add pay to anchor script and address type

src/main/java/com/sparrowwallet/drongo/address/Address.java

@@ -134,6 +134,8 @@ public abstract class Address {
                             byte[] witnessProgram = Bech32.convertBits(convertedProgram, 0, convertedProgram.length, 5, 8, false);
                             if(witnessProgram.length == 32) {
                                 return new P2TRAddress(witnessProgram);
+                            } else if(Arrays.equals(witnessProgram, ScriptType.ANCHOR_WITNESS_PROGRAM)) {
+                                return new P2AAddress(witnessProgram);
                             }
                         }
                     }

src/main/java/com/sparrowwallet/drongo/address/P2AAddress.java

@@ -0,0 +1,31 @@
+package com.sparrowwallet.drongo.address;
+
+import com.sparrowwallet.drongo.Network;
+import com.sparrowwallet.drongo.protocol.Bech32;
+import com.sparrowwallet.drongo.protocol.ScriptType;
+
+public class P2AAddress extends Address {
+    public P2AAddress(byte[] data) {
+        super(data);
+    }
+
+    @Override
+    public int getVersion(Network network) {
+        return 1;
+    }
+
+    @Override
+    public String getAddress(Network network) {
+        return Bech32.encode(network.getBech32AddressHRP(), getVersion(), data);
+    }
+
+    @Override
+    public ScriptType getScriptType() {
+        return ScriptType.P2A;
+    }
+
+    @Override
+    public String getOutputScriptDataType() {
+        return "Anchor";
+    }
+}

src/main/java/com/sparrowwallet/drongo/protocol/Script.java

@@ -212,6 +212,10 @@ public class Script {
             return addresses.toArray(new Address[addresses.size()]);
         }
 
+        if(P2A.isScriptType(this)) {
+            return new Address[] { P2A.getAddress(P2A.getDataFromScript(this)) };
+        }
+
         throw new NonStandardScriptException("Cannot find addresses in non standard script: " + toString());
     }
 

src/main/java/com/sparrowwallet/drongo/protocol/ScriptType.java

@@ -1134,6 +1134,122 @@ public enum ScriptType {
         public List<PolicyType> getAllowedPolicyTypes() {
             return List.of(SINGLE);
         }
+    },
+    P2A("P2A", "Anchor (P2A)", "m/86'/0'/0'") {
+        @Override
+        public Address getAddress(byte[] data) {
+            return new P2AAddress(data);
+        }
+
+        @Override
+        public Address getAddress(ECKey derivedKey) {
+            throw new ProtocolException("Cannot create a anchor address with a key");
+        }
+
+        @Override
+        public Address getAddress(Script script) {
+            throw new ProtocolException("Cannot create a anchor address with a script");
+        }
+
+        @Override
+        public Script getOutputScript(byte[] data) {
+            List<ScriptChunk> chunks = new ArrayList<>();
+            chunks.add(new ScriptChunk(OP_1, null));
+            chunks.add(new ScriptChunk(data.length, data));
+
+            return new Script(chunks);
+        }
+
+        @Override
+        public Script getOutputScript(ECKey derivedKey) {
+            throw new ProtocolException("Cannot create an anchor output script with a key");
+        }
+
+        @Override
+        public Script getOutputScript(Script script) {
+            throw new ProtocolException("Cannot create an anchor output script with a script");
+        }
+
+        @Override
+        public String getOutputDescriptor(ECKey derivedKey) {
+            throw new ProtocolException("Cannot create an anchor output descriptor with a key");
+        }
+
+        @Override
+        public String getOutputDescriptor(Script script) {
+            throw new ProtocolException("Cannot create an anchor output descriptor with a script");
+        }
+
+        @Override
+        public String getDescriptor() {
+            return "addr(";
+        }
+
+        @Override
+        public boolean isScriptType(Script script) {
+            List<ScriptChunk> chunks = script.chunks;
+            if (chunks.size() != 2)
+                return false;
+            if (!chunks.get(0).equalsOpCode(OP_1))
+                return false;
+            byte[] chunk1data = chunks.get(1).data;
+            if (chunk1data == null)
+                return false;
+            if (!Arrays.equals(chunk1data, ANCHOR_WITNESS_PROGRAM)) {
+                return false;
+            }
+            return true;
+        }
+
+        @Override
+        public byte[] getDataFromScript(Script script) {
+            return script.chunks.get(1).data;
+        }
+
+        @Override
+        public byte[] getHashFromScript(Script script) {
+            throw new ProtocolException("P2A does not contain a hash");
+        }
+
+        @Override
+        public ECKey getPublicKeyFromScript(Script script) {
+            throw new ProtocolException("P2A does not contain a key");
+        }
+
+        @Override
+        public Script getScriptSig(Script scriptPubKey, ECKey pubKey, TransactionSignature signature) {
+            if(!isScriptType(scriptPubKey)) {
+                throw new ProtocolException("Provided scriptPubKey is not a " + getName() + " script");
+            }
+
+            return new Script(new byte[0]);
+        }
+
+        @Override
+        public TransactionInput addSpendingInput(Transaction transaction, TransactionOutput prevOutput, ECKey pubKey, TransactionSignature signature) {
+            Script scriptSig = getScriptSig(prevOutput.getScript(), pubKey, signature);
+            return transaction.addInput(prevOutput.getHash(), prevOutput.getIndex(), scriptSig);
+        }
+
+        @Override
+        public Script getMultisigScriptSig(Script scriptPubKey, int threshold, Map<ECKey, TransactionSignature> pubKeySignatures) {
+            throw new UnsupportedOperationException("Constructing Taproot inputs is not yet supported");
+        }
+
+        @Override
+        public TransactionInput addMultisigSpendingInput(Transaction transaction, TransactionOutput prevOutput, int threshold, Map<ECKey, TransactionSignature> pubKeySignatures) {
+            throw new UnsupportedOperationException("Constructing Taproot inputs is not yet supported");
+        }
+
+        @Override
+        public TransactionSignature.Type getSignatureType() {
+            return TransactionSignature.Type.SCHNORR;
+        };
+
+        @Override
+        public List<PolicyType> getAllowedPolicyTypes() {
+            return Collections.emptyList();
+        }
     };
 
     private final String name;
@@ -1250,6 +1366,10 @@ public enum ScriptType {
 
     public abstract boolean isScriptType(Script script);
 
+    public byte[] getDataFromScript(Script script) {
+        throw new ProtocolException("Script type " + this + " does not contain data");
+    }
+
     public abstract byte[] getHashFromScript(Script script);
 
     public Address[] getAddresses(Script script) {
@@ -1282,11 +1402,13 @@ public enum ScriptType {
 
     public static final ScriptType[] SINGLE_HASH_TYPES = {P2PKH, P2SH, P2SH_P2WPKH, P2SH_P2WSH, P2WPKH, P2WSH};
 
-    public static final ScriptType[] ADDRESSABLE_TYPES = {P2PKH, P2SH, P2SH_P2WPKH, P2SH_P2WSH, P2WPKH, P2WSH, P2TR};
+    public static final ScriptType[] ADDRESSABLE_TYPES = {P2PKH, P2SH, P2SH_P2WPKH, P2SH_P2WSH, P2WPKH, P2WSH, P2TR, P2A};
 
     public static final ScriptType[] NON_WITNESS_TYPES = {P2PK, P2PKH, P2SH};
 
-    public static final ScriptType[] WITNESS_TYPES = {P2SH_P2WPKH, P2SH_P2WSH, P2WPKH, P2WSH, P2TR};
+    public static final ScriptType[] WITNESS_TYPES = {P2SH_P2WPKH, P2SH_P2WSH, P2WPKH, P2WSH, P2TR, P2A};
+
+    public static final byte[] ANCHOR_WITNESS_PROGRAM = new byte[] {78, 115};
 
     public static List<ScriptType> getScriptTypesForPolicyType(PolicyType policyType) {
         return Arrays.stream(values()).filter(scriptType -> scriptType.isAllowed(policyType)).collect(Collectors.toList());
@@ -1364,6 +1486,8 @@ public enum ScriptType {
         } else if(P2TR.equals(this)) {
             //Assume a default keypath spend
             return (32 + 4 + 1 + ((double)66 / WITNESS_SCALE_FACTOR) + 4);
+        } else if(P2A.equals(this)) {
+            return 32 + 4 + 1 + 4;
         } else if(Arrays.asList(WITNESS_TYPES).contains(this)) {
             //Return length of spending input with 75% discount to script size
             return (32 + 4 + 1 + ((double)107 / WITNESS_SCALE_FACTOR) + 4);

src/main/java/com/sparrowwallet/drongo/wallet/Payment.java

@@ -1,6 +1,7 @@
 package com.sparrowwallet.drongo.wallet;
 
 import com.sparrowwallet.drongo.address.Address;
+import com.sparrowwallet.drongo.address.P2AAddress;
 
 public class Payment {
     private Address address;
@@ -15,10 +16,10 @@ public class Payment {
 
     public Payment(Address address, String label, long amount, boolean sendMax, Type type) {
         this.address = address;
-        this.label = label;
+        this.label = label == null && address instanceof P2AAddress ? address.getOutputScriptDataType() : label;
         this.amount = amount;
         this.sendMax = sendMax;
-        this.type = type;
+        this.type = type == Type.DEFAULT && address instanceof P2AAddress ? Type.ANCHOR : type;
     }
 
     public Address getAddress() {
@@ -62,6 +63,6 @@ public class Payment {
     }
 
     public enum Type {
-        DEFAULT, WHIRLPOOL_FEE, FAKE_MIX, MIX;
+        DEFAULT, WHIRLPOOL_FEE, FAKE_MIX, MIX, ANCHOR;
     }
 }