chore: Add reference scripts

Author: satran004

function/src/main/java/com/bloxbean/cardano/client/function/TxBuilderContext.java

@@ -19,12 +19,14 @@
 import com.bloxbean.cardano.client.transaction.spec.MultiAsset;
 import com.bloxbean.cardano.client.transaction.spec.Transaction;
 import com.bloxbean.cardano.client.util.HexUtil;
+import com.bloxbean.cardano.client.util.Tuple;
 import lombok.AccessLevel;
 import lombok.Data;
 import lombok.Setter;
 import lombok.SneakyThrows;
 
 import java.util.*;
+import java.util.stream.Collectors;
 
 /**
  * Provides necessary services which are required to build the transaction
@@ -47,11 +49,12 @@ public class TxBuilderContext {
     //Stores utxos used in the transaction.
     //This list is cleared after each build() call.
     private Set<Utxo> utxos = new HashSet<>();
-    private Map<String, byte[]> refScripts = new HashMap<>();
+
+    @Setter(AccessLevel.NONE)
+    private Map<String, Tuple<PlutusScript, byte[]>> refScripts = new HashMap<>();
 
     @Setter(AccessLevel.NONE)
     private boolean mergeOutputs = true;
-    private Language referenceInputLanguage = Language.PLUTUS_V2;
 
     public TxBuilderContext(UtxoSupplier utxoSupplier, ProtocolParamsSupplier protocolParamsSupplier) {
         this(utxoSupplier, protocolParamsSupplier.getProtocolParams());
@@ -184,15 +187,32 @@ public void clearUtxos() {
 
     @SneakyThrows
     public void addRefScripts(PlutusScript plutusScript) {
-        refScripts.put(HexUtil.encodeHexString(plutusScript.getScriptHash()), plutusScript.scriptRefBytes());
+        refScripts.put(HexUtil.encodeHexString(plutusScript.getScriptHash()), new Tuple<>(plutusScript, plutusScript.scriptRefBytes()));
     }
 
-    public byte[] getRefScript(String scriptHash) {
-        return refScripts.get(scriptHash);
+    public Optional<byte[]> getRefScript(String scriptHash) {
+        var tuple = refScripts.get(scriptHash);
+        return tuple != null ? Optional.of(tuple._2) : Optional.empty();
     }
 
     public List<byte[]> getRefScripts() {
-        return new ArrayList<>(refScripts.values());
+        return refScripts.values().stream().map(tuple -> tuple._2)
+                .collect(Collectors.toList());
+    }
+
+    public List<PlutusScript> getRefPlutusScripts() {
+        return refScripts.values().stream().map(tuple -> tuple._1)
+                .collect(Collectors.toList());
+    }
+
+    public List<Language> getRefScriptLanguages() {
+        if (refScripts.size() == 0)
+            return Collections.emptyList();
+
+        return refScripts.values().stream().map(tuple -> tuple._1.getLanguage())
+                .collect(Collectors.toSet())
+                .stream().sorted(Comparator.comparing(Language::getKey))
+                .collect(Collectors.toList());
     }
 
     public void clearRefScripts() {