gistfile1.txt

// prisma/schema.prisma

model User {
  id        String   @id @default(cuid())
  // ... other user fields ...
  ledger    Ledger?
  journals  Journal[]
}

model Ledger {
  id           String   @id @default(cuid())
  userId       String   @unique
  user         User     @relation(fields: [userId], references: [id])
  balance      Float    @default(0)
  lastUpdated  DateTime @updatedAt
}

model Journal {
  id              String   @id @default(cuid())
  userId          String
  user            User     @relation(fields: [userId], references: [id])
  credit          Float    @default(0)
  debit           Float    @default(0)
  runningTotal    Float
  transactionType TransactionType
  description     String
  createdAt       DateTime @default(now())
}

enum TransactionType {
  DEPOSIT
  USAGE
}


/// CODE:

import { prisma } from '@repo/database'
import { TransactionType } from '@prisma/client'

interface CreditOperation {
  userId: string
  amount: number
  description: string
}

export async function addCredit({ userId, amount, description }: CreditOperation) {
  return prisma.$transaction(async (tx) => {
    const ledger = await tx.ledger.upsert({
      where: { userId },
      update: { balance: { increment: amount } },
      create: { userId, balance: amount },
    })

    const journal = await tx.journal.create({
      data: {
        userId,
        credit: amount,
        debit: 0,
        runningTotal: ledger.balance,
        transactionType: TransactionType.DEPOSIT,
        description,
      },
    })

    return { ledger, journal }
  })
}

export async function debitCredit({ userId, amount, description }: CreditOperation) {
  return prisma.$transaction(async (tx) => {
    const ledger = await tx.ledger.findUnique({ where: { userId } })

    if (!ledger || ledger.balance < amount) {
      throw new Error('Insufficient balance')
    }

    const updatedLedger = await tx.ledger.update({
      where: { userId },
      data: { balance: { decrement: amount } },
    })

    const journal = await tx.journal.create({
      data: {
        userId,
        credit: 0,
        debit: amount,
        runningTotal: updatedLedger.balance,
        transactionType: TransactionType.USAGE,
        description,
      },
    })

    return { ledger: updatedLedger, journal }
  })
}