 (segments like "ADRs (12)").

- IUR constructor: count (optional non-negative integer, default nil) on segment
  options via normalize_options/1; raises ArgumentError for negative or
  non-integer values
- Renderer: passes count through segmented_button_group_options/2 helper
- Stage-4 Phoenix.Component: renders <span class="live-ui-segmented-button-group-option-count"
  aria-hidden="true"> inline when count is non-nil; zero renders "0"; nil omits
  the span
- Tests: 6 IUR (positive: count pass-through, zero, nil-omit; negative: negative int,
  non-integer, float) + 6 Stage-4 widget (positive: badge present, aria-hidden,
  zero; negative: nil, absent-key, mixed options)

Closes The-Metagraph/unified_ui#187.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 packages/live_ui/lib/live_ui/renderer.ex      |  1 +
 .../live_ui/widgets/segmented_button_group.ex |  6 ++
 .../widgets/segmented_button_group_test.exs   | 79 +++++++++++++++++++
 .../lib/unified_iur/widgets/components.ex     | 10 +++
 .../unified_iur/widgets/components_test.exs   | 55 +++++++++++++
 5 files changed, 151 insertions(+)

diff --git a/packages/live_ui/lib/live_ui/renderer.ex b/packages/live_ui/lib/live_ui/renderer.ex
index 1203e39c..a299c704 100644
--- a/packages/live_ui/lib/live_ui/renderer.ex
+++ b/packages/live_ui/lib/live_ui/renderer.ex
@@ -1705,6 +1705,7 @@ defmodule LiveUi.Renderer do
         value: value,
         label: Map.get(option, :label, Map.get(option, "label", "")),
         disabled?: disabled?,
+        count: Map.get(option, :count, Map.get(option, "count")),
         attrs: segmented_button_group_option_attrs(element, event_target, value, disabled?)
       }
     end)
diff --git a/packages/live_ui/lib/live_ui/widgets/segmented_button_group.ex b/packages/live_ui/lib/live_ui/widgets/segmented_button_group.ex
index 706736e5..bdeb505c 100644
--- a/packages/live_ui/lib/live_ui/widgets/segmented_button_group.ex
+++ b/packages/live_ui/lib/live_ui/widgets/segmented_button_group.ex
@@ -48,6 +48,11 @@ defmodule LiveUi.Widgets.SegmentedButtonGroup do
         {option_attrs(option)}
       >
         {option_label(option)}
+        <span
+          :if={option_count(option) != nil}
+          class="live-ui-segmented-button-group-option-count"
+          aria-hidden="true"
+        >{option_count(option)}</span>
       </button>
     </div>
     """
@@ -56,6 +61,7 @@ defmodule LiveUi.Widgets.SegmentedButtonGroup do
   defp option_value(option), do: fetch_option(option, :value)
   defp option_label(option), do: fetch_option(option, :label, "")
   defp option_attrs(option), do: fetch_option(option, :attrs, %{})
+  defp option_count(option), do: fetch_option(option, :count)
 
   defp option_disabled?(option) do
     fetch_option(option, :disabled?) || fetch_option(option, :disabled) || false
diff --git a/packages/live_ui/test/live_ui/widgets/segmented_button_group_test.exs b/packages/live_ui/test/live_ui/widgets/segmented_button_group_test.exs
index 7687f240..af4c0f1d 100644
--- a/packages/live_ui/test/live_ui/widgets/segmented_button_group_test.exs
+++ b/packages/live_ui/test/live_ui/widgets/segmented_button_group_test.exs
@@ -203,4 +203,83 @@ defmodule LiveUi.Widgets.SegmentedButtonGroupTest do
       assert metadata.mountable?
     end
   end
+
+  describe "count badge" do
+    test "option with count renders count badge span" do
+      html =
+        render_component(&SegmentedButtonGroup.component/1, %{
+          id: "test-sbg",
+          options: [
+            %{value: "adrs", label: "ADRs", count: 12},
+            %{value: "specs", label: "Specs", count: 8}
+          ],
+          label: "Document type"
+        })
+
+      assert html =~ ~s(class="live-ui-segmented-button-group-option-count")
+      assert html =~ "12"
+      assert html =~ "8"
+    end
+
+    test "count badge has aria-hidden=true" do
+      html =
+        render_component(&SegmentedButtonGroup.component/1, %{
+          id: "test-sbg",
+          options: [%{value: "a", label: "All", count: 5}],
+          label: "Test group"
+        })
+
+      assert html =~ ~s(aria-hidden="true")
+    end
+
+    test "option without count does not render count badge span" do
+      html =
+        render_component(&SegmentedButtonGroup.component/1, %{
+          id: "test-sbg",
+          options: @options,
+          label: "Test group"
+        })
+
+      refute html =~ ~s(live-ui-segmented-button-group-option-count)
+    end
+
+    test "option with count nil does not render count badge span" do
+      html =
+        render_component(&SegmentedButtonGroup.component/1, %{
+          id: "test-sbg",
+          options: [%{value: "a", label: "Option A", count: nil}],
+          label: "Test group"
+        })
+
+      refute html =~ ~s(live-ui-segmented-button-group-option-count)
+    end
+
+    test "count of zero renders a badge with '0'" do
+      html =
+        render_component(&SegmentedButtonGroup.component/1, %{
+          id: "test-sbg",
+          options: [%{value: "plans", label: "Plans", count: 0}],
+          label: "Test group"
+        })
+
+      assert html =~ ~s(live-ui-segmented-button-group-option-count)
+      assert html =~ ">0<"
+    end
+
+    test "mixed options: some with count, some without" do
+      html =
+        render_component(&SegmentedButtonGroup.component/1, %{
+          id: "test-sbg",
+          options: [
+            %{value: "adrs", label: "ADRs", count: 12},
+            %{value: "specs", label: "Specs"}
+          ],
+          label: "Document type"
+        })
+
+      assert html =~ "12"
+      assert html =~ "ADRs"
+      assert html =~ "Specs"
+    end
+  end
 end
diff --git a/packages/unified_iur/lib/unified_iur/widgets/components.ex b/packages/unified_iur/lib/unified_iur/widgets/components.ex
index e030b894..c0ac5fbb 100644
--- a/packages/unified_iur/lib/unified_iur/widgets/components.ex
+++ b/packages/unified_iur/lib/unified_iur/widgets/components.ex
@@ -851,9 +851,19 @@ defmodule UnifiedIUR.Widgets.Components do
       |> maybe_put(:value, option(option_value, :value))
       |> maybe_put(:label, option(option_value, :label))
       |> maybe_put(:disabled?, option(option_value, :disabled?))
+      |> maybe_put(:count, normalize_option_count(option(option_value, :count)))
     end)
   end
 
+  defp normalize_option_count(nil), do: nil
+
+  defp normalize_option_count(count) when is_integer(count) and count >= 0, do: count
+
+  defp normalize_option_count(count) do
+    raise ArgumentError,
+          "option :count must be a non-negative integer or nil, got: #{inspect(count)}"
+  end
+
   defp normalize_maps(values) when is_list(values) do
     Enum.map(values, &normalize_map/1)
   end
diff --git a/packages/unified_iur/test/unified_iur/widgets/components_test.exs b/packages/unified_iur/test/unified_iur/widgets/components_test.exs
index 0a3b26b0..510c7112 100644
--- a/packages/unified_iur/test/unified_iur/widgets/components_test.exs
+++ b/packages/unified_iur/test/unified_iur/widgets/components_test.exs
@@ -379,4 +379,59 @@ defmodule UnifiedIUR.Widgets.ComponentsTest do
 
     assert [%{slot: :default, element: %Element{id: :sources_body, kind: :text}}] = rail.children
   end
+
+  describe "segmented_button_group count prop" do
+    test "passes count through to normalized options when present" do
+      element =
+        Components.segmented_button_group(
+          [
+            %{value: :adrs, label: "ADRs", count: 12},
+            %{value: :specs, label: "Specs", count: 8},
+            %{value: :plans, label: "Plans"}
+          ],
+          active_value: :adrs
+        )
+
+      [adrs, specs, plans] = element.attributes.selection.options
+
+      assert adrs == %{value: :adrs, label: "ADRs", count: 12}
+      assert specs == %{value: :specs, label: "Specs", count: 8}
+      # no count key when absent (maybe_put drops nil)
+      refute Map.has_key?(plans, :count)
+    end
+
+    test "count of zero is preserved in normalized options" do
+      element =
+        Components.segmented_button_group([%{value: :empty, label: "Empty", count: 0}])
+
+      [opt] = element.attributes.selection.options
+      assert opt.count == 0
+    end
+
+    test "explicit count nil is omitted from normalized options" do
+      element =
+        Components.segmented_button_group([%{value: :a, label: "A", count: nil}])
+
+      [opt] = element.attributes.selection.options
+      refute Map.has_key?(opt, :count)
+    end
+
+    test "negative count raises ArgumentError" do
+      assert_raise ArgumentError, ~r/non-negative integer/, fn ->
+        Components.segmented_button_group([%{value: :a, label: "A", count: -1}])
+      end
+    end
+
+    test "non-integer count raises ArgumentError" do
+      assert_raise ArgumentError, ~r/non-negative integer/, fn ->
+        Components.segmented_button_group([%{value: :a, label: "A", count: "12"}])
+      end
+    end
+
+    test "float count raises ArgumentError" do
+      assert_raise ArgumentError, ~r/non-negative integer/, fn ->
+        Components.segmented_button_group([%{value: :a, label: "A", count: 3.5}])
+      end
+    end
+  end
 end