feat: implement DRep vote delegation read operations and refactor delegation entities

Add complete read path for DRep vote delegations including database entities, repository, and service layer integration. Rename DelegationEntity to PoolDelegationEntity across codebase to distinguish pool delegation from vote delegation. Add GovernanceTransactions test generator for creating DRep registration and delegation test data.

Key changes:
- Add DrepVoteDelegationEntity, DrepVoteDelegationId, and DrepVoteDelegationRepository
- Rename DelegationEntity → PoolDelegationEntity and update all references
- Integrate DRep delegation queries with certIndex filter in LedgerBlockServiceImpl
- Add mapper methods for DRep delegation entity-to-domain conversion
- Add GovernanceTransactions class with DRep registration and delegation transactions
- Update TestTransactionNames enum with DREP_REGISTER and DREP_VOTE_DELEGATION

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: Mateusz Czeladka

api/src/main/java/org/cardanofoundation/rosetta/api/block/mapper/TransactionMapper.java

@@ -47,7 +47,7 @@ public interface TransactionMapper {
   @Mapping(target = "operationIdentifier", source = "index", qualifiedByName = "OperationIdentifier")
   Operation mapPoolRetirementToOperation(PoolRetirement model, OperationStatus status, int index);
 
-  StakePoolDelegation mapDelegationEntityToDelegation(DelegationEntity entity);
+  StakePoolDelegation mapPoolDelegationEntityToDelegation(PoolDelegationEntity entity);
 
   @Mapping(target = "status", source = "status.status")
   @Mapping(target = "type", constant = Constants.OPERATION_TYPE_STAKE_DELEGATION)
@@ -56,6 +56,24 @@ public interface TransactionMapper {
   @Mapping(target = "metadata.poolKeyHash", source = "model.poolId")
   Operation mapStakeDelegationToOperation(StakePoolDelegation model, OperationStatus status, int index);
 
+  default DRepDelegation mapDrepVoteDelegationEntityToDRepDelegation(DrepVoteDelegationEntity entity) {
+    if (entity == null) {
+      return null;
+    }
+
+    return DRepDelegation.builder()
+            .txHash(entity.getTxHash())
+            .certIndex(entity.getCertIndex())
+            .address(entity.getAddress())
+            .drep(new DRepDelegation.DRep(
+                    entity.getDrepId(),
+                    convertDrepTypeStringToEnum(entity.getDrepType())
+            ))
+            .build();
+  }
+
+  com.bloxbean.cardano.client.transaction.spec.governance.DRepType convertDrepTypeStringToEnum(String drepType);
+
   @Mapping(target = "status", source = "status.status")
   @Mapping(target = "type", constant = Constants.OPERATION_TYPE_DREP_VOTE_DELEGATION)
   @Mapping(target = "operationIdentifier", source = "index", qualifiedByName = "OperationIdentifier")

api/src/main/java/org/cardanofoundation/rosetta/api/block/mapper/TransactionMapperUtils.java

@@ -84,6 +84,21 @@ public DRepParams convertDRepFromRosetta(DRepDelegation.DRep drep) {
     return DRepDelegation.DRep.convertDRepFromRosetta(drep);
   }
 
+  @Named("convertDrepTypeStringToEnum")
+  public com.bloxbean.cardano.client.transaction.spec.governance.DRepType convertDrepTypeStringToEnum(@Nullable String drepType) {
+    if (drepType == null) {
+      return null;
+    }
+
+    return switch (drepType) {
+      case "ADDR_KEYHASH" -> com.bloxbean.cardano.client.transaction.spec.governance.DRepType.ADDR_KEYHASH;
+      case "SCRIPTHASH" -> com.bloxbean.cardano.client.transaction.spec.governance.DRepType.SCRIPTHASH;
+      case "ABSTAIN" -> com.bloxbean.cardano.client.transaction.spec.governance.DRepType.ABSTAIN;
+      case "NO_CONFIDENCE" -> com.bloxbean.cardano.client.transaction.spec.governance.DRepType.NO_CONFIDENCE;
+      default -> null;
+    };
+  }
+
   @Named("mapAmountsToOperationMetadataInputWithCache")
   public OperationMetadata mapToOperationMetaDataInputWithCache(List<Amt> amounts,
                                                                 @Context Map<AssetFingerprint, TokenRegistryCurrencyData> metadataMap) {

api/src/main/java/org/cardanofoundation/rosetta/api/block/model/entity/DrepVoteDelegationEntity.java

@@ -0,0 +1,49 @@
+package org.cardanofoundation.rosetta.api.block.model.entity;
+
+import jakarta.persistence.*;
+
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+@Getter
+@Setter
+@NoArgsConstructor
+@Entity
+@Table(name = "vote_delegation")
+@IdClass(DrepVoteDelegationId.class)
+public class DrepVoteDelegationEntity {
+
+  @Id
+  @Column(name = "tx_hash")
+  private String txHash;
+
+  @Id
+  @Column(name = "cert_index")
+  private long certIndex;
+
+  @Column(name = "slot")
+  private Long slot;
+
+  @Column(name = "block_number")
+  private Long blockNumber;
+
+  @Column(name = "block_hash")
+  private String blockHash;
+
+  @Column(name = "address")
+  private String address;
+
+  @Column(name = "drep_hash")
+  private String drepHash;
+
+  @Column(name = "drep_id")
+  private String drepId;
+
+  @Column(name = "drep_type")
+  private String drepType;
+
+  @Column(name = "credential")
+  private String credential;
+
+}

api/src/main/java/org/cardanofoundation/rosetta/api/block/model/entity/DrepVoteDelegationId.java

@@ -0,0 +1,12 @@
+package org.cardanofoundation.rosetta.api.block.model.entity;
+
+import java.io.Serializable;
+
+import lombok.EqualsAndHashCode;
+
+@EqualsAndHashCode
+public class DrepVoteDelegationId implements Serializable {
+
+  private String txHash;
+  private long certIndex;
+}

api/src/main/java/org/cardanofoundation/rosetta/api/block/model/entity/DelegationEntity.java renamed to api/src/main/java/org/cardanofoundation/rosetta/api/block/model/entity/PoolDelegationEntity.java

@@ -11,8 +11,8 @@
 @NoArgsConstructor
 @Entity
 @Table(name = "delegation")
-@IdClass(DelegationId.class)
-public class DelegationEntity {
+@IdClass(PoolDelegationId.class)
+public class PoolDelegationEntity {
 
   @Id
   @Column(name = "tx_hash")

api/src/main/java/org/cardanofoundation/rosetta/api/block/model/entity/DelegationId.java renamed to api/src/main/java/org/cardanofoundation/rosetta/api/block/model/entity/PoolDelegationId.java

@@ -5,7 +5,7 @@
 import lombok.EqualsAndHashCode;
 
 @EqualsAndHashCode
-public class DelegationId implements Serializable {
+public class PoolDelegationId implements Serializable {
 
   private String txHash;
   private long certIndex;

api/src/main/java/org/cardanofoundation/rosetta/api/block/model/repository/DelegationRepository.java

@@ -0,0 +1,16 @@
+package org.cardanofoundation.rosetta.api.block.model.repository;
+
+import java.util.List;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import org.cardanofoundation.rosetta.api.block.model.entity.DrepVoteDelegationEntity;
+import org.cardanofoundation.rosetta.api.block.model.entity.DrepVoteDelegationId;
+
+@Repository
+public interface DrepVoteDelegationRepository extends JpaRepository<DrepVoteDelegationEntity, DrepVoteDelegationId> {
+
+  List<DrepVoteDelegationEntity> findByTxHashInAndCertIndex(List<String> txHashes, long certIndex);
+
+}

api/src/main/java/org/cardanofoundation/rosetta/api/block/model/repository/DrepVoteDelegationRepository.java

@@ -0,0 +1,16 @@
+package org.cardanofoundation.rosetta.api.block.model.repository;
+
+import java.util.List;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import org.cardanofoundation.rosetta.api.block.model.entity.PoolDelegationEntity;
+import org.cardanofoundation.rosetta.api.block.model.entity.PoolDelegationId;
+
+@Repository
+public interface PoolDelegationRepository extends JpaRepository<PoolDelegationEntity, PoolDelegationId> {
+
+  List<PoolDelegationEntity> findByTxHashIn(List<String> txHashes);
+
+}

api/src/main/java/org/cardanofoundation/rosetta/api/block/model/repository/PoolDelegationRepository.java

@@ -47,7 +47,8 @@ public class LedgerBlockServiceImpl implements LedgerBlockService {
   private final BlockRepository blockRepository;
   private final TxRepository txRepository;
   private final StakeRegistrationRepository stakeRegistrationRepository;
-  private final DelegationRepository delegationRepository;
+  private final PoolDelegationRepository poolDelegationRepository;
+  private final DrepVoteDelegationRepository drepVoteDelegationRepository;
   private final PoolRegistrationRepository poolRegistrationRepository;
   private final PoolRetirementRepository poolRetirementRepository;
   private final WithdrawalRepository withdrawalRepository;
@@ -233,7 +234,8 @@ private TransactionInfo findByTxHash(List<BlockTx> transactions) {
     try (ShutdownOnFailure scope = new ShutdownOnFailure()) {
       StructuredTaskScope.Subtask<List<AddressUtxoEntity>> utxos = scope.fork(() -> addressUtxoRepository.findByTxHashIn(utxHashes));
       StructuredTaskScope.Subtask<List<StakeRegistrationEntity>> sReg = scope.fork(() -> stakeRegistrationRepository.findByTxHashIn(txHashes));
-      StructuredTaskScope.Subtask<List<DelegationEntity>> delegations = scope.fork(() -> delegationRepository.findByTxHashIn(txHashes));
+      StructuredTaskScope.Subtask<List<PoolDelegationEntity>> poolDelegations = scope.fork(() -> poolDelegationRepository.findByTxHashIn(txHashes));
+      StructuredTaskScope.Subtask<List<DrepVoteDelegationEntity>> drepDelegations = scope.fork(() -> drepVoteDelegationRepository.findByTxHashInAndCertIndex(txHashes, 0L));
       StructuredTaskScope.Subtask<List<PoolRegistrationEntity>> pReg = scope.fork(() -> poolRegistrationRepository.findByTxHashIn(txHashes));
       StructuredTaskScope.Subtask<List<PoolRetirementEntity>> pRet = scope.fork(() -> poolRetirementRepository.findByTxHashIn(txHashes));
       StructuredTaskScope.Subtask<List<WithdrawalEntity>> withdrawals = scope.fork(() -> withdrawalRepository.findByTxHashIn(txHashes));
@@ -245,7 +247,8 @@ private TransactionInfo findByTxHash(List<BlockTx> transactions) {
       return new TransactionInfo(
               utxos.get(),
               sReg.get(),
-              delegations.get(),
+              poolDelegations.get(),
+              drepDelegations.get(),
               pReg.get(),
               pRet.get(),
               withdrawals.get(),
@@ -293,10 +296,10 @@ void populateTransaction(BlockTx transaction,
                     .toList());
 
     transaction.setStakePoolDelegations(
-            fetched.delegations
+            fetched.poolDelegations
                     .stream()
                     .filter(tx -> tx.getTxHash().equals(transaction.getHash()))
-                    .map(transactionMapper::mapDelegationEntityToDelegation)
+                    .map(transactionMapper::mapPoolDelegationEntityToDelegation)
                     .toList());
 
     transaction.setWithdrawals(
@@ -319,8 +322,13 @@ void populateTransaction(BlockTx transaction,
                     .filter(tx -> tx.getTxHash().equals(transaction.getHash()))
                     .map(transactionMapper::mapEntityToPoolRetirement)
                     .toList());
-    // TODO dRep Vote Delegations
-    //transaction.setDRepDelegations(fetched.delegations
+
+    transaction.setDRepDelegations(
+            fetched.drepDelegations
+                    .stream()
+                    .filter(tx -> tx.getTxHash().equals(transaction.getHash()))
+                    .map(transactionMapper::mapDrepVoteDelegationEntityToDRepDelegation)
+                    .toList());
 
     // TODO governance votes
     //transaction.setGovernanceVotes(fetched.);
@@ -345,7 +353,8 @@ private static Map<UtxoKey, AddressUtxoEntity> getUtxoMapFromEntities(Transactio
 
   record TransactionInfo(List<AddressUtxoEntity> utxos,
                          List<StakeRegistrationEntity> stakeRegistrations,
-                         List<DelegationEntity> delegations,
+                         List<PoolDelegationEntity> poolDelegations,
+                         List<DrepVoteDelegationEntity> drepDelegations,
                          List<PoolRegistrationEntity> poolRegistrations,
                          List<PoolRetirementEntity> poolRetirements,
                          List<WithdrawalEntity> withdrawals,