user-added liquidity provision panel (#90)

* user-added liquidity provision panel

* AddLiquidityPanel: handle loading, errors

* ContractInfoDialog: don't show add liquidity when market is closed

* ContractInfoDialog: hide add liquidity for FR

common/add-liquidity.ts

@@ -0,0 +1,35 @@
+import { addCpmmLiquidity, getCpmmLiquidity } from './calculate-cpmm'
+import { Binary, CPMM, FullContract } from './contract'
+import { LiquidityProvision } from './liquidity-provision'
+import { User } from './user'
+
+export const getNewLiquidityProvision = (
+  user: User,
+  amount: number,
+  contract: FullContract<CPMM, Binary>,
+  newLiquidityProvisionId: string
+) => {
+  const { pool, p, totalLiquidity } = contract
+
+  const { newPool, newP } = addCpmmLiquidity(pool, p, amount)
+
+  const liquidity =
+    getCpmmLiquidity(newPool, newP) - getCpmmLiquidity(pool, newP)
+
+  const newLiquidityProvision: LiquidityProvision = {
+    id: newLiquidityProvisionId,
+    userId: user.id,
+    contractId: contract.id,
+    amount,
+    pool: newPool,
+    p: newP,
+    liquidity,
+    createdTime: Date.now(),
+  }
+
+  const newTotalLiquidity = (totalLiquidity ?? 0) + amount
+
+  const newBalance = user.balance - amount
+
+  return { newLiquidityProvision, newPool, newP, newBalance, newTotalLiquidity }
+}

functions/src/add-liquidity.ts

@@ -0,0 +1,103 @@
+import * as functions from 'firebase-functions'
+import * as admin from 'firebase-admin'
+
+import { Contract } from '../../common/contract'
+import { User } from '../../common/user'
+import { removeUndefinedProps } from '../../common/util/object'
+import { redeemShares } from './redeem-shares'
+import { getNewLiquidityProvision } from '../../common/add-liquidity'
+
+export const addLiquidity = functions.runWith({ minInstances: 1 }).https.onCall(
+  async (
+    data: {
+      amount: number
+      contractId: string
+    },
+    context
+  ) => {
+    const userId = context?.auth?.uid
+    if (!userId) return { status: 'error', message: 'Not authorized' }
+
+    const { amount, contractId } = data
+
+    if (amount <= 0 || isNaN(amount) || !isFinite(amount))
+      return { status: 'error', message: 'Invalid amount' }
+
+    // run as transaction to prevent race conditions
+    return await firestore
+      .runTransaction(async (transaction) => {
+        const userDoc = firestore.doc(`users/${userId}`)
+        const userSnap = await transaction.get(userDoc)
+        if (!userSnap.exists)
+          return { status: 'error', message: 'User not found' }
+        const user = userSnap.data() as User
+
+        const contractDoc = firestore.doc(`contracts/${contractId}`)
+        const contractSnap = await transaction.get(contractDoc)
+        if (!contractSnap.exists)
+          return { status: 'error', message: 'Invalid contract' }
+        const contract = contractSnap.data() as Contract
+        if (
+          contract.mechanism !== 'cpmm-1' ||
+          contract.outcomeType !== 'BINARY'
+        )
+          return { status: 'error', message: 'Invalid contract' }
+
+        const { closeTime } = contract
+        if (closeTime && Date.now() > closeTime)
+          return { status: 'error', message: 'Trading is closed' }
+
+        if (user.balance < amount)
+          return { status: 'error', message: 'Insufficient balance' }
+
+        const newLiquidityProvisionDoc = firestore
+          .collection(`contracts/${contractId}/liquidity`)
+          .doc()
+
+        const {
+          newLiquidityProvision,
+          newPool,
+          newP,
+          newBalance,
+          newTotalLiquidity,
+        } = getNewLiquidityProvision(
+          user,
+          amount,
+          contract,
+          newLiquidityProvisionDoc.id
+        )
+
+        if (newP !== undefined && !isFinite(newP)) {
+          return {
+            status: 'error',
+            message: 'Liquidity injection rejected due to overflow error.',
+          }
+        }
+
+        transaction.update(
+          contractDoc,
+          removeUndefinedProps({
+            pool: newPool,
+            p: newP,
+            totalLiquidity: newTotalLiquidity,
+          })
+        )
+
+        if (!isFinite(newBalance)) {
+          throw new Error('Invalid user balance for ' + user.username)
+        }
+
+        transaction.update(userDoc, { balance: newBalance })
+
+        transaction.create(newLiquidityProvisionDoc, newLiquidityProvision)
+
+        return { status: 'success', newLiquidityProvision }
+      })
+      .then(async (result) => {
+        await redeemShares(userId, contractId)
+        return result
+      })
+  }
+)
+
+const firestore = admin.firestore()

functions/src/index.ts

@@ -21,3 +21,4 @@ export * from './update-user-metrics'
 export * from './backup-db'
 export * from './change-user-info'
 export * from './market-close-emails'
+export * from './add-liquidity'

web/components/add-liquidity-panel.tsx

@@ -0,0 +1,85 @@
+import clsx from 'clsx'
+import { useState } from 'react'
+
+import { Contract } from '../../common/contract'
+import { formatMoney } from '../../common/util/format'
+import { useUser } from '../hooks/use-user'
+import { addLiquidity } from '../lib/firebase/api-call'
+import { AmountInput } from './amount-input'
+import { Row } from './layout/row'
+
+export function AddLiquidityPanel(props: { contract: Contract }) {
+  const { contract } = props
+  const { id: contractId } = contract
+
+  const user = useUser()
+
+  const [amount, setAmount] = useState<number | undefined>(undefined)
+  const [error, setError] = useState<string | undefined>(undefined)
+  const [isSuccess, setIsSuccess] = useState(false)
+  const [isLoading, setIsLoading] = useState(false)
+
+  const onAmountChange = (amount: number | undefined) => {
+    setIsSuccess(false)
+    setAmount(amount)
+
+    // Check for errors.
+    if (amount !== undefined) {
+      if (user && user.balance < amount) {
+        setError('Insufficient balance')
+      } else if (amount < 1) {
+        setError('Minimum amount: ' + formatMoney(1))
+      } else {
+        setError(undefined)
+      }
+    }
+  }
+
+  const submit = () => {
+    if (!amount) return
+
+    setIsLoading(true)
+    setIsSuccess(false)
+
+    addLiquidity({ amount, contractId })
+      .then((r) => {
+        if (r.status === 'success') {
+          setIsSuccess(true)
+          setError(undefined)
+          setIsLoading(false)
+        } else {
+          setError('Server error')
+        }
+      })
+      .catch((e) => setError('Server error'))
+  }
+
+  return (
+    <>
+      <div>Subsidize this market by adding liquidity for traders.</div>
+
+      <Row>
+        <AmountInput
+          amount={amount}
+          onChange={onAmountChange}
+          label="M$"
+          error={error}
+          disabled={isLoading}
+        />
+        <button
+          className={clsx('btn btn-primary ml-2', isLoading && 'btn-disabled')}
+          onClick={submit}
+          disabled={isLoading}
+        >
+          Add
+        </button>
+      </Row>
+
+      {isSuccess && amount && (
+        <div>Success! Added {formatMoney(amount)} in liquidity.</div>
+      )}
+
+      {isLoading && <div>Processing...</div>}
+    </>
+  )
+}

web/components/contract/contract-info-dialog.tsx

@@ -11,6 +11,7 @@ import {
   contractPath,
   getBinaryProbPercent,
 } from '../../lib/firebase/contracts'
+import { AddLiquidityPanel } from '../add-liquidity-panel'
 import { CopyLinkButton } from '../copy-link-button'
 import { Col } from '../layout/col'
 import { Modal } from '../layout/modal'
@@ -110,8 +111,16 @@ export function ContractInfoDialog(props: { contract: Contract; bets: Bet[] }) {
 
           <div className="text-gray-500">Tags</div>
           <TagsInput contract={contract} />
-
           <div />
+
+          {contract.mechanism === 'cpmm-1' &&
+            !contract.resolution &&
+            (!closeTime || closeTime > Date.now()) && (
+              <>
+                <div className="text-gray-500">Add liquidity</div>
+                <AddLiquidityPanel contract={contract} />
+              </>
+            )}
         </Col>
       </Modal>
     </>

web/lib/firebase/api-call.ts

@@ -66,3 +66,9 @@ export const changeUserInfo = (data: {
     .then((r) => r.data as { status: string; message?: string })
     .catch((e) => ({ status: 'error', message: e.message }))
 }
+
+export const addLiquidity = (data: { amount: number; contractId: string }) => {
+  return cloudFunction('addLiquidity')(data)
+    .then((r) => r.data as { status: string })
+    .catch((e) => ({ status: 'error', message: e.message }))
+}