Range bet executes both bets immediately.

common/new-bet.ts

@@ -265,6 +265,53 @@ export const getBinaryBetStats = (
   return { currentPayout, currentReturn, totalFees }
 }
 
+export const getBinaryRangeBetInfo = (
+  betAmount: number,
+  contract: CPMMBinaryContract | PseudoNumericContract,
+  lowLimitProb: number,
+  highLimitProb: number,
+  unfilledBets: LimitBet[]
+) => {
+  const shares = Math.min(
+    betAmount / lowLimitProb,
+    betAmount / (1 - highLimitProb)
+  )
+  const yesAmount = shares * lowLimitProb
+  const noAmount = shares * (1 - highLimitProb)
+
+  const yesResult = getBinaryCpmmBetInfo(
+    'YES',
+    yesAmount,
+    contract,
+    lowLimitProb,
+    unfilledBets
+  )
+  const noResult = getBinaryCpmmBetInfo(
+    'NO',
+    noAmount,
+    {
+      ...contract,
+      pool: yesResult.newPool,
+      p: yesResult.newP,
+      totalLiquidity: yesResult.newTotalLiquidity,
+    },
+    highLimitProb,
+    unfilledBets
+  )
+
+  const { newP, newPool, newTotalLiquidity } = noResult
+  const makers = [...yesResult.makers, ...noResult.makers]
+
+  return {
+    yesBet: yesResult.newBet,
+    noBet: noResult.newBet,
+    newP,
+    newPool,
+    newTotalLiquidity,
+    makers,
+  }
+}
+
 export const getNewBinaryDpmBetInfo = (
   outcome: 'YES' | 'NO',
   amount: number,

functions/src/place-bet.ts

@@ -14,6 +14,7 @@ import { User } from '../../common/user'
 import {
   BetInfo,
   getBinaryCpmmBetInfo,
+  getBinaryRangeBetInfo,
   getNewMultiBetInfo,
   getNumericBetsInfo,
 } from '../../common/new-bet'
@@ -28,10 +29,16 @@ const bodySchema = z.object({
   amount: z.number().gte(1),
 })
 
-const binarySchema = z.object({
-  outcome: z.enum(['YES', 'NO']),
-  limitProb: z.number().gte(0.001).lte(0.999).optional(),
-})
+const binarySchema = z.union([
+  z.object({
+    outcome: z.enum(['YES', 'NO']),
+    limitProb: z.number().gte(0.001).lte(0.999).optional(),
+  }),
+  z.object({
+    lowLimitProb: z.number().gte(0.001).lte(0.999),
+    highLimitProb: z.number().gte(0.001).lte(0.999),
+  }),
+])
 
 const freeResponseSchema = z.object({
   outcome: z.string(),
@@ -82,20 +89,32 @@ export const placebet = newEndpoint({}, async (req, auth) => {
         (outcomeType == 'BINARY' || outcomeType === 'PSEUDO_NUMERIC') &&
         mechanism == 'cpmm-1'
       ) {
-        const { outcome, limitProb } = validate(binarySchema, req.body)
-
         const unfilledBetsSnap = await trans.get(
           getUnfilledBetsQuery(contractDoc)
         )
         const unfilledBets = unfilledBetsSnap.docs.map((doc) => doc.data())
+        const data = validate(binarySchema, req.body)
+        if ('outcome' in data) {
+          const { outcome, limitProb } = data
 
-        return getBinaryCpmmBetInfo(
-          outcome,
-          amount,
-          contract,
-          limitProb,
-          unfilledBets
-        )
+          return getBinaryCpmmBetInfo(
+            outcome,
+            amount,
+            contract,
+            limitProb,
+            unfilledBets
+          )
+        } else {
+          const { lowLimitProb, highLimitProb } = data
+          const result = getBinaryRangeBetInfo(
+            amount,
+            contract,
+            lowLimitProb,
+            highLimitProb,
+            unfilledBets
+          )
+          return { newBet: result.yesBet, ...result }
+        }
       } else if (outcomeType == 'FREE_RESPONSE' && mechanism == 'dpm-2') {
         const { outcome } = validate(freeResponseSchema, req.body)
         const answerDoc = contractDoc.collection('answers').doc(outcome)