import { createRouter, createWebHistory } from 'vue-router'

const routes = []
const router = createRouter({
  history: createWebHistory(),
  routes
})

let dbPromise

function openDB(name, view, version = 1, autoIncrement = false) {
  if (!dbPromise) {
    dbPromise = new Promise((resolve, reject) => {
      const req = indexedDB.open(name, version)
      req.onupgradeneeded = () =>
        req.result.createObjectStore(view, { autoIncrement })
      req.onerror = () => reject(req.error)
      req.onsuccess = () => resolve(req.result)
    })
  }
  return dbPromise
}

router.beforeEach((to) => {
  // Open the connection when the page is loaded or restored from bfcache.
  window.addEventListener('pageshow', (event) => {
    if (event.persisted) {
      console.log('This page was restored from the bfcache.')
    } else {
      console.log('This page was loaded normally.')
    }
    openDB('bfcache', to.name)
  })

  // Close the connection to the database when the user is leaving.
  window.addEventListener('pagehide', (event) => {
    if (event.persisted) {
      console.log('This page *might* be entering the bfcache.')
    } else {
      console.log('This page will unload normally and be discarded.')
    }
    if (dbPromise) {
      dbPromise.then((db) => db.close())
      dbPromise = null
    }
  })
})

export default router