import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest'
import { render, screen, fireEvent, waitFor } from '@testing-library/react'
import { Settings } from './Settings'
import * as hooks from '@/hooks'
import { useWorkspace } from '@/context'
import * as api from '@/services/api'
import { ApiRequestError } from '@/services/errors'
import { LanguageProvider } from '@/i18n'
import {
  makeWorkspaceContextValue,
  makeWorkspaceMembersResult,
  makeVacationDaysResult,
  makeShowWeekNumbersTuple,
  makeChildSettingsResult,
  makeDayOverridesResult,
  makeCalendarDaysResult,
  makeParentalLeaveFetch,
  makeTierData,
} from '../../tests/fixtures'

vi.mock('@/hooks')
vi.mock('@/context')
vi.mock('@/services/api')

// Layout pulls in useAuth/useNavigate, which need a full AuthProvider/Router tree
// to work. Settings.tsx only cares that its content renders inside Layout, so
// stub Layout out — same pattern used by Calendar.test.tsx.
vi.mock('@/components/layout/Layout', () => ({
  Layout: ({ children }: { children: React.ReactNode }) => <div>{children}</div>,
}))

function renderSettings() {
  return render(<Settings />)
}

// The language selector tests exercise real locale switching, which needs an
// actual <LanguageProvider> in the tree (the other tests in this file render
// Settings unwrapped and get the i18n module's non-reactive default context,
// which is fine since they never touch the locale).
function renderSettingsWithLanguageProvider() {
  return render(
    <LanguageProvider>
      <Settings />
    </LanguageProvider>,
  )
}

const CURRENT_YEAR = new Date().getFullYear()
// Turns 4 three years from now -> vacation table should span CURRENT_YEAR..CURRENT_YEAR+3
const CHILD_BIRTH_DATE = `${CURRENT_YEAR - 1}-01-01`

describe('Settings', () => {

  const mockVacationDays = [
    {
      id: 'vd-1',
      personalDataUuid: 'pd-1',
      workspaceId: 'ws-1',
      year: CURRENT_YEAR,
      totalDays: 10,
      savedDaysIn: 2,
      createdAt: '2026-01-01T00:00:00',
      updatedAt: '2026-01-01T00:00:00',
    },
  ]

  const mockChildDetails = {
    id: 'c-1',
    workspaceId: 'ws-1',
    name: 'Child 1',
    birthDate: CHILD_BIRTH_DATE,
    preschoolStartDate: null,
    preschoolPlanningDaysPerYear: 6,
    createdAt: '2026-01-01T00:00:00',
  }

  const selfMember = {
    uuid: 'pd-1',
    workspaceId: 'ws-1',
    name: 'Test Parent',
    salaryType: 'monthly' as const,
    employmentStatus: 'employed' as const,
    createdAt: '2026-01-01T00:00:00',
  }

  const partnerMember = {
    uuid: 'pd-2',
    workspaceId: 'ws-1',
    name: 'Sam',
    salaryType: 'monthly' as const,
    employmentStatus: 'employed' as const,
    createdAt: '2026-01-01T00:00:00',
  }

  let mockUpsertVacationDays: ReturnType<typeof vi.fn>
  let mockUpdateChildDetails: ReturnType<typeof vi.fn>
  let mockUpsertDayOverride: ReturnType<typeof vi.fn>
  let mockRemoveDayOverride: ReturnType<typeof vi.fn>
  let mockRefreshMembers: ReturnType<typeof vi.fn>

  const mockCalendarWindow = {
    startYear: CURRENT_YEAR,
    endYear: CURRENT_YEAR + 3,
    minYear: 2026,
    maxYear: 2035,
    days: [],
  }

  beforeEach(() => {
    vi.clearAllMocks()
    mockUpsertVacationDays = vi.fn().mockResolvedValue(undefined)
    mockUpdateChildDetails = vi.fn().mockResolvedValue(undefined)
    mockUpsertDayOverride = vi.fn().mockResolvedValue(undefined)
    mockRemoveDayOverride = vi.fn().mockResolvedValue(undefined)
    mockRefreshMembers = vi.fn().mockResolvedValue(undefined)

    vi.mocked(useWorkspace).mockReturnValue(
      makeWorkspaceContextValue({
        workspace: {
          id: 'ws-1',
          name: 'Test Workspace',
          createdAt: '2026-01-01',
        },
        workspaceId: 'ws-1',
        children: [{ id: 'c-1', name: 'Child 1', birth_date: CHILD_BIRTH_DATE }],
        selectedChildId: 'c-1',
        personalDataUuid: 'pd-1',
        parentName: 'Test Parent',
      })
    )
    // Default: solo workspace (only the logged-in user) — the add-partner
    // form should be visible. Tests that need a linked partner override this.
    vi.mocked(hooks.useWorkspaceMembers).mockReturnValue(
      makeWorkspaceMembersResult({
        data: [selfMember],
        refresh: mockRefreshMembers,
      })
    )
    vi.mocked(hooks.useVacationDays).mockReturnValue(
      makeVacationDaysResult({
        data: mockVacationDays,
        upsert: mockUpsertVacationDays,
      })
    )
    vi.mocked(hooks.useShowWeekNumbers).mockReturnValue(makeShowWeekNumbersTuple(false, vi.fn()))
    vi.mocked(hooks.useChildSettings).mockReturnValue(
      makeChildSettingsResult({
        data: mockChildDetails,
        update: mockUpdateChildDetails,
      })
    )
    vi.mocked(hooks.useDayOverrides).mockReturnValue(
      makeDayOverridesResult({
        data: [],
        upsert: mockUpsertDayOverride,
        remove: mockRemoveDayOverride,
      })
    )
    vi.mocked(hooks.useCalendarDays).mockReturnValue(
      makeCalendarDaysResult({
        data: mockCalendarWindow,
      })
    )
    vi.mocked(api.updateParentSettings).mockResolvedValue({
      uuid: 'pd-1',
      name: 'Test Parent',
      salary_type: 'monthly',
      employment_status: 'employed',
    })
    vi.mocked(api.addPartner).mockResolvedValue({
      uuid: 'pd-2',
      name: 'Sam',
      salary_type: 'monthly',
      employment_status: 'employed',
    })
    vi.mocked(api.renameWorkspaceParent).mockResolvedValue(partnerMember)
    vi.mocked(api.removeWorkspaceParent).mockResolvedValue(undefined)
    // Default: nothing saved yet for whoever's balance form gets opened —
    // `useLatestBalance` (a real hook, imported directly by Settings.tsx to
    // bypass the `vi.mock('@/hooks')` above) falls back to the form's
    // preset. Tests that care about a saved balance override this.
    vi.mocked(api.getParentalLeave).mockResolvedValue(null)
  })

  it('renders loading spinner while workspace loads', () => {
    vi.mocked(useWorkspace).mockReturnValue(
      makeWorkspaceContextValue({
        workspace: {
          id: 'ws-1',
          name: 'Test Workspace',
          createdAt: '2026-01-01',
        },
        workspaceId: 'ws-1',
        children: [{ id: 'c-1', name: 'Child 1', birth_date: CHILD_BIRTH_DATE }],
        selectedChildId: 'c-1',
        personalDataUuid: 'pd-1',
        parentName: 'Test Parent',
        isLoading: true,
      })
    )
    renderSettings()
    expect(screen.getByText(/Laddar inställningar/)).toBeInTheDocument()
  })

  it('renders consistently Swedish section headings', () => {
    renderSettings()
    expect(screen.getByRole('heading', { name: 'Barn' })).toBeInTheDocument()
    expect(screen.getByRole('heading', { name: 'Din profil' })).toBeInTheDocument()
    expect(screen.getByRole('heading', { name: 'Partner' })).toBeInTheDocument()
    expect(screen.getByRole('heading', { name: 'Semesterdagar' })).toBeInTheDocument()
    expect(screen.getByRole('heading', { name: 'Kalender' })).toBeInTheDocument()
    expect(screen.getByRole('heading', { name: 'Undantag i kalendern' })).toBeInTheDocument()
    expect(screen.getByRole('heading', { name: 'Röda dagar' })).toBeInTheDocument()
  })

  it('renders the partner section where the removed planning-mode selector used to be, right after the profile section, and never renders a planning-mode selector', () => {
    renderSettings()
    const headings = screen.getAllByRole('heading', { level: 2 }).map((h) => h.textContent)
    const profileIndex = headings.indexOf('Din profil')
    const partnerIndex = headings.indexOf('Partner')
    const vacationIndex = headings.indexOf('Semesterdagar')
    expect(profileIndex).toBeGreaterThanOrEqual(0)
    expect(partnerIndex).toBe(profileIndex + 1)
    expect(vacationIndex).toBe(partnerIndex + 1)
    expect(screen.queryByTestId('planning-mode-selector')).not.toBeInTheDocument()
    expect(screen.queryByRole('heading', { name: 'Planering' })).not.toBeInTheDocument()
  })

  describe('vacation days table', () => {
    it('renders one row per year from the current year through the year the child turns 4', () => {
      renderSettings()
      for (let year = CURRENT_YEAR; year <= CURRENT_YEAR + 3; year++) {
        expect(screen.getByTestId(`vacation-year-row-${year}`)).toBeInTheDocument()
      }
      expect(screen.queryByTestId(`vacation-year-row-${CURRENT_YEAR + 4}`)).not.toBeInTheDocument()
    })

    it('prefills a year that already has saved data', () => {
      renderSettings()
      const totalInput = screen.getByTestId(`vacation-total-days-${CURRENT_YEAR}`) as HTMLInputElement
      const savedInput = screen.getByTestId(`vacation-saved-days-${CURRENT_YEAR}`) as HTMLInputElement
      expect(totalInput.value).toBe('10')
      expect(savedInput.value).toBe('2')
    })

    it('defaults a year with no saved data to 25 vacation days', () => {
      renderSettings()
      const totalInput = screen.getByTestId(`vacation-total-days-${CURRENT_YEAR + 1}`) as HTMLInputElement
      expect(totalInput.value).toBe('25')
    })

    it('saves the edited year with its total days when Spara is clicked', async () => {
      renderSettings()
      const year = CURRENT_YEAR + 1
      const totalInput = screen.getByTestId(`vacation-total-days-${year}`)
      fireEvent.change(totalInput, { target: { value: '30' } })
      fireEvent.click(screen.getByTestId(`vacation-save-${year}`))

      await waitFor(() =>
        expect(mockUpsertVacationDays).toHaveBeenCalledWith({
          personalDataUuid: 'pd-1',
          workspaceId: 'ws-1',
          year,
          totalDays: 30,
          savedDaysIn: 0,
        }),
      )
    })

    it('saves saved-days-in alongside total days', async () => {
      renderSettings()
      const savedInput = screen.getByTestId(`vacation-saved-days-${CURRENT_YEAR}`)
      fireEvent.change(savedInput, { target: { value: '7' } })
      fireEvent.click(screen.getByTestId(`vacation-save-${CURRENT_YEAR}`))

      await waitFor(() =>
        expect(mockUpsertVacationDays).toHaveBeenCalledWith({
          personalDataUuid: 'pd-1',
          workspaceId: 'ws-1',
          year: CURRENT_YEAR,
          totalDays: 10,
          savedDaysIn: 7,
        }),
      )
    })
  })

  describe('child settings', () => {
    it('prefills birth date and preschool planning days from the child', () => {
      renderSettings()
      const birthInput = screen.getByTestId('birth-date-input') as HTMLInputElement
      const preschoolInput = screen.getByTestId('vacation-days-field') as HTMLInputElement
      expect(birthInput.value).toBe(CHILD_BIRTH_DATE)
      expect(preschoolInput.value).toBe('6')
    })

    it('saves birth date and preschool planning days together', async () => {
      renderSettings()
      const preschoolInput = screen.getByTestId('vacation-days-field')
      fireEvent.change(preschoolInput, { target: { value: '10' } })
      fireEvent.click(screen.getByTestId('save-child-button'))

      await waitFor(() =>
        expect(mockUpdateChildDetails).toHaveBeenCalledWith({
          birthDate: CHILD_BIRTH_DATE,
          preschoolPlanningDaysPerYear: 10,
        }),
      )
    })
  })

  it('saves parent profile fields', async () => {
    renderSettings()
    fireEvent.change(screen.getByTestId('salary-type'), { target: { value: 'monthly' } })
    fireEvent.change(screen.getByTestId('employment-status'), { target: { value: 'employed' } })
    fireEvent.click(screen.getByTestId('save-parent-button'))

    await waitFor(() =>
      expect(api.updateParentSettings).toHaveBeenCalledWith('pd-1', {
        salary_type: 'monthly',
        employment_status: 'employed',
      }),
    )
  })

  it('adds a partner', async () => {
    renderSettings()
    fireEvent.change(screen.getByPlaceholderText('Partnerns namn'), { target: { value: 'Partner Name' } })
    fireEvent.click(screen.getByTestId('add-partner-button'))

    await waitFor(() => expect(api.addPartner).toHaveBeenCalledWith('ws-1', 'Partner Name'))
    await waitFor(() => expect(mockRefreshMembers).toHaveBeenCalled())
  })

  it('shows an add-partner error without a raw message_key when the name is rejected', async () => {
    vi.mocked(api.addPartner).mockRejectedValue(
      new ApiRequestError(422, {
        code: 'workspace.parents.invalidName',
        message: 'workspace.parents.invalidName',
        details: { messageKey: 'workspace.parents.invalidName', data: {} },
      }),
    )
    renderSettings()
    fireEvent.change(screen.getByPlaceholderText('Partnerns namn'), { target: { value: 'X' } })
    fireEvent.click(screen.getByTestId('add-partner-button'))

    const message = await screen.findByTestId('save-message')
    expect(message).toHaveTextContent('Partnerns namn är ogiltigt.')
  })

  describe('parent balance ("Dagar kvar")', () => {
    it('opens the balance form for a solo workspace with a 480-day total', async () => {
      renderSettings()
      fireEvent.click(screen.getByTestId('settings-balance-pd-1'))
      expect(await screen.findByText('Dina dagar kvar')).toBeInTheDocument()
    })

    it('prefills the form with the parent\'s saved balance instead of the preset', async () => {
      vi.mocked(api.getParentalLeave).mockResolvedValue(
        makeParentalLeaveFetch({
          personalDataUuid: 'pd-1',
          childId: 'c-1',
          dubbeldagarLeft: 12,
          reservedDaysLeft: 34,
          tierData: makeTierData({ sjukpenningLeft: 111, lagstaNivaLeft: 22 }),
        }),
      )
      renderSettings()

      fireEvent.click(screen.getByTestId('settings-balance-pd-1'))

      expect(await screen.findByText('Dina dagar kvar')).toBeInTheDocument()
      expect((screen.getByLabelText(/Sjukpenningnivå/) as HTMLInputElement).value).toBe('111')
      expect((screen.getByLabelText(/Lägstanivå/) as HTMLInputElement).value).toBe('22')
      expect((screen.getByLabelText(/Dubbeldagar/) as HTMLInputElement).value).toBe('12')
    })

    it('falls back to the preset when the parent has no saved balance yet', async () => {
      vi.mocked(api.getParentalLeave).mockResolvedValue(null)
      renderSettings()

      fireEvent.click(screen.getByTestId('settings-balance-pd-1'))

      expect(await screen.findByText('Dina dagar kvar')).toBeInTheDocument()
      // Solo workspace -> 480-day preset, split 390:90.
      expect((screen.getByLabelText(/Sjukpenningnivå/) as HTMLInputElement).value).toBe('390')
      expect((screen.getByLabelText(/Lägstanivå/) as HTMLInputElement).value).toBe('90')
    })

    it("falls back to the workspace's first child when no child is selected yet", async () => {
      vi.mocked(useWorkspace).mockReturnValue(
        makeWorkspaceContextValue({
          workspace: { id: 'ws-1', name: 'Test Workspace', createdAt: '2026-01-01' },
          workspaceId: 'ws-1',
          children: [{ id: 'c-9', name: 'Child 9', birth_date: CHILD_BIRTH_DATE }],
          selectedChildId: null,
          personalDataUuid: 'pd-1',
          parentName: 'Test Parent',
        })
      )
      renderSettings()

      fireEvent.click(screen.getByTestId('settings-balance-pd-1'))
      await screen.findByText('Dina dagar kvar')
      const saveButtons = screen.getAllByRole('button', { name: 'Spara' })
      fireEvent.click(saveButtons[saveButtons.length - 1]!)

      await waitFor(() =>
        expect(api.saveManualFetch).toHaveBeenCalledWith(
          expect.objectContaining({ personalDataUuid: 'pd-1', workspaceId: 'ws-1', childId: 'c-9', source: 'manual' })
        )
      )
    })

    it('does nothing when there is no child to attach the balance to', async () => {
      vi.mocked(useWorkspace).mockReturnValue(
        makeWorkspaceContextValue({
          workspace: { id: 'ws-1', name: 'Test Workspace', createdAt: '2026-01-01' },
          workspaceId: 'ws-1',
          children: [],
          selectedChildId: null,
          personalDataUuid: 'pd-1',
          parentName: 'Test Parent',
        })
      )
      renderSettings()

      fireEvent.click(screen.getByTestId('settings-balance-pd-1'))
      await screen.findByText('Dina dagar kvar')
      const saveButtons = screen.getAllByRole('button', { name: 'Spara' })
      fireEvent.click(saveButtons[saveButtons.length - 1]!)

      expect(api.saveManualFetch).not.toHaveBeenCalled()
    })

    it('shows an error when saving a balance fails', async () => {
      vi.mocked(api.saveManualFetch).mockRejectedValue(new Error('balance save failed'))
      renderSettings()

      fireEvent.click(screen.getByTestId('settings-balance-pd-1'))
      await screen.findByText('Dina dagar kvar')
      const saveButtons = screen.getAllByRole('button', { name: 'Spara' })
      fireEvent.click(saveButtons[saveButtons.length - 1]!)

      expect(await screen.findByText('balance save failed')).toBeInTheDocument()
    })
  })

  describe('workspace members', () => {
    beforeEach(() => {
      vi.mocked(hooks.useWorkspaceMembers).mockReturnValue(
        makeWorkspaceMembersResult({
          data: [selfMember, partnerMember],
          refresh: mockRefreshMembers,
        })
      )
    })

    it('shows the linked partner and hides the add-partner form', () => {
      renderSettings()
      expect(screen.getByTestId('member-name-pd-2')).toHaveTextContent('Sam')
      expect(screen.queryByTestId('add-partner-button')).not.toBeInTheDocument()
    })

    it('shows a "you" badge on the logged-in user\'s own row', () => {
      renderSettings()
      expect(screen.getByTestId('member-name-pd-1')).toHaveTextContent('Test Parent')
      expect(screen.getByTestId('member-name-pd-1')).toHaveTextContent('(Du)')
    })

    it('does not offer a remove button on the logged-in user\'s own row', () => {
      renderSettings()
      expect(screen.queryByTestId('remove-button-pd-1')).not.toBeInTheDocument()
    })

    it('renames a member and refreshes the member list', async () => {
      renderSettings()
      fireEvent.click(screen.getByTestId('rename-button-pd-2'))
      fireEvent.change(screen.getByTestId('rename-input-pd-2'), { target: { value: 'Samuel' } })
      fireEvent.click(screen.getByTestId('rename-save-pd-2'))

      await waitFor(() =>
        expect(api.renameWorkspaceParent).toHaveBeenCalledWith('ws-1', 'pd-2', 'Samuel'),
      )
      await waitFor(() => expect(mockRefreshMembers).toHaveBeenCalled())
    })

    it('allows renaming the logged-in user\'s own profile too', () => {
      renderSettings()
      fireEvent.click(screen.getByTestId('rename-button-pd-1'))
      expect(screen.getByTestId('rename-input-pd-1')).toBeInTheDocument()
    })

    it('cancels a rename without calling the API', () => {
      renderSettings()
      fireEvent.click(screen.getByTestId('rename-button-pd-2'))
      fireEvent.change(screen.getByTestId('rename-input-pd-2'), { target: { value: 'Something else' } })
      fireEvent.click(screen.getByTestId('rename-cancel-pd-2'))

      expect(screen.queryByTestId('rename-input-pd-2')).not.toBeInTheDocument()
      expect(api.renameWorkspaceParent).not.toHaveBeenCalled()
    })

    it('requires an in-app confirmation before removing a member', async () => {
      renderSettings()
      fireEvent.click(screen.getByTestId('remove-button-pd-2'))

      expect(api.removeWorkspaceParent).not.toHaveBeenCalled()
      expect(screen.getByTestId('remove-confirm-pd-2')).toBeInTheDocument()

      fireEvent.click(screen.getByTestId('remove-confirm-pd-2'))
      await waitFor(() =>
        expect(api.removeWorkspaceParent).toHaveBeenCalledWith('ws-1', 'pd-2'),
      )
    })

    it('cancelling the remove confirmation does not call the API', () => {
      renderSettings()
      fireEvent.click(screen.getByTestId('remove-button-pd-2'))
      fireEvent.click(screen.getByTestId('remove-cancel-pd-2'))

      expect(screen.queryByTestId('remove-confirm-pd-2')).not.toBeInTheDocument()
      expect(api.removeWorkspaceParent).not.toHaveBeenCalled()
    })

    it('refreshes the member list after a successful removal', async () => {
      renderSettings()
      fireEvent.click(screen.getByTestId('remove-button-pd-2'))
      fireEvent.click(screen.getByTestId('remove-confirm-pd-2'))

      await waitFor(() => expect(mockRefreshMembers).toHaveBeenCalled())
    })

    it('shows the has-login refusal without a raw message_key', async () => {
      vi.mocked(api.removeWorkspaceParent).mockRejectedValue(
        new ApiRequestError(422, {
          code: 'workspace.parents.remove.hasLogin',
          message: 'workspace.parents.remove.hasLogin',
          details: { messageKey: 'workspace.parents.remove.hasLogin', data: {} },
        }),
      )
      renderSettings()
      fireEvent.click(screen.getByTestId('remove-button-pd-2'))
      fireEvent.click(screen.getByTestId('remove-confirm-pd-2'))

      const message = await screen.findByTestId('member-action-error-pd-2')
      expect(message).toHaveTextContent('den här personen har ett eget konto och egen inloggning')
      expect(message).not.toHaveTextContent('workspace.parents.remove.hasLogin')
    })

    it('names each blocker on a hasDependentData refusal, not a raw message_key', async () => {
      vi.mocked(api.removeWorkspaceParent).mockRejectedValue(
        new ApiRequestError(422, {
          code: 'workspace.parents.remove.hasDependentData',
          message: 'workspace.parents.remove.hasDependentData',
          details: {
            messageKey: 'workspace.parents.remove.hasDependentData',
            data: { blockers: ['leave_wishes', 'planned_leave'] },
          },
        }),
      )
      renderSettings()
      fireEvent.click(screen.getByTestId('remove-button-pd-2'))
      fireEvent.click(screen.getByTestId('remove-confirm-pd-2'))

      const message = await screen.findByTestId('member-action-error-pd-2')
      expect(message).toHaveTextContent('önskemål om ledighet')
      expect(message).toHaveTextContent('planerade lediga dagar')
      expect(message).not.toHaveTextContent('hasDependentData')
    })

    it('shows the remove-self refusal without a raw message_key', async () => {
      // Defence in depth: the UI never renders a remove button for the
      // caller's own row, but the handler still routes a self-removal
      // refusal from the backend through the same safe error mapping.
      vi.mocked(api.removeWorkspaceParent).mockRejectedValue(
        new ApiRequestError(422, {
          code: 'workspace.parents.remove.self',
          message: 'workspace.parents.remove.self',
          details: { messageKey: 'workspace.parents.remove.self', data: {} },
        }),
      )
      renderSettings()
      fireEvent.click(screen.getByTestId('remove-button-pd-2'))
      fireEvent.click(screen.getByTestId('remove-confirm-pd-2'))

      const message = await screen.findByTestId('member-action-error-pd-2')
      expect(message).not.toHaveTextContent('workspace.parents.remove.self')
    })

    it('opens the balance form for the clicked member and saves with that member\'s uuid', async () => {
      vi.mocked(api.saveManualFetch).mockResolvedValue({
        id: 'plf-1',
        personalDataUuid: 'pd-2',
        workspaceId: 'ws-1',
        childId: 'c-1',
        source: 'manual',
        fetchedAt: '2026-01-01',
        totalDays: 240,
        daysUsed: 0,
        daysLeft: 240,
        reservedDaysTotal: 45,
        reservedDaysLeft: 45,
        transferableDaysLeft: 0,
        dubbeldagarLeft: 60,
        tierData: {
          sjukpenningTotal: 195,
          sjukpenningUsed: 0,
          sjukpenningLeft: 195,
          lagstaNivaTotal: 45,
          lagstaNivaUsed: 0,
          lagstaNivaLeft: 45,
        },
        createdAt: '2026-01-01',
        updatedAt: '2026-01-01',
      })
      renderSettings()

      fireEvent.click(screen.getByTestId('settings-balance-pd-2'))
      expect(await screen.findByText('Sams dagar kvar')).toBeInTheDocument()
      // The vacation-days table above also has per-year "Spara" buttons —
      // the balance form's is the last one rendered (it's mounted at the
      // very end of the page).
      const saveButtons = screen.getAllByRole('button', { name: 'Spara' })
      fireEvent.click(saveButtons[saveButtons.length - 1]!)

      await waitFor(() =>
        expect(api.saveManualFetch).toHaveBeenCalledWith(
          expect.objectContaining({ personalDataUuid: 'pd-2', workspaceId: 'ws-1', childId: 'c-1', source: 'manual' })
        )
      )
    })

    it('opens the balance form for the logged-in user\'s own row too', async () => {
      renderSettings()

      fireEvent.click(screen.getByTestId('settings-balance-pd-1'))
      expect(await screen.findByText('Dina dagar kvar')).toBeInTheDocument()
    })
  })

  it('toggles week numbers', () => {
    const setShowWeekNumbers = vi.fn()
    vi.mocked(hooks.useShowWeekNumbers).mockReturnValue(makeShowWeekNumbersTuple(false, setShowWeekNumbers))
    renderSettings()
    fireEvent.click(screen.getByTestId('show-week-numbers-checkbox'))
    expect(setShowWeekNumbers).toHaveBeenCalledWith(true)
  })

  describe('take PL on red days', () => {
    it('renders unchecked by default', () => {
      renderSettings()
      expect(screen.getByTestId('take-pl-on-red-days-checkbox')).not.toBeChecked()
    })

    it('renders checked when the workspace has it enabled', () => {
      vi.mocked(useWorkspace).mockReturnValue(
        makeWorkspaceContextValue({
          workspace: {
            id: 'ws-1',
            name: 'Test Workspace',
            createdAt: '2026-01-01',
            takePlOnRedDays: true,
          },
          workspaceId: 'ws-1',
          children: [{ id: 'c-1', name: 'Child 1', birth_date: CHILD_BIRTH_DATE }],
          selectedChildId: 'c-1',
          personalDataUuid: 'pd-1',
          parentName: 'Test Parent',
        })
      )
      renderSettings()
      expect(screen.getByTestId('take-pl-on-red-days-checkbox')).toBeChecked()
    })

    it('saves the setting and refreshes the workspace context on toggle', async () => {
      vi.mocked(api.updateWorkspace).mockResolvedValue({
        id: 'ws-1',
        name: 'Test Workspace',
        createdAt: '2026-01-01',
        takePlOnRedDays: true,
      })
      const mockRefreshContext = vi.fn().mockResolvedValue(undefined)
      vi.mocked(useWorkspace).mockReturnValue(
        makeWorkspaceContextValue({
          workspace: { id: 'ws-1', name: 'Test Workspace', createdAt: '2026-01-01' },
          workspaceId: 'ws-1',
          children: [{ id: 'c-1', name: 'Child 1', birth_date: CHILD_BIRTH_DATE }],
          selectedChildId: 'c-1',
          personalDataUuid: 'pd-1',
          parentName: 'Test Parent',
          refreshContext: mockRefreshContext,
        })
      )
      renderSettings()

      fireEvent.click(screen.getByTestId('take-pl-on-red-days-checkbox'))

      await waitFor(() =>
        expect(api.updateWorkspace).toHaveBeenCalledWith('ws-1', { takePlOnRedDays: true })
      )
      expect(mockRefreshContext).toHaveBeenCalled()
    })

    it('shows an error message when saving fails', async () => {
      vi.mocked(api.updateWorkspace).mockRejectedValue(new Error('network down'))
      renderSettings()

      fireEvent.click(screen.getByTestId('take-pl-on-red-days-checkbox'))

      expect(await screen.findByTestId('save-message')).toHaveTextContent('network down')
    })
  })

  describe('language selector', () => {
    // Node's own experimental `localStorage` global shadows jsdom's working
    // implementation in this environment and throws on every call — stub a
    // real in-memory Storage, matching the idiom used in
    // WorkspaceContext.test.tsx and useCalendarPreferences.test.ts.
    function createStorageMock(): Storage {
      let store: Record<string, string> = {}
      return {
        getItem: (key: string) => (key in store ? store[key]! : null),
        setItem: (key: string, value: string) => {
          store[key] = value
        },
        removeItem: (key: string) => {
          delete store[key]
        },
        clear: () => {
          store = {}
        },
        key: (index: number) => Object.keys(store)[index] ?? null,
        get length() {
          return Object.keys(store).length
        },
      }
    }

    beforeEach(() => {
      vi.stubGlobal('localStorage', createStorageMock())
    })

    afterEach(() => {
      vi.unstubAllGlobals()
    })

    it('is labelled understandably regardless of the active language', () => {
      renderSettingsWithLanguageProvider()
      expect(screen.getByText('Språk / Language')).toBeInTheDocument()
      expect(screen.getByText('Välj språk / Select language')).toBeInTheDocument()
    })

    it('offers automatic, Swedish, and English options', () => {
      renderSettingsWithLanguageProvider()
      const select = screen.getByTestId('language-select') as HTMLSelectElement
      const optionValues = Array.from(select.options).map((o) => o.value)
      expect(optionValues).toEqual(['auto', 'sv', 'en'])
    })

    it('defaults to "auto" when no explicit preference is stored', () => {
      renderSettingsWithLanguageProvider()
      const select = screen.getByTestId('language-select') as HTMLSelectElement
      expect(select.value).toBe('auto')
    })

    it('switching to English updates the UI immediately, without a reload', () => {
      renderSettingsWithLanguageProvider()
      expect(screen.getByRole('heading', { name: 'Inställningar' })).toBeInTheDocument()

      fireEvent.change(screen.getByTestId('language-select'), { target: { value: 'en' } })

      expect(screen.getByRole('heading', { name: 'Settings' })).toBeInTheDocument()
      expect(screen.queryByRole('heading', { name: 'Inställningar' })).not.toBeInTheDocument()
    })

    it('persists the explicit choice to localStorage', () => {
      renderSettingsWithLanguageProvider()
      fireEvent.change(screen.getByTestId('language-select'), { target: { value: 'en' } })
      expect(localStorage.getItem('language_preference')).toBe('en')
    })

    it('going back to "Automatic" clears the stored preference', () => {
      renderSettingsWithLanguageProvider()
      fireEvent.change(screen.getByTestId('language-select'), { target: { value: 'en' } })
      fireEvent.change(screen.getByTestId('language-select'), { target: { value: 'auto' } })
      expect(localStorage.getItem('language_preference')).toBeNull()
    })
  })

  describe('red days list (§3.8)', () => {
    it('passes the fetched calendar window through to the list, four years at a time', () => {
      vi.mocked(hooks.useCalendarDays).mockReturnValue(
        makeCalendarDaysResult({
          data: {
            startYear: CURRENT_YEAR,
            endYear: CURRENT_YEAR + 3,
            minYear: 2026,
            maxYear: 2035,
            days: [
              {
                date: `${CURRENT_YEAR}-01-01`,
                name: 'Nyårsdagen',
                dayType: 'red_day',
                isOverride: false,
                overrideIsWorkingDay: null,
                isFree: true,
              },
            ],
          },
        })
      )

      renderSettings()

      expect(screen.getByTestId('red-days-range')).toHaveTextContent(`${CURRENT_YEAR}–${CURRENT_YEAR + 3}`)
      expect(screen.getByTestId(`red-days-item-${CURRENT_YEAR}-01-01`)).toHaveTextContent('Nyårsdagen')
    })

    it('requests the next 4-year window when paginating forward', () => {
      renderSettings()

      fireEvent.click(screen.getByTestId('red-days-next'))

      expect(hooks.useCalendarDays).toHaveBeenLastCalledWith('ws-1', CURRENT_YEAR + 4, 4)
    })

    it('requests the previous 4-year window when paginating backward', () => {
      // minYear well below the current window so the "previous" button isn't disabled.
      vi.mocked(hooks.useCalendarDays).mockReturnValue(
        makeCalendarDaysResult({
          data: { ...mockCalendarWindow, minYear: 2000 },
        })
      )

      renderSettings()

      fireEvent.click(screen.getByTestId('red-days-prev'))

      expect(hooks.useCalendarDays).toHaveBeenLastCalledWith('ws-1', CURRENT_YEAR - 4, 4)
    })

    it('wires the toggle button through to the shared day-overrides hook', async () => {
      vi.mocked(hooks.useCalendarDays).mockReturnValue(
        makeCalendarDaysResult({
          data: {
            ...mockCalendarWindow,
            days: [
              {
                date: `${CURRENT_YEAR}-01-01`,
                name: 'Nyårsdagen',
                dayType: 'red_day',
                isOverride: false,
                overrideIsWorkingDay: null,
                isFree: true,
              },
            ],
          },
        })
      )

      renderSettings()

      fireEvent.click(screen.getByTestId(`red-days-toggle-${CURRENT_YEAR}-01-01`))

      await waitFor(() => {
        expect(mockUpsertDayOverride).toHaveBeenCalledWith({
          workspaceId: 'ws-1',
          date: `${CURRENT_YEAR}-01-01`,
          isWorkingDay: true,
          note: null,
        })
      })
    })
  })
})