7c4ec2a8e3
* Refactor contract types slightly * Refactor contract types greatly * Kill dead binary DPM contract creation code * Use BinaryContract, DPMContract, etc. type aliases
96 lines
2.9 KiB
TypeScript
96 lines
2.9 KiB
TypeScript
import * as admin from 'firebase-admin'
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import { partition, sumBy } from 'lodash'
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import { Bet } from '../../common/bet'
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import { getProbability } from '../../common/calculate'
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import { Contract } from '../../common/contract'
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import { noFees } from '../../common/fees'
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import { User } from '../../common/user'
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export const redeemShares = async (userId: string, contractId: string) => {
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return await firestore.runTransaction(async (transaction) => {
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const contractDoc = firestore.doc(`contracts/${contractId}`)
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const contractSnap = await transaction.get(contractDoc)
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if (!contractSnap.exists)
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return { status: 'error', message: 'Invalid contract' }
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const contract = contractSnap.data() as Contract
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if (contract.outcomeType !== 'BINARY' || contract.mechanism !== 'cpmm-1')
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return { status: 'success' }
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const betsSnap = await transaction.get(
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firestore
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.collection(`contracts/${contract.id}/bets`)
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.where('userId', '==', userId)
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)
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const bets = betsSnap.docs.map((doc) => doc.data() as Bet)
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const [yesBets, noBets] = partition(bets, (b) => b.outcome === 'YES')
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const yesShares = sumBy(yesBets, (b) => b.shares)
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const noShares = sumBy(noBets, (b) => b.shares)
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const amount = Math.min(yesShares, noShares)
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if (amount <= 0) return
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const prevLoanAmount = sumBy(bets, (bet) => bet.loanAmount ?? 0)
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const loanPaid = Math.min(prevLoanAmount, amount)
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const netAmount = amount - loanPaid
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const p = getProbability(contract)
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const createdTime = Date.now()
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const yesDoc = firestore.collection(`contracts/${contract.id}/bets`).doc()
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const yesBet: Bet = {
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id: yesDoc.id,
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userId: userId,
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contractId: contract.id,
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amount: p * -amount,
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shares: -amount,
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loanAmount: loanPaid ? -loanPaid / 2 : 0,
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outcome: 'YES',
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probBefore: p,
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probAfter: p,
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createdTime,
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isRedemption: true,
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fees: noFees,
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}
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const noDoc = firestore.collection(`contracts/${contract.id}/bets`).doc()
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const noBet: Bet = {
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id: noDoc.id,
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userId: userId,
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contractId: contract.id,
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amount: (1 - p) * -amount,
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shares: -amount,
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loanAmount: loanPaid ? -loanPaid / 2 : 0,
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outcome: 'NO',
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probBefore: p,
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probAfter: p,
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createdTime,
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isRedemption: true,
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fees: noFees,
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}
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const userDoc = firestore.doc(`users/${userId}`)
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const userSnap = await transaction.get(userDoc)
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if (!userSnap.exists) return { status: 'error', message: 'User not found' }
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const user = userSnap.data() as User
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const newBalance = user.balance + netAmount
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if (!isFinite(newBalance)) {
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throw new Error('Invalid user balance for ' + user.username)
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}
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transaction.update(userDoc, { balance: newBalance })
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transaction.create(yesDoc, yesBet)
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transaction.create(noDoc, noBet)
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return { status: 'success' }
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})
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}
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const firestore = admin.firestore()
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