import { describe, it, expect, vi } from 'vitest';
import { render, screen, fireEvent } from '@testing-library/react';
import '@testing-library/jest-dom';
import TimeAdjuster from '../../src/components/tracker/TimeAdjuster';

describe('TimeAdjuster', () => {
  it('renders with default value', () => {
    const { container } = render(<TimeAdjuster onTimeChange={() => {}} />);
    const input = container.querySelector('input'); 
    expect(input).toBeInTheDocument();
  });

  it('calls onTimeChange when value changes', () => {
    const handleChange = vi.fn();
    const { container } = render(<TimeAdjuster onTimeChange={handleChange} />);
    const input = container.querySelector('input');
    
    vi.clearAllMocks();
    
    fireEvent.change(input!, { target: { value: '2024-01-01T12:00' } });
    expect(handleChange).toHaveBeenCalledWith(new Date('2024-01-01T12:00').toISOString());
  });

  it('resets to now when reset button is clicked', async () => {
    const handleChange = vi.fn();
    render(<TimeAdjuster onTimeChange={handleChange} />);
    const resetButton = screen.getByText(/Reset to now/i);
    
    fireEvent.click(resetButton);
    expect(handleChange).toHaveBeenCalled();
  });

  it('handles invalid date input gracefully (returns empty string)', async () => {
    // Since we changed the implementation, it should no longer throw.
    // We can't easily test the useEffect error anymore because it doesn't throw,
    // but we can check if onTimeChange is called with "" for invalid input.
    const handleChange = vi.fn();
    const { container } = render(<TimeAdjuster onTimeChange={handleChange} />);
    const input = container.querySelector('input');

    fireEvent.change(input!, { target: { value: '2026-06-0' } });
    // We might need to wait for the effect
    await new Promise((r) => setTimeout(r, 0));
    expect(handleChange).toHaveBeenCalledWith("");
  });
});