Allow users a free daily market

functions/src/create-contract.ts

@@ -1,7 +1,7 @@
 import * as functions from 'firebase-functions'
 import * as admin from 'firebase-admin'
 import * as _ from 'lodash'
-
+import { query, where } from 'firebase/firestore'
 import { chargeUser, getUser } from './utils'
 import {
   Binary,
@@ -109,7 +109,16 @@ export const createContract = functions
         tags ?? []
       )
 
-      if (ante) await chargeUser(creator.id, ante)
+      // uses utc time on server:
+      const today = new Date().setHours(0, 0, 0, 0)
+      const userContractsCreatedTodaySnapshot = await firestore
+        .collection(`contracts`)
+        .where('creatorId', '==', userId)
+        .where('createdTime', '>=', today)
+        .get()
+      const isFree = userContractsCreatedTodaySnapshot.size === 0
+
+      if (!isFree && ante) await chargeUser(creator.id, ante)
 
       await contractRef.create(contract)
 

web/components/nav/sidebar.tsx

@@ -19,6 +19,13 @@ import { firebaseLogin, firebaseLogout } from '../../lib/firebase/users'
 import { ManifoldLogo } from './manifold-logo'
 import { MenuButton } from './menu'
 import { getNavigationOptions, ProfileSummary } from './profile-menu'
+import { CreatorContractsList } from '../contract/contracts-list'
+import {
+  Contract,
+  listContracts,
+  userHasCreatedContractToday,
+} from '../../lib/firebase/contracts'
+import { useState } from 'react'
 
 const navigation = [
   { name: 'Home', href: '/home', icon: HomeIcon },
@@ -96,6 +103,11 @@ export default function Sidebar() {
   const user = useUser()
   let folds = useFollowedFolds(user) || []
   folds = _.sortBy(folds, 'followCount').reverse()
+  const [deservesDailyFreeMarket, setDeservesDailyFreeMarket] = useState(false)
+  user &&
+    userHasCreatedContractToday(user.id).then((result) => {
+      setDeservesDailyFreeMarket(result)
+    })
 
   const navigationOptions = user === null ? signedOutNavigation : navigation
   const mobileNavigationOptions =
@@ -159,10 +171,24 @@ export default function Sidebar() {
         />
       </div>
 
+      {/*// check their markets for if any have a created time of today, if they haven't made a market today, let them know they get a free market*/}
+      {deservesDailyFreeMarket ? (
+        <div className=" text-primary mt-4 text-center">
+          Use your daily free market!
+        </div>
+      ) : (
+        <div />
+      )}
+
+      {/*// check their markets for if any have a created time of today, if they haven't made a market today, give let them know they get a free market*/}
       {user && (
-        <Link href={'/create'}>
-          <button className="btn btn-primary btn-md mt-4">Create Market</button>
-        </Link>
+        <div className={'aligncenter flex justify-center'}>
+          <Link href={'/create'}>
+            <button className="btn btn-primary btn-md mt-4">
+              Create Market
+            </button>
+          </Link>
+        </div>
       )}
     </nav>
   )

web/lib/firebase/contracts.ts

@@ -121,6 +121,19 @@ export async function listAllContracts(): Promise<Contract[]> {
   return snapshot.docs.map((doc) => doc.data() as Contract)
 }
 
+export async function userHasCreatedContractToday(
+  userId: string
+): Promise<boolean> {
+  // uses utc time like the server
+  const todayAtMidnight = dayjs.utc().startOf('day').valueOf()
+  return listContracts(userId).then((contracts) => {
+    const todayContracts = contracts.filter((contract) => {
+      return contract.createdTime > todayAtMidnight
+    })
+    return todayContracts.length === 0
+  })
+}
+
 export function listenForContracts(
   setContracts: (contracts: Contract[]) => void
 ) {

web/pages/create.tsx

@@ -6,7 +6,11 @@ import Textarea from 'react-expanding-textarea'
 
 import { Spacer } from '../components/layout/spacer'
 import { useUser } from '../hooks/use-user'
-import { Contract, contractPath } from '../lib/firebase/contracts'
+import {
+  Contract,
+  contractPath,
+  userHasCreatedContractToday,
+} from '../lib/firebase/contracts'
 import { createContract } from '../lib/firebase/api-call'
 import { FIXED_ANTE, MINIMUM_ANTE } from '../../common/antes'
 import { InfoTooltip } from '../components/info-tooltip'
@@ -70,6 +74,13 @@ export function NewContract(props: { question: string; tag?: string }) {
   const tags = parseWordsAsTags(tagText)
 
   const [ante, setAnte] = useState(FIXED_ANTE)
+
+  const [deservesDailyFreeMarket, setDeservesDailyFreeMarket] = useState(false)
+  creator &&
+    userHasCreatedContractToday(creator.id).then((result) => {
+      setDeservesDailyFreeMarket(result)
+    })
+
   // useEffect(() => {
   //   if (ante === null && creator) {
   //     const initialAnte = creator.balance < 100 ? MINIMUM_ANTE : 100
@@ -241,10 +252,14 @@ export function NewContract(props: { question: string; tag?: string }) {
             text={`Cost to create your market. This amount is used to subsidize trading.`}
           />
         </label>
-
-        <div className="label-text text-neutral pl-1">{formatMoney(ante)}</div>
-
-        {ante > balance && (
+        {deservesDailyFreeMarket ? (
+          <div className="label-text text-primary pl-1">FREE</div>
+        ) : (
+          <div className="label-text text-neutral pl-1">
+            {formatMoney(ante)}
+          </div>
+        )}
+        {!deservesDailyFreeMarket && ante > balance && (
           <div className="mb-2 mt-2 mr-auto self-center whitespace-nowrap text-xs font-medium tracking-wide">
             <span className="mr-2 text-red-500">Insufficient balance</span>
             <button