configurable wallet gap limit

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

@@ -20,6 +20,6 @@ public class SettingsChangedEvent {
     }
 
     public enum Type {
-        POLICY, SCRIPT_TYPE, MUTLISIG_THRESHOLD, MULTISIG_TOTAL, KEYSTORE_LABEL, KEYSTORE_FINGERPRINT, KEYSTORE_DERIVATION, KEYSTORE_XPUB;
+        POLICY, SCRIPT_TYPE, MUTLISIG_THRESHOLD, MULTISIG_TOTAL, KEYSTORE_LABEL, KEYSTORE_FINGERPRINT, KEYSTORE_DERIVATION, KEYSTORE_XPUB, GAP_LIMIT;
     }
 }

src/main/java/com/sparrowwallet/sparrow/net/ElectrumServer.java

@@ -137,18 +137,18 @@ public class ElectrumServer {
         //Because node children are added sequentially in WalletNode.fillToIndex, we can simply look at the number of children to determine the highest filled index
         int historySize = purposeNode.getChildren().size();
         //The gap limit size takes the highest used index in the retrieved history and adds the gap limit (plus one to be comparable to the number of children since index is zero based)
-        int gapLimitSize = getGapLimitSize(nodeTransactionMap);
+        int gapLimitSize = getGapLimitSize(wallet, nodeTransactionMap);
         while(historySize < gapLimitSize) {
             purposeNode.fillToIndex(gapLimitSize - 1);
             getHistory(wallet, purposeNode.getChildren(), nodeTransactionMap, historySize);
             historySize = purposeNode.getChildren().size();
-            gapLimitSize = getGapLimitSize(nodeTransactionMap);
+            gapLimitSize = getGapLimitSize(wallet, nodeTransactionMap);
         }
     }
 
-    private int getGapLimitSize(Map<WalletNode, Set<BlockTransactionHash>> nodeTransactionMap) {
+    private int getGapLimitSize(Wallet wallet, Map<WalletNode, Set<BlockTransactionHash>> nodeTransactionMap) {
         int highestIndex = nodeTransactionMap.entrySet().stream().filter(entry -> !entry.getValue().isEmpty()).map(entry -> entry.getKey().getIndex()).max(Comparator.comparing(Integer::valueOf)).orElse(-1);
-        return highestIndex + Wallet.DEFAULT_LOOKAHEAD + 1;
+        return highestIndex + wallet.getGapLimit() + 1;
     }
 
     public void getHistory(Wallet wallet, Collection<WalletNode> nodes, Map<WalletNode, Set<BlockTransactionHash>> nodeTransactionMap, int startIndex) throws ServerException {

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

@@ -0,0 +1,30 @@
+package com.sparrowwallet.sparrow.wallet;
+
+import com.sparrowwallet.drongo.wallet.Wallet;
+import com.sparrowwallet.sparrow.EventManager;
+import com.sparrowwallet.sparrow.event.SettingsChangedEvent;
+import javafx.fxml.FXML;
+import javafx.fxml.Initializable;
+import javafx.scene.control.Spinner;
+import javafx.scene.control.SpinnerValueFactory;
+
+import java.net.URL;
+import java.util.ResourceBundle;
+
+public class AdvancedController implements Initializable {
+    @FXML
+    private Spinner<Integer> gapLimit;
+
+    @Override
+    public void initialize(URL location, ResourceBundle resources) {
+
+    }
+
+    public void initializeView(Wallet wallet) {
+        gapLimit.setValueFactory(new SpinnerValueFactory.IntegerSpinnerValueFactory(Wallet.DEFAULT_LOOKAHEAD, 10000, wallet.getGapLimit()));
+        gapLimit.valueProperty().addListener((observable, oldValue, newValue) -> {
+            wallet.setGapLimit(newValue);
+            EventManager.get().post(new SettingsChangedEvent(wallet, SettingsChangedEvent.Type.GAP_LIMIT));
+        });
+    }
+}

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

@@ -0,0 +1,35 @@
+package com.sparrowwallet.sparrow.wallet;
+
+import com.sparrowwallet.drongo.wallet.Wallet;
+import com.sparrowwallet.sparrow.AppController;
+import javafx.fxml.FXMLLoader;
+import javafx.scene.control.ButtonBar;
+import javafx.scene.control.ButtonType;
+import javafx.scene.control.Dialog;
+import javafx.scene.control.DialogPane;
+import org.controlsfx.tools.Borders;
+
+import java.io.IOException;
+
+public class AdvancedDialog extends Dialog<Void> {
+    public AdvancedDialog(Wallet wallet) {
+        final DialogPane dialogPane = getDialogPane();
+        AppController.setStageIcon(dialogPane.getScene().getWindow());
+
+        try {
+            FXMLLoader advancedLoader = new FXMLLoader(AppController.class.getResource("wallet/advanced.fxml"));
+            dialogPane.setContent(Borders.wrap(advancedLoader.load()).lineBorder().outerPadding(0).innerPadding(0).buildAll());
+            AdvancedController settingsAdvancedController = advancedLoader.getController();
+            settingsAdvancedController.initializeView(wallet);
+
+            final ButtonType closeButtonType = new javafx.scene.control.ButtonType("Close", ButtonBar.ButtonData.CANCEL_CLOSE);
+            dialogPane.getButtonTypes().addAll(closeButtonType);
+
+            dialogPane.setPrefWidth(400);
+            dialogPane.setPrefHeight(300);
+        }
+        catch(IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}

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

@@ -21,6 +21,7 @@ import com.sparrowwallet.sparrow.event.TimedEvent;
 import com.sparrowwallet.sparrow.io.Storage;
 import javafx.beans.property.SimpleIntegerProperty;
 import javafx.collections.FXCollections;
+import javafx.event.ActionEvent;
 import javafx.fxml.FXML;
 import javafx.fxml.FXMLLoader;
 import javafx.fxml.Initializable;
@@ -247,6 +248,11 @@ public class SettingsController extends WalletFormController implements Initiali
         }
     }
 
+    public void showAdvanced(ActionEvent event) {
+        AdvancedDialog advancedDialog = new AdvancedDialog(walletForm.getWallet());
+        advancedDialog.showAndWait();
+    }
+
     @Override
     protected String describeKeystore(Keystore keystore) {
         if(!keystore.isValid()) {

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

@@ -77,6 +77,10 @@ public class SettingsWalletForm extends WalletForm {
             }
         }
 
+        if(original.getGapLimit() != changed.getGapLimit()) {
+            return true;
+        }
+
         return false;
     }
 }