import calculationStartPageAndEndPage from '../../src/utils/calculationStartPageAndEndPage'

describe('CalculationStartPageAndEndPage', () => {
  it('should calculate the start and end page when all pages fit in the window', () => {
    expect(calculationStartPageAndEndPage(10, 10, 5)).toStrictEqual({
      endPage: 10,
      startPage: 1,
    })
  })

  it('should show all pages when total pages is less than maxPages', () => {
    expect(calculationStartPageAndEndPage(3, 10, 2)).toStrictEqual({
      startPage: 1,
      endPage: 3,
    })
  })

  it('should keep the window at the beginning when currentPage is near the first page', () => {
    expect(calculationStartPageAndEndPage(20, 10, 2)).toStrictEqual({
      startPage: 1,
      endPage: 10,
    })
  })

  it('should keep the window at the end when currentPage is near the last page', () => {
    expect(calculationStartPageAndEndPage(20, 10, 19)).toStrictEqual({
      startPage: 11,
      endPage: 20,
    })
  })

  it('should center the window when currentPage is in the middle', () => {
    expect(calculationStartPageAndEndPage(20, 10, 10)).toStrictEqual({
      startPage: 5,
      endPage: 14,
    })
  })

  it('should return the same start and end page when there is only one page', () => {
    expect(calculationStartPageAndEndPage(1, 10, 1)).toStrictEqual({
      startPage: 1,
      endPage: 1,
    })
  })
})