import { login as loginMasto } from 'masto'
import type { ServerInfo, UserLogin } from '~/types'

const ServerInfoTTL = 60 * 60 * 1000 * 12 // 12 hour

function createClientState() {
  const { server, token } = useAppCookies()

  const accounts = useLocalStorage<UserLogin[]>('nuxtodon-accounts', [], { deep: true })
  const currentId = useLocalStorage<string>('nuxtodon-current-user', '')

  const currentUser = computed<UserLogin | undefined>(() => {
    let user: UserLogin | undefined
    if (currentId.value) {
      user = accounts.value.find(user => user.account?.id === currentId.value)
      if (user)
        return user
    }
    // Fallback to the first account
    return accounts.value[0]
  })

  async function login(user: UserLogin) {
    const existing = accounts.value.findIndex(u => u.server === user.server && u.token === user.token)
    if (existing !== -1) {
      if (currentId.value === accounts.value[existing].account?.id)
        return null
      currentId.value = user.account?.id
      server.value = user.server
      token.value = user.token
      return true
    }

    const masto = await loginMasto({
      url: `https://${user.server}`,
      accessToken: user.token,
    })
    const me = await masto.accounts.verifyCredentials()
    user.account = me

    accounts.value.push(user)
    currentId.value = me.id
    server.value = user.server
    token.value = user.token
    return true
  }

  const serverInfos = useLocalStorage<Record<string, ServerInfo>>('nuxtodon-server-info', {})

  async function fetchServerInfo(server: string) {
    if (!serverInfos.value[server]) {
      // @ts-expect-error init
      serverInfos.value[server] = {
        timeUpdated: 0,
        server,
      }
    }
    if (serverInfos.value[server].timeUpdated + ServerInfoTTL < Date.now()) {
      const masto = await useMasto()
      await Promise.allSettled([
        masto.instances.fetch().then((r) => {
          Object.assign(serverInfos.value[server], r)
        }),
        masto.customEmojis.fetchAll().then((r) => {
          serverInfos.value[server].customEmojis = Object.fromEntries(r.map(i => [i.shortcode, i]))
        }),
      ])
    }
    return serverInfos.value[server]
  }

  if (server.value)
    fetchServerInfo(server.value)

  return {
    currentUser,
    accounts,
    login,
    serverInfos,
    fetchServerInfo,
  }
}

export type ClientState = ReturnType<typeof createClientState>

export default defineNuxtPlugin((nuxt) => {
  nuxt.$clientState = createClientState()
})