From 01e43abd17c630f62ba3f05731fac88aa23e092b Mon Sep 17 00:00:00 2001
From: James Grugett <jahooma@gmail.com>
Date: Wed, 20 Apr 2022 16:36:41 -0500
Subject: [PATCH] Add factors to weight new contracts higher, contracts with
 unseen comments, and contracts with prob closer to 50%

---
 common/calculate.ts                       | 21 ++++++++++-
 web/components/contract/contract-card.tsx | 14 +-------
 web/hooks/use-algo-feed.ts                | 44 +++++++++++++++++------
 3 files changed, 54 insertions(+), 25 deletions(-)

diff --git a/common/calculate.ts b/common/calculate.ts
index d6834295..cc6451c5 100644
--- a/common/calculate.ts
+++ b/common/calculate.ts
@@ -18,7 +18,14 @@ import {
   getDpmProbabilityAfterSale,
 } from './calculate-dpm'
 import { calculateFixedPayout } from './calculate-fixed-payouts'
-import { Binary, Contract, CPMM, DPM, FullContract } from './contract'
+import {
+  Binary,
+  Contract,
+  CPMM,
+  DPM,
+  FreeResponseContract,
+  FullContract,
+} from './contract'
 
 export function getProbability(contract: FullContract<DPM | CPMM, Binary>) {
   return contract.mechanism === 'cpmm-1'
@@ -170,3 +177,15 @@ export function getContractBetNullMetrics() {
     profitPercent: 0,
   }
 }
+
+export function getTopAnswer(contract: FreeResponseContract) {
+  const { answers } = contract
+  const top = _.maxBy(
+    answers.map((answer) => ({
+      answer,
+      prob: getOutcomeProbability(contract, answer.id),
+    })),
+    ({ prob }) => prob
+  )
+  return top?.answer
+}
diff --git a/web/components/contract/contract-card.tsx b/web/components/contract/contract-card.tsx
index f415a38c..41373679 100644
--- a/web/components/contract/contract-card.tsx
+++ b/web/components/contract/contract-card.tsx
@@ -23,7 +23,7 @@ import {
   BinaryContractOutcomeLabel,
   FreeResponseOutcomeLabel,
 } from '../outcome-label'
-import { getOutcomeProbability } from '../../../common/calculate'
+import { getOutcomeProbability, getTopAnswer } from '../../../common/calculate'
 import { AbbrContractDetails } from './contract-details'
 
 export function ContractCard(props: {
@@ -122,18 +122,6 @@ export function BinaryResolutionOrChance(props: {
   )
 }
 
-function getTopAnswer(contract: FreeResponseContract) {
-  const { answers } = contract
-  const top = _.maxBy(
-    answers.map((answer) => ({
-      answer,
-      prob: getOutcomeProbability(contract, answer.id),
-    })),
-    ({ prob }) => prob
-  )
-  return top?.answer
-}
-
 export function FreeResponseResolutionOrChance(props: {
   contract: FreeResponseContract
   truncate: 'short' | 'long' | 'none'
diff --git a/web/hooks/use-algo-feed.ts b/web/hooks/use-algo-feed.ts
index 68958821..365f4baa 100644
--- a/web/hooks/use-algo-feed.ts
+++ b/web/hooks/use-algo-feed.ts
@@ -8,6 +8,12 @@ import { logInterpolation } from '../../common/util/math'
 import { getRecommendedContracts } from '../../common/recommended-contracts'
 import { useSeenContracts } from './use-seen-contracts'
 import { useGetUserBetContractIds, useUserBetContracts } from './use-user-bets'
+import { DAY_MS } from '../../common/util/time'
+import {
+  getProbability,
+  getOutcomeProbability,
+  getTopAnswer,
+} from '../../common/calculate'
 
 const MAX_FEED_CONTRACTS = 75
 
@@ -120,11 +126,13 @@ function getContractsActivityScores(
   )
 
   const scoredContracts = contracts.map((contract) => {
+    const { outcomeType } = contract
+
     const seenTime = seenContracts[contract.id]
     const lastCommentTime = contractMostRecentComment[contract.id]?.createdTime
     const hasNewComments =
       !seenTime || (lastCommentTime && lastCommentTime > seenTime)
-    const newCommentScore = hasNewComments ? 1 : 0.75
+    const newCommentScore = hasNewComments ? 1 : 0.5
 
     const commentCount = contractComments[contract.id]?.length ?? 0
     const betCount = contractBets[contract.id]?.length ?? 0
@@ -132,25 +140,39 @@ function getContractsActivityScores(
     const activityCountScore =
       0.5 + 0.5 * logInterpolation(0, 200, activtyCount)
 
-    const lastBetTime = contractMostRecentBet[contract.id]?.createdTime
-    const timeSinceLastBet = !lastBetTime
-      ? contract.createdTime
-      : Date.now() - lastBetTime
-    const daysAgo = timeSinceLastBet / oneDayMs
+    const lastBetTime =
+      contractMostRecentBet[contract.id]?.createdTime ?? contract.createdTime
+    const timeSinceLastBet = Date.now() - lastBetTime
+    const daysAgo = timeSinceLastBet / DAY_MS
     const timeAgoScore = 1 - logInterpolation(0, 3, daysAgo)
 
-    const score = newCommentScore * activityCountScore * timeAgoScore
+    let prob = 0.5
+    if (outcomeType === 'BINARY') {
+      prob = getProbability(contract)
+    } else if (outcomeType === 'FREE_RESPONSE') {
+      const topAnswer = getTopAnswer(contract)
+      if (topAnswer)
+        prob = Math.max(0.5, getOutcomeProbability(contract, topAnswer.id))
+    }
+    const frac = 1 - Math.abs(prob - 0.5) ** 2 / 0.25
+    const probScore = 0.5 + frac * 0.5
+
+    const score =
+      newCommentScore * activityCountScore * timeAgoScore * probScore
 
     // Map score to [0.5, 1] since no recent activty is not a deal breaker.
     const mappedScore = 0.5 + score / 2
-    return [contract.id, mappedScore] as [string, number]
+    const newMappedScore = 0.75 + score / 4
+
+    const isNew = Date.now() < contract.createdTime + DAY_MS
+    const activityScore = isNew ? newMappedScore : mappedScore
+
+    return [contract.id, activityScore] as [string, number]
   })
 
   return _.fromPairs(scoredContracts)
 }
 
-const oneDayMs = 24 * 60 * 60 * 1000
-
 function getSeenContractsScore(
   contract: Contract,
   seenContracts: { [contractId: string]: number }
@@ -160,7 +182,7 @@ function getSeenContractsScore(
     return 1
   }
 
-  const daysAgo = (Date.now() - lastSeen) / oneDayMs
+  const daysAgo = (Date.now() - lastSeen) / DAY_MS
 
   if (daysAgo < 0.5) {
     const frac = logInterpolation(0, 0.5, daysAgo)