manifold/common/new-bet.ts
2022-01-10 16:49:13 -06:00

57 lines
1.5 KiB
TypeScript

import { Bet } from "./bet";
import { Contract } from "./contract";
import { User } from "./user";
export const getNewBetInfo = (
user: User,
outcome: "YES" | "NO",
amount: number,
contract: Contract,
newBetId: string
) => {
const { YES: yesPool, NO: noPool } = contract.pool;
const newPool =
outcome === "YES"
? { YES: yesPool + amount, NO: noPool }
: { YES: yesPool, NO: noPool + amount };
const shares =
outcome === "YES"
? amount + (amount * noPool ** 2) / (yesPool ** 2 + amount * yesPool)
: amount + (amount * yesPool ** 2) / (noPool ** 2 + amount * noPool);
const { YES: yesShares, NO: noShares } = contract.totalShares;
const newTotalShares =
outcome === "YES"
? { YES: yesShares + shares, NO: noShares }
: { YES: yesShares, NO: noShares + shares };
const { YES: yesBets, NO: noBets } = contract.totalBets;
const newTotalBets =
outcome === "YES"
? { YES: yesBets + amount, NO: noBets }
: { YES: yesBets, NO: noBets + amount };
const probBefore = yesPool ** 2 / (yesPool ** 2 + noPool ** 2);
const probAfter = newPool.YES ** 2 / (newPool.YES ** 2 + newPool.NO ** 2);
const newBet: Bet = {
id: newBetId,
userId: user.id,
contractId: contract.id,
amount,
shares,
outcome,
probBefore,
probAfter,
createdTime: Date.now(),
};
const newBalance = user.balance - amount;
return { newBet, newPool, newTotalShares, newTotalBets, newBalance };
};