catcrafts.net/tests/ShouldParseBunqPayments/main.cpp

/*
catcrafts.net
Copyright (C) 2026 Catcrafts

The source code of this website is made available for viewing purposes only.
No permission is granted to copy, modify, distribute, or create derivative works.
*/

// Decoding bunq's payment list into credits. The HTTP around this is thin; the
// decoding is where a mistake costs money and says nothing, which is the same
// reason ParseEthCallUint and ParseEurcChains are pinned here rather than
// trusted to integration.
//
// Two properties carry real weight:
//
//   * The SIGN. bunq quotes an outgoing payment as a negative value, and the
//     shop sends refunds quoting the very reference of the order they refund.
//     Lose the minus and a refund pays for the order it reversed.
//   * The METHOD. `Payment.type` decides whether an order is safe to post: a
//     SEPA credit transfer is final, a card payment can be reversed for
//     months. Collapsing them to "paid" is how a chargeback becomes a
//     shipped parcel.

import std;
import Catcrafts.Shared;
import Catcrafts.Server;

using namespace Catcrafts;

namespace {

int failures = 0;

void Check(bool ok, std::string_view what, std::string_view got = {}) {
    if (ok) return;
    ++failures;
    std::println(std::cerr, "FAIL: {}{}{}", what,
                 got.empty() ? "" : "  got: ", got);
}

// The shape bunq actually answers with: everything wrapped in Response, one
// object per entry keyed by type.
constexpr std::string_view kList = R"({
  "Response": [
    {"Payment": {
      "id": 4155551,
      "type": "EBA_SCT",
      "description": "CC-2B6457 catcrafts.net",
      "amount": {"currency": "EUR", "value": "57.38"}
    }},
    {"Payment": {
      "id": 4155552,
      "type": "IDEAL",
      "description": "donation cc2b6457",
      "amount": {"currency": "EUR", "value": "5.00"}
    }},
    {"Payment": {
      "id": 4155553,
      "type": "EBA_SCT",
      "description": "supplier invoice",
      "amount": {"currency": "EUR", "value": "-513.00"}
    }},
    {"Payment": {
      "id": 4155554,
      "type": "FIS",
      "description": "card payment",
      "amount": {"currency": "USD", "value": "20.00"}
    }}
  ]
})";

} // namespace

int main() {
    const std::vector<Server::BankCredit> credits = Server::ParseBunqPayments(kList);

    // The USD entry is dropped: counting 20 of something else as 20 euro is
    // the kind of bug that only shows up as a shortfall nobody can explain.
    Check(credits.size() == 3, "only the euro payments are decoded",
          std::format("{}", credits.size()));

    if (credits.size() == 3) {
        Check(credits[0].id == "4155551", "the bank's own id is kept, for dedupe",
              credits[0].id);
        Check(credits[0].reference == "CC-2B6457 catcrafts.net",
              "the description is the remittance text, verbatim", credits[0].reference);
        Check(credits[0].amountMinor == 5738, "57.38 decodes to 5738 minor units",
              std::format("{}", credits[0].amountMinor));
        Check(credits[0].method == "sepa", "EBA_SCT is a plain SEPA transfer",
              credits[0].method);
        Check(credits[1].method == "ideal", "IDEAL is carried as its own method",
              credits[1].method);
        // The load-bearing one.
        Check(credits[2].amountMinor == -51300,
              "an outgoing payment keeps its minus sign",
              std::format("{}", credits[2].amountMinor));
    }

    // End to end through the matcher: the outgoing line must not pay for
    // anything, and the two incoming ones must sum.
    {
        const Server::TransferMatch m = Server::MatchCredits(credits, "CC-2B6457");
        Check(m.paidMinor == 6238,
              "the two incoming credits sum and the outgoing one is ignored",
              std::format("{}", m.paidMinor));
        Check(m.count == 2, "two credits matched", std::format("{}", m.count));
    }

    // ── the method mapping, pinned individually ───────────────────────
    Check(Server::BunqMethodFor("EBA_SCT") == "sepa", "EBA_SCT -> sepa");
    Check(Server::BunqMethodFor("IDEAL") == "ideal", "IDEAL -> ideal");
    Check(Server::BunqMethodFor("FIS") == "card", "FIS -> card (reversible!)");
    Check(Server::BunqMethodFor("BUNQ") == "bunq", "BUNQ -> bunq");
    Check(Server::BunqMethodFor("SWIFT") == "swift", "SWIFT -> swift");
    Check(Server::BunqMethodFor("EBA_SDD") == "directdebit", "EBA_SDD -> directdebit");
    // An unknown type reaches the ledger verbatim rather than as a comfortable
    // guess: the `via` column should show what bunq said, so a new payment
    // type is visible instead of silently filed as an ordinary transfer.
    Check(Server::BunqMethodFor("SOMETHING_NEW") == "SOMETHING_NEW",
          "an unknown type is passed through, not guessed at");
    Check(Server::BunqMethodFor("") == "bank", "an absent type falls back to 'bank'");

    // ── signed amount parsing ─────────────────────────────────────────
    Check(Server::ParseSignedAmountToMinor("0.01") == 1, "one cent");
    Check(Server::ParseSignedAmountToMinor("-0.01") == -1, "minus one cent");
    Check(Server::ParseSignedAmountToMinor("57.4") == 5740, "one decimal is tenths");
    Check(Server::ParseSignedAmountToMinor("665") == 66500, "no decimal point");
    Check(!Server::ParseSignedAmountToMinor("1.234").has_value(),
          "three decimals is not money");
    Check(!Server::ParseSignedAmountToMinor("1,00").has_value(),
          "a comma decimal is refused rather than guessed");
    Check(!Server::ParseSignedAmountToMinor("1e2").has_value(), "no exponents");
    Check(!Server::ParseSignedAmountToMinor("").has_value(), "empty is not zero");
    Check(!Server::ParseSignedAmountToMinor("-").has_value(), "a bare sign is not zero");
    Check(!Server::ParseSignedAmountToMinor(" 1.00").has_value(), "no leading space");

    // ── malformed input yields nothing, never a wrong number ──────────
    Check(Server::ParseBunqPayments("").empty(), "empty input decodes to nothing");
    Check(Server::ParseBunqPayments("not json").empty(), "garbage decodes to nothing");
    Check(Server::ParseBunqPayments(R"({"Response":[]})").empty(),
          "an empty account decodes to nothing");
    Check(Server::ParseBunqPayments(R"({"Response":"nope"})").empty(),
          "a Response that is not an array decodes to nothing");
    // A payment whose amount will not parse is SKIPPED, not counted as zero:
    // an unparseable amount means we do not know what arrived.
    Check(Server::ParseBunqPayments(
              R"({"Response":[{"Payment":{"id":1,"type":"EBA_SCT","description":"x",)"
              R"("amount":{"currency":"EUR","value":"1.234"}}}]})").empty(),
          "an unparseable amount is skipped rather than read as zero");

    if (failures != 0) {
        std::println(std::cerr, "{} check(s) failed", failures);
        return 1;
    }
    std::println("ShouldParseBunqPayments: all checks passed");
    return 0;
}