website/src/lib/server/bank-sync.test.ts

import { describe, expect, it } from 'vitest';
import { generateKeyPairSync } from 'node:crypto';
import { decodeProtectedHeader, jwtVerify } from 'jose';
import {
	amountToCents,
	externalIdFor,
	findMatch,
	mapBankTransaction,
	planAccountMapping
} from './bank-sync';
import { createEnableBankingClient, parseAuthCode, type BankTransaction } from './enable-banking';

const tx = (overrides: Partial<BankTransaction> = {}): BankTransaction => ({
	entry_reference: 'ref-1',
	transaction_amount: { currency: 'EUR', amount: '12.34' },
	credit_debit_indicator: 'DBIT',
	status: 'BOOK',
	booking_date: '2026-10-20',
	value_date: '2026-10-19',
	creditor: { name: 'Albert Heijn' },
	remittance_information: ['AH 1234 Gouda'],
	...overrides
});

describe('bank transaction mapping', () => {
	it('parses decimal amounts exactly', () => {
		expect(amountToCents('12.34')).toBe(1234);
		expect(amountToCents('-0.5')).toBe(-50);
		expect(amountToCents('100')).toBe(10000);
		expect(amountToCents('1.005')).toBe(101);
	});

	it('signs debits negative and uses the counterparty as description', () => {
		const row = mapBankTransaction(tx())!;
		expect(row).toMatchObject({
			externalId: 'ref-1',
			date: '2026-10-20',
			valueDate: '2026-10-19',
			amountCents: -1234,
			description: 'Albert Heijn',
			counterparty: 'Albert Heijn',
			bookingStatus: 'BOOK'
		});
		const credit = mapBankTransaction(
			tx({ credit_debit_indicator: 'CRDT', creditor: null, debtor: { name: 'Juhee' } })
		)!;
		expect(credit.amountCents).toBe(1234);
		expect(credit.description).toBe('Juhee');
	});

	it('skips pending transactions', () => {
		expect(mapBankTransaction(tx({ status: 'PDNG' }))).toBeNull();
	});

	it('falls back to remittance info and to a stable content hash', () => {
		const anonymous = tx({ entry_reference: null, creditor: null });
		const row = mapBankTransaction(anonymous)!;
		expect(row.description).toBe('AH 1234 Gouda');
		expect(row.externalId).toMatch(/^h:[0-9a-f]{32}$/);
		expect(externalIdFor(anonymous)).toBe(row.externalId);
		expect(
			externalIdFor({ ...anonymous, transaction_amount: { currency: 'EUR', amount: '1.00' } })
		).not.toBe(row.externalId);
	});
});

describe('reconcile matching', () => {
	const rows = [
		{ id: 1, date: '2026-10-18', amountCents: -1234, description: 'Groceries' },
		{ id: 2, date: '2026-10-21', amountCents: -1234, description: 'Albert Heijn' },
		{ id: 3, date: '2026-10-20', amountCents: -999, description: 'Albert Heijn' }
	];
	it('matches same amount within one day, preferring description overlap', () => {
		const m = findMatch(
			{ date: '2026-10-20', amountCents: -1234, description: 'Albert Heijn' },
			rows,
			new Set()
		);
		expect(m?.id).toBe(2);
	});
	it('never reuses a row and ignores rows more than a day away', () => {
		expect(
			findMatch({ date: '2026-10-20', amountCents: -1234, description: 'x' }, rows, new Set([2]))
		).toBeNull();
	});
});

describe('account mapping', () => {
	const tracker = [
		{ id: 1, name: 'Revolut', scope: 'personal', iban: null, external_uid: null },
		{ id: 4, name: 'Joint', scope: 'joint', iban: null, external_uid: null }
	];
	it('maps the joint account and the personal EUR account', () => {
		const plan = planAccountMapping(
			[
				{ uid: 'a', account_id: { iban: 'LT1' }, name: 'Stan Runge', currency: 'EUR' },
				{ uid: 'b', account_id: { iban: 'LT2' }, name: 'Stan Runge & Juhee', currency: 'EUR' },
				{ uid: 'c', account_id: { iban: 'LT3' }, name: 'Stan Runge', currency: 'USD' }
			],
			tracker
		);
		expect(plan.map((p) => [p.bank.uid, p.tracker?.name ?? null])).toEqual([
			['b', 'Joint'],
			['a', 'Revolut'],
			['c', null]
		]);
	});
	it('honours overrides and existing IBANs', () => {
		const plan = planAccountMapping(
			[
				{ uid: 'a', account_id: { iban: 'LT1' }, name: 'X', currency: 'EUR' },
				{ uid: 'b', account_id: { iban: 'LT2' }, name: 'Y', currency: 'EUR' }
			],
			[{ ...tracker[0], iban: 'LT2' }, tracker[1]],
			{ a: 'Joint' }
		);
		expect(plan.map((p) => [p.bank.uid, p.tracker?.name])).toEqual([
			['a', 'Joint'],
			['b', 'Revolut']
		]);
	});
});

describe('enable banking client', () => {
	it('parses codes from redirect URLs, query strings and bare codes', () => {
		expect(
			parseAuthCode(
				'https://stanrunge.dev/projects/money-tracker/bank-callback?state=s&code=abc-123'
			)
		).toEqual({
			code: 'abc-123',
			state: 's',
			error: undefined
		});
		expect(parseAuthCode('abc-123').code).toBe('abc-123');
		expect(parseAuthCode('?error=access_denied&error_description=Cancelled').error).toBe(
			'access_denied: Cancelled'
		);
	});

	it('signs RS256 JWTs with the app id as kid and pages through transactions', async () => {
		const { privateKey, publicKey } = generateKeyPairSync('rsa', { modulusLength: 2048 });
		const calls: string[] = [];
		const fakeFetch = (async (url: string, init: RequestInit) => {
			calls.push(url);
			const auth = String((init.headers as Record<string, string>).Authorization).slice(7);
			expect(decodeProtectedHeader(auth)).toMatchObject({
				alg: 'RS256',
				kid: 'app-id',
				typ: 'JWT'
			});
			const { payload } = await jwtVerify(auth, publicKey, {
				issuer: 'enablebanking.com',
				audience: 'api.enablebanking.com'
			});
			expect(payload.exp! - payload.iat!).toBeLessThanOrEqual(86400);
			const page = new URL(url).searchParams.get('continuation_key');
			return new Response(
				JSON.stringify(
					page
						? { transactions: [tx({ entry_reference: 'r2' })] }
						: { transactions: [tx()], continuation_key: 'next' }
				)
			);
		}) as unknown as typeof fetch;
		const client = createEnableBankingClient({
			appId: 'app-id',
			privateKeyPem: privateKey.export({ type: 'pkcs8', format: 'pem' }).toString(),
			fetch: fakeFetch
		});
		const all = await client.transactions('uid-1', { dateFrom: '2026-01-01' });
		expect(all.map((t) => t.entry_reference)).toEqual(['ref-1', 'r2']);
		expect(calls[1]).toContain('continuation_key=next');
		expect(calls[0]).toContain('date_from=2026-01-01');
	});
});