simple resolver for createTransactionLink

backend/src/graphql/arg/TransactionLinkArgs.ts

@@ -0,0 +1,14 @@
+import { ArgsType, Field } from 'type-graphql'
+import Decimal from 'decimal.js-light'
+
+@ArgsType()
+export default class TransactionLinkArgs {
+  @Field(() => Decimal)
+  amount: Decimal
+
+  @Field(() => String)
+  memo: string
+
+  @Field(() => Boolean, { nullable: true })
+  showEmail?: boolean
+}

backend/src/graphql/resolver/TransactionLinkResolver.test.ts

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+import { transactionLinkCode } from './TransactionLinkResolver'
+
+describe('transactionLinkCode', () => {
+  const date = new Date()
+
+  it('returns a string of length 96', () => {
+    expect(transactionLinkCode(date)).toHaveLength(96)
+  })
+
+  it('returns a string that ends with the hex value of date', () => {
+    const regexp = new RegExp(date.getTime().toString(16) + '$')
+    expect(transactionLinkCode(date)).toEqual(expect.stringMatching(regexp))
+  })
+})

backend/src/graphql/resolver/TransactionLinkResolver.ts

@@ -0,0 +1,65 @@
+/* eslint-disable @typescript-eslint/no-explicit-any */
+/* eslint-disable @typescript-eslint/explicit-module-boundary-types */
+
+import { Resolver, Args, Authorized, Ctx, Mutation } from 'type-graphql'
+import { getCustomRepository } from '@dbTools/typeorm'
+import { TransactionLink } from '@model/TransactionLink'
+import { TransactionLink as dbTransactionLink } from '@entity/TransactionLink'
+import TransactionLinkArgs from '@arg/TransactionLinkArgs'
+import { UserRepository } from '@repository/User'
+import { calculateBalance } from '@/util/validate'
+import { RIGHTS } from '@/auth/RIGHTS'
+import { randomBytes } from 'crypto'
+import { User } from '@model/User'
+
+// TODO: do not export, test it inside the resolver
+export const transactionLinkCode = (date: Date): string => {
+  const time = date.getTime().toString(16)
+  return (
+    randomBytes(48)
+      .toString('hex')
+      .substring(0, 96 - time.length) + time
+  )
+}
+
+const transactionLinkExpireDate = (date: Date): Date => {
+  // valid for 14 days
+  return new Date(date.setDate(date.getDate() + 14))
+}
+
+@Resolver()
+export class TransactionLinkResolver {
+  @Authorized([RIGHTS.CREATE_TRANSACTION_LINK])
+  @Mutation(() => TransactionLink)
+  async createTransactionLink(
+    @Args() { amount, memo, showEmail = false }: TransactionLinkArgs,
+    @Ctx() context: any,
+  ): Promise<TransactionLink> {
+    const userRepository = getCustomRepository(UserRepository)
+    const user = await userRepository.findByPubkeyHex(context.pubKey)
+
+    // validate amount
+    // TODO taken from transaction resolver, duplicate code
+    const createdDate = new Date()
+    const sendBalance = await calculateBalance(user.id, amount.mul(-1), createdDate)
+    if (!sendBalance) {
+      throw new Error("user hasn't enough GDD or amount is < 0")
+    }
+
+    // TODO!!!! Test balance for pending transaction links
+
+    const transactionLink = dbTransactionLink.create()
+    transactionLink.userId = user.id
+    transactionLink.amount = amount
+    transactionLink.memo = memo
+    transactionLink.code = transactionLinkCode(createdDate)
+    transactionLink.createdAt = createdDate
+    transactionLink.validUntil = transactionLinkExpireDate(createdDate)
+    transactionLink.showEmail = showEmail
+    await dbTransactionLink.save(transactionLink).catch((error) => {
+      throw error
+    })
+
+    return new TransactionLink(transactionLink, new User(user))
+  }
+}