import React from 'react';
import { render, screen, fireEvent, waitFor, within } from '@testing-library/react';
import ExperimentDayView from '../src/pages/ExperimentDayView';

// ── Mocks ──────────────────────────────────────────────────────────────────────

const mockNavigate = jest.fn();
jest.mock('react-router-dom', () => ({
  useParams: jest.fn(),
  useSearchParams: jest.fn(),
  useNavigate: () => mockNavigate,
  Link: ({ to, children, ...props }) => <a href={to} {...props}>{children}</a>,
}));
const { useParams, useSearchParams } = require('react-router-dom');
const { experimentsApi, dailyStatusesApi } = require('../src/api/client');

jest.mock('../src/api/client', () => ({
  experimentsApi: {
    get: jest.fn(),
    getDayStatuses: jest.fn(),
    getCalendar: jest.fn(),
  },
  dailyStatusesApi: {
    update: jest.fn(),
  },
}));

// DailyStatusForm is a complex form component; stub it to keep tests focused
jest.mock('../src/components/DailyStatusForm', () =>
  function MockDailyStatusForm({ onSuccess, onCancel }) {
    return (
      <div data-testid="daily-status-form">
        <button onClick={() => onSuccess({ id: 'updated-id' })}>Submit</button>
        <button onClick={onCancel}>Cancel</button>
      </div>
    );
  }
);

// recharts uses ResizeObserver which is not available in jsdom
jest.mock('recharts', () => ({
  ResponsiveContainer: ({ children }) => <div>{children}</div>,
  BarChart: ({ children }) => <div data-testid="bar-chart">{children}</div>,
  Bar: () => null,
  XAxis: () => null,
  YAxis: () => null,
  CartesianGrid: () => null,
  Tooltip: () => null,
  Legend: () => null,
}));

// ── Fixtures ───────────────────────────────────────────────────────────────────

const EXP_ID   = 'exp-0001-0000-0000-0000-000000000001';
const DATE_STR = '2026-04-23';
const FIELD_ID = 'ww000000-0000-0000-0000-000000000099';

const TEMPLATE = [
  { fieldId: '00000000-0000-0000-0000-000000000001', key: 'vitals',   label: 'Vitals',   type: 'text',     builtin: true,  active: true },
  { fieldId: FIELD_ID,                               key: 'weight',   label: 'Weight',   type: 'text',     builtin: false, active: true  },
  { fieldId: 'zz000000-0000-0000-0000-000000000001', key: 'notes',    label: 'Notes',    type: 'textarea', builtin: true,  active: false },
];

const ANIMALS = [
  { id: 'a1000000-0000-0000-0000-000000000001', animal_name: 'Rat A', animal_id_string: 'R001' },
  { id: 'a2000000-0000-0000-0000-000000000002', animal_name: 'Rat B', animal_id_string: 'R002' },
  { id: 'a3000000-0000-0000-0000-000000000003', animal_name: 'Rat C', animal_id_string: 'R003' },
];

const EXPERIMENT = {
  id: EXP_ID,
  title: 'Reach Task Study',
  template: TEMPLATE,
  animals: ANIMALS,
};

function makeStatus(animalId, overrides = {}) {
  return {
    id: `status-${animalId}`,
    animal_id: animalId,
    date: `${DATE_STR}T00:00:00.000Z`,
    experiment_description: null,
    vitals: null,
    treatment: null,
    notes: null,
    custom_fields: {},
    analysis_summary: null,
    ...overrides,
  };
}

function makeSearchParams(field = FIELD_ID) {
  const params = new URLSearchParams(field ? `field=${field}` : '');
  return [params, jest.fn()];
}

// ── Setup ──────────────────────────────────────────────────────────────────────

beforeEach(() => {
  jest.clearAllMocks();
  useParams.mockReturnValue({ id: EXP_ID, date: DATE_STR });
  useSearchParams.mockReturnValue(makeSearchParams(FIELD_ID));
  experimentsApi.get.mockResolvedValue(EXPERIMENT);
  experimentsApi.getDayStatuses.mockResolvedValue([]);
  experimentsApi.getCalendar.mockResolvedValue({ field: FIELD_ID, days: {} });
  dailyStatusesApi.update.mockResolvedValue({});
});

// ── Loading & error states ────────────────────────────────────────────────────

describe('loading and error states', () => {
  it('shows a loading indicator while data is being fetched', () => {
    experimentsApi.get.mockReturnValue(new Promise(() => {})); // never resolves
    render(<ExperimentDayView />);
    expect(screen.getByText(/loading/i)).toBeInTheDocument();
  });

  it('shows an error message when the API call fails', async () => {
    experimentsApi.get.mockRejectedValue({ message: 'Network error' });
    render(<ExperimentDayView />);
    await waitFor(() => expect(screen.getByText(/network error/i)).toBeInTheDocument());
  });

  it('shows empty state when no data for the day', async () => {
    render(<ExperimentDayView />);
    await waitFor(() =>
      expect(screen.getByText(/no data recorded for this day/i)).toBeInTheDocument()
    );
  });
});

// ── Breadcrumb ────────────────────────────────────────────────────────────────

describe('breadcrumb', () => {
  it('renders dashboard, experiment title, and formatted date', async () => {
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Reach Task Study'));
    expect(screen.getByRole('link', { name: 'Dashboard' })).toHaveAttribute('href', '/');
    expect(screen.getByRole('link', { name: 'Reach Task Study' })).toHaveAttribute('href', `/experiments/${EXP_ID}`);
    expect(screen.getAllByText('April 23, 2026').length).toBeGreaterThan(0);
  });
});

// ── Row filtering by selected field ──────────────────────────────────────────

describe('row filtering', () => {
  it('shows animals that have a non-empty value for the selected field', async () => {
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001', { custom_fields: { [FIELD_ID]: '325' } }),
      makeStatus('a2000000-0000-0000-0000-000000000002', { custom_fields: { [FIELD_ID]: '310' } }),
    ]);
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    expect(screen.getByText('Rat A')).toBeInTheDocument();
    expect(screen.getByText('Rat B')).toBeInTheDocument();
  });

  it('excludes animals whose selected field value is empty', async () => {
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001', { custom_fields: { [FIELD_ID]: '325' } }),
      makeStatus('a2000000-0000-0000-0000-000000000002', { custom_fields: {} }), // no weight
    ]);
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    expect(screen.queryByText('Rat B')).not.toBeInTheDocument();
  });

  it('excludes animals whose selected field value is null', async () => {
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001', { custom_fields: { [FIELD_ID]: null } }),
    ]);
    render(<ExperimentDayView />);
    await waitFor(() =>
      expect(screen.getByText(/no data recorded/i)).toBeInTheDocument()
    );
  });

  it('excludes animals with no status record for that day', async () => {
    // Only Rat A has a status; Rat B and C have no record returned
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001', { custom_fields: { [FIELD_ID]: '325' } }),
    ]);
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    expect(screen.queryByText('Rat B')).not.toBeInTheDocument();
    expect(screen.queryByText('Rat C')).not.toBeInTheDocument();
  });

  it('shows all animals with a status record when no field filter is set', async () => {
    useSearchParams.mockReturnValue(makeSearchParams(null));
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001'),
      makeStatus('a2000000-0000-0000-0000-000000000002'),
    ]);
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    expect(screen.getByText('Rat A')).toBeInTheDocument();
    expect(screen.getByText('Rat B')).toBeInTheDocument();
  });

  it('filters by builtin field (vitals)', async () => {
    useSearchParams.mockReturnValue(makeSearchParams('vitals'));
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001', { vitals: 'HR 72' }),
      makeStatus('a2000000-0000-0000-0000-000000000002', { vitals: null }),
    ]);
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    expect(screen.queryByText('Rat B')).not.toBeInTheDocument();
  });
});

// ── Table structure ───────────────────────────────────────────────────────────

describe('table structure', () => {
  beforeEach(() => {
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001', {
        vitals: 'HR 72',
        custom_fields: { [FIELD_ID]: '325' },
      }),
    ]);
  });

  it('renders a column header for each active template field', async () => {
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    // Active fields: Vitals, Weight. Notes is inactive.
    expect(screen.getByText('Vitals')).toBeInTheDocument();
    expect(screen.getByText('Weight')).toBeInTheDocument();
    expect(screen.queryByText('Notes')).not.toBeInTheDocument();
  });

  it('renders field values in the correct cells', async () => {
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('325'));
    expect(screen.getByText('HR 72')).toBeInTheDocument();
    expect(screen.getByText('325')).toBeInTheDocument();
  });

  it('renders dash for empty field values', async () => {
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001', {
        vitals: null,
        custom_fields: { [FIELD_ID]: '325' },
      }),
    ]);
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    expect(screen.getByText('—')).toBeInTheDocument();
  });

  it('renders the subject name with animal_id_string alongside', async () => {
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    expect(screen.getByText('R001')).toBeInTheDocument();
  });

  it('renders an Edit button for each row', async () => {
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    expect(screen.getByRole('button', { name: /edit/i })).toBeInTheDocument();
  });
});

// ── Subject name navigation ───────────────────────────────────────────────────

describe('subject name click', () => {
  it('navigates to /daily-statuses/:id when subject name is clicked', async () => {
    const statusId = 'status-a1000000-0000-0000-0000-000000000001';
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001', { custom_fields: { [FIELD_ID]: '325' } }),
    ]);
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    fireEvent.click(screen.getByText('Rat A'));
    expect(mockNavigate).toHaveBeenCalledWith(`/daily-statuses/${statusId}`);
  });
});

// ── Edit modal ────────────────────────────────────────────────────────────────

describe('edit modal', () => {
  beforeEach(() => {
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001', { custom_fields: { [FIELD_ID]: '325' } }),
    ]);
  });

  it('opens the edit modal when Edit button is clicked', async () => {
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    fireEvent.click(screen.getByRole('button', { name: /edit/i }));
    await waitFor(() =>
      expect(screen.getByTestId('daily-status-form')).toBeInTheDocument()
    );
  });

  it('closes the edit modal when Cancel is clicked', async () => {
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    fireEvent.click(screen.getByRole('button', { name: /edit/i }));
    await waitFor(() => screen.getByTestId('daily-status-form'));
    fireEvent.click(screen.getByRole('button', { name: /cancel/i }));
    await waitFor(() =>
      expect(screen.queryByTestId('daily-status-form')).not.toBeInTheDocument()
    );
  });

  it('closes the edit modal and updates the row after successful submit', async () => {
    const originalStatus = makeStatus('a1000000-0000-0000-0000-000000000001', {
      custom_fields: { [FIELD_ID]: '325' },
    });
    experimentsApi.getDayStatuses.mockResolvedValue([originalStatus]);
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    fireEvent.click(screen.getByRole('button', { name: /edit/i }));
    await waitFor(() => screen.getByTestId('daily-status-form'));
    // Submit with updated status
    fireEvent.click(screen.getByRole('button', { name: /submit/i }));
    await waitFor(() =>
      expect(screen.queryByTestId('daily-status-form')).not.toBeInTheDocument()
    );
  });
});

// ── Session metrics bar chart ─────────────────────────────────────────────────
//
// Bar chart reads from status.analysis_summary — pre-computed trial-level
// session metrics: { total, counts: { Success, Failure }, success_rate }
// X-axis: animals visible in the table (have non-empty selected field value).
// Hidden when no visible animal has analysis_summary.total > 0.

describe('session metrics bar chart', () => {
  it('renders bar chart when at least one visible animal has analysis_summary', async () => {
    const summary = { total: 18, counts: { Success: 5, Failure: 13 }, success_rate: 0.28 };
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001', {
        custom_fields: { [FIELD_ID]: '325' },
        analysis_summary: summary,
      }),
    ]);
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    expect(screen.getByTestId('bar-chart')).toBeInTheDocument();
  });

  it('hides bar chart when no visible animal has analysis_summary', async () => {
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001', {
        custom_fields: { [FIELD_ID]: '325' },
        analysis_summary: null,
      }),
    ]);
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    expect(screen.queryByTestId('bar-chart')).not.toBeInTheDocument();
  });

  it('hides bar chart when analysis_summary.total is 0', async () => {
    const emptySummary = { total: 0, counts: { Success: 0, Failure: 0 }, success_rate: null };
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001', {
        custom_fields: { [FIELD_ID]: '325' },
        analysis_summary: emptySummary,
      }),
    ]);
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    expect(screen.queryByTestId('bar-chart')).not.toBeInTheDocument();
  });

  it('excludes from chart animals that are filtered out by the selected field', async () => {
    // Rat A: has field value + analysis_summary → in table and chart
    // Rat B: NO field value, has analysis_summary → excluded from both
    const summary = { total: 10, counts: { Success: 7, Failure: 3 }, success_rate: 0.7 };
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001', {
        custom_fields: { [FIELD_ID]: '325' },
        analysis_summary: summary,
      }),
      makeStatus('a2000000-0000-0000-0000-000000000002', {
        custom_fields: {},
        analysis_summary: summary,
      }),
    ]);
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    // Chart still renders because Rat A has data
    expect(screen.getByTestId('bar-chart')).toBeInTheDocument();
    // Rat B not in table
    expect(screen.queryByText('Rat B')).not.toBeInTheDocument();
  });

  it('shows bar chart for multiple animals each with their own analysis_summary', async () => {
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001', {
        custom_fields: { [FIELD_ID]: '325' },
        analysis_summary: { total: 18, counts: { Success: 5, Failure: 13 }, success_rate: 0.28 },
      }),
      makeStatus('a2000000-0000-0000-0000-000000000002', {
        custom_fields: { [FIELD_ID]: '310' },
        analysis_summary: { total: 10, counts: { Success: 7, Failure: 3 }, success_rate: 0.7 },
      }),
    ]);
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    expect(screen.getByText('Rat B')).toBeInTheDocument();
    expect(screen.getByTestId('bar-chart')).toBeInTheDocument();
  });
});

// ── API call parameters ───────────────────────────────────────────────────────

describe('API calls', () => {
  it('calls getDayStatuses with the experiment id and date from the URL', async () => {
    render(<ExperimentDayView />);
    await waitFor(() =>
      expect(experimentsApi.getDayStatuses).toHaveBeenCalledWith(EXP_ID, DATE_STR)
    );
  });

  it('calls experimentsApi.get with the experiment id', async () => {
    render(<ExperimentDayView />);
    await waitFor(() =>
      expect(experimentsApi.get).toHaveBeenCalledWith(EXP_ID)
    );
  });

  it('calls getCalendar with experiment id and selected field for day navigation', async () => {
    render(<ExperimentDayView />);
    await waitFor(() =>
      expect(experimentsApi.getCalendar).toHaveBeenCalledWith(EXP_ID, FIELD_ID)
    );
  });
});

// ── Inline cell editing ───────────────────────────────────────────────────────

describe('inline cell editing', () => {
  const STATUS_ID = 'status-a1000000-0000-0000-0000-000000000001';

  beforeEach(() => {
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001', {
        custom_fields: { [FIELD_ID]: '325' },
        vitals: 'HR 72',
      }),
    ]);
    dailyStatusesApi.update.mockResolvedValue(
      makeStatus('a1000000-0000-0000-0000-000000000001', {
        custom_fields: { [FIELD_ID]: '330' },
        vitals: 'HR 72',
      })
    );
  });

  it('shows an input when a cell value is clicked', async () => {
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('325'));
    fireEvent.click(screen.getByText('325'));
    expect(screen.getByRole('textbox')).toBeInTheDocument();
  });

  it('shows an input when a dash (empty cell) is clicked', async () => {
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('Rat A'));
    // Vitals is shown as "HR 72" but weight is selected, click on a dash cell in vitals column
    // After the status above vitals = 'HR 72' (not empty), let's use a status without vitals
    experimentsApi.getDayStatuses.mockResolvedValue([
      makeStatus('a1000000-0000-0000-0000-000000000001', {
        custom_fields: { [FIELD_ID]: '325' },
        vitals: null,
      }),
    ]);
    // Re-render
    const { unmount } = render(<ExperimentDayView />);
    await waitFor(() => screen.getAllByText('Rat A'));
    const dashCell = screen.getAllByText('—')[0];
    fireEvent.click(dashCell);
    expect(screen.getByRole('textbox')).toBeInTheDocument();
    unmount();
  });

  it('saves a custom field value on Enter key', async () => {
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('325'));
    fireEvent.click(screen.getByText('325'));
    const input = screen.getByRole('textbox');
    fireEvent.change(input, { target: { value: '330' } });
    fireEvent.keyDown(input, { key: 'Enter' });
    await waitFor(() =>
      expect(dailyStatusesApi.update).toHaveBeenCalledWith(
        STATUS_ID,
        expect.objectContaining({ custom_fields: expect.objectContaining({ [FIELD_ID]: '330' }) })
      )
    );
  });

  it('saves on blur', async () => {
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('325'));
    fireEvent.click(screen.getByText('325'));
    const input = screen.getByRole('textbox');
    fireEvent.change(input, { target: { value: '328' } });
    fireEvent.blur(input);
    await waitFor(() =>
      expect(dailyStatusesApi.update).toHaveBeenCalledWith(
        STATUS_ID,
        expect.objectContaining({ custom_fields: expect.objectContaining({ [FIELD_ID]: '328' }) })
      )
    );
  });

  it('cancels edit on Escape without saving', async () => {
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('325'));
    fireEvent.click(screen.getByText('325'));
    const input = screen.getByRole('textbox');
    fireEvent.change(input, { target: { value: '999' } });
    fireEvent.keyDown(input, { key: 'Escape' });
    expect(dailyStatusesApi.update).not.toHaveBeenCalled();
    await waitFor(() => expect(screen.queryByRole('textbox')).not.toBeInTheDocument());
  });

  it('skips the API call when the value is unchanged', async () => {
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('325'));
    fireEvent.click(screen.getByText('325'));
    const input = screen.getByRole('textbox');
    // value unchanged — blur without editing
    fireEvent.blur(input);
    expect(dailyStatusesApi.update).not.toHaveBeenCalled();
  });

  it('saves a builtin field (vitals) with the field key as payload key', async () => {
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText('HR 72'));
    fireEvent.click(screen.getByText('HR 72'));
    const input = screen.getByRole('textbox');
    fireEvent.change(input, { target: { value: 'HR 80' } });
    fireEvent.keyDown(input, { key: 'Enter' });
    await waitFor(() =>
      expect(dailyStatusesApi.update).toHaveBeenCalledWith(
        STATUS_ID,
        expect.objectContaining({ vitals: 'HR 80' })
      )
    );
    // custom_fields must NOT be in the payload for a builtin field
    const payload = dailyStatusesApi.update.mock.calls[0][1];
    expect(payload).not.toHaveProperty('custom_fields');
  });
});

// ── Prev / next day navigation ────────────────────────────────────────────────

describe('prev/next day navigation', () => {
  it('shows no navigation buttons when there are no other days', async () => {
    experimentsApi.getCalendar.mockResolvedValue({
      field: FIELD_ID,
      days: { [DATE_STR]: 2 },
    });
    render(<ExperimentDayView />);
    await waitFor(() => expect(experimentsApi.getCalendar).toHaveBeenCalled());
    expect(screen.queryByText(/← April/)).not.toBeInTheDocument();
    expect(screen.queryByText(/April.*→/)).not.toBeInTheDocument();
  });

  it('shows a previous day button when an earlier day has data', async () => {
    experimentsApi.getCalendar.mockResolvedValue({
      field: FIELD_ID,
      days: { '2026-04-22': 1, [DATE_STR]: 2 },
    });
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText(/April 22, 2026/));
    expect(screen.getByText(/← April 22, 2026/)).toBeInTheDocument();
  });

  it('shows a next day button when a later day has data', async () => {
    experimentsApi.getCalendar.mockResolvedValue({
      field: FIELD_ID,
      days: { [DATE_STR]: 2, '2026-04-24': 1 },
    });
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText(/April 24, 2026/));
    expect(screen.getByText(/April 24, 2026 →/)).toBeInTheDocument();
  });

  it('shows both prev and next buttons when surrounded by days with data', async () => {
    experimentsApi.getCalendar.mockResolvedValue({
      field: FIELD_ID,
      days: { '2026-04-21': 1, [DATE_STR]: 2, '2026-04-25': 3 },
    });
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText(/April 21, 2026/));
    expect(screen.getByText(/← April 21, 2026/)).toBeInTheDocument();
    expect(screen.getByText(/April 25, 2026 →/)).toBeInTheDocument();
  });

  it('navigates to the previous day with the field param preserved', async () => {
    experimentsApi.getCalendar.mockResolvedValue({
      field: FIELD_ID,
      days: { '2026-04-22': 1, [DATE_STR]: 2 },
    });
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText(/← April 22, 2026/));
    fireEvent.click(screen.getByText(/← April 22, 2026/));
    expect(mockNavigate).toHaveBeenCalledWith(
      `/experiments/${EXP_ID}/day/2026-04-22?field=${FIELD_ID}`
    );
  });

  it('navigates to the next day with the field param preserved', async () => {
    experimentsApi.getCalendar.mockResolvedValue({
      field: FIELD_ID,
      days: { [DATE_STR]: 2, '2026-04-24': 1 },
    });
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText(/April 24, 2026 →/));
    fireEvent.click(screen.getByText(/April 24, 2026 →/));
    expect(mockNavigate).toHaveBeenCalledWith(
      `/experiments/${EXP_ID}/day/2026-04-24?field=${FIELD_ID}`
    );
  });

  it('only shows adjacent days, not all days (prev is immediately before in sorted list)', async () => {
    experimentsApi.getCalendar.mockResolvedValue({
      field: FIELD_ID,
      days: { '2026-04-10': 1, '2026-04-20': 2, [DATE_STR]: 3, '2026-04-30': 1 },
    });
    render(<ExperimentDayView />);
    await waitFor(() => screen.getByText(/April 20, 2026/));
    // Prev should be April 20 (immediately before), not April 10
    expect(screen.getByText(/← April 20, 2026/)).toBeInTheDocument();
    expect(screen.queryByText(/April 10/)).not.toBeInTheDocument();
    // Next should be April 30 (immediately after)
    expect(screen.getByText(/April 30, 2026 →/)).toBeInTheDocument();
  });
});
