feat(cli): add useHistoryManager hook for chat history (#234)

Co-authored-by: Brandon Keiji <brandonkeiji@google.com>

packages/cli/src/ui/hooks/useHistoryManager.test.ts

@@ -0,0 +1,141 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect } from 'vitest';
+import { renderHook, act } from '@testing-library/react';
+import { useHistoryManager } from './useHistoryManager.js';
+import { HistoryItem } from '../types.js';
+
+describe('useHistoryManager', () => {
+  it('should initialize with an empty history', () => {
+    const { result } = renderHook(() => useHistoryManager());
+    expect(result.current.history).toEqual([]);
+  });
+
+  it('should add an item to history with a unique ID', () => {
+    const { result } = renderHook(() => useHistoryManager());
+    const timestamp = Date.now();
+    const itemData: Omit<HistoryItem, 'id'> = {
+      type: 'user', // Replaced HistoryItemType.User
+      text: 'Hello',
+    };
+
+    act(() => {
+      result.current.addItemToHistory(itemData, timestamp);
+    });
+
+    expect(result.current.history).toHaveLength(1);
+    expect(result.current.history[0]).toEqual(
+      expect.objectContaining({
+        ...itemData,
+        id: expect.any(Number),
+      }),
+    );
+    // Basic check that ID incorporates timestamp
+    expect(result.current.history[0].id).toBeGreaterThanOrEqual(timestamp);
+  });
+
+  it('should generate unique IDs for items added with the same base timestamp', () => {
+    const { result } = renderHook(() => useHistoryManager());
+    const timestamp = Date.now();
+    const itemData1: Omit<HistoryItem, 'id'> = {
+      type: 'user', // Replaced HistoryItemType.User
+      text: 'First',
+    };
+    const itemData2: Omit<HistoryItem, 'id'> = {
+      type: 'gemini', // Replaced HistoryItemType.Gemini
+      text: 'Second',
+    };
+
+    let id1!: number;
+    let id2!: number;
+
+    act(() => {
+      id1 = result.current.addItemToHistory(itemData1, timestamp);
+      id2 = result.current.addItemToHistory(itemData2, timestamp);
+    });
+
+    expect(result.current.history).toHaveLength(2);
+    expect(id1).not.toEqual(id2);
+    expect(result.current.history[0].id).toEqual(id1);
+    expect(result.current.history[1].id).toEqual(id2);
+    // IDs should be sequential based on the counter
+    expect(id2).toBeGreaterThan(id1);
+  });
+
+  it('should update an existing history item', () => {
+    const { result } = renderHook(() => useHistoryManager());
+    const timestamp = Date.now();
+    const initialItem: Omit<HistoryItem, 'id'> = {
+      type: 'gemini', // Replaced HistoryItemType.Gemini
+      text: 'Initial content',
+    };
+    let itemId!: number;
+
+    act(() => {
+      itemId = result.current.addItemToHistory(initialItem, timestamp);
+    });
+
+    const updatedText = 'Updated content';
+    act(() => {
+      result.current.updateHistoryItem(itemId, { text: updatedText });
+    });
+
+    expect(result.current.history).toHaveLength(1);
+    expect(result.current.history[0]).toEqual({
+      ...initialItem,
+      id: itemId,
+      text: updatedText,
+    });
+  });
+
+  it('should not change history if updateHistoryItem is called with a non-existent ID', () => {
+    const { result } = renderHook(() => useHistoryManager());
+    const timestamp = Date.now();
+    const itemData: Omit<HistoryItem, 'id'> = {
+      type: 'user', // Replaced HistoryItemType.User
+      text: 'Hello',
+    };
+
+    act(() => {
+      result.current.addItemToHistory(itemData, timestamp);
+    });
+
+    const originalHistory = [...result.current.history]; // Clone before update attempt
+
+    act(() => {
+      result.current.updateHistoryItem(99999, { text: 'Should not apply' }); // Non-existent ID
+    });
+
+    expect(result.current.history).toEqual(originalHistory);
+  });
+
+  it('should clear the history', () => {
+    const { result } = renderHook(() => useHistoryManager());
+    const timestamp = Date.now();
+    const itemData1: Omit<HistoryItem, 'id'> = {
+      type: 'user', // Replaced HistoryItemType.User
+      text: 'First',
+    };
+    const itemData2: Omit<HistoryItem, 'id'> = {
+      type: 'gemini', // Replaced HistoryItemType.Gemini
+      text: 'Second',
+    };
+
+    act(() => {
+      result.current.addItemToHistory(itemData1, timestamp);
+      result.current.addItemToHistory(itemData2, timestamp);
+    });
+
+    expect(result.current.history).toHaveLength(2);
+
+    act(() => {
+      result.current.clearHistory();
+    });
+
+    expect(result.current.history).toEqual([]);
+  });
+});