feat(cli): consolidate shell inactivity and redirection monitoring (#17086)

packages/cli/src/ui/hooks/useTurnActivityMonitor.ts

@@ -0,0 +1,69 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { useState, useEffect, useRef, useMemo } from 'react';
+import { StreamingState } from '../types.js';
+import { hasRedirection } from '@google/gemini-cli-core';
+import { type TrackedToolCall } from './useReactToolScheduler.js';
+
+export interface TurnActivityStatus {
+  operationStartTime: number;
+  isRedirectionActive: boolean;
+}
+
+/**
+ * Monitors the activity of a Gemini turn to detect when a new operation starts
+ * and whether it involves shell redirections that should suppress inactivity prompts.
+ */
+export const useTurnActivityMonitor = (
+  streamingState: StreamingState,
+  activePtyId: number | string | null | undefined,
+  pendingToolCalls: TrackedToolCall[] = [],
+): TurnActivityStatus => {
+  const [operationStartTime, setOperationStartTime] = useState(0);
+
+  // Reset operation start time whenever a new operation begins.
+  // We consider an operation to have started when we enter Responding state,
+  // OR when the active PTY changes (meaning a new command started within the turn).
+  const prevPtyIdRef = useRef<number | string | null | undefined>(undefined);
+  const prevStreamingStateRef = useRef<StreamingState | undefined>(undefined);
+
+  useEffect(() => {
+    const isNowResponding = streamingState === StreamingState.Responding;
+    const wasResponding =
+      prevStreamingStateRef.current === StreamingState.Responding;
+    const ptyChanged = activePtyId !== prevPtyIdRef.current;
+
+    if (isNowResponding && (!wasResponding || ptyChanged)) {
+      setOperationStartTime(Date.now());
+    } else if (!isNowResponding && wasResponding) {
+      setOperationStartTime(0);
+    }
+
+    prevPtyIdRef.current = activePtyId;
+    prevStreamingStateRef.current = streamingState;
+  }, [streamingState, activePtyId]);
+
+  // Detect redirection in the current query or tool calls.
+  // We derive this directly during render to ensure it's accurate from the first frame.
+  const isRedirectionActive = useMemo(
+    () =>
+      // Check active tool calls for run_shell_command
+      pendingToolCalls.some((tc) => {
+        if (tc.request.name !== 'run_shell_command') return false;
+
+        const command =
+          (tc.request.args as { command?: string })?.command || '';
+        return hasRedirection(command);
+      }),
+    [pendingToolCalls],
+  );
+
+  return {
+    operationStartTime,
+    isRedirectionActive,
+  };
+};