import { beforeEach, describe, it, vi } from 'vitest'
import { debounce } from './debounce'

vi.useFakeTimers()

describe('debounce()', () => {
  let debouncedFunc: Function
  let testFunc: Function
  let testWait: number
  let testImmediate: boolean

  beforeEach(() => {
    testFunc = vi.fn()
    testWait = 1000
    testImmediate = true
    debouncedFunc = debounce(testFunc, testWait, testImmediate)
  })

  it('should be throw error if first argument passed is not function type', () => {
    testFunc = ''

    const resultFn = () => {
      debounce(testFunc, testWait, testImmediate)()
    }

    expect(resultFn).toThrow(/is not a function/)
  })

  it('should execute testFunc', () => {
    debouncedFunc()

    expect(testFunc).toBeCalled()
  })

  it('should be execute just once', () => {
    for (let i = 0; i < 100; i++)
      debouncedFunc()

    vi.runAllTimers()

    expect(testFunc).toBeCalledTimes(1)
  })

  it('should not be executed twice with passed wait parametr equal 1000', () => {
    for (let i = 0; i < 100; i++)
      debouncedFunc()

    vi.runAllTimers()

    expect(testFunc).not.toBeCalledTimes(2)
  })
})