import {
  getFirestore,
  doc,
  setDoc,
  getDoc,
  collection,
  query,
  where,
  limit,
  getDocs,
  orderBy,
  updateDoc,
  deleteDoc,
  collectionGroup,
  onSnapshot,
} from 'firebase/firestore'
import { getAuth } from 'firebase/auth'
import { ref, getStorage, uploadBytes, getDownloadURL } from 'firebase/storage'
import {
  onAuthStateChanged,
  GoogleAuthProvider,
  signInWithPopup,
} from 'firebase/auth'
import { throttle, zip } from 'lodash'

import { app } from './init'
import { PortfolioMetrics, PrivateUser, User } from 'common/user'
import { createUser } from './fn-call'
import { getValue, getValues, listenForValue, listenForValues } from './utils'
import { feed } from 'common/feed'
import { CATEGORY_LIST } from 'common/categories'
import { safeLocalStorage } from '../util/local'
import { filterDefined } from 'common/util/array'

export type { User }

export type Period = 'daily' | 'weekly' | 'monthly' | 'allTime'

const db = getFirestore(app)
export const auth = getAuth(app)

export const userDocRef = (userId: string) => doc(db, 'users', userId)

export async function getUser(userId: string) {
  const docSnap = await getDoc(userDocRef(userId))
  return docSnap.data() as User
}

export async function getUserByUsername(username: string) {
  // Find a user whose username matches the given username, or null if no such user exists.
  const userCollection = collection(db, 'users')
  const q = query(userCollection, where('username', '==', username), limit(1))
  const docs = await getDocs(q)
  const users = docs.docs.map((doc) => doc.data() as User)
  return users[0] || null
}

export async function setUser(userId: string, user: User) {
  await setDoc(doc(db, 'users', userId), user)
}

export async function updateUser(userId: string, update: Partial<User>) {
  await updateDoc(doc(db, 'users', userId), { ...update })
}

export async function updatePrivateUser(
  userId: string,
  update: Partial<PrivateUser>
) {
  await updateDoc(doc(db, 'private-users', userId), { ...update })
}

export function listenForUser(
  userId: string,
  setUser: (user: User | null) => void
) {
  const userRef = doc(db, 'users', userId)
  return listenForValue<User>(userRef, setUser)
}

export function listenForPrivateUser(
  userId: string,
  setPrivateUser: (privateUser: PrivateUser | null) => void
) {
  const userRef = doc(db, 'private-users', userId)
  return listenForValue<PrivateUser>(userRef, setPrivateUser)
}

const CACHED_USER_KEY = 'CACHED_USER_KEY'

// used to avoid weird race condition
let createUserPromise: Promise<User | null> | undefined = undefined

const warmUpCreateUser = throttle(createUser, 5000 /* ms */)

export function listenForLogin(onUser: (user: User | null) => void) {
  const local = safeLocalStorage()
  const cachedUser = local?.getItem(CACHED_USER_KEY)
  onUser(cachedUser && JSON.parse(cachedUser))

  if (!cachedUser) warmUpCreateUser()

  return onAuthStateChanged(auth, async (fbUser) => {
    if (fbUser) {
      let user: User | null = await getUser(fbUser.uid)

      if (!user) {
        if (!createUserPromise) {
          createUserPromise = createUser()
        }
        user = (await createUserPromise) || null
      }

      onUser(user)

      // Persist to local storage, to reduce login blink next time.
      // Note: Cap on localStorage size is ~5mb
      local?.setItem(CACHED_USER_KEY, JSON.stringify(user))
    } else {
      // User logged out; reset to null
      onUser(null)
      local?.removeItem(CACHED_USER_KEY)
      createUserPromise = undefined
    }
  })
}

export async function firebaseLogin() {
  const provider = new GoogleAuthProvider()
  return signInWithPopup(auth, provider)
}

export async function firebaseLogout() {
  auth.signOut()
}

const storage = getStorage(app)
// Example: uploadData('avatars/ajfi8iejsf.png', data)
export async function uploadData(
  path: string,
  data: ArrayBuffer | Blob | Uint8Array
) {
  const uploadRef = ref(storage, path)
  // Uploaded files should be cached for 1 day, then revalidated
  // See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control
  const metadata = { cacheControl: 'public, max-age=86400, must-revalidate' }
  await uploadBytes(uploadRef, data, metadata)
  return await getDownloadURL(uploadRef)
}

export async function listUsers(userIds: string[]) {
  if (userIds.length > 10) {
    throw new Error('Too many users requested at once; Firestore limits to 10')
  }
  const userCollection = collection(db, 'users')
  const q = query(userCollection, where('id', 'in', userIds))
  const docs = await getDocs(q)
  return docs.docs.map((doc) => doc.data() as User)
}

export async function listAllUsers() {
  const userCollection = collection(db, 'users')
  const q = query(userCollection)
  const docs = await getDocs(q)
  return docs.docs.map((doc) => doc.data() as User)
}

export function listenForAllUsers(setUsers: (users: User[]) => void) {
  const userCollection = collection(db, 'users')
  const q = query(userCollection)
  listenForValues(q, setUsers)
}

export function listenForPrivateUsers(
  setUsers: (users: PrivateUser[]) => void
) {
  const userCollection = collection(db, 'private-users')
  const q = query(userCollection)
  listenForValues(q, setUsers)
}

export function getTopTraders(period: Period) {
  const topTraders = query(
    collection(db, 'users'),
    orderBy('profitCached.' + period, 'desc'),
    limit(20)
  )

  return getValues(topTraders)
}

export function getTopCreators(period: Period) {
  const topCreators = query(
    collection(db, 'users'),
    orderBy('creatorVolumeCached.' + period, 'desc'),
    limit(20)
  )
  return getValues(topCreators)
}

export async function getTopFollowed() {
  const users = await getValues<User>(topFollowedQuery)
  return users.slice(0, 20)
}

const topFollowedQuery = query(
  collection(db, 'users'),
  orderBy('followerCountCached', 'desc'),
  limit(20)
)

export function getUsers() {
  return getValues<User>(collection(db, 'users'))
}

export async function getUserFeed(userId: string) {
  const feedDoc = doc(db, 'private-users', userId, 'cache', 'feed')
  const userFeed = await getValue<{
    feed: feed
  }>(feedDoc)
  return userFeed?.feed ?? []
}

export async function getCategoryFeeds(userId: string) {
  const cacheCollection = collection(db, 'private-users', userId, 'cache')
  const feedData = await Promise.all(
    CATEGORY_LIST.map((category) =>
      getValue<{ feed: feed }>(doc(cacheCollection, `feed-${category}`))
    )
  )
  const feeds = feedData.map((data) => data?.feed ?? [])
  return Object.fromEntries(zip(CATEGORY_LIST, feeds) as [string, feed][])
}

export async function follow(userId: string, followedUserId: string) {
  const followDoc = doc(db, 'users', userId, 'follows', followedUserId)
  await setDoc(followDoc, {
    userId: followedUserId,
    timestamp: Date.now(),
  })
}

export async function unfollow(userId: string, unfollowedUserId: string) {
  const followDoc = doc(db, 'users', userId, 'follows', unfollowedUserId)
  await deleteDoc(followDoc)
}

export async function getPortfolioHistory(userId: string) {
  return getValues<PortfolioMetrics>(
    query(
      collectionGroup(db, 'portfolioHistory'),
      where('userId', '==', userId),
      orderBy('timestamp', 'asc')
    )
  )
}

export function listenForFollows(
  userId: string,
  setFollowIds: (followIds: string[]) => void
) {
  const follows = collection(db, 'users', userId, 'follows')
  return listenForValues<{ userId: string }>(follows, (docs) =>
    setFollowIds(docs.map(({ userId }) => userId))
  )
}

export function listenForFollowers(
  userId: string,
  setFollowerIds: (followerIds: string[]) => void
) {
  const followersQuery = query(
    collectionGroup(db, 'follows'),
    where('userId', '==', userId)
  )
  return onSnapshot(
    followersQuery,
    { includeMetadataChanges: true },
    (snapshot) => {
      if (snapshot.metadata.fromCache) return

      const values = snapshot.docs.map((doc) => doc.ref.parent.parent?.id)
      setFollowerIds(filterDefined(values))
    }
  )
}