support for standardized child wallet accounts

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

@@ -7,6 +7,7 @@ public class Payment {
     private String label;
     private long amount;
     private boolean sendMax;
+    private Type type = Type.DEFAULT;
 
     public Payment(Address address, String label, long amount, boolean sendMax) {
         this.address = address;
@@ -46,4 +47,16 @@ public class Payment {
     public void setSendMax(boolean sendMax) {
         this.sendMax = sendMax;
     }
+
+    public Type getType() {
+        return type;
+    }
+
+    public void setType(Type type) {
+        this.type = type;
+    }
+
+    public enum Type {
+        DEFAULT, WHIRLPOOL_FEE;
+    }
 }

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

@@ -0,0 +1,48 @@
+package com.sparrowwallet.drongo.wallet;
+
+import com.sparrowwallet.drongo.crypto.ChildNumber;
+
+import java.util.List;
+
+public enum StandardAccount {
+    ACCOUNT_0("Account #0", new ChildNumber(0, true)),
+    ACCOUNT_1("Account #1", new ChildNumber(1, true)),
+    ACCOUNT_2("Account #2", new ChildNumber(2, true)),
+    ACCOUNT_3("Account #3", new ChildNumber(3, true)),
+    ACCOUNT_4("Account #4", new ChildNumber(4, true)),
+    ACCOUNT_5("Account #5", new ChildNumber(5, true)),
+    ACCOUNT_6("Account #6", new ChildNumber(6, true)),
+    ACCOUNT_7("Account #7", new ChildNumber(7, true)),
+    ACCOUNT_8("Account #8", new ChildNumber(8, true)),
+    ACCOUNT_9("Account #9", new ChildNumber(9, true)),
+    WHIRLPOOL_PREMIX("Premix", new ChildNumber(2147483645, true)),
+    WHIRLPOOL_POSTMIX("Postmix", new ChildNumber(2147483646, true)),
+    WHIRLPOOL_BADBANK("Badbank", new ChildNumber(2147483644, true));
+
+    public static final List<StandardAccount> WHIRLPOOL_ACCOUNTS = List.of(WHIRLPOOL_PREMIX, WHIRLPOOL_POSTMIX, WHIRLPOOL_BADBANK);
+
+    StandardAccount(String name, ChildNumber childNumber) {
+        this.name = name;
+        this.childNumber = childNumber;
+    }
+
+    private final String name;
+    private final ChildNumber childNumber;
+
+    public String getName() {
+        return name;
+    }
+
+    public ChildNumber getChildNumber() {
+        return childNumber;
+    }
+
+    public int getAccountNumber() {
+        return childNumber.num();
+    }
+
+    @Override
+    public String toString() {
+        return name;
+    }
+}

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

@@ -1,9 +1,11 @@
 package com.sparrowwallet.drongo.wallet;
 
 import com.sparrowwallet.drongo.BitcoinUnit;
+import com.sparrowwallet.drongo.KeyDerivation;
 import com.sparrowwallet.drongo.KeyPurpose;
 import com.sparrowwallet.drongo.Network;
 import com.sparrowwallet.drongo.address.Address;
+import com.sparrowwallet.drongo.crypto.ChildNumber;
 import com.sparrowwallet.drongo.crypto.ECKey;
 import com.sparrowwallet.drongo.crypto.Key;
 import com.sparrowwallet.drongo.policy.Policy;
@@ -77,6 +79,92 @@ public class Wallet extends Persistable {
         return getMasterWallet().getName();
     }
 
+    public Wallet addChildWallet(StandardAccount standardAccount) {
+        Wallet childWallet = this.copy();
+
+        if(!isMasterWallet()) {
+            throw new IllegalStateException("Cannot add child wallet to existing child wallet");
+        }
+
+        if(!childWallet.containsPrivateKeys()) {
+            throw new IllegalStateException("Cannot derive child wallet xpub without private keys");
+        }
+
+        if(childWallet.isEncrypted()) {
+            throw new IllegalStateException("Cannot derive child wallet xpub from encrypted wallet");
+        }
+
+        childWallet.setId(null);
+        childWallet.setName(standardAccount.getName());
+        childWallet.purposeNodes.clear();
+        childWallet.transactions.clear();
+        childWallet.storedBlockHeight = null;
+        childWallet.gapLimit = null;
+        childWallet.birthDate = null;
+
+        for(Keystore keystore : childWallet.getKeystores()) {
+            KeyDerivation keyDerivation = keystore.getKeyDerivation();
+            List<ChildNumber> childDerivation = new ArrayList<>(keyDerivation.getDerivation().subList(0, keyDerivation.getDerivation().size() - 1));
+            childDerivation.add(standardAccount.getChildNumber());
+
+            try {
+                Keystore derivedKeystore = Keystore.fromSeed(keystore.getSeed(), childDerivation);
+                keystore.setKeyDerivation(derivedKeystore.getKeyDerivation());
+                keystore.setExtendedPublicKey(derivedKeystore.getExtendedPublicKey());
+                keystore.getSeed().setPassphrase(keystore.getSeed().getPassphrase());
+            } catch(Exception e) {
+                throw new IllegalStateException("Cannot derive keystore for " + standardAccount + " account", e);
+            }
+        }
+
+        childWallet.setMasterWallet(this);
+        getChildWallets().add(childWallet);
+        return childWallet;
+    }
+
+    public Wallet getChildWallet(StandardAccount account) {
+        for(Wallet childWallet : getChildWallets()) {
+            for(Keystore keystore : childWallet.getKeystores()) {
+                if(keystore.getKeyDerivation().getDerivation().get(keystore.getKeyDerivation().getDerivation().size() - 1).equals(account.getChildNumber())) {
+                    return childWallet;
+                }
+            }
+        }
+
+        return null;
+    }
+
+    public StandardAccount getStandardAccountType() {
+        int accountIndex = getAccountIndex();
+        return Arrays.stream(StandardAccount.values()).filter(standardAccount -> standardAccount.getChildNumber().num() == accountIndex).findFirst().orElse(null);
+    }
+
+    public int getAccountIndex() {
+        int index = -1;
+
+        for(Keystore keystore : getKeystores()) {
+            int keystoreAccount = getScriptType().getAccount(keystore.getKeyDerivation().getDerivationPath());
+            if(keystoreAccount != -1 && (index == -1 || keystoreAccount == index)) {
+                index = keystoreAccount;
+            }
+        }
+
+        return index;
+    }
+
+    public boolean isWhirlpoolMasterWallet() {
+        if(!isMasterWallet()) {
+            return false;
+        }
+
+        Set<StandardAccount> whirlpoolAccounts = new HashSet<>(Set.of(StandardAccount.WHIRLPOOL_PREMIX, StandardAccount.WHIRLPOOL_POSTMIX, StandardAccount.WHIRLPOOL_BADBANK));
+        for(Wallet childWallet : getChildWallets()) {
+            whirlpoolAccounts.remove(childWallet.getStandardAccountType());
+        }
+
+        return whirlpoolAccounts.isEmpty();
+    }
+
     public void setName(String name) {
         this.name = name;
     }

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

@@ -98,8 +98,20 @@ public class WalletTransaction {
     }
 
     public boolean isConsolidationSend(Payment payment) {
-        if(payment.getAddress() != null && getWallet() != null) {
-            return getWallet().isWalletOutputScript(payment.getAddress().getOutputScript());
+        return isWalletSend(getWallet(), payment);
+    }
+
+    public boolean isPremixSend(Payment payment) {
+        return isWalletSend(getWallet().getChildWallet(StandardAccount.WHIRLPOOL_PREMIX), payment);
+    }
+
+    public boolean isBadbankSend(Payment payment) {
+        return isWalletSend(getWallet().getChildWallet(StandardAccount.WHIRLPOOL_BADBANK), payment);
+    }
+
+    public boolean isWalletSend(Wallet wallet, Payment payment) {
+        if(payment.getAddress() != null && wallet != null) {
+            return wallet.isWalletOutputScript(payment.getAddress().getOutputScript());
         }
 
         return false;