52 lines
1.4 KiB
TypeScript
52 lines
1.4 KiB
TypeScript
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import { Contract, getContract, setContract } from '../firebase/contracts'
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import { User } from '../firebase/users'
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import { randomString } from '../util/random-string'
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import { slugify } from '../util/slugify'
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// consider moving to cloud function for security
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export async function createContract(question: string, description: string, initialProb: number, creator: User) {
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const slug = slugify(question).substr(0, 35)
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const preexistingContract = await getContract(slug)
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const contractId = preexistingContract
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? slug + '-' + randomString()
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: slug
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const { seedYes, seedNo } = calcSeedBets(initialProb)
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const contract: Contract = {
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id: contractId,
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outcomeType: 'BINARY',
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creatorId: creator.id,
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creatorName: creator.name,
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question: question.trim(),
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description: description.trim(),
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seedAmounts: { YES: seedYes, NO: seedNo },
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pot: { YES: seedYes, NO: seedNo },
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// TODO: Set create time to Firestore timestamp
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createdTime: Date.now(),
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lastUpdatedTime: Date.now(),
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}
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await setContract(contract)
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return contract
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}
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export function calcSeedBets(initialProb: number, initialCapital = 1000) {
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const p = initialProb / 100.0
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const seedYes = p === 0.5
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? p * initialCapital
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: -(initialCapital * (-p + Math.sqrt((-1 + p) * -p))) / (-1 + 2 * p)
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const seedNo = initialCapital - seedYes
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return { seedYes, seedNo }
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}
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