import {afterEach, beforeEach, describe, expect, it, vi} from 'vitest'
import {nextTick, ref} from 'vue'
import {useCalendarView} from './useCalendarView'

describe('useCalendarView', () => {
  beforeEach(() => {
    vi.useFakeTimers()
    vi.setSystemTime(new Date(2026, 4, 19)) // 19 mai 2026
  })
  afterEach(() => vi.useRealTimers())

  it('initialises to the current month and year', () => {
    const {currentMonth, currentYear} = useCalendarView(ref('days'))
    expect(currentMonth.value).toBe(4)
    expect(currentYear.value).toBe(2026)
  })

  it('goToNext advances the month in days view', () => {
    const {currentMonth, goToNext} = useCalendarView(ref('days'))
    goToNext()
    expect(currentMonth.value).toBe(5)
  })

  it('rolls December to January and bumps the year', () => {
    const {currentMonth, currentYear, goToNext} = useCalendarView(ref('days'))
    currentMonth.value = 11
    goToNext()
    expect(currentMonth.value).toBe(0)
    expect(currentYear.value).toBe(2027)
  })

  it('rolls January to December backwards', () => {
    const {currentMonth, currentYear, goToPrev} = useCalendarView(ref('days'))
    currentMonth.value = 0
    goToPrev()
    expect(currentMonth.value).toBe(11)
    expect(currentYear.value).toBe(2025)
  })

  it('navigates the year in months view', () => {
    const {currentYear, goToNext, goToPrev} = useCalendarView(ref('months'))
    goToNext()
    expect(currentYear.value).toBe(2027)
    goToPrev()
    expect(currentYear.value).toBe(2026)
  })

  it('selectMonth sets the current month', () => {
    const {currentMonth, selectMonth} = useCalendarView(ref('days'))
    selectMonth(0)
    expect(currentMonth.value).toBe(0)
  })

  it('syncToIso sets month/year from a valid ISO', () => {
    const {currentMonth, currentYear, syncToIso} = useCalendarView(ref('days'))
    syncToIso('2025-12-25')
    expect(currentMonth.value).toBe(11)
    expect(currentYear.value).toBe(2025)
  })

  it('syncToIso falls back to today for null/invalid', () => {
    const {currentMonth, currentYear, syncToIso} = useCalendarView(ref('days'))
    syncToIso('2025-12-25')
    syncToIso(null)
    expect(currentMonth.value).toBe(4)
    expect(currentYear.value).toBe(2026)
  })

  it('paginates years by 12 in years view', () => {
    const {yearPageStart, goToNext, goToPrev} = useCalendarView(ref('years'))
    const start = yearPageStart.value
    goToNext()
    expect(yearPageStart.value).toBe(start + 12)
    goToPrev()
    expect(yearPageStart.value).toBe(start)
  })

  it('selectYear sets the current year', () => {
    const {currentYear, selectYear} = useCalendarView(ref('days'))
    selectYear(2030)
    expect(currentYear.value).toBe(2030)
  })

  it('recenters the year page on entering years view (current - 4)', async () => {
    const mode = ref<'days' | 'months' | 'years'>('days')
    const {yearPageStart} = useCalendarView(mode)
    mode.value = 'years'
    await nextTick()
    expect(yearPageStart.value).toBe(2022) // 2026 - 4 (année courante en 2e ligne / 2e col)
  })
})