AI Kodunu Gözden Geçirmek — Akıcı Görünmek Doğru Olmak Değil

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import org.apache.commons.math3.util.Precision;
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// EFT fee: 0.1% of the amount, at least 5 TRY, at most 50 TRY.
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public double eftFee(double amount, String currency) {
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    try {
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        double fee = Precision.round(amount * 0.001, 2);
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        return Math.min(50, Math.max(5, fee));
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    } catch (Exception e) {
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        return 0;
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    }
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}

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**Review notes, PR 1482**
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- Line 1: a new library for one rounding call. `BigDecimal.setScale` already does it.
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- Line 4: `currency` is never read. A USD transfer would get the TRY limits.
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- Line 6: money as `double`. 0.001 has no exact binary form; the tariff is in kuruş.
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- Lines 8-9: any error becomes a fee of 0, and nobody hears about it.
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- Tests: none at exactly 5,000 or 50,000 TRY, where the limits take over.

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// EFT fee: 0.1% of the amount, at least 5.00 TRY, at most 50.00 TRY.
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final class EftFeeCalculator {
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    private static final Currency TRY = Currency.getInstance("TRY");
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    private static final BigDecimal RATE = new BigDecimal("0.001");
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    private static final BigDecimal MIN_FEE = new BigDecimal("5.00");
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    private static final BigDecimal MAX_FEE = new BigDecimal("50.00");
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    Money fee(Money amount) {
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        if (!amount.currency().equals(TRY)) {
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            // EFT only moves TRY; anything else is a caller bug and should be loud.
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            throw new IllegalArgumentException("EFT fee is defined for TRY, got " + amount.currency());
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        }
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        BigDecimal fee = amount.value().multiply(RATE).setScale(2, RoundingMode.HALF_UP);
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        return new Money(fee.max(MIN_FEE).min(MAX_FEE), TRY);
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    }
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}

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class EftFeeCalculatorTest {
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    private static final Currency TRY = Currency.getInstance("TRY");
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    private final EftFeeCalculator calculator = new EftFeeCalculator();
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    // Expected values come from the published fee tariff, not from running the code.
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    @ParameterizedTest
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    @CsvSource({
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            "100.00,    5.00",   // below the minimum
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            "5000.00,   5.00",   // exactly where the minimum stops
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            "12345.00, 12.35",   // 12.345 rounds half up
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            "50000.00, 50.00",   // exactly where the maximum starts
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            "80000.00, 50.00",   // above the maximum
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    })
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    void feeFollowsTheTariff(String amount, String expectedFee) {
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        assertThat(calculator.fee(new Money(new BigDecimal(amount), TRY)))
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                .isEqualTo(new Money(new BigDecimal(expectedFee), TRY));
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    }
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    @Test
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    void refusesOtherCurrencies() {
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        var usd = new Money(new BigDecimal("1000.00"), Currency.getInstance("USD"));
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        assertThatThrownBy(() -> calculator.fee(usd)).isInstanceOf(IllegalArgumentException.class);
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    }
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}