Refactor: Add GeminiRespondingSpinner to make use of streamingState idiomatic (#583)

packages/cli/src/ui/components/GeminiRespondingSpinner.tsx

@@ -0,0 +1,34 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import React from 'react';
+import { Text } from 'ink';
+import Spinner from 'ink-spinner';
+import type { SpinnerName } from 'cli-spinners';
+import { useStreamingContext } from '../contexts/StreamingContext.js';
+import { StreamingState } from '../types.js';
+
+interface GeminiRespondingSpinnerProps {
+  /**
+   * Optional string to display when not in Responding state.
+   * If not provided and not Responding, renders null.
+   */
+  nonRespondingDisplay?: string;
+  spinnerType?: SpinnerName;
+}
+
+export const GeminiRespondingSpinner: React.FC<
+  GeminiRespondingSpinnerProps
+> = ({ nonRespondingDisplay, spinnerType = 'dots' }) => {
+  const { streamingState } = useStreamingContext();
+
+  if (streamingState === StreamingState.Responding) {
+    return <Spinner type={spinnerType} />;
+  } else if (nonRespondingDisplay) {
+    return <Text>{nonRespondingDisplay}</Text>;
+  }
+  return null;
+};