112 lines
3.7 KiB
TypeScript
112 lines
3.7 KiB
TypeScript
import { sumBy, uniq } from 'lodash'
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import * as admin from 'firebase-admin'
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import { z } from 'zod'
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import { APIError, newEndpoint, validate } from './api'
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import { Contract, CPMM_MIN_POOL_QTY } from '../../common/contract'
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import { User } from '../../common/user'
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import { getCpmmSellBetInfo } from '../../common/sell-bet'
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import { addObjects, removeUndefinedProps } from '../../common/util/object'
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import { getValues, log } from './utils'
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import { Bet } from '../../common/bet'
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import { floatingLesserEqual } from '../../common/util/math'
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import { getUnfilledBetsQuery, updateMakers } from './place-bet'
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import { FieldValue } from 'firebase-admin/firestore'
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import { redeemShares } from './redeem-shares'
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const bodySchema = z.object({
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contractId: z.string(),
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shares: z.number(),
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outcome: z.enum(['YES', 'NO']),
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})
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export const sellshares = newEndpoint({}, async (req, auth) => {
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const { contractId, shares, outcome } = validate(bodySchema, req.body)
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// Run as transaction to prevent race conditions.
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const result = await firestore.runTransaction(async (transaction) => {
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const contractDoc = firestore.doc(`contracts/${contractId}`)
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const userDoc = firestore.doc(`users/${auth.uid}`)
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const betsQ = contractDoc.collection('bets').where('userId', '==', auth.uid)
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const [[contractSnap, userSnap], userBets] = await Promise.all([
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transaction.getAll(contractDoc, userDoc),
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getValues<Bet>(betsQ), // TODO: why is this not in the transaction??
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])
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if (!contractSnap.exists) throw new APIError(400, 'Contract not found.')
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if (!userSnap.exists) throw new APIError(400, 'User not found.')
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const contract = contractSnap.data() as Contract
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const user = userSnap.data() as User
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const { closeTime, mechanism, collectedFees, volume } = contract
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if (mechanism !== 'cpmm-1')
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throw new APIError(400, 'You can only sell shares on CPMM-1 contracts.')
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if (closeTime && Date.now() > closeTime)
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throw new APIError(400, 'Trading is closed.')
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const prevLoanAmount = sumBy(userBets, (bet) => bet.loanAmount ?? 0)
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const outcomeBets = userBets.filter((bet) => bet.outcome == outcome)
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const maxShares = sumBy(outcomeBets, (bet) => bet.shares)
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if (!floatingLesserEqual(shares, maxShares))
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throw new APIError(400, `You can only sell up to ${maxShares} shares.`)
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const soldShares = Math.min(shares, maxShares)
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const unfilledBetsSnap = await transaction.get(
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getUnfilledBetsQuery(contractDoc)
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)
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const unfilledBets = unfilledBetsSnap.docs.map((doc) => doc.data())
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const { newBet, newPool, newP, fees, makers } = getCpmmSellBetInfo(
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soldShares,
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outcome,
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contract,
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prevLoanAmount,
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unfilledBets
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)
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if (
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!newP ||
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!isFinite(newP) ||
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Math.min(...Object.values(newPool ?? {})) < CPMM_MIN_POOL_QTY
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) {
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throw new APIError(400, 'Sale too large for current liquidity pool.')
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}
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const newBetDoc = firestore.collection(`contracts/${contractId}/bets`).doc()
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updateMakers(makers, newBetDoc.id, contractDoc, transaction)
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transaction.update(userDoc, {
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balance: FieldValue.increment(-newBet.amount),
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})
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transaction.create(newBetDoc, {
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id: newBetDoc.id,
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userId: user.id,
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...newBet,
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})
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transaction.update(
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contractDoc,
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removeUndefinedProps({
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pool: newPool,
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p: newP,
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collectedFees: addObjects(fees, collectedFees),
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volume: volume + Math.abs(newBet.amount),
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})
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)
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return { newBet, makers }
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})
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const userIds = uniq(result.makers.map((maker) => maker.bet.userId))
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await Promise.all(userIds.map((userId) => redeemShares(userId, contractId)))
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log('Share redemption transaction finished.')
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return { status: 'success' }
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})
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const firestore = admin.firestore()
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