import { Bet } from '../firebase/bets' import { Contract } from '../firebase/contracts' const fees = 0.02 export function getProbability(pool: { YES: number; NO: number }) { const [yesPool, noPool] = [pool.YES, pool.NO] const numerator = Math.pow(yesPool, 2) const denominator = Math.pow(yesPool, 2) + Math.pow(noPool, 2) return numerator / denominator } export function getProbabilityAfterBet( pool: { YES: number; NO: number }, outcome: 'YES' | 'NO', bet: number ) { const [YES, NO] = [ pool.YES + (outcome === 'YES' ? bet : 0), pool.NO + (outcome === 'NO' ? bet : 0), ] return getProbability({ YES, NO }) } export function getDpmWeight( pool: { YES: number; NO: number }, bet: number, betChoice: 'YES' | 'NO' ) { const [yesPool, noPool] = [pool.YES, pool.NO] return betChoice === 'YES' ? (bet * Math.pow(noPool, 2)) / (Math.pow(yesPool, 2) + bet * yesPool) : (bet * Math.pow(yesPool, 2)) / (Math.pow(noPool, 2) + bet * noPool) } export function calculatePayout( contract: Contract, bet: Bet, outcome: 'YES' | 'NO' | 'CANCEL' ) { const { amount, outcome: betOutcome, dpmWeight } = bet if (outcome === 'CANCEL') return amount if (betOutcome !== outcome) return 0 let { dpmWeights, pool, startPool } = contract // Fake data if not set. if (!dpmWeights) dpmWeights = { YES: 100, NO: 100 } // Fake data if not set. if (!pool) pool = { YES: 100, NO: 100 } const otherOutcome = outcome === 'YES' ? 'NO' : 'YES' const poolSize = pool[otherOutcome] - startPool[otherOutcome] return (1 - fees) * (dpmWeight / dpmWeights[outcome]) * poolSize + amount } export function resolvedPayout(contract: Contract, bet: Bet) { if (contract.resolution) return calculatePayout(contract, bet, contract.resolution) throw new Error('Contract was not resolved') } export function currentValue(contract: Contract, bet: Bet) { const prob = getProbability(contract.pool) const yesPayout = calculatePayout(contract, bet, 'YES') const noPayout = calculatePayout(contract, bet, 'NO') return prob * yesPayout + (1 - prob) * noPayout }