Answer datatype and MULTI outcome type for Contract

common/answer.ts

@@ -0,0 +1,12 @@
+export type Answer = {
+  id: string
+  contractId: string
+  createdTime: number
+
+  userId: string
+  username: string
+  name: string
+  avatarUrl?: string
+
+  text: string
+}

common/contract.ts

@@ -1,4 +1,4 @@
-export type Contract = {
+export type Contract<outcomeType extends 'BINARY' | 'MULTI' = 'BINARY'> = {
   id: string
   slug: string // auto-generated; must be unique
 
@@ -11,14 +11,26 @@ export type Contract = {
   description: string // More info about what the contract is about
   tags: string[]
   lowercaseTags: string[]
-  outcomeType: 'BINARY' // | 'MULTI' | 'interval' | 'date'
+  outcomeType: outcomeType
   visibility: 'public' | 'unlisted'
 
   mechanism: 'dpm-2'
-  phantomShares: { YES: number; NO: number }
-  pool: { YES: number; NO: number }
-  totalShares: { YES: number; NO: number }
-  totalBets: { YES: number; NO: number }
+  phantomShares: {
+    BINARY: { YES: number; NO: number }
+    MULTI: { [answerId: string]: number }
+  }[outcomeType]
+  pool: {
+    BINARY: { YES: number; NO: number }
+    MULTI: { [answerId: string]: number }
+  }[outcomeType]
+  totalShares: {
+    BINARY: { YES: number; NO: number }
+    MULTI: { [answerId: string]: number }
+  }[outcomeType]
+  totalBets: {
+    BINARY: { YES: number; NO: number }
+    MULTI: { [answerId: string]: number }
+  }[outcomeType]
 
   createdTime: number // Milliseconds since epoch
   lastUpdatedTime: number // If the question or description was changed
@@ -26,7 +38,10 @@ export type Contract = {
 
   isResolved: boolean
   resolutionTime?: number // When the contract creator resolved the market
-  resolution?: outcome // Chosen by creator; must be one of outcomes
+  resolution?: {
+    BINARY: outcome
+    MULTI: string
+  }[outcomeType]
   resolutionProbability?: number
 
   volume24Hours: number

web/hooks/use-answers.ts

@@ -0,0 +1,13 @@
+import { useEffect, useState } from 'react'
+import { Answer } from '../../common/answer'
+import { listenForAnswers } from '../lib/firebase/answers'
+
+export const useAnswers = (contractId: string) => {
+  const [answers, setAnswers] = useState<Answer[] | undefined>()
+
+  useEffect(() => {
+    if (contractId) return listenForAnswers(contractId, setAnswers)
+  }, [contractId])
+
+  return answers
+}

web/lib/firebase/answers.ts

@@ -0,0 +1,52 @@
+import { doc, collection, setDoc } from 'firebase/firestore'
+
+import { getValues, listenForValues } from './utils'
+import { db } from './init'
+import { User } from '../../../common/user'
+import { Answer } from '../../../common/answer'
+
+function getAnswersCollection(contractId: string) {
+  return collection(db, 'contracts', contractId, 'answers')
+}
+
+export async function createAnswer(
+  contractId: string,
+  text: string,
+  user: User
+) {
+  const { id: userId, username, name, avatarUrl } = user
+
+  const ref = doc(getAnswersCollection(contractId))
+
+  const answer: Answer = {
+    id: ref.id,
+    contractId,
+    createdTime: Date.now(),
+    userId,
+    username,
+    name,
+    avatarUrl,
+    text,
+  }
+
+  return await setDoc(ref, answer)
+}
+
+export async function listAllAnswers(contractId: string) {
+  const answers = await getValues<Answer>(getAnswersCollection(contractId))
+  answers.sort((c1, c2) => c1.createdTime - c2.createdTime)
+  return answers
+}
+
+export function listenForAnswers(
+  contractId: string,
+  setAnswers: (answers: Answer[]) => void
+) {
+  return listenForValues<Answer>(
+    getAnswersCollection(contractId),
+    (answers) => {
+      answers.sort((c1, c2) => c1.createdTime - c2.createdTime)
+      setAnswers(answers)
+    }
+  )
+}