resolve markets

functions/package.json

@@ -14,7 +14,8 @@
   "main": "lib/index.js",
   "dependencies": {
     "firebase-admin": "10.0.0",
-    "firebase-functions": "3.16.0"
+    "firebase-functions": "3.16.0",
+    "lodash": "4.17.21"
   },
   "devDependencies": {
     "firebase-functions-test": "0.3.3",

functions/src/index.ts

@@ -2,4 +2,5 @@ import * as admin from 'firebase-admin'
 
 admin.initializeApp()
 
-export * from './place-bet'
+export * from './place-bet'
+export * from './resolve-market'

functions/src/resolve-market.ts

@@ -0,0 +1,107 @@
+import * as functions from 'firebase-functions'
+import * as admin from 'firebase-admin'
+import * as _ from 'lodash'
+
+import { Contract } from './types/contract'
+import { User } from './types/user'
+import { Bet } from './types/bet'
+
+export const PLATFORM_FEE = 0.01 // 1%
+export const CREATOR_FEE = 0.01 // 1%
+
+export const resolveMarket = functions
+  .runWith({ minInstances: 1 })
+  .https
+  .onCall(async (data: {
+    outcome: string
+    contractId: string
+  }, context) => {
+    const userId = context?.auth?.uid
+    if (!userId) return { status: 'error', message: 'Not authorized' }
+
+    const { outcome, contractId } = data
+
+    if (!['YES', 'NO', 'CANCEL'].includes(outcome))
+      return { status: 'error', message: 'Invalid outcome' }
+
+    const contractDoc = firestore.doc(`contracts/${contractId}`)
+    const contractSnap = await contractDoc.get()
+    if (!contractSnap.exists)
+      return { status: 'error', message: 'Invalid contract' }
+    const contract = contractSnap.data() as Contract
+
+    if (contract.creatorId !== userId)
+      return { status: 'error', message: 'User not creator of contract' }
+
+    if (contract.resolution)
+      return { status: 'error', message: 'Contract already resolved' }
+
+    await contractDoc.update({
+      isResolved: true,
+      resolution: outcome,
+      resolutionTime: Date.now()
+    })
+
+    console.log('contract ', contractId, 'resolved to:', outcome)
+
+    const betsSnap = await firestore.collection(`contracts/${contractId}/bets`).get()
+    const bets = betsSnap.docs.map(doc => doc.data() as Bet)
+
+    const payouts = outcome === 'CANCEL'
+      ? bets.map(bet => ({
+        userId: bet.userId,
+        payout: bet.amount
+      }))
+
+      : getPayouts(outcome, contract, bets)
+
+    console.log('payouts:', payouts)
+
+    const groups = _.groupBy(payouts, payout => payout.userId)
+    const userPayouts = _.mapValues(groups, group => _.sumBy(group, g => g.payout))
+
+    const payoutPromises = Object
+      .entries(userPayouts)
+      .map(payUser)
+
+    return await Promise.all(payoutPromises)
+      .catch(e => ({ status: 'error', message: e }))
+      .then(() => ({ status: 'success' }))
+  })
+
+const firestore = admin.firestore()
+
+const getPayouts = (outcome: string, contract: Contract, bets: Bet[]) => {
+  const [yesBets, noBets] = _.partition(bets, bet => bet.outcome === 'YES')
+
+  const [pot, winningBets] = outcome === 'YES'
+    ? [contract.pot.NO, yesBets]
+    : [contract.pot.YES, noBets]
+
+  const finalPot = (1 - PLATFORM_FEE - CREATOR_FEE) * pot
+  const creatorPayout = CREATOR_FEE * pot
+  console.log('final pot:', finalPot, 'creator fee:', creatorPayout)
+
+  const sumWeights = _.sumBy(winningBets, bet => bet.dpmWeight)
+
+  const winnerPayouts = winningBets.map(bet => ({
+    userId: bet.userId,
+    payout: bet.amount + (bet.dpmWeight / sumWeights * finalPot)
+  }))
+
+  return winnerPayouts
+    .concat([{ userId: contract.creatorId, payout: creatorPayout }]) // add creator fee
+}
+
+const payUser = ([userId, payout]: [string, number]) => {
+  return firestore.runTransaction(async transaction => {
+    const userDoc = firestore.doc(`users/${userId}`)
+    const userSnap = await transaction.get(userDoc)
+    if (!userSnap.exists) return
+    const user = userSnap.data() as User
+
+    const newUserBalance = user.balance + payout
+    transaction.update(userDoc, { balance: newUserBalance })
+  })
+}
+

web/components/resolution-panel.tsx

@@ -1,5 +1,6 @@
 import clsx from 'clsx'
 import React, { useState } from 'react'
+import { getFunctions, httpsCallable } from 'firebase/functions'
 
 import { Contract } from '../lib/firebase/contracts'
 import { Col } from './layout/col'
@@ -9,6 +10,9 @@ import { YesNoCancelSelector } from './yes-no-selector'
 import { Spacer } from './layout/spacer'
 import { ConfirmationModal } from './confirmation-modal'
 
+const functions = getFunctions()
+export const resolveMarket = httpsCallable(functions, 'resolveMarket')
+
 export function ResolutionPanel(props: {
   creator: User
   contract: Contract
@@ -18,18 +22,19 @@ export function ResolutionPanel(props: {
 
   const [outcome, setOutcome] = useState<'YES' | 'NO' | 'CANCEL' | undefined>()
 
-  function resolve() {
-    console.log('resolved', outcome)
+  const resolve = async () => {
+    const result = await resolveMarket({ outcome, contractId: contract.id })
+    console.log('resolved', outcome, 'result:', result.data)
   }
 
   const submitButtonClass =
     outcome === 'YES'
       ? 'btn-primary'
       : outcome === 'NO'
-      ? 'bg-red-400 hover:bg-red-500'
-      : outcome === 'CANCEL'
-      ? 'bg-yellow-400 hover:bg-yellow-500'
-      : 'btn-disabled'
+        ? 'bg-red-400 hover:bg-red-500'
+        : outcome === 'CANCEL'
+          ? 'bg-yellow-400 hover:bg-yellow-500'
+          : 'btn-disabled'
 
   return (
     <Col