import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest'
import { renderHook, act } from '@testing-library/react'
import {
  useShowWeekNumbers,
  getLastLeaveType,
  setLastLeaveType,
} from './useCalendarPreferences'

const SHOW_WEEK_NUMBERS_KEY = 'calendar_show_week_numbers'
const LAST_LEAVE_TYPE_KEY = 'calendar_last_leave_type'

// Node's own experimental `localStorage`/`sessionStorage` globals (active in
// newer Node runtimes without a valid --localstorage-file) shadow jsdom's
// working implementation and throw on every call. Stub a real in-memory
// Storage for these tests, matching the idiom used in WorkspaceContext.test.tsx.
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
    },
  }
}

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

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

  it('defaults to false when nothing is stored', () => {
    const { result } = renderHook(() => useShowWeekNumbers())
    expect(result.current[0]).toBe(false)
  })

  it('reads the persisted value on mount', () => {
    localStorage.setItem(SHOW_WEEK_NUMBERS_KEY, 'true')
    const { result } = renderHook(() => useShowWeekNumbers())
    expect(result.current[0]).toBe(true)
  })

  it('treats any non-"true" stored value as false', () => {
    localStorage.setItem(SHOW_WEEK_NUMBERS_KEY, 'garbage')
    const { result } = renderHook(() => useShowWeekNumbers())
    expect(result.current[0]).toBe(false)
  })

  it('persists the new value and updates state when the setter is called', () => {
    const { result } = renderHook(() => useShowWeekNumbers())

    act(() => {
      result.current[1](true)
    })

    expect(localStorage.getItem(SHOW_WEEK_NUMBERS_KEY)).toBe('true')
    expect(result.current[0]).toBe(true)

    act(() => {
      result.current[1](false)
    })

    expect(localStorage.getItem(SHOW_WEEK_NUMBERS_KEY)).toBe('false')
    expect(result.current[0]).toBe(false)
  })

  it('syncs across instances via the custom preferences-changed event', () => {
    const { result: a } = renderHook(() => useShowWeekNumbers())
    const { result: b } = renderHook(() => useShowWeekNumbers())

    act(() => {
      a.current[1](true)
    })

    expect(b.current[0]).toBe(true)
  })

  it('syncs across tabs via the native storage event', () => {
    const { result } = renderHook(() => useShowWeekNumbers())

    act(() => {
      window.dispatchEvent(
        new StorageEvent('storage', { key: SHOW_WEEK_NUMBERS_KEY, newValue: 'true' }),
      )
    })

    expect(result.current[0]).toBe(true)
  })

  it('ignores storage events for unrelated keys', () => {
    const { result } = renderHook(() => useShowWeekNumbers())

    act(() => {
      window.dispatchEvent(
        new StorageEvent('storage', { key: 'some_other_key', newValue: 'true' }),
      )
    })

    expect(result.current[0]).toBe(false)
  })

  it('removes its listeners on unmount', () => {
    const removeSpy = vi.spyOn(window, 'removeEventListener')
    const { unmount } = renderHook(() => useShowWeekNumbers())

    unmount()

    expect(removeSpy).toHaveBeenCalledWith('storage', expect.any(Function))
    expect(removeSpy).toHaveBeenCalledWith('calendar:preferences-changed', expect.any(Function))
    removeSpy.mockRestore()
  })
})

describe('getLastLeaveType / setLastLeaveType', () => {
  beforeEach(() => {
    vi.stubGlobal('sessionStorage', createStorageMock())
  })

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

  it('returns null when nothing is stored', () => {
    expect(getLastLeaveType()).toBeNull()
  })

  it('returns null when the stored value is not a valid leave type', () => {
    sessionStorage.setItem(LAST_LEAVE_TYPE_KEY, 'not-a-real-type')
    expect(getLastLeaveType()).toBeNull()
  })

  it('round-trips a valid leave type', () => {
    setLastLeaveType('vacation')
    expect(sessionStorage.getItem(LAST_LEAVE_TYPE_KEY)).toBe('vacation')
    expect(getLastLeaveType()).toBe('vacation')
  })

  it('accepts every valid leave type', () => {
    for (const type of ['sjukpenning', 'lagsta', 'vacation'] as const) {
      setLastLeaveType(type)
      expect(getLastLeaveType()).toBe(type)
    }
  })
})