change wallet gap limit and subscribe to new addresses if an address beyond gap limit range is requested

src/main/java/com/sparrowwallet/sparrow/event/WalletGapLimitChangedEvent.java

@@ -1,17 +1,41 @@
 package com.sparrowwallet.sparrow.event;
 
 import com.sparrowwallet.drongo.wallet.Wallet;
+import com.sparrowwallet.drongo.wallet.WalletNode;
 
 /**
  * This event is posted if the wallet's gap limit has changed, and triggers a history fetch for the new nodes.
  *
  */
 public class WalletGapLimitChangedEvent extends WalletChangedEvent {
-    public WalletGapLimitChangedEvent(Wallet wallet) {
+    private final String walletId;
+    private final int previousGapLimit;
+
+    public WalletGapLimitChangedEvent(String walletId, Wallet wallet, int previousGapLimit) {
         super(wallet);
+        this.walletId = walletId;
+        this.previousGapLimit = previousGapLimit;
+    }
+
+    public String getWalletId() {
+        return walletId;
     }
 
     public int getGapLimit() {
         return getWallet().getGapLimit();
     }
+
+    public int getPreviousGapLimit() {
+        return previousGapLimit;
+    }
+
+    public int getPreviousLookAheadIndex(WalletNode node) {
+        int lookAheadIndex = getPreviousGapLimit() - 1;
+        Integer highestUsed = node.getHighestUsedIndex();
+        if(highestUsed != null) {
+            lookAheadIndex = highestUsed + getPreviousGapLimit();
+        }
+
+        return lookAheadIndex;
+    }
 }

src/main/java/com/sparrowwallet/sparrow/wallet/ReceiveController.java

@@ -189,6 +189,9 @@ public class ReceiveController extends WalletFormController implements Initializ
 
     public void getNewAddress(ActionEvent event) {
         refreshAddress();
+        if(currentEntry != null) {
+            ensureSufficientGapLimit(currentEntry.getNode().getIndex());
+        }
     }
 
     public void refreshAddress() {
@@ -196,6 +199,17 @@ public class ReceiveController extends WalletFormController implements Initializ
         setNodeEntry(freshEntry);
     }
 
+    private void ensureSufficientGapLimit(int index) {
+        Wallet wallet = getWalletForm().getWallet();
+        Integer highestIndex = wallet.getNode(KeyPurpose.RECEIVE).getHighestUsedIndex();
+        int highestUsedIndex = highestIndex == null ? -1 : highestIndex;
+        int existingGapLimit = wallet.getGapLimit();
+        if(index > highestUsedIndex + existingGapLimit) {
+            wallet.setGapLimit(Math.max(wallet.getGapLimit(), index - highestUsedIndex));
+            EventManager.get().post(new WalletGapLimitChangedEvent(getWalletForm().getWalletId(), wallet, existingGapLimit));
+        }
+    }
+
     @SuppressWarnings("unchecked")
     public void displayAddress(ActionEvent event) {
         Wallet wallet = getWalletForm().getWallet();

src/main/java/com/sparrowwallet/sparrow/wallet/SettingsController.java

@@ -730,6 +730,13 @@ public class SettingsController extends WalletFormController implements Initiali
         }
     }
 
+    @Subscribe
+    public void walletGapLimitChanged(WalletGapLimitChangedEvent event) {
+        if(walletForm.getWalletId().equals(event.getWalletId())) {
+            ((SettingsWalletForm)walletForm).gapLimitChanged(event.getGapLimit());
+        }
+    }
+
     @Subscribe
     public void existingWalletImported(ExistingWalletImportedEvent event) {
         if(event.getExistingWalletId().equals(getWalletForm().getWalletId())) {

src/main/java/com/sparrowwallet/sparrow/wallet/SettingsWalletForm.java

@@ -253,4 +253,8 @@ public class SettingsWalletForm extends WalletForm {
             masterWalletCopy.getChildWallets().add(childWallet.copy());
         }
     }
+
+    public void gapLimitChanged(int gapLimit) {
+        walletCopy.setGapLimit(gapLimit);
+    }
 }

src/main/java/com/sparrowwallet/sparrow/wallet/WalletForm.java

@@ -604,7 +604,9 @@ public class WalletForm {
                 Optional<WalletNode> optPurposeNode = wallet.getPurposeNodes().stream().filter(node -> node.getKeyPurpose() == keyPurpose).findFirst();
                 if(optPurposeNode.isPresent()) {
                     WalletNode purposeNode = optPurposeNode.get();
-                    newNodes.addAll(purposeNode.fillToIndex(wallet, wallet.getLookAheadIndex(purposeNode)));
+                    purposeNode.fillToIndex(wallet, wallet.getLookAheadIndex(purposeNode));
+                    int previousLookAheadIndex = event.getPreviousLookAheadIndex(purposeNode);
+                    newNodes.addAll(purposeNode.getChildren().stream().filter(node -> node.getIndex() > previousLookAheadIndex).collect(Collectors.toList()));
                 }
             }
 

src/main/java/com/sparrowwallet/sparrow/whirlpool/dataSource/SparrowIndexHandler.java

@@ -4,6 +4,7 @@ import com.samourai.wallet.client.indexHandler.AbstractIndexHandler;
 import com.sparrowwallet.drongo.KeyPurpose;
 import com.sparrowwallet.drongo.wallet.Wallet;
 import com.sparrowwallet.drongo.wallet.WalletNode;
+import com.sparrowwallet.sparrow.AppServices;
 import com.sparrowwallet.sparrow.EventManager;
 import com.sparrowwallet.sparrow.event.WalletGapLimitChangedEvent;
 import com.sparrowwallet.sparrow.event.WalletMixConfigChangedEvent;
@@ -75,7 +76,15 @@ public class SparrowIndexHandler extends AbstractIndexHandler {
         int existingGapLimit = wallet.getGapLimit();
         if(index > highestUsedIndex + existingGapLimit) {
             wallet.setGapLimit(Math.max(wallet.getGapLimit(), index - highestUsedIndex));
-            EventManager.get().post(new WalletGapLimitChangedEvent(wallet));
+            EventManager.get().post(new WalletGapLimitChangedEvent(getWalletId(), wallet, existingGapLimit));
+        }
+    }
+
+    private String getWalletId() {
+        try {
+            return AppServices.get().getOpenWallets().get(wallet).getWalletId(wallet);
+        } catch(Exception e) {
+            return null;
         }
     }
 }