Deduct user balance only on each fill. Store orderAmount of bet. Timestamp of fills.

common/bet.ts

@@ -1,4 +1,3 @@
-import { Truthy } from 'lodash'
 import { Fees } from './fees'
 
 export type Bet = {
@@ -27,17 +26,10 @@ export type Bet = {
   isAnte?: boolean
   isLiquidityProvision?: boolean
   isRedemption?: boolean
-
   // A record of each transaction that partially (or fully) fills the bet amount.
   // I.e. A limit order could be filled by partially matching with several bets.
   // Non-limit orders can also be filled by matching with multiple limit orders.
-  fills?: {
+  fills?: fill[]
-    // The id the bet matched against, or null if the bet was matched by
-    // the pool.
-    matchedBetId: string | null
-    amount: number
-    shares: number
-  }[]
 }
 
 export type NumericBet = Bet & {
@@ -48,10 +40,19 @@ export type NumericBet = Bet & {
 
 // Binary market limit order.
 export type LimitBet = Bet & {
+  orderAmount: number // Amount of limit order.
   limitProb: number // [0, 1]. Bet to this probability.
   isFilled: boolean // Whether all of the bet amount has been filled.
   isCancelled: boolean // Whether to prevent any further fills.
-  fills: Truthy<Bet['fills']>
+  fills: fill[]
+}
+
+export type fill = {
+  // The id the bet matched against, or null if the bet was matched by the pool.
+  matchedBetId: string | null
+  amount: number
+  shares: number
+  timestamp: number
 }
 
 export const MAX_LOAN_PER_CONTRACT = 20

common/new-bet.ts

@@ -1,6 +1,6 @@
 import { sortBy, sumBy } from 'lodash'
 
-import { Bet, LimitBet, MAX_LOAN_PER_CONTRACT, NumericBet } from './bet'
+import { Bet, fill, LimitBet, MAX_LOAN_PER_CONTRACT, NumericBet } from './bet'
 import {
   calculateDpmShares,
   getDpmProbability,
@@ -62,6 +62,8 @@ const computeFill = (
     return undefined
   }
 
+  const timestamp = Date.now()
+
   if (
     !matchedBet ||
     (outcome === 'YES'
@@ -103,18 +105,19 @@ const computeFill = (
         amount: poolAmount,
         state: newState,
         fees,
+        timestamp,
       },
       taker: {
         matchedBetId: null,
         shares,
         amount: poolAmount,
+        timestamp,
       },
     }
   }
 
   // Fill from matchedBet.
-  const matchRemaining =
+  const matchRemaining = matchedBet.orderAmount - matchedBet.amount
-    matchedBet.amount - sumBy(matchedBet.fills, (fill) => fill.amount)
   const shares = Math.min(
     amount /
       (outcome === 'YES' ? matchedBet.limitProb : 1 - matchedBet.limitProb),
@@ -138,6 +141,7 @@ const computeFill = (
       shares *
       (outcome === 'YES' ? 1 - matchedBet.limitProb : matchedBet.limitProb),
     shares,
+    timestamp,
   }
   const taker = {
     matchedBetId: matchedBet.id,
@@ -145,6 +149,7 @@ const computeFill = (
       shares *
       (outcome === 'YES' ? matchedBet.limitProb : 1 - matchedBet.limitProb),
     shares,
+    timestamp,
   }
   return { maker, taker }
 }
@@ -164,12 +169,13 @@ export const getBinaryCpmmBetInfo = (
 
   console.log({ outcome, betAmount, limitProb, sortedBets })
 
-  const takers: {
+  const takers: fill[] = []
-    matchedBetId: string | null
+  const makers: {
+    bet: LimitBet
     amount: number
     shares: number
+    timestamp: number
   }[] = []
-  const makers: { bet: LimitBet; amount: number; shares: number }[] = []
 
   let amount = betAmount
   let cpmmState = { pool: contract.pool, p: contract.p }
@@ -210,13 +216,14 @@ export const getBinaryCpmmBetInfo = (
   const isFilled = floatingEqual(betAmount, takerAmount)
 
   const newBet: CandidateBet = removeUndefinedProps({
-    amount: betAmount,
+    orderAmount: betAmount,
+    amount: takerAmount,
+    shares: takerShares,
     limitProb,
     isFilled,
     isCancelled: false,
     fills: takers,
     contractId: contract.id,
-    shares: takerShares,
     outcome,
     probBefore,
     probAfter,

functions/src/place-bet.ts

@@ -1,7 +1,7 @@
 import * as admin from 'firebase-admin'
 import { z } from 'zod'
-import { Query } from 'firebase-admin/firestore'
+import { FieldValue, Query } from 'firebase-admin/firestore'
-import { sumBy } from 'lodash'
+import { groupBy, mapValues, sumBy } from 'lodash'
 
 import { APIError, newEndpoint, validate } from './api'
 import { Contract, CPMM_MIN_POOL_QTY } from '../../common/contract'
@@ -74,6 +74,7 @@ export const placebet = newEndpoint({}, async (req, auth) => {
           bet: LimitBet
           amount: number
           shares: number
+          timestamp: number
         }[]
       }
     > => {
@@ -128,29 +129,44 @@ export const placebet = newEndpoint({}, async (req, auth) => {
       throw new APIError(400, 'Bet too large for current liquidity pool.')
     }
 
-    const newBalance = user.balance - amount - loanAmount
     const betDoc = contractDoc.collection('bets').doc()
     trans.create(betDoc, { id: betDoc.id, userId: user.id, ...newBet })
     log('Created new bet document.')
 
     if (makers) {
-      for (const maker of makers) {
+      const makersByBet = groupBy(makers, (maker) => maker.bet.id)
-        const { bet, amount, shares } = maker
+      for (const makers of Object.values(makersByBet)) {
-        const newFill = { amount, shares, matchedBetId: betDoc.id }
+        const bet = makers[0].bet
-        const fills = [...bet.fills, newFill]
+        const newFills = makers.map((maker) => {
+          const { amount, shares, timestamp } = maker
+          return { amount, shares, matchedBetId: betDoc.id, timestamp }
+        })
+        const fills = [...bet.fills, ...newFills]
         const totalShares = sumBy(fills, 'shares')
-        const isFilled = floatingEqual(sumBy(fills, 'amount'), bet.amount)
+        const totalAmount = sumBy(fills, 'amount')
+        const isFilled = floatingEqual(totalAmount, bet.orderAmount)
 
         log('Updated a matched limit bet.')
         trans.update(contractDoc.collection('bets').doc(bet.id), {
           fills,
           isFilled,
+          amount: totalAmount,
           shares: totalShares,
         })
       }
+
+      // Deduct balance of makers.
+      const spentByUser = mapValues(
+        groupBy(makers, (maker) => maker.bet.userId),
+        (makers) => sumBy(makers, (maker) => maker.amount)
+      )
+      for (const [userId, spent] of Object.entries(spentByUser)) {
+        const userDoc = firestore.collection('users').doc(userId)
+        trans.update(userDoc, { balance: FieldValue.increment(-spent) })
+      }
     }
 
-    trans.update(userDoc, { balance: newBalance })
+    trans.update(userDoc, { balance: FieldValue.increment(-amount) })
     log('Updated user balance.')
     trans.update(
       contractDoc,

web/components/bet-panel.tsx

@@ -24,10 +24,7 @@ import { sellShares } from 'web/lib/firebase/api-call'
 import { AmountInput, BuyAmountInput } from './amount-input'
 import { InfoTooltip } from './info-tooltip'
 import { BinaryOutcomeLabel, PseudoNumericOutcomeLabel } from './outcome-label'
-import {
+import { getProbability } from 'common/calculate'
-  calculatePayoutAfterCorrectBet,
-  getProbability,
-} from 'common/calculate'
 import { useFocus } from 'web/hooks/use-focus'
 import { useUserContractBets } from 'web/hooks/use-user-bets'
 import {

web/components/bet-row.tsx

@@ -28,7 +28,6 @@ export default function BetRow(props: {
     contract,
     userBets
   )
-  
 
   return (
     <>

web/components/bets-list.tsx

@@ -505,7 +505,7 @@ export function ContractBetsTable(props: {
   const { contract, className, isYourBets } = props
 
   const bets = sortBy(
-    props.bets.filter((b) => !b.isAnte),
+    props.bets.filter((b) => !b.isAnte && b.amount !== 0),
     (bet) => bet.createdTime
   ).reverse()
 

web/components/feed/contract-activity.tsx

@@ -31,7 +31,9 @@ export function ContractActivity(props: {
   const comments = updatedComments ?? props.comments
 
   const updatedBets = useBets(contract.id)
-  const bets = (updatedBets ?? props.bets).filter((bet) => !bet.isRedemption)
+  const bets = (updatedBets ?? props.bets).filter(
+    (bet) => !bet.isRedemption && bet.amount !== 0
+  )
   const items = getSpecificContractActivityItems(
     contract,
     bets,

web/components/limit-bets.tsx

@@ -28,7 +28,7 @@ export function LimitBets(props: { bets: LimitBet[]; className?: string }) {
 
 function LimitBet(props: { bet: LimitBet }) {
   const { bet } = props
-  const filledAmount = sumBy(bet.fills, (fill) => fill.amount)
+  const { orderAmount, amount, limitProb, outcome } = bet
   const [isCancelling, setIsCancelling] = useState(false)
 
   const onCancel = () => {
@@ -40,11 +40,11 @@ function LimitBet(props: { bet: LimitBet }) {
     <tr>
       <td>
         <div className="pl-2">
-          <BinaryOutcomeLabel outcome={bet.outcome as 'YES' | 'NO'} />
+          <BinaryOutcomeLabel outcome={outcome as 'YES' | 'NO'} />
         </div>
       </td>
-      <td>{formatMoney(bet.amount - filledAmount)}</td>
+      <td>{formatMoney(orderAmount - amount)}</td>
-      <td>{formatPercent(bet.limitProb)}</td>
+      <td>{formatPercent(limitProb)}</td>
       <td>
         {isCancelling ? (
           <LoadingIndicator />