import {renderHook, act} from '@testing-library/react-hooks'
import {useDebounce, useDebounceCallback} from './index'

const renderDebounce = (callback, ...args) =>
  renderHook(() => useDebounce(callback, ...args))
const renderDebounceCallback = (fn, ...args) =>
  renderHook(() => useDebounceCallback(fn, ...args))

describe('useDebounce()', () => {
  jest.useFakeTimers()

  it('should wait 100ms before invoking the callback', () => {
    const cb = jest.fn()
    const {result} = renderDebounceCallback(cb)

    act(result.current)
    act(result.current)
    act(result.current)

    act(() => jest.advanceTimersByTime(50))
    expect(cb).toBeCalledTimes(0)
    act(() => jest.advanceTimersByTime(100))
    expect(cb).toBeCalledTimes(1)

    act(result.current)
    act(result.current)
    act(result.current)

    act(() => jest.advanceTimersByTime(99))
    expect(cb).toHaveBeenCalledTimes(1)
    act(() => jest.advanceTimersByTime(1))
    expect(cb).toHaveBeenCalledTimes(2)
  })

  it('should invoke the callback on the leading edge', () => {
    const cb = jest.fn()
    const {result} = renderDebounceCallback(cb, 100, true)

    act(result.current)
    expect(cb).toHaveBeenCalledTimes(1)

    act(result.current)
    act(result.current)
    act(result.current)
    expect(cb).toHaveBeenCalledTimes(1)

    act(() => jest.advanceTimersByTime(100))
    expect(cb).toHaveBeenCalledTimes(2)

    act(result.current)
    expect(cb).toHaveBeenCalledTimes(3)

    act(result.current)
    act(result.current)
    act(result.current)

    expect(cb).toHaveBeenCalledTimes(3)
    act(() => jest.advanceTimersByTime(100))
    expect(cb).toHaveBeenCalledTimes(4)
  })

  it('should set the last value the callback was invoked with after 100ms', () => {
    const {result} = renderDebounce(1, 100)

    act(() => result.current[1](2))
    expect(result.current[0]).toBe(1)

    act(() => result.current[1](3))
    act(() => jest.advanceTimersByTime(50))

    act(() => result.current[1](4))
    act(() => jest.advanceTimersByTime(50))
    expect(result.current[0]).toBe(1)

    act(() => jest.advanceTimersByTime(50))
    expect(result.current[0]).toBe(4)
  })

  test('it should set the value on the leading edge', () => {
    const {result} = renderDebounce(1, 100, true)

    act(() => result.current[1](2))
    expect(result.current[0]).toBe(2)

    act(() => result.current[1](3))
    act(() => result.current[1](4))

    act(() => jest.advanceTimersByTime(50))
    expect(result.current[0]).toBe(2)

    act(() => jest.advanceTimersByTime(50))
    expect(result.current[0]).toBe(4)
  })
})