backend/src/modules/banking/bank-cards/application/bank-cards.service.ts

import { Injectable } from '@nestjs/common';

import { BankCard, Prisma } from '../../../../../generated/prisma/client';
import { PrismaService } from '../../../../prisma/prisma.service';
import { bankBalance } from '../domain/bank-card.calculations';
import { rubMoney } from '../domain/rub-money';
import { BankCardsRepository } from '../infrastructure/bank-cards.repository';
import {
  BankCardDto,
  CreateBankCardDto,
  UpdateBankCardDto,
} from '../presentation/bank-card.dto';
import {
  BankErrorCode,
  cardInput,
  conflict,
  currentDate,
  fail,
  fingerprint,
  missing,
} from './bank-card-input';

const EXPECTED_UPDATED_CARDS = 1;

type Tx = Prisma.TransactionClient;
@Injectable()
export class BankCardsService {
  constructor(
    private readonly prisma: PrismaService,
    private readonly repository: BankCardsRepository,
  ) {}

  private async cardView(tx: Tx, card: BankCard): Promise<BankCardDto> {
    const rows = await tx.bankCardOperation.findMany({
      where: {
        userId: card.userId,
        deletedAt: null,
        OR: [{ cardId: card.id }, { targetCardId: card.id }],
      },
    });
    return {
      id: card.id,
      name: card.name,
      bankName: card.bankName,
      lastFour: card.lastFour,
      paymentSystem: card.paymentSystem,
      openingDate: card.openingDate,
      openingBalance: rubMoney(card.openingBalanceKopecks),
      balance: rubMoney(bankBalance(card.id, card.openingBalanceKopecks, rows)),
      version: card.version,
      archivedAt: card.archivedAt?.toISOString() ?? null,
    };
  }

  list(userId: string, includeArchived = false) {
    return this.prisma.$transaction(async (tx) =>
      Promise.all(
        (
          await tx.bankCard.findMany({
            where: { userId, ...(includeArchived ? {} : { archivedAt: null }) },
            orderBy: [{ createdAt: 'asc' }, { id: 'asc' }],
          })
        ).map((card) => this.cardView(tx, card)),
      ),
    );
  }

  get(userId: string, id: string) {
    return this.prisma.$transaction(async (tx) =>
      this.cardView(tx, await this.repository.card(tx, userId, id)),
    );
  }

  createCard(userId: string, dto: CreateBankCardDto) {
    const input = cardInput(dto),
      hash = fingerprint(input);
    return this.repository.write(async (tx) => {
      const existing = await tx.bankCard.findUnique({ where: { id: dto.id } });
      if (existing) {
        if (existing.userId !== userId) missing();
        // eslint-disable-next-line security/detect-possible-timing-attacks -- This compares an idempotency fingerprint after ownership validation, not a secret.
        if (existing.createFingerprint !== hash) {
          conflict(BankErrorCode.IntentConflict);
        }
        return this.cardView(tx, existing);
      }
      currentDate(input.openingDate);
      await this.repository.seed(tx, userId);
      return this.cardView(
        tx,
        await tx.bankCard.create({
          data: { ...input, id: dto.id, userId, createFingerprint: hash },
        }),
      );
    });
  }

  updateCard(userId: string, id: string, dto: UpdateBankCardDto) {
    return this.repository.write(async (tx) => {
      const previous = await this.repository.card(tx, userId, id);
      if (previous.version !== dto.version) conflict();
      const input = cardInput({
        id,
        name: dto.name ?? previous.name,
        bankName:
          dto.bankName === undefined ? previous.bankName : dto.bankName,
        lastFour:
          dto.lastFour === undefined ? previous.lastFour : dto.lastFour,
        paymentSystem:
          dto.paymentSystem === undefined
            ? previous.paymentSystem
            : dto.paymentSystem,
        openingBalance:
          dto.openingBalance ?? rubMoney(previous.openingBalanceKopecks),
        openingDate: dto.openingDate ?? previous.openingDate,
      });
      const financial =
        input.openingBalanceKopecks !== previous.openingBalanceKopecks ||
        input.openingDate !== previous.openingDate;
      if (financial && previous.archivedAt) {
        conflict(BankErrorCode.CardArchived);
      }
      currentDate(input.openingDate);
      if (
        await tx.bankCardOperation.findFirst({
          where: {
            userId,
            deletedAt: null,
            date: { lt: input.openingDate },
            OR: [{ cardId: id }, { targetCardId: id }],
          },
        })
      ) {
        fail(BankErrorCode.OpeningDateConflict);
      }
      const changed = await tx.bankCard.updateMany({
        where: { id, userId, version: dto.version },
        data: {
          ...input,
          paymentSystem: input.paymentSystem ?? null,
          version: { increment: 1 },
          ...(dto.archived === undefined
            ? {}
            : {
                archivedAt: dto.archived
                  ? (previous.archivedAt ?? new Date())
                  : null,
              }),
        },
      });
      if (changed.count !== EXPECTED_UPDATED_CARDS) conflict();
      return this.cardView(tx, await this.repository.card(tx, userId, id));
    });
  }
}