Allow to follow/unfollow markets, backfill as well

common/contract.ts

@@ -57,6 +57,7 @@ export type Contract<T extends AnyContractType = AnyContractType> = {
   uniqueBettorIds?: string[]
   uniqueBettorCount?: number
   popularityScore?: number
+  followerCount?: number
 } & T
 
 export type BinaryContract = Contract & Binary

common/notification.ts

@@ -70,3 +70,4 @@ export type notification_reason_types =
   | 'challenge_accepted'
   | 'betting_streak_incremented'
   | 'loan_income'
+  | 'you_follow_contract'

firestore.rules

@@ -44,6 +44,11 @@ service cloud.firestore {
       allow read;
     }
 
+    match /contracts/{contractId}/follows/{userId} {
+      allow read;
+      allow create, delete: if userId == request.auth.uid;
+    }
+
     match /contracts/{contractId}/challenges/{challengeId}{
       allow read;
       allow create: if request.auth.uid == request.resource.data.creatorId;

functions/package.json

@@ -13,7 +13,7 @@
     "deploy": "firebase deploy --only functions",
     "logs": "firebase functions:log",
     "dev": "nodemon src/serve.ts",
-    "firestore": "firebase emulators:start --only firestore --import=./firestore_export",
+    "firestore": "firebase emulators:start --only firestore,pubsub --import=./firestore_export",
     "serve": "firebase use dev && yarn build && firebase emulators:start --only functions,firestore,pubsub --import=./firestore_export",
     "db:update-local-from-remote": "yarn db:backup-remote && gsutil rsync -r gs://$npm_package_config_firestore/firestore_export ./firestore_export",
     "db:backup-local": "firebase emulators:export --force ./firestore_export",

functions/src/create-notification.ts

@@ -7,7 +7,7 @@ import {
 } from '../../common/notification'
 import { User } from '../../common/user'
 import { Contract } from '../../common/contract'
-import { getValues } from './utils'
+import { getValues, log } from './utils'
 import { Comment } from '../../common/comment'
 import { uniq } from 'lodash'
 import { Bet, LimitBet } from '../../common/bet'
@@ -33,19 +33,12 @@ export const createNotification = async (
   sourceText: string,
   miscData?: {
     contract?: Contract
-    relatedSourceType?: notification_source_types
     recipients?: string[]
     slug?: string
     title?: string
   }
 ) => {
-  const {
+  const { contract: sourceContract, recipients, slug, title } = miscData ?? {}
-    contract: sourceContract,
-    relatedSourceType,
-    recipients,
-    slug,
-    title,
-  } = miscData ?? {}
 
   const shouldGetNotification = (
     userId: string,
@@ -90,24 +83,6 @@ export const createNotification = async (
     )
   }
 
-  const notifyLiquidityProviders = async (
-    userToReasonTexts: user_to_reason_texts,
-    contract: Contract
-  ) => {
-    const liquidityProviders = await firestore
-      .collection(`contracts/${contract.id}/liquidity`)
-      .get()
-    const liquidityProvidersIds = uniq(
-      liquidityProviders.docs.map((doc) => doc.data().userId)
-    )
-    liquidityProvidersIds.forEach((userId) => {
-      if (!shouldGetNotification(userId, userToReasonTexts)) return
-      userToReasonTexts[userId] = {
-        reason: 'on_contract_with_users_shares_in',
-      }
-    })
-  }
-
   const notifyUsersFollowers = async (
     userToReasonTexts: user_to_reason_texts
   ) => {
@@ -129,23 +104,6 @@ export const createNotification = async (
     })
   }
 
-  const notifyRepliedUser = (
-    userToReasonTexts: user_to_reason_texts,
-    relatedUserId: string,
-    relatedSourceType: notification_source_types
-  ) => {
-    if (!shouldGetNotification(relatedUserId, userToReasonTexts)) return
-    if (relatedSourceType === 'comment') {
-      userToReasonTexts[relatedUserId] = {
-        reason: 'reply_to_users_comment',
-      }
-    } else if (relatedSourceType === 'answer') {
-      userToReasonTexts[relatedUserId] = {
-        reason: 'reply_to_users_answer',
-      }
-    }
-  }
-
   const notifyFollowedUser = (
     userToReasonTexts: user_to_reason_texts,
     followedUserId: string
@@ -182,71 +140,6 @@ export const createNotification = async (
       }
   }
 
-  const notifyOtherAnswerersOnContract = async (
-    userToReasonTexts: user_to_reason_texts,
-    sourceContract: Contract
-  ) => {
-    const answers = await getValues<Answer>(
-      firestore
-        .collection('contracts')
-        .doc(sourceContract.id)
-        .collection('answers')
-    )
-    const recipientUserIds = uniq(answers.map((answer) => answer.userId))
-    recipientUserIds.forEach((userId) => {
-      if (shouldGetNotification(userId, userToReasonTexts))
-        userToReasonTexts[userId] = {
-          reason: 'on_contract_with_users_answer',
-        }
-    })
-  }
-
-  const notifyOtherCommentersOnContract = async (
-    userToReasonTexts: user_to_reason_texts,
-    sourceContract: Contract
-  ) => {
-    const comments = await getValues<Comment>(
-      firestore
-        .collection('contracts')
-        .doc(sourceContract.id)
-        .collection('comments')
-    )
-    const recipientUserIds = uniq(comments.map((comment) => comment.userId))
-    recipientUserIds.forEach((userId) => {
-      if (shouldGetNotification(userId, userToReasonTexts))
-        userToReasonTexts[userId] = {
-          reason: 'on_contract_with_users_comment',
-        }
-    })
-  }
-
-  const notifyBettorsOnContract = async (
-    userToReasonTexts: user_to_reason_texts,
-    sourceContract: Contract
-  ) => {
-    const betsSnap = await firestore
-      .collection(`contracts/${sourceContract.id}/bets`)
-      .get()
-    const bets = betsSnap.docs.map((doc) => doc.data() as Bet)
-    // filter bets for only users that have an amount invested still
-    const recipientUserIds = uniq(bets.map((bet) => bet.userId)).filter(
-      (userId) => {
-        return (
-          getContractBetMetrics(
-            sourceContract,
-            bets.filter((bet) => bet.userId === userId)
-          ).invested > 0
-        )
-      }
-    )
-    recipientUserIds.forEach((userId) => {
-      if (shouldGetNotification(userId, userToReasonTexts))
-        userToReasonTexts[userId] = {
-          reason: 'on_contract_with_users_shares_in',
-        }
-    })
-  }
-
   const notifyUserAddedToGroup = (
     userToReasonTexts: user_to_reason_texts,
     relatedUserId: string
@@ -266,58 +159,289 @@ export const createNotification = async (
     }
   }
 
-  const getUsersToNotify = async () => {
+  const userToReasonTexts: user_to_reason_texts = {}
-    const userToReasonTexts: user_to_reason_texts = {}
+  // The following functions modify the userToReasonTexts object in place.
-    // The following functions modify the userToReasonTexts object in place.
-    if (sourceType === 'follow' && recipients?.[0]) {
-      notifyFollowedUser(userToReasonTexts, recipients[0])
-    } else if (
-      sourceType === 'group' &&
-      sourceUpdateType === 'created' &&
-      recipients
-    ) {
-      recipients.forEach((r) => notifyUserAddedToGroup(userToReasonTexts, r))
-    }
 
-    // The following functions need sourceContract to be defined.
+  if (sourceType === 'follow' && recipients?.[0]) {
-    if (!sourceContract) return userToReasonTexts
+    notifyFollowedUser(userToReasonTexts, recipients[0])
-
+  } else if (
-    if (
+    sourceType === 'group' &&
-      sourceType === 'comment' ||
+    sourceUpdateType === 'created' &&
-      sourceType === 'answer' ||
+    recipients
-      (sourceType === 'contract' &&
+  ) {
-        (sourceUpdateType === 'updated' || sourceUpdateType === 'resolved'))
+    recipients.forEach((r) => notifyUserAddedToGroup(userToReasonTexts, r))
-    ) {
+  } else if (
-      if (sourceType === 'comment') {
+    sourceType === 'contract' &&
-        if (recipients?.[0] && relatedSourceType)
+    sourceUpdateType === 'created' &&
-          notifyRepliedUser(userToReasonTexts, recipients[0], relatedSourceType)
+    sourceContract
-        if (sourceText) notifyTaggedUsers(userToReasonTexts, recipients ?? [])
+  ) {
-      }
+    await notifyUsersFollowers(userToReasonTexts)
-      await notifyContractCreator(userToReasonTexts, sourceContract)
+    notifyTaggedUsers(userToReasonTexts, recipients ?? [])
-      await notifyOtherAnswerersOnContract(userToReasonTexts, sourceContract)
+  } else if (
-      await notifyLiquidityProviders(userToReasonTexts, sourceContract)
+    sourceType === 'contract' &&
-      await notifyBettorsOnContract(userToReasonTexts, sourceContract)
+    sourceUpdateType === 'closed' &&
-      await notifyOtherCommentersOnContract(userToReasonTexts, sourceContract)
+    sourceContract
-    } else if (sourceType === 'contract' && sourceUpdateType === 'created') {
+  ) {
-      await notifyUsersFollowers(userToReasonTexts)
+    await notifyContractCreator(userToReasonTexts, sourceContract, {
-      notifyTaggedUsers(userToReasonTexts, recipients ?? [])
+      force: true,
-    } else if (sourceType === 'contract' && sourceUpdateType === 'closed') {
+    })
-      await notifyContractCreator(userToReasonTexts, sourceContract, {
+  } else if (
-        force: true,
+    sourceType === 'liquidity' &&
-      })
+    sourceUpdateType === 'created' &&
-    } else if (sourceType === 'liquidity' && sourceUpdateType === 'created') {
+    sourceContract
-      await notifyContractCreator(userToReasonTexts, sourceContract)
+  ) {
-    } else if (sourceType === 'bonus' && sourceUpdateType === 'created') {
+    await notifyContractCreator(userToReasonTexts, sourceContract)
-      // Note: the daily bonus won't have a contract attached to it
+  } else if (
-      await notifyContractCreatorOfUniqueBettorsBonus(
+    sourceType === 'bonus' &&
-        userToReasonTexts,
+    sourceUpdateType === 'created' &&
-        sourceContract.creatorId
+    sourceContract
-      )
+  ) {
-    }
+    // Note: the daily bonus won't have a contract attached to it
-    return userToReasonTexts
+    await notifyContractCreatorOfUniqueBettorsBonus(
+      userToReasonTexts,
+      sourceContract.creatorId
+    )
   }
 
-  const userToReasonTexts = await getUsersToNotify()
+  await createUsersNotifications(userToReasonTexts)
+}
+
+export const createCommentOrAnswerOrUpdatedContractNotification = async (
+  sourceId: string,
+  sourceType: notification_source_types,
+  sourceUpdateType: notification_source_update_types,
+  sourceUser: User,
+  idempotencyKey: string,
+  sourceText: string,
+  sourceContract: Contract,
+  miscData?: {
+    relatedSourceType?: notification_source_types
+    repliedUserId?: string
+    taggedUserIds?: string[]
+  }
+) => {
+  const { relatedSourceType, repliedUserId, taggedUserIds } = miscData ?? {}
+
+  const createUsersNotifications = async (
+    userToReasonTexts: user_to_reason_texts
+  ) => {
+    await Promise.all(
+      Object.keys(userToReasonTexts).map(async (userId) => {
+        const notificationRef = firestore
+          .collection(`/users/${userId}/notifications`)
+          .doc(idempotencyKey)
+        const notification: Notification = {
+          id: idempotencyKey,
+          userId,
+          reason: userToReasonTexts[userId].reason,
+          createdTime: Date.now(),
+          isSeen: false,
+          sourceId,
+          sourceType,
+          sourceUpdateType,
+          sourceContractId: sourceContract.id,
+          sourceUserName: sourceUser.name,
+          sourceUserUsername: sourceUser.username,
+          sourceUserAvatarUrl: sourceUser.avatarUrl,
+          sourceText,
+          sourceContractCreatorUsername: sourceContract.creatorUsername,
+          sourceContractTitle: sourceContract.question,
+          sourceContractSlug: sourceContract.slug,
+          sourceSlug: sourceContract.slug,
+          sourceTitle: sourceContract.question,
+        }
+        await notificationRef.set(removeUndefinedProps(notification))
+      })
+    )
+  }
+
+  // get contract follower documents and check here if they're a follower
+  const contractFollowersSnap = await firestore
+    .collection(`contracts/${sourceContract.id}/follows`)
+    .get()
+  const contractFollowersIds = contractFollowersSnap.docs.map(
+    (doc) => doc.data().id
+  )
+  log('contractFollowerIds', contractFollowersIds)
+
+  const stillFollowingContract = (userId: string) => {
+    return contractFollowersIds.includes(userId)
+  }
+
+  const shouldGetNotification = (
+    userId: string,
+    userToReasonTexts: user_to_reason_texts
+  ) => {
+    return (
+      sourceUser.id != userId &&
+      !Object.keys(userToReasonTexts).includes(userId)
+    )
+  }
+
+  const notifyContractFollowers = async (
+    userToReasonTexts: user_to_reason_texts
+  ) => {
+    for (const userId of contractFollowersIds) {
+      if (shouldGetNotification(userId, userToReasonTexts))
+        userToReasonTexts[userId] = {
+          reason: 'you_follow_contract',
+        }
+    }
+  }
+
+  const notifyContractCreator = async (
+    userToReasonTexts: user_to_reason_texts
+  ) => {
+    if (
+      shouldGetNotification(sourceContract.creatorId, userToReasonTexts) &&
+      stillFollowingContract(sourceContract.creatorId)
+    )
+      userToReasonTexts[sourceContract.creatorId] = {
+        reason: 'on_users_contract',
+      }
+  }
+
+  const notifyOtherAnswerersOnContract = async (
+    userToReasonTexts: user_to_reason_texts
+  ) => {
+    const answers = await getValues<Answer>(
+      firestore
+        .collection('contracts')
+        .doc(sourceContract.id)
+        .collection('answers')
+    )
+    const recipientUserIds = uniq(answers.map((answer) => answer.userId))
+    recipientUserIds.forEach((userId) => {
+      if (
+        shouldGetNotification(userId, userToReasonTexts) &&
+        stillFollowingContract(userId)
+      )
+        userToReasonTexts[userId] = {
+          reason: 'on_contract_with_users_answer',
+        }
+    })
+  }
+
+  const notifyOtherCommentersOnContract = async (
+    userToReasonTexts: user_to_reason_texts
+  ) => {
+    const comments = await getValues<Comment>(
+      firestore
+        .collection('contracts')
+        .doc(sourceContract.id)
+        .collection('comments')
+    )
+    const recipientUserIds = uniq(comments.map((comment) => comment.userId))
+    recipientUserIds.forEach((userId) => {
+      if (
+        shouldGetNotification(userId, userToReasonTexts) &&
+        stillFollowingContract(userId)
+      )
+        userToReasonTexts[userId] = {
+          reason: 'on_contract_with_users_comment',
+        }
+    })
+  }
+
+  const notifyBettorsOnContract = async (
+    userToReasonTexts: user_to_reason_texts
+  ) => {
+    const betsSnap = await firestore
+      .collection(`contracts/${sourceContract.id}/bets`)
+      .get()
+    const bets = betsSnap.docs.map((doc) => doc.data() as Bet)
+    // filter bets for only users that have an amount invested still
+    const recipientUserIds = uniq(bets.map((bet) => bet.userId)).filter(
+      (userId) => {
+        return (
+          getContractBetMetrics(
+            sourceContract,
+            bets.filter((bet) => bet.userId === userId)
+          ).invested > 0
+        )
+      }
+    )
+    recipientUserIds.forEach((userId) => {
+      if (
+        shouldGetNotification(userId, userToReasonTexts) &&
+        stillFollowingContract(userId)
+      )
+        userToReasonTexts[userId] = {
+          reason: 'on_contract_with_users_shares_in',
+        }
+    })
+  }
+
+  const notifyRepliedUser = (
+    userToReasonTexts: user_to_reason_texts,
+    relatedUserId: string,
+    relatedSourceType: notification_source_types
+  ) => {
+    if (
+      shouldGetNotification(relatedUserId, userToReasonTexts) &&
+      stillFollowingContract(relatedUserId)
+    ) {
+      if (relatedSourceType === 'comment') {
+        userToReasonTexts[relatedUserId] = {
+          reason: 'reply_to_users_comment',
+        }
+      } else if (relatedSourceType === 'answer') {
+        userToReasonTexts[relatedUserId] = {
+          reason: 'reply_to_users_answer',
+        }
+      }
+    }
+  }
+
+  const notifyTaggedUsers = (
+    userToReasonTexts: user_to_reason_texts,
+    userIds: (string | undefined)[]
+  ) => {
+    userIds.forEach((id) => {
+      console.log('tagged user: ', id)
+      // Allowing non-following users to get tagged
+      if (id && shouldGetNotification(id, userToReasonTexts))
+        userToReasonTexts[id] = {
+          reason: 'tagged_user',
+        }
+    })
+  }
+
+  const notifyLiquidityProviders = async (
+    userToReasonTexts: user_to_reason_texts
+  ) => {
+    const liquidityProviders = await firestore
+      .collection(`contracts/${sourceContract.id}/liquidity`)
+      .get()
+    const liquidityProvidersIds = uniq(
+      liquidityProviders.docs.map((doc) => doc.data().userId)
+    )
+    liquidityProvidersIds.forEach((userId) => {
+      if (
+        shouldGetNotification(userId, userToReasonTexts) &&
+        stillFollowingContract(userId)
+      ) {
+        userToReasonTexts[userId] = {
+          reason: 'on_contract_with_users_shares_in',
+        }
+      }
+    })
+  }
+  const userToReasonTexts: user_to_reason_texts = {}
+
+  if (sourceType === 'comment') {
+    if (repliedUserId && relatedSourceType)
+      notifyRepliedUser(userToReasonTexts, repliedUserId, relatedSourceType)
+    if (sourceText) notifyTaggedUsers(userToReasonTexts, taggedUserIds ?? [])
+  }
+  await notifyContractCreator(userToReasonTexts)
+  await notifyOtherAnswerersOnContract(userToReasonTexts)
+  await notifyLiquidityProviders(userToReasonTexts)
+  await notifyBettorsOnContract(userToReasonTexts)
+  await notifyOtherCommentersOnContract(userToReasonTexts)
+  // if they weren't added previously, add them now
+  await notifyContractFollowers(userToReasonTexts)
+
   await createUsersNotifications(userToReasonTexts)
 }
 

functions/src/follow-market.ts

@@ -0,0 +1,30 @@
+import { Contract } from '../../common/lib/contract'
+import { User } from '../../common/lib/user'
+import * as admin from 'firebase-admin'
+import { FieldValue } from 'firebase-admin/firestore'
+
+const firestore = admin.firestore()
+
+export const addUserToContractFollowers = async (
+  contract: Contract,
+  user: User
+) => {
+  const followerDoc = await firestore
+    .collection(`contracts/${contract.id}/follows`)
+    .doc(user.id)
+    .get()
+  if (followerDoc.exists) return
+  await firestore
+    .collection(`contracts/${contract.id}/follows`)
+    .doc(user.id)
+    .set({
+      id: user.id,
+      createdTime: Date.now(),
+    })
+  await firestore
+    .collection(`contracts`)
+    .doc(contract.id)
+    .update({
+      followerCount: FieldValue.increment(1),
+    })
+}

functions/src/on-create-answer.ts

@@ -1,7 +1,8 @@
 import * as functions from 'firebase-functions'
 import { getContract, getUser } from './utils'
-import { createNotification } from './create-notification'
+import { createCommentOrAnswerOrUpdatedContractNotification } from './create-notification'
 import { Answer } from '../../common/answer'
+import { addUserToContractFollowers } from './follow-market'
 
 export const onCreateAnswer = functions.firestore
   .document('contracts/{contractId}/answers/{answerNumber}')
@@ -20,14 +21,14 @@ export const onCreateAnswer = functions.firestore
 
     const answerCreator = await getUser(answer.userId)
     if (!answerCreator) throw new Error('Could not find answer creator')
-
+    await addUserToContractFollowers(contract, answerCreator)
-    await createNotification(
+    await createCommentOrAnswerOrUpdatedContractNotification(
       answer.id,
       'answer',
       'created',
       answerCreator,
       eventId,
       answer.text,
-      { contract }
+      contract
     )
   })

functions/src/on-create-bet.ts

@@ -24,6 +24,7 @@ import {
 } from '../../common/antes'
 import { APIError } from '../../common/api'
 import { User } from '../../common/user'
+import { addUserToContractFollowers } from './follow-market'
 
 const firestore = admin.firestore()
 const BONUS_START_DATE = new Date('2022-07-13T15:30:00.000Z').getTime()
@@ -54,14 +55,13 @@ export const onCreateBet = functions.firestore
       log(`Could not find contract ${contractId}`)
       return
     }
-    await updateUniqueBettorsAndGiveCreatorBonus(contract, eventId, bet.userId)
-
     const bettor = await getUser(bet.userId)
     if (!bettor) return
 
+    await addUserToContractFollowers(contract, bettor)
+    await updateUniqueBettorsAndGiveCreatorBonus(contract, eventId, bet.userId)
     await notifyFills(bet, contract, eventId, bettor)
     await updateBettingStreak(bettor, bet, contract, eventId)
-
     await firestore.collection('users').doc(bettor.id).update({ lastBetTime })
   })
 

functions/src/on-create-comment-on-contract.ts

@@ -6,8 +6,9 @@ import { ContractComment } from '../../common/comment'
 import { sendNewCommentEmail } from './emails'
 import { Bet } from '../../common/bet'
 import { Answer } from '../../common/answer'
-import { createNotification } from './create-notification'
+import { createCommentOrAnswerOrUpdatedContractNotification } from './create-notification'
 import { parseMentions, richTextToString } from '../../common/util/parse'
+import { addUserToContractFollowers } from './follow-market'
 
 const firestore = admin.firestore()
 
@@ -35,6 +36,8 @@ export const onCreateCommentOnContract = functions
     const commentCreator = await getUser(comment.userId)
     if (!commentCreator) throw new Error('Could not find comment creator')
 
+    await addUserToContractFollowers(contract, commentCreator)
+
     await firestore
       .collection('contracts')
       .doc(contract.id)
@@ -77,18 +80,19 @@ export const onCreateCommentOnContract = functions
       ? comments.find((c) => c.id === comment.replyToCommentId)?.userId
       : answer?.userId
 
-    const recipients = uniq(
+    await createCommentOrAnswerOrUpdatedContractNotification(
-      compact([...parseMentions(comment.content), repliedUserId])
-    )
-
-    await createNotification(
       comment.id,
       'comment',
       'created',
       commentCreator,
       eventId,
       richTextToString(comment.content),
-      { contract, relatedSourceType, recipients }
+      contract,
+      {
+        relatedSourceType,
+        repliedUserId,
+        taggedUserIds: compact(parseMentions(comment.content)),
+      }
     )
 
     const recipientUserIds = uniq([

functions/src/on-create-contract.ts

@@ -5,6 +5,7 @@ import { createNotification } from './create-notification'
 import { Contract } from '../../common/contract'
 import { parseMentions, richTextToString } from '../../common/util/parse'
 import { JSONContent } from '@tiptap/core'
+import { addUserToContractFollowers } from './follow-market'
 
 export const onCreateContract = functions
   .runWith({ secrets: ['MAILGUN_KEY'] })
@@ -18,6 +19,7 @@ export const onCreateContract = functions
 
     const desc = contract.description as JSONContent
     const mentioned = parseMentions(desc)
+    await addUserToContractFollowers(contract, contractCreator)
 
     await createNotification(
       contract.id,

functions/src/on-create-liquidity-provision.ts

@@ -2,6 +2,7 @@ import * as functions from 'firebase-functions'
 import { getContract, getUser } from './utils'
 import { createNotification } from './create-notification'
 import { LiquidityProvision } from 'common/liquidity-provision'
+import { addUserToContractFollowers } from './follow-market'
 
 export const onCreateLiquidityProvision = functions.firestore
   .document('contracts/{contractId}/liquidity/{liquidityId}')
@@ -18,6 +19,7 @@ export const onCreateLiquidityProvision = functions.firestore
 
     const liquidityProvider = await getUser(liquidity.userId)
     if (!liquidityProvider) throw new Error('Could not find liquidity provider')
+    await addUserToContractFollowers(contract, liquidityProvider)
 
     await createNotification(
       contract.id,

functions/src/on-update-contract.ts

@@ -1,6 +1,6 @@
 import * as functions from 'firebase-functions'
 import { getUser } from './utils'
-import { createNotification } from './create-notification'
+import { createCommentOrAnswerOrUpdatedContractNotification } from './create-notification'
 import { Contract } from '../../common/contract'
 
 export const onUpdateContract = functions.firestore
@@ -29,14 +29,14 @@ export const onUpdateContract = functions.firestore
           resolutionText = `${contract.resolutionValue}`
       }
 
-      await createNotification(
+      await createCommentOrAnswerOrUpdatedContractNotification(
         contract.id,
         'contract',
         'resolved',
         contractUpdater,
         eventId,
         resolutionText,
-        { contract }
+        contract
       )
     } else if (
       previousValue.closeTime !== contract.closeTime ||
@@ -52,14 +52,14 @@ export const onUpdateContract = functions.firestore
         sourceText = contract.question
       }
 
-      await createNotification(
+      await createCommentOrAnswerOrUpdatedContractNotification(
         contract.id,
         'contract',
         'updated',
         contractUpdater,
         eventId,
         sourceText,
-        { contract }
+        contract
       )
     }
   })

functions/src/scripts/backfill-contract-followers.ts

@@ -0,0 +1,74 @@
+import * as admin from 'firebase-admin'
+
+import { initAdmin } from './script-init'
+initAdmin()
+
+import { getValues } from '../utils'
+import { Contract } from 'common/lib/contract'
+import { Comment } from 'common/lib/comment'
+import { uniq } from 'lodash'
+import { Bet } from 'common/lib/bet'
+import {
+  DEV_HOUSE_LIQUIDITY_PROVIDER_ID,
+  HOUSE_LIQUIDITY_PROVIDER_ID,
+} from 'common/lib/antes'
+
+const firestore = admin.firestore()
+
+async function backfillContractFollowers() {
+  console.log('Backfilling contract followers')
+  const contracts = await getValues<Contract>(
+    firestore.collection('contracts').where('isResolved', '==', false)
+  )
+  let count = 0
+  for (const contract of contracts) {
+    const comments = await getValues<Comment>(
+      firestore.collection('contracts').doc(contract.id).collection('comments')
+    )
+    const commenterIds = uniq(comments.map((comment) => comment.userId))
+    const betsSnap = await firestore
+      .collection(`contracts/${contract.id}/bets`)
+      .get()
+    const bets = betsSnap.docs.map((doc) => doc.data() as Bet)
+    // filter bets for only users that have an amount invested still
+    const bettorIds = uniq(bets.map((bet) => bet.userId))
+    const liquidityProviders = await firestore
+      .collection(`contracts/${contract.id}/liquidity`)
+      .get()
+    const liquidityProvidersIds = uniq(
+      liquidityProviders.docs.map((doc) => doc.data().userId)
+      // exclude free market liquidity provider
+    ).filter(
+      (id) =>
+        id !== HOUSE_LIQUIDITY_PROVIDER_ID ||
+        id !== DEV_HOUSE_LIQUIDITY_PROVIDER_ID
+    )
+    const followerIds = uniq([
+      ...commenterIds,
+      ...bettorIds,
+      ...liquidityProvidersIds,
+      contract.creatorId,
+    ])
+    for (const followerId of followerIds) {
+      await firestore
+        .collection(`contracts/${contract.id}/follows`)
+        .doc(followerId)
+        .set({ id: followerId, createdTime: Date.now() })
+    }
+    const followerCount = followerIds.length
+    await firestore
+      .collection(`contracts`)
+      .doc(contract.id)
+      .update({ followerCount: followerCount })
+    count += 1
+    if (count % 100 === 0) {
+      console.log(`${count} contracts processed`)
+    }
+  }
+}
+
+if (require.main === module) {
+  backfillContractFollowers()
+    .then(() => process.exit())
+    .catch(console.log)
+}

web/components/contract/share-row.tsx

@@ -1,8 +1,8 @@
 import clsx from 'clsx'
-import { ShareIcon } from '@heroicons/react/outline'
+import { EyeIcon, EyeOffIcon, ShareIcon } from '@heroicons/react/outline'
 
 import { Row } from '../layout/row'
-import { Contract } from 'web/lib/firebase/contracts'
+import { Contract, contracts } from 'web/lib/firebase/contracts'
 import { useState } from 'react'
 import { Button } from 'web/components/button'
 import { CreateChallengeModal } from '../challenges/create-challenge-modal'
@@ -10,6 +10,9 @@ import { User } from 'common/user'
 import { CHALLENGES_ENABLED } from 'common/challenge'
 import { ShareModal } from './share-modal'
 import { withTracking } from 'web/lib/service/analytics'
+import { collection, deleteDoc, doc } from 'firebase/firestore'
+import { users } from 'web/lib/firebase/users'
+import { useContractFollows } from 'web/hooks/use-follows'
 
 export function ShareRow(props: {
   contract: Contract
@@ -23,6 +26,7 @@ export function ShareRow(props: {
 
   const [isOpen, setIsOpen] = useState(false)
   const [isShareOpen, setShareOpen] = useState(false)
+  const followers = useContractFollows(contract.id)
 
   return (
     <Row className="mt-2">
@@ -62,6 +66,38 @@ export function ShareRow(props: {
           />
         </Button>
       )}
+      {user && (
+        <Button
+          size={'lg'}
+          color={'gray-white'}
+          onClick={async () => {
+            // remove user doc from contract follows collection
+            const followDoc = doc(
+              collection(contracts, contract.id, 'follows'),
+              user.id
+            )
+            await deleteDoc(followDoc)
+          }}
+        >
+          {followers?.includes(user.id) ? (
+            <Row>
+              <EyeOffIcon
+                className={clsx('mr-2 h-[24px] w-5')}
+                aria-hidden="true"
+              />
+              Unfollow
+            </Row>
+          ) : (
+            <Row>
+              <EyeIcon
+                className={clsx('mr-2 h-[24px] w-5')}
+                aria-hidden="true"
+              />
+              Follow
+            </Row>
+          )}
+        </Button>
+      )}
     </Row>
   )
 }

web/hooks/use-follows.ts

@@ -1,5 +1,6 @@
 import { useEffect, useState } from 'react'
 import { listenForFollowers, listenForFollows } from 'web/lib/firebase/users'
+import { contracts, listenForContractFollows } from 'web/lib/firebase/contracts'
 
 export const useFollows = (userId: string | null | undefined) => {
   const [followIds, setFollowIds] = useState<string[] | undefined>()
@@ -29,3 +30,13 @@ export const useFollowers = (userId: string | undefined) => {
 
   return followerIds
 }
+
+export const useContractFollows = (contractId: string) => {
+  const [followIds, setFollowIds] = useState<string[] | undefined>()
+
+  useEffect(() => {
+    return listenForContractFollows(contractId, setFollowIds)
+  }, [contractId])
+
+  return followIds
+}

web/lib/firebase/contracts.ts

@@ -23,6 +23,7 @@ import { Bet } from 'common/bet'
 import { Comment } from 'common/comment'
 import { ENV_CONFIG } from 'common/envs/constants'
 import { getBinaryProb } from 'common/contract-details'
+import { users } from 'web/lib/firebase/users'
 
 export const contracts = coll<Contract>('contracts')
 
@@ -212,6 +213,16 @@ export function listenForContract(
   return listenForValue<Contract>(contractRef, setContract)
 }
 
+export function listenForContractFollows(
+  contractId: string,
+  setFollowIds: (followIds: string[]) => void
+) {
+  const follows = collection(contracts, contractId, 'follows')
+  return listenForValues<{ id: string }>(follows, (docs) =>
+    setFollowIds(docs.map(({ id }) => id))
+  )
+}
+
 function chooseRandomSubset(contracts: Contract[], count: number) {
   const fiveMinutes = 5 * 60 * 1000
   const seed = Math.round(Date.now() / fiveMinutes).toString()