import { act, renderHook, waitFor } from '@testing-library/react-native'
import { AccessibilityInfo, EmitterSubscription } from 'react-native'
import * as Reanimated from 'react-native-reanimated'
import { useReduceMotion } from '../use_reduce_motion'

type ReduceMotionListener = (enabled: boolean) => void

describe('useReduceMotion', () => {
  let listener: ReduceMotionListener | undefined
  const remove = jest.fn()

  beforeEach(() => {
    listener = undefined
    remove.mockClear()
    jest.spyOn(Reanimated, 'useReducedMotion').mockReturnValue(false)
    jest.spyOn(AccessibilityInfo, 'isReduceMotionEnabled').mockResolvedValue(true)
    const addEventListener: typeof AccessibilityInfo.addEventListener = (_event, handler) => {
      listener = handler as ReduceMotionListener
      return { remove } as unknown as EmitterSubscription
    }
    jest.spyOn(AccessibilityInfo, 'addEventListener').mockImplementation(addEventListener)
  })

  afterEach(() => jest.restoreAllMocks())

  it('seeds synchronously from the launch-time setting', async () => {
    jest.spyOn(Reanimated, 'useReducedMotion').mockReturnValue(true)
    jest.mocked(AccessibilityInfo.isReduceMotionEnabled).mockResolvedValue(false)

    const { result } = renderHook(() => useReduceMotion())

    expect(result.current).toBe(true)
    await waitFor(() => expect(result.current).toBe(false))
  })

  it('updates to the live setting once it resolves', async () => {
    const { result } = renderHook(() => useReduceMotion())

    expect(result.current).toBe(false)
    await waitFor(() => expect(result.current).toBe(true))
  })

  it('follows reduceMotionChanged while mounted', async () => {
    const { result } = renderHook(() => useReduceMotion())
    await waitFor(() => expect(result.current).toBe(true))

    act(() => listener?.(false))
    expect(result.current).toBe(false)

    act(() => listener?.(true))
    expect(result.current).toBe(true)
  })

  it('removes the listener on unmount', () => {
    const { unmount } = renderHook(() => useReduceMotion())

    expect(remove).not.toHaveBeenCalled()
    unmount()
    expect(remove).toHaveBeenCalledTimes(1)
  })
})