Cache likes and liked by user ids on contract

common/contract.ts

@@ -59,6 +59,8 @@ export type Contract<T extends AnyContractType = AnyContractType> = {
   popularityScore?: number
   followerCount?: number
   featuredOnHomeRank?: number
+  likedByUserIds?: string[]
+  likedByUserCount?: number
 } & T
 
 export type BinaryContract = Contract & Binary

common/like.ts

@@ -1,7 +1,7 @@
 export type Like = {
-  id: string
+  id: string // will be id of the object liked, i.e. contract.id
   userId: string
-  contractId: string
+  type: 'contract'
   createdTime: number
   tipTxnId?: string
 }

functions/src/index.ts

@@ -32,6 +32,7 @@ export * from './reset-betting-streaks'
 export * from './reset-weekly-emails-flag'
 export * from './on-update-contract-follow'
 export * from './on-create-like'
+export * from './on-delete-like'
 
 // v2
 export * from './health'

functions/src/on-create-like.ts

@@ -4,6 +4,7 @@ import { Like } from '../../common/like'
 import { getContract, getUser, log } from './utils'
 import { createLikeNotification } from './create-notification'
 import { TipTxn } from '../../common/txn'
+import { uniq } from 'lodash'
 
 const firestore = admin.firestore()
 
@@ -12,11 +13,28 @@ export const onCreateLike = functions.firestore
   .onCreate(async (change, context) => {
     const like = change.data() as Like
     const { eventId } = context
-    await handleCreateLike(like, eventId)
+    if (like.type === 'contract') {
+      await handleCreateLikeNotification(like, eventId)
+      await updateContractLikes(like)
+    }
   })
 
-const handleCreateLike = async (like: Like, eventId: string) => {
-  const contract = await getContract(like.contractId)
+const updateContractLikes = async (like: Like) => {
+  const contract = await getContract(like.id)
+  if (!contract) {
+    log('Could not find contract')
+    return
+  }
+  const likedByUserIds = uniq(contract.likedByUserIds ?? [])
+  likedByUserIds.push(like.userId)
+  await firestore
+    .collection('contracts')
+    .doc(like.id)
+    .update({ likedByUserIds, likedByUserCount: likedByUserIds.length })
+}
+
+const handleCreateLikeNotification = async (like: Like, eventId: string) => {
+  const contract = await getContract(like.id)
   if (!contract) {
     log('Could not find contract')
     return

functions/src/on-delete-like.ts

@@ -0,0 +1,32 @@
+import * as functions from 'firebase-functions'
+import * as admin from 'firebase-admin'
+import { Like } from '../../common/like'
+import { getContract, log } from './utils'
+import { uniq } from 'lodash'
+
+const firestore = admin.firestore()
+
+export const onDeleteLike = functions.firestore
+  .document('users/{userId}/likes/{likeId}')
+  .onDelete(async (change) => {
+    const like = change.data() as Like
+    if (like.type === 'contract') {
+      await removeContractLike(like)
+    }
+  })
+
+const removeContractLike = async (like: Like) => {
+  const contract = await getContract(like.id)
+  if (!contract) {
+    log('Could not find contract')
+    return
+  }
+  const likedByUserIds = uniq(contract.likedByUserIds ?? [])
+  const newLikedByUserIds = likedByUserIds.filter(
+    (userId) => userId !== like.userId
+  )
+  await firestore.collection('contracts').doc(like.id).update({
+    likedByUserIds: newLikedByUserIds,
+    likedByUserCount: newLikedByUserIds.length,
+  })
+}

functions/src/on-update-contract-follow.ts

@@ -2,6 +2,7 @@ import * as functions from 'firebase-functions'
 import * as admin from 'firebase-admin'
 import { FieldValue } from 'firebase-admin/firestore'
 
+// TODO: should cache the follower user ids in the contract as these triggers aren't idempotent
 export const onDeleteContractFollow = functions.firestore
   .document('contracts/{contractId}/follows/{userId}')
   .onDelete(async (change, context) => {

web/components/contract/like-market-button.tsx

@@ -19,7 +19,9 @@ export function LikeMarketButton(props: {
   const { contract, user } = props
 
   const likes = useUserLikes(user?.id)
-  const likedContractIds = likes?.map((l) => l.contractId)
+  const likedContractIds = likes
+    ?.filter((l) => l.type === 'contract')
+    .map((l) => l.id)
   if (!user) return <div />
 
   const onLike = async () => {

web/components/profile/user-likes-button.tsx

@@ -35,10 +35,8 @@ export function UserLikesButton(props: { user: User }) {
                   {likedContract.question}
                 </SiteLink>
                 <XIcon
-                  className="ml-2 h-5 w-5 cursor-pointer"
-                  onClick={() => async () => {
-                    await unLikeContract(user.id, likedContract.id)
-                  }}
+                  className="ml-2 h-5 w-5 shrink-0 cursor-pointer"
+                  onClick={() => unLikeContract(user.id, likedContract.id)}
                 />
               </Row>
             ))}

web/hooks/use-likes.ts

@@ -15,21 +15,24 @@ export const useUserLikes = (userId: string | undefined) => {
   return contractIds
 }
 export const useUserLikedContracts = (userId: string | undefined) => {
-  const [contractIds, setContractIds] = useState<Like[] | undefined>()
+  const [likes, setLikes] = useState<Like[] | undefined>()
   const [contracts, setContracts] = useState<Contract[] | undefined>()
 
   useEffect(() => {
-    if (userId) return listenForLikes(userId, setContractIds)
+    if (userId)
+      return listenForLikes(userId, (likes) => {
+        setLikes(likes.filter((l) => l.type === 'contract'))
+      })
   }, [userId])
 
   useEffect(() => {
-    if (contractIds)
+    if (likes)
       Promise.all(
-        contractIds.map(async (like) => {
-          return await getContractFromId(like.contractId)
+        likes.map(async (like) => {
+          return await getContractFromId(like.id)
         })
       ).then((contracts) => setContracts(filterDefined(contracts)))
-  }, [contractIds])
+  }, [likes])
 
   return contracts
 }

web/lib/firebase/likes.ts

@@ -1,19 +1,12 @@
-import {
-  collection,
-  deleteDoc,
-  doc,
-  query,
-  setDoc,
-  where,
-} from 'firebase/firestore'
+import { collection, deleteDoc, doc, setDoc } from 'firebase/firestore'
 import { db } from 'web/lib/firebase/init'
 import toast from 'react-hot-toast'
 import { transact } from 'web/lib/firebase/api'
-import { removeUndefinedProps } from 'common/lib/util/object'
-import { Like } from 'common/lib/like'
+import { removeUndefinedProps } from 'common/util/object'
+import { Like } from 'common/like'
 import { track } from '@amplitude/analytics-browser'
 import { User } from 'common/user'
-import { Contract } from 'common/lib/contract'
+import { Contract } from 'common/contract'
 
 export const LIKE_TIP_AMOUNT = 5
 
@@ -22,11 +15,7 @@ function getLikesCollection(userId: string) {
 }
 
 export const unLikeContract = async (userId: string, contractId: string) => {
-  const ref = await query(
-    getLikesCollection(userId),
-    where('contractId', '==', contractId)
-  )
-  const snapshot = await ref.get()
+  const ref = await doc(getLikesCollection(userId), contractId)
   return await deleteDoc(ref)
 }
 
@@ -51,13 +40,13 @@ export const likeContract = async (user: User, contract: Contract) => {
     console.log('result', result)
   }
   // create new like in db under users collection
-  const ref = doc(getLikesCollection(user.id))
+  const ref = doc(getLikesCollection(user.id), contract.id)
   // contract slug and question are set via trigger
   const like = removeUndefinedProps({
     id: ref.id,
     userId: user.id,
     createdTime: Date.now(),
-    contractId: contract.id,
+    type: 'contract',
     tipTxnId: result.txn.id,
   } as Like)
   track('like', {