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

// Mock time utils to avoid timezone issues in tests
vi.mock('../../../src/utils/time', () => ({
  toLocalDatetimeInputValue: vi.fn((d) => d.toISOString().slice(0, 16)),
  toUTCFromLocalInput: vi.fn((val) => val), // simple identity for testing
}));

describe('TimeAdjuster', () => {
  const onChange = vi.fn();

  beforeEach(() => {
    vi.clearAllMocks();
  });

  it('renders with default value if provided', () => {
    const defaultValue = '2024-01-01T12:00';
    render(<TimeAdjuster onTimeChange={onChange} defaultValue={defaultValue} />);

    const input = screen.getByLabelText(/Time/i) as HTMLInputElement;
    expect(input.value).toBe(defaultValue);
  });

  it('calls onTimeChange when input value changes', async () => {
    render(<TimeAdjuster onTimeChange={onChange} />);

    const input = screen.getByLabelText(/Time/i) as HTMLInputElement;
    fireEvent.change(input, { target: { value: '2024-01-01T13:00' } });

    expect(onChange).toHaveBeenLastCalledWith('2024-01-01T12:00:00.000Z');
  });

  it('resets to now when reset button is clicked', () => {
    const mockNow = new Date('2024-01-01T10:00:00');
    vi.useFakeTimers();
    vi.setSystemTime(mockNow);

    render(<TimeAdjuster onTimeChange={onChange} />);
    
    const resetButton = screen.getByText(/Reset to now/i);
    fireEvent.click(resetButton);

    const input = screen.getByLabelText(/Time/i) as HTMLInputElement;
    // The component calls toLocalDatetimeInputValue(new Date())
    // Our mock returns the iso string slice.
    expect(input.value).toBe('2024-01-01T10:00');
    expect(onChange).toHaveBeenCalled();

    vi.useRealTimers();
  });
});