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Amir-GolmoradiAmir-Golmoradi
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Add loan and collateral lending domains (#15)
1 parent e312ca5 commit ff248bb

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‎payguard-collateral-service/src/main/java/dev/amg/payguard/collateral/application/CollateralApplicationService.java‎

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package dev.amg.payguard.collateral.application;
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import dev.amg.payguard.collateral.domain.Collateral;
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import dev.amg.payguard.collateral.domain.CollateralStatus;
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import dev.amg.payguard.collateral.domain.PriceOracle;
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import dev.amg.payguard.collateral.domain.Valuation;
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import java.math.BigDecimal;
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import java.time.Instant;
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import java.util.UUID;
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public final class CollateralApplicationService {
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private final CollateralRepository repository;
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private final CollateralLiquidationPort liquidation;
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public CollateralApplicationService(
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CollateralRepository repository, CollateralLiquidationPort liquidation) {
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this.repository = repository;
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this.liquidation = liquidation;
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}
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public Collateral lock(Collateral collateral) {
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collateral.lock();
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return repository.save(collateral);
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}
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public Collateral refresh(
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UUID id,
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BigDecimal exposure,
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PriceOracle oracle,
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java.util.Currency loanCurrency,
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Instant now) {
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Collateral c = repository.find(id).orElseThrow();
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PriceOracle.Quote q =
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oracle.quote(id, java.util.Currency.getInstance(c.assetCurrency()), loanCurrency, now);
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Collateral.Risk risk =
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c.updateValuation(new Valuation(q.assetValue(), q.fxRate(), q.observedAt()), exposure);
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if (risk.status() == CollateralStatus.LIQUIDATING)
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liquidation.liquidate(
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id,
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exposure,
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c.assetCurrency(),
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loanCurrency.getCurrencyCode(),
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id.toString() + ":" + q.observedAt());
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return repository.save(c);
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}
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}

‎payguard-collateral-service/src/main/java/dev/amg/payguard/collateral/application/CollateralDataExportPort.java‎

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package dev.amg.payguard.collateral.application;
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import java.util.Map;
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import java.util.UUID;
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/** Restricted port used by the identity/privacy service for Articles 15, 17 and 20 requests. */
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public interface CollateralDataExportPort {
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Map<String, Object> export(UUID collateralId);
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void pseudonymize(UUID collateralId, String retainedToken);
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}

‎payguard-collateral-service/src/main/java/dev/amg/payguard/collateral/application/CollateralLiquidationPort.java‎

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package dev.amg.payguard.collateral.application;
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import java.math.BigDecimal;
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import java.util.UUID;
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@FunctionalInterface
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public interface CollateralLiquidationPort {
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void liquidate(
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UUID collateralId, BigDecimal amount, String assetCurrency, String loanCurrency, String key);
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}

‎payguard-collateral-service/src/main/java/dev/amg/payguard/collateral/application/CollateralRepository.java‎

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package dev.amg.payguard.collateral.application;
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import dev.amg.payguard.collateral.domain.Collateral;
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import java.util.Optional;
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import java.util.UUID;
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public interface CollateralRepository {
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Collateral save(Collateral collateral);
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Optional<Collateral> find(UUID id);
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}

‎payguard-collateral-service/src/main/java/dev/amg/payguard/collateral/application/SubjectTokenVault.java‎

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package dev.amg.payguard.collateral.application;
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/** Boundary for KMS-backed encryption of the service-local linkage token. */
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public interface SubjectTokenVault {
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String encrypt(String subjectId);
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String decrypt(String encryptedToken);
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}

‎payguard-collateral-service/src/main/java/dev/amg/payguard/collateral/domain/Collateral.java‎

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package dev.amg.payguard.collateral.domain;
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import java.math.BigDecimal;
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import java.math.RoundingMode;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.Objects;
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import java.util.UUID;
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@SuppressWarnings({"PMD.AvoidFieldNameMatchingMethodName"})
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public final class Collateral {
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private final UUID id;
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private final String ownerId;
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private final UUID loanId;
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private final BigDecimal amount;
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private final String assetCurrency;
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private final BigDecimal warningLtv;
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private final BigDecimal marginLtv;
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private final BigDecimal liquidationLtv;
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private CollateralStatus status;
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private Valuation latest;
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private final List<Valuation> history = new ArrayList<>();
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public Collateral(
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UUID id,
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String ownerId,
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UUID loanId,
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BigDecimal amount,
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String assetCurrency,
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BigDecimal warningLtv,
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BigDecimal marginLtv,
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BigDecimal liquidationLtv) {
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this.id = Objects.requireNonNull(id);
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this.ownerId = Objects.requireNonNull(ownerId);
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this.loanId = Objects.requireNonNull(loanId);
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if (amount == null || amount.signum() <= 0) throw new IllegalArgumentException("amount");
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this.amount = amount;
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this.assetCurrency = Objects.requireNonNull(assetCurrency);
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this.warningLtv = threshold(warningLtv);
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this.marginLtv = threshold(marginLtv);
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this.liquidationLtv = threshold(liquidationLtv);
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if (this.warningLtv.compareTo(this.marginLtv) >= 0
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|| this.marginLtv.compareTo(this.liquidationLtv) >= 0)
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throw new IllegalArgumentException("threshold order");
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status = CollateralStatus.AVAILABLE;
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}
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public void lock() {
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if (status != CollateralStatus.AVAILABLE)
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throw new IllegalStateException("collateral unavailable");
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status = CollateralStatus.LOCKED;
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}
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public Risk updateValuation(Valuation valuation, BigDecimal exposure) {
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Objects.requireNonNull(valuation);
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if (status == CollateralStatus.RELEASED || status == CollateralStatus.LIQUIDATED)
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throw new IllegalStateException("collateral closed");
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latest = valuation;
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history.add(valuation);
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BigDecimal ltv =
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exposure.signum() == 0
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? BigDecimal.ZERO
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: exposure.divide(valuation.amount(), 18, RoundingMode.HALF_EVEN);
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if (ltv.compareTo(liquidationLtv) >= 0) status = CollateralStatus.LIQUIDATING;
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else if (ltv.compareTo(marginLtv) >= 0) status = CollateralStatus.MARGIN_CALL;
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else if (status == CollateralStatus.MARGIN_CALL && ltv.compareTo(warningLtv) < 0)
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status = CollateralStatus.LOCKED;
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return new Risk(ltv, status);
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}
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public void markLiquidated() {
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if (status != CollateralStatus.LIQUIDATING && status != CollateralStatus.MARGIN_CALL)
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throw new IllegalStateException("not liquidatable");
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status = CollateralStatus.LIQUIDATED;
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}
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public void release() {
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if (status != CollateralStatus.LOCKED && status != CollateralStatus.MARGIN_CALL)
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throw new IllegalStateException("not releasable");
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status = CollateralStatus.RELEASED;
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}
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private static BigDecimal threshold(BigDecimal v) {
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if (v == null || v.signum() < 0 || v.compareTo(BigDecimal.ONE) > 0)
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throw new IllegalArgumentException("LTV threshold");
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return v;
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}
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public record Risk(BigDecimal ltv, CollateralStatus status) {}
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public UUID id() {
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return id;
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}
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public String ownerId() {
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return ownerId;
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}
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public UUID loanId() {
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return loanId;
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}
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public BigDecimal amount() {
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return amount;
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}
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public String assetCurrency() {
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return assetCurrency;
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}
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public CollateralStatus status() {
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return status;
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}
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public Valuation latest() {
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return latest;
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}
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public List<Valuation> history() {
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return List.copyOf(history);
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}
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}

‎payguard-collateral-service/src/main/java/dev/amg/payguard/collateral/domain/CollateralStatus.java‎

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package dev.amg.payguard.collateral.domain;
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public enum CollateralStatus {
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AVAILABLE,
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LOCKED,
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MARGIN_CALL,
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LIQUIDATING,
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LIQUIDATED,
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RELEASED
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}

‎payguard-collateral-service/src/main/java/dev/amg/payguard/collateral/domain/PriceOracle.java‎

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package dev.amg.payguard.collateral.domain;
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import java.math.BigDecimal;
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import java.time.Instant;
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import java.util.Currency;
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import java.util.UUID;
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@FunctionalInterface
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public interface PriceOracle {
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Quote quote(UUID collateralId, Currency assetCurrency, Currency loanCurrency, Instant now);
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record Quote(BigDecimal assetValue, BigDecimal fxRate, Instant observedAt) {}
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}

‎payguard-collateral-service/src/main/java/dev/amg/payguard/collateral/domain/Valuation.java‎

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package dev.amg.payguard.collateral.domain;
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import java.math.BigDecimal;
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import java.time.Instant;
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public record Valuation(BigDecimal amount, BigDecimal fxRate, Instant observedAt) {
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public Valuation {
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if (amount == null
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|| amount.signum() < 0
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|| fxRate == null
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|| fxRate.signum() <= 0
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|| observedAt == null) throw new IllegalArgumentException("invalid valuation");
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}
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}

‎payguard-collateral-service/src/test/java/dev/amg/payguard/collateral/domain/CollateralDomainTest.java‎

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package dev.amg.payguard.collateral.domain;
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import static org.junit.jupiter.api.Assertions.*;
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import java.math.BigDecimal;
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import java.time.Instant;
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import java.util.UUID;
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import org.junit.jupiter.api.Test;
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class CollateralDomainTest {
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@Test
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void crossesMarginAndLiquidationThresholds() {
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Collateral c =
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new Collateral(
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UUID.randomUUID(),
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"owner-token",
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UUID.randomUUID(),
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new BigDecimal("1000"),
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"USD",
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new BigDecimal(".60"),
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new BigDecimal(".70"),
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new BigDecimal(".80"));
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c.lock();
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assertEquals(
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CollateralStatus.MARGIN_CALL,
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c.updateValuation(
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new Valuation(new BigDecimal("1400"), new BigDecimal("1"), Instant.now()),
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new BigDecimal("1000"))
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.status());
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assertEquals(
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CollateralStatus.LIQUIDATING,
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c.updateValuation(
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new Valuation(new BigDecimal("1200"), new BigDecimal("1"), Instant.now()),
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new BigDecimal("1000"))
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.status());
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}
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}

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