import { nextTick } from 'vue'
import router from '@/router'

let recoveryTimers: ReturnType<typeof setTimeout>[] = []

function clearRecoveryTimers() {
  recoveryTimers.forEach(clearTimeout)
  recoveryTimers = []
}

function blurFocusedField() {
  const active = document.activeElement
  if (active instanceof HTMLElement && active !== document.body) {
    active.blur()
  }
}

function clearBodyScrollLock() {
  document.body.classList.remove('van-overflow-hidden')
  document.body.style.removeProperty('position')
  document.body.style.removeProperty('top')
  document.body.style.removeProperty('left')
  document.body.style.removeProperty('right')
  document.body.style.removeProperty('width')
  document.body.style.removeProperty('height')
  document.body.style.removeProperty('min-height')
  document.body.style.removeProperty('overflow')
  document.body.style.removeProperty('transform')
  document.documentElement.style.removeProperty('overflow')
  document.documentElement.style.removeProperty('height')
  document.documentElement.style.removeProperty('transform')

  const appRoot = document.getElementById('app')
  if (appRoot) {
    appRoot.style.removeProperty('position')
    appRoot.style.removeProperty('top')
    appRoot.style.removeProperty('height')
    appRoot.style.removeProperty('min-height')
    appRoot.style.removeProperty('overflow')
    appRoot.style.removeProperty('transform')
  }
}

function resetAllScrollPositions() {
  window.scrollTo(0, 0)
  document.documentElement.scrollTop = 0
  document.body.scrollTop = 0

  document
    .querySelectorAll('.main-with-bottom-chrome-inner, .login-page, .login-page-root')
    .forEach((node) => {
      if (node instanceof HTMLElement) {
        node.scrollTop = 0
      }
    })
}

function kickViewportReflow() {
  window.dispatchEvent(new Event('resize'))

  if (window.visualViewport) {
    window.scrollTo(0, 0)
  }
}

function runViewportRecovery() {
  clearBodyScrollLock()
  resetAllScrollPositions()
  kickViewportReflow()
}

function scheduleViewportRecovery() {
  clearRecoveryTimers()
  runViewportRecovery()

  nextTick(() => {
    requestAnimationFrame(() => {
      runViewportRecovery()

      for (const delay of [50, 150, 300, 500]) {
        recoveryTimers.push(window.setTimeout(runViewportRecovery, delay))
      }
    })
  })
}

/** Reset scroll offsets after navigation — fixes iOS safe-area drift. */
export function resetMobileAppScroll() {
  runViewportRecovery()

  nextTick(() => {
    requestAnimationFrame(runViewportRecovery)
  })
}

export async function dismissMobileKeyboard() {
  blurFocusedField()
  await new Promise((resolve) => window.setTimeout(resolve, 120))
}

export async function prepareMobileViewportForAppShell() {
  blurFocusedField()
  resetAllScrollPositions()
  await dismissMobileKeyboard()
}

/** Full recovery after auth — runs after home shell is mounted. */
export function recoverMobileViewportAfterAuth() {
  scheduleViewportRecovery()
}

export const resetMobileAppScrollAfterLogin = recoverMobileViewportAfterAuth

export async function completeLoginNavigation() {
  await prepareMobileViewportForAppShell()
  await router.push({ name: 'home' })
  await router.isReady()
  recoverMobileViewportAfterAuth()
}

export function initMobileScrollRestoration() {
  if (typeof history !== 'undefined' && 'scrollRestoration' in history) {
    history.scrollRestoration = 'manual'
  }
}