import {FullUser} from 'common/api/user-types'
import {filterDefined} from 'common/util/array'
import {uniq, uniqBy} from 'lodash'
import {useEffect, useState} from 'react'
import {usePersistentLocalState} from 'web/hooks/use-persistent-local-state'
import {DisplayUser, getDisplayUsers, getFullUserById} from 'web/lib/supabase/users'

import {useEffectCheckEquality} from './use-effect-check-equality'
import {usePersistentInMemoryState} from './use-persistent-in-memory-state'

export function useUserById(userId: string | undefined) {
  const [user, setUser] = usePersistentInMemoryState<FullUser | null | undefined>(
    undefined,
    `user-${userId}`,
  )
  useEffect(() => {
    if (userId) {
      getFullUserById(userId)
        .then((result) => {
          setUser(result)
        })
        .catch(() => {
          console.error('Failed to fetch user')
        })
    }
  }, [userId])
  return user
}

// const cache = new Map<string, DisplayUser | null>()
//
// export function useDisplayUserById(userId: string | undefined) {
//   const [user, setUser] = usePersistentInMemoryState<
//     DisplayUser | null | undefined
//   >(undefined, `user-${userId}`)
//
//   useEffect(() => {
//     if (userId) {
//       if (cache.has(userId)) {
//         setUser(cache.get(userId))
//       } else {
//         getUserById(userId)
//           .then((result) => {
//             cache.set(userId, result)
//             setUser(result)
//           })
//           .catch(() => {
//             setUser(null)
//           })
//       }
//     }
//   }, [userId])
//   return user
// }

// export function useUsers(userIds: string[]) {
//   const [users, setUsers] = useState<(DisplayUser | null)[] | undefined>(
//     undefined
//   )
//
//   const requestIdRef = useRef(0)
//   useEffectCheckEquality(() => {
//     const requestId = ++requestIdRef.current
//
//     const missing = userIds.filter((id) => !cache.has(id))
//
//     getDisplayUsers(missing).then((users) => {
//       users.forEach((user) => {
//         cache.set(user.id, user)
//       })
//       if (requestId !== requestIdRef.current) return
//       setUsers(userIds.map((id) => cache.get(id) ?? null))
//     })
//   }, [userIds])
//
//   return users
// }

// TODO: decide whether in-memory or in-localstorage is better and stick to it

export function useUsersInStore(userIds: (string | null)[], key: string, limit?: number) {
  const validUserIds = Array.from(new Set(userIds.filter((id): id is string => !!id)))

  const [users, setUsers] = usePersistentLocalState<DisplayUser[] | undefined>(
    undefined,
    'use-users-in-local-storage-' + key,
  )

  // Fetch all users at least once on load.
  const [userIdsFetched, setUserIdsFetched] = useState<string[]>([])
  const fetchedSet = new Set(userIdsFetched)

  const userIdsNotFetched = validUserIds.filter((id) => !fetchedSet.has(id))
  const userIdsToFetch = limit ? userIdsNotFetched.slice(0, limit) : userIdsNotFetched

  useEffectCheckEquality(() => {
    if (userIdsToFetch.length === 0) return
    getDisplayUsers(userIdsToFetch).then((newUsers) => {
      setUsers((currentUsers) => uniqBy(filterDefined(newUsers).concat(currentUsers ?? []), 'id'))
      setUserIdsFetched((currentIds) => uniq(currentIds.concat(userIdsToFetch)))
    })
  }, [userIdsToFetch])

  return users?.filter((user) => validUserIds.includes(user?.id))
}

export function useUserInStore(userId: string | null) {
  const users = useUsersInStore(userId ? [userId] : [], userId ?? 'empty')
  if (!userId) return null
  return users?.[0] ?? null
}