From f80ef1cd34216a58406d0fed9a945ee286c0a8a6 Mon Sep 17 00:00:00 2001
From: James Grugett <jahooma@gmail.com>
Date: Wed, 2 Feb 2022 00:40:46 -0600
Subject: [PATCH] Add hot markets to home feed

---
 web/lib/firebase/bets.ts            | 14 ++++++++++++++
 web/pages/activity.tsx              | 23 +++++++++++++++++++++++
 web/pages/fold/[...slugs]/index.tsx |  1 +
 web/pages/home.tsx                  | 11 ++++++++---
 4 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/web/lib/firebase/bets.ts b/web/lib/firebase/bets.ts
index 982d4f89..717551b4 100644
--- a/web/lib/firebase/bets.ts
+++ b/web/lib/firebase/bets.ts
@@ -4,6 +4,7 @@ import {
   query,
   onSnapshot,
   where,
+  orderBy,
 } from 'firebase/firestore'
 import _ from 'lodash'
 
@@ -23,6 +24,19 @@ export async function listAllBets(contractId: string) {
   return bets
 }
 
+const DAY_IN_MS = 24 * 60 * 60 * 1000
+
+// Define "recent" as "<24 hours ago" for now
+const recentBetsQuery = query(
+  collectionGroup(db, 'bets'),
+  where('createdTime', '>', Date.now() - DAY_IN_MS),
+  orderBy('createdTime', 'desc')
+)
+
+export async function getRecentBets() {
+  return getValues<Bet>(recentBetsQuery)
+}
+
 export function listenForBets(
   contractId: string,
   setBets: (bets: Bet[]) => void
diff --git a/web/pages/activity.tsx b/web/pages/activity.tsx
index e59aae32..b740d580 100644
--- a/web/pages/activity.tsx
+++ b/web/pages/activity.tsx
@@ -7,6 +7,7 @@ import { Col } from '../components/layout/col'
 import { Bet } from '../../common/bet'
 
 const MAX_ACTIVE_CONTRACTS = 75
+const MAX_HOT_MARKETS = 10
 
 // This does NOT include comment times, since those aren't part of the contract atm.
 // TODO: Maybe store last activity time directly in the contract?
@@ -23,9 +24,11 @@ function lastActivityTime(contract: Contract) {
 // - Comment on a market
 // - New market created
 // - Market resolved
+// - Markets with most betting in last 24 hours
 export function findActiveContracts(
   allContracts: Contract[],
   recentComments: Comment[],
+  recentBets: Bet[],
   daysAgo = 3
 ) {
   const idToActivityTime = new Map<string, number>()
@@ -56,6 +59,26 @@ export function findActiveContracts(
     }
   }
 
+  // Add recent top-trading contracts, ordered by last bet.
+  const contractBets = _.groupBy(recentBets, (bet) => bet.contractId)
+  const contractTotalBets = _.mapValues(contractBets, (bets) =>
+    _.sumBy(bets, (bet) => bet.amount)
+  )
+  const topTradedContracts = _.sortBy(
+    _.toPairs(contractTotalBets),
+    ([_, total]) => -1 * total
+  )
+    .map(([id]) => contractsById.get(id) as Contract)
+    .slice(0, MAX_HOT_MARKETS)
+
+  for (const contract of topTradedContracts) {
+    const bet = recentBets.find((bet) => bet.contractId === contract.id)
+    if (bet) {
+      contracts.push(contract)
+      record(contract.id, bet.createdTime)
+    }
+  }
+
   contracts = _.uniqBy(contracts, (c) => c.id)
   contracts = contracts.filter((contract) => contract.visibility === 'public')
   contracts = _.sortBy(contracts, (c) => -(idToActivityTime.get(c.id) ?? 0))
diff --git a/web/pages/fold/[...slugs]/index.tsx b/web/pages/fold/[...slugs]/index.tsx
index 30a7edba..2776f6c8 100644
--- a/web/pages/fold/[...slugs]/index.tsx
+++ b/web/pages/fold/[...slugs]/index.tsx
@@ -50,6 +50,7 @@ export async function getStaticProps(props: { params: { slugs: string[] } }) {
   let activeContracts = findActiveContracts(
     contracts,
     _.flatten(contractComments),
+    [],
     365
   )
   const [resolved, unresolved] = _.partition(
diff --git a/web/pages/home.tsx b/web/pages/home.tsx
index 54c2af24..840e1746 100644
--- a/web/pages/home.tsx
+++ b/web/pages/home.tsx
@@ -10,7 +10,7 @@ import {
   Comment,
   listAllComments,
 } from '../lib/firebase/comments'
-import { Bet, listAllBets } from '../lib/firebase/bets'
+import { Bet, getRecentBets, listAllBets } from '../lib/firebase/bets'
 import FeedCreate from '../components/feed-create'
 import { Spacer } from '../components/layout/spacer'
 import { Col } from '../components/layout/col'
@@ -18,12 +18,17 @@ import { useUser } from '../hooks/use-user'
 import { useContracts } from '../hooks/use-contracts'
 
 export async function getStaticProps() {
-  const [contracts, recentComments] = await Promise.all([
+  const [contracts, recentComments, recentBets] = await Promise.all([
     listAllContracts().catch((_) => []),
     getRecentComments().catch(() => []),
+    getRecentBets().catch(() => []),
   ])
 
-  const activeContracts = findActiveContracts(contracts, recentComments)
+  const activeContracts = findActiveContracts(
+    contracts,
+    recentComments,
+    recentBets
+  )
   const activeContractBets = await Promise.all(
     activeContracts.map((contract) => listAllBets(contract.id).catch((_) => []))
   )