refactor(tbank): centralize access rules

src/tbank/tbank-access.service.ts

@@ -0,0 +1,59 @@
+import {
+  ConflictException,
+  Injectable,
+  NotFoundException,
+} from '@nestjs/common';
+import { PrismaService } from '../prisma/prisma.service';
+import { BrokerageAccountDto } from './brokerage-account.dto';
+import {
+  accessibleTbankAccount,
+  supportedTbankAccounts,
+} from './tbank-account-policy';
+import { TbankClient, TbankAccount } from './tbank.client';
+import { TbankTokenService } from './tbank-token.service';
+
+export type TbankAccountContext = {
+  token: string;
+  account: TbankAccount;
+};
+
+@Injectable()
+export class TbankAccessService {
+  constructor(
+    private readonly prisma: PrismaService,
+    private readonly tokens: TbankTokenService,
+    private readonly tbank: TbankClient,
+  ) {}
+
+  async listSupportedAccounts(userId: string): Promise<BrokerageAccountDto[]> {
+    const { token } = await this.connection(userId);
+    return this.tokens.translateInvalidToken(async () =>
+      supportedTbankAccounts(await this.tbank.getOpenAccounts(token)),
+    );
+  }
+
+  async withAccount<T>(
+    userId: string,
+    accountId: string,
+    handler: (context: TbankAccountContext) => Promise<T>,
+  ): Promise<T> {
+    const { token } = await this.connection(userId);
+    return this.tokens.translateInvalidToken(async () => {
+      const account = accessibleTbankAccount(
+        await this.tbank.getOpenAccounts(token),
+        accountId,
+      );
+      if (!account) throw new NotFoundException();
+      return handler({ token, account });
+    });
+  }
+
+  private async connection(userId: string): Promise<{ token: string }> {
+    const connection = await this.prisma.tbankConnection.findUnique({
+      where: { userId },
+    });
+    if (!connection)
+      throw new ConflictException({ code: 'TBANK_NOT_CONNECTED' });
+    return { token: this.tokens.decrypt(connection.encryptedToken) };
+  }
+}