Add canShowThreat getter to AnalysisState for readability

Co-authored-by: tom-anders <13141438+tom-anders@users.noreply.github.com>

Author: Copilot

lib/src/model/analysis/analysis_controller.dart

@@ -695,9 +695,7 @@ class AnalysisController extends AsyncNotifier<AnalysisState>
   Future<void> toggleEngineThreatMode() async {
     if (state.hasValue) {
       final curState = state.requireValue;
-      // Cannot show threat when the king is in check, checkmate, or stalemate.
-      if (!curState.engineInThreatMode &&
-          (curState.currentPosition.isCheck || curState.currentPosition.isStalemate)) {
+      if (!curState.engineInThreatMode && !curState.canShowThreat) {
         return;
       }
       state = AsyncData(curState.copyWith(engineInThreatMode: !curState.engineInThreatMode));
@@ -1016,6 +1014,13 @@ sealed class AnalysisState
   bool get canGoNext => currentNode.hasChild;
   bool get canGoBack => currentPath.size > UciPath.empty.size;
 
+  /// Whether the "show threat" feature can be used in the current position.
+  ///
+  /// Threat mode makes the engine analyze from the opponent's perspective, which
+  /// is invalid when the king is in check (including checkmate) or in stalemate.
+  bool get canShowThreat =>
+      !currentPosition.isCheck && !currentPosition.isStalemate;
+
   EngineGaugeParams engineGaugeParams(EngineEvaluationPrefState prefs) => (
     isLocalEngineAvailable: isEngineAvailable(prefs),
     orientation: pov,

lib/src/view/analysis/analysis_screen.dart

@@ -616,9 +616,7 @@ class _BottomBar extends ConsumerWidget {
               ),
             ),
         ],
-        if (analysisState.isEngineAvailable(evalPrefs) &&
-            !analysisState.currentPosition.isCheck &&
-            !analysisState.currentPosition.isStalemate)
+        if (analysisState.isEngineAvailable(evalPrefs) && analysisState.canShowThreat)
           BottomSheetAction(
             makeLabel: (context) => Text(
               analysisState.engineInThreatMode