Sell bet UI

web/components/bet-panel.tsx

@@ -14,7 +14,7 @@ import {
   getProbability,
   calculateShares,
   getProbabilityAfterBet,
-} from '../lib/calculation/contract'
+} from '../lib/calculate'
 import { firebaseLogin } from '../lib/firebase/users'
 
 export function BetPanel(props: { contract: Contract; className?: string }) {

web/components/bets-list.tsx

@@ -13,11 +13,13 @@ import { Row } from './layout/row'
 import { UserLink } from './user-page'
 import {
   calculatePayout,
+  calculateSaleAmount,
   currentValue,
   resolvedPayout,
-} from '../lib/calculation/contract'
+} from '../lib/calculate'
 import clsx from 'clsx'
 import { cloudFunction } from '../lib/firebase/api-call'
+import { ConfirmationButton } from './confirmation-button'
 
 export function BetsList(props: { user: User }) {
   const { user } = props
@@ -229,6 +231,11 @@ export function ContractBetsTable(props: {
 }) {
   const { contract, bets, className } = props
 
+  const [sales, buys] = _.partition(bets, (bet) => bet.sale)
+  const salesDict = _.fromPairs(
+    sales.map((sale) => [sale.sale?.betId ?? '', sale])
+  )
+
   const { isResolved } = contract
 
   return (
@@ -238,16 +245,21 @@ export function ContractBetsTable(props: {
           <tr className="p-2">
             <th>Date</th>
             <th>Outcome</th>
-            <th>Bet</th>
+            <th>Amount</th>
             <th>Probability</th>
             {!isResolved && <th>Est. max payout</th>}
             <th>{isResolved ? <>Payout</> : <>Current value</>}</th>
-            {!isResolved && <th></th>}
+            <th></th>
           </tr>
         </thead>
         <tbody>
-          {bets.map((bet) => (
-            <BetRow key={bet.id} bet={bet} contract={contract} />
+          {buys.map((bet) => (
+            <BetRow
+              key={bet.id}
+              bet={bet}
+              sale={salesDict[bet.id]}
+              contract={contract}
+            />
           ))}
         </tbody>
       </table>
@@ -255,8 +267,8 @@ export function ContractBetsTable(props: {
   )
 }
 
-function BetRow(props: { bet: Bet; contract: Contract }) {
-  const { bet, contract } = props
+function BetRow(props: { bet: Bet; contract: Contract; sale?: Bet }) {
+  const { bet, sale, contract } = props
   const {
     amount,
     outcome,
@@ -264,14 +276,13 @@ function BetRow(props: { bet: Bet; contract: Contract }) {
     probBefore,
     probAfter,
     shares,
-    sale,
     isSold,
   } = bet
   const { isResolved } = contract
 
   return (
     <tr>
-      <td>{dayjs(createdTime).format('MMM D, H:mma')}</td>
+      <td>{dayjs(createdTime).format('MMM D, h:mma')}</td>
       <td>
         <OutcomeLabel outcome={outcome} />
       </td>
@@ -281,25 +292,39 @@ function BetRow(props: { bet: Bet; contract: Contract }) {
       </td>
       {!isResolved && <td>{formatMoney(shares)}</td>}
       <td>
-        {formatMoney(
-          isResolved
-            ? resolvedPayout(contract, bet)
-            : currentValue(contract, bet)
-        )}
+        {bet.isSold
+          ? 'N/A'
+          : formatMoney(
+              isResolved
+                ? resolvedPayout(contract, bet)
+                : bet.sale
+                ? bet.sale.amount ?? 0
+                : currentValue(contract, bet)
+            )}
       </td>
 
-      {!isResolved && !sale && !isSold && (
-        <td>
-          <button
-            className="btn"
-            onClick={async (e) => {
-              e.preventDefault()
-              await sellBet({ contractId: contract.id, betId: bet.id })
-            }}
-          >
-            Sell
-          </button>
-        </td>
+      {sale ? (
+        <td>SOLD for {formatMoney(Math.abs(sale.amount))}</td>
+      ) : (
+        !isResolved &&
+        !isSold && (
+          <td className="text-neutral">
+            <ConfirmationButton
+              id={`sell-${bet.id}`}
+              openModelBtn={{ className: 'btn-sm', label: 'Sell' }}
+              submitBtn={{ className: 'btn-primary' }}
+              onSubmit={async () => {
+                await sellBet({ contractId: contract.id, betId: bet.id })
+              }}
+            >
+              <div className="text-2xl mb-4">Sell</div>
+              <div>
+                Do you want to sell your {formatMoney(bet.amount)} bet for{' '}
+                {formatMoney(calculateSaleAmount(contract, bet))}?
+              </div>
+            </ConfirmationButton>
+          </td>
+        )
       )}
     </tr>
   )

web/lib/calculate.ts

@@ -1,5 +1,5 @@
-import { Bet } from '../firebase/bets'
-import { Contract } from '../firebase/contracts'
+import { Bet } from './firebase/bets'
+import { Contract } from './firebase/contracts'
 
 const fees = 0.02
 
@@ -44,16 +44,24 @@ export function calculatePayout(
   if (outcome === 'CANCEL') return amount
   if (betOutcome !== outcome) return 0
 
-  let { totalShares } = contract
+  const { totalShares } = contract
 
-  // Fake data if not set.
-  // if (!totalShares) totalShares = { YES: 100, NO: 100 }
+  if (totalShares[outcome] === 0) return 0
 
   const startPool = contract.startPool.YES + contract.startPool.NO
   const pool = contract.pool.YES + contract.pool.NO - startPool
 
+  console.log(
+    'calcPayout',
+    'shares',
+    shares,
+    'totalShares',
+    totalShares,
+    'pool'
+  )
   return (1 - fees) * (shares / totalShares[outcome]) * pool
 }
+
 export function resolvedPayout(contract: Contract, bet: Bet) {
   if (contract.resolution)
     return calculatePayout(contract, bet, contract.resolution)
@@ -65,5 +73,51 @@ export function currentValue(contract: Contract, bet: Bet) {
   const yesPayout = calculatePayout(contract, bet, 'YES')
   const noPayout = calculatePayout(contract, bet, 'NO')
 
+  console.log('calculate value', {
+    prob,
+    yesPayout,
+    noPayout,
+    amount: bet.amount,
+  })
+
   return prob * yesPayout + (1 - prob) * noPayout
 }
+export function calculateSaleAmount(contract: Contract, bet: Bet) {
+  const { shares, outcome } = bet
+
+  const { YES: yesPool, NO: noPool } = contract.pool
+  const { YES: yesStart, NO: noStart } = contract.startPool
+  const { YES: yesShares, NO: noShares } = contract.totalShares
+
+  const [y, n, s] = [yesPool, noPool, shares]
+
+  const shareValue =
+    outcome === 'YES'
+      ? // https://www.wolframalpha.com/input/?i=b+%2B+%28b+n%5E2%29%2F%28y+%28-b+%2B+y%29%29+%3D+c+solve+b
+        (n ** 2 +
+          s * y +
+          y ** 2 -
+          Math.sqrt(
+            n ** 4 + (s - y) ** 2 * y ** 2 + 2 * n ** 2 * y * (s + y)
+          )) /
+        (2 * y)
+      : (y ** 2 +
+          s * n +
+          n ** 2 -
+          Math.sqrt(
+            y ** 4 + (s - n) ** 2 * n ** 2 + 2 * y ** 2 * n * (s + n)
+          )) /
+        (2 * n)
+
+  const startPool = yesStart + noStart
+  const pool = yesPool + noPool - startPool
+
+  const f = outcome === 'YES' ? pool / yesShares : pool / noShares
+
+  const myPool = outcome === 'YES' ? yesPool - yesStart : noPool - noStart
+
+  const adjShareValue = Math.min(Math.min(1, f) * shareValue, myPool)
+
+  const saleAmount = (1 - fees) * adjShareValue
+  return saleAmount
+}