Including a test harness for it, and making sure the cursor is always at the end.

1 files changed, 177 insertions, 0 deletions

diff --git a/packages/cli/src/ui/hooks/useInputHistory.test.ts b/packages/cli/src/ui/hooks/useInputHistory.test.ts
new file mode 100644
index 00000000..34af31b2
--- /dev/null
+++ b/packages/cli/src/ui/hooks/useInputHistory.test.ts
@@ -0,0 +1,177 @@
+// packages/cli/src/ui/hooks/useInputHistory.test.ts
+import { renderHook, act } from '@testing-library/react';
+import { useInput } from 'ink';
+import { vi, describe, test, expect, beforeEach, Mock } from 'vitest';
+import { useInputHistory } from './useInputHistory.js';
+
+// Mock the useInput hook from Ink
+vi.mock('ink', async (importOriginal) => {
+  const originalInk = await importOriginal<typeof import('ink')>();
+  return {
+    ...originalInk, // Keep other exports
+    useInput: vi.fn(), // Mock useInput
+  };
+});
+
+// Helper type for the mocked useInput callback
+type UseInputCallback = (input: string, key: any) => void;
+
+describe('useInputHistory Hook', () => {
+  let mockUseInputCallback: UseInputCallback | undefined;
+  const mockUserMessages = ['msg1', 'msg2', 'msg3']; // Sample history
+
+  beforeEach(() => {
+    // Reset the mock before each test and capture the callback
+    (useInput as Mock).mockImplementation((callback, options) => {
+      // Only store the callback if the hook is active in the test
+      if (options?.isActive !== false) {
+        mockUseInputCallback = callback;
+      } else {
+        mockUseInputCallback = undefined;
+      }
+    });
+  });
+
+  // Helper function to simulate key press by invoking the captured callback
+  const simulateKeyPress = (key: object, input: string = '') => {
+    act(() => {
+      if (mockUseInputCallback) {
+        mockUseInputCallback(input, key);
+      } else {
+        // Optionally throw an error if trying to press key when inactive
+        // console.warn('Simulated key press while useInput was inactive');
+      }
+    });
+  };
+
+  test('should initialize with empty query', () => {
+    const { result } = renderHook(() =>
+      useInputHistory({ userMessages: [], isActive: true }),
+    );
+    expect(result.current.query).toBe('');
+  });
+
+  test('up arrow should do nothing if history is empty', () => {
+    const { result } = renderHook(() =>
+      useInputHistory({ userMessages: [], isActive: true }),
+    );
+    simulateKeyPress({ upArrow: true });
+    expect(result.current.query).toBe('');
+  });
+
+  test('up arrow should recall the last message', () => {
+    const { result } = renderHook(() =>
+      useInputHistory({ userMessages: mockUserMessages, isActive: true }),
+    );
+    simulateKeyPress({ upArrow: true });
+    expect(result.current.query).toBe('msg3'); // Last message
+  });
+
+  test('repeated up arrows should navigate history', () => {
+    const { result } = renderHook(() =>
+      useInputHistory({ userMessages: mockUserMessages, isActive: true }),
+    );
+    simulateKeyPress({ upArrow: true }); // -> msg3
+    simulateKeyPress({ upArrow: true }); // -> msg2
+    expect(result.current.query).toBe('msg2');
+    simulateKeyPress({ upArrow: true }); // -> msg1
+    expect(result.current.query).toBe('msg1');
+    simulateKeyPress({ upArrow: true }); // -> stays on msg1
+    expect(result.current.query).toBe('msg1');
+  });
+
+  test('down arrow should navigate history forward', () => {
+    const { result } = renderHook(() =>
+      useInputHistory({ userMessages: mockUserMessages, isActive: true }),
+    );
+    simulateKeyPress({ upArrow: true }); // -> msg3
+    simulateKeyPress({ upArrow: true }); // -> msg2
+    simulateKeyPress({ upArrow: true }); // -> msg1
+    expect(result.current.query).toBe('msg1');
+
+    simulateKeyPress({ downArrow: true }); // -> msg2
+    expect(result.current.query).toBe('msg2');
+    simulateKeyPress({ downArrow: true }); // -> msg3
+    expect(result.current.query).toBe('msg3');
+  });
+
+  test('down arrow should restore original query', () => {
+    const { result } = renderHook(() =>
+      useInputHistory({ userMessages: mockUserMessages, isActive: true }),
+    );
+
+    // Set initial query
+    act(() => {
+      result.current.setQuery('original typing');
+    });
+    expect(result.current.query).toBe('original typing');
+
+    simulateKeyPress({ upArrow: true }); // -> msg3
+    expect(result.current.query).toBe('msg3');
+
+    simulateKeyPress({ downArrow: true }); // -> original typing
+    expect(result.current.query).toBe('original typing');
+
+    // Pressing down again should do nothing
+    simulateKeyPress({ downArrow: true });
+    expect(result.current.query).toBe('original typing');
+  });
+
+  test('typing should reset navigation', () => {
+    const { result } = renderHook(() =>
+      useInputHistory({ userMessages: mockUserMessages, isActive: true }),
+    );
+
+    simulateKeyPress({ upArrow: true }); // -> msg3
+    expect(result.current.query).toBe('msg3');
+
+    // Simulate typing 'x' (Note: we manually call setQuery here, as useInput is mocked)
+    act(() => {
+      result.current.setQuery(result.current.query + 'x');
+    });
+    // Also simulate the input event that would trigger the reset
+    simulateKeyPress({}, 'x');
+    expect(result.current.query).toBe('msg3x');
+
+    simulateKeyPress({ upArrow: true }); // Should restart navigation -> msg3
+    expect(result.current.query).toBe('msg3');
+  });
+
+  test('calling resetHistoryNav should clear navigation state', () => {
+    const { result } = renderHook(() =>
+      useInputHistory({ userMessages: mockUserMessages, isActive: true }),
+    );
+
+    // Set initial query and navigate
+    act(() => {
+      result.current.setQuery('original');
+    });
+    simulateKeyPress({ upArrow: true }); // -> msg3
+    expect(result.current.query).toBe('msg3');
+
+    // Reset
+    act(() => {
+      result.current.resetHistoryNav();
+    });
+
+    // Press down - should restore original query ('original') because nav was reset
+    // However, our current resetHistoryNav also clears originalQueryBeforeNav.
+    // Let's test that down does nothing because historyIndex is -1
+    simulateKeyPress({ downArrow: true });
+    expect(result.current.query).toBe('msg3'); // Stays msg3 because downArrow doesn't run when index is -1
+
+    // Press up - should start nav again from the top
+    simulateKeyPress({ upArrow: true });
+    expect(result.current.query).toBe('msg3');
+  });
+
+  test('should not trigger callback if isActive is false', () => {
+    renderHook(() =>
+      useInputHistory({ userMessages: mockUserMessages, isActive: false }),
+    );
+    // mockUseInputCallback should be undefined because isActive was false
+    expect(mockUseInputCallback).toBeUndefined();
+    // Attempting to simulate should not throw error (or check internal state if possible)
+    expect(() => simulateKeyPress({ upArrow: true })).not.toThrow();
+  });
+});