recommend backup of output descriptor when saving new multisig wallets

src/main/java/com/sparrowwallet/sparrow/control/DescriptorQRDisplayDialog.java

@@ -1,28 +1,13 @@
 package com.sparrowwallet.sparrow.control;
 
-import com.lowagie.text.*;
-import com.lowagie.text.Font;
-import com.lowagie.text.Image;
-import com.lowagie.text.pdf.PdfWriter;
 import com.sparrowwallet.hummingbird.UR;
-import com.sparrowwallet.hummingbird.UREncoder;
+import com.sparrowwallet.sparrow.glyphfont.FontAwesome5;
-import com.sparrowwallet.sparrow.AppServices;
+import com.sparrowwallet.sparrow.io.PdfUtils;
-import javafx.embed.swing.SwingFXUtils;
 import javafx.event.ActionEvent;
 import javafx.scene.control.*;
 import javafx.scene.control.Button;
-import javafx.stage.FileChooser;
-import javafx.stage.Stage;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import java.awt.*;
-import java.io.File;
-import java.io.FileOutputStream;
 
 public class DescriptorQRDisplayDialog extends QRDisplayDialog {
-    private static final Logger log = LoggerFactory.getLogger(DescriptorQRDisplayDialog.class);
-
     public DescriptorQRDisplayDialog(String walletName, String outputDescriptor, UR ur) {
         super(ur);
 
@@ -31,43 +16,11 @@ public class DescriptorQRDisplayDialog extends QRDisplayDialog {
         dialogPane.getButtonTypes().add(pdfButtonType);
 
         Button pdfButton = (Button)dialogPane.lookupButton(pdfButtonType);
+        pdfButton.setGraphicTextGap(5);
+        pdfButton.setGraphic(getGlyph(FontAwesome5.Glyph.FILE_PDF));
         pdfButton.addEventFilter(ActionEvent.ACTION, event -> {
-            savePdf(walletName, outputDescriptor, ur);
+            PdfUtils.saveOutputDescriptor(walletName, outputDescriptor, ur);
             event.consume();
         });
     }
-
-    private void savePdf(String walletName, String outputDescriptor, UR ur) {
-        Stage window = new Stage();
-        FileChooser fileChooser = new FileChooser();
-        fileChooser.setTitle("Save PDF");
-        fileChooser.setInitialFileName(walletName + ".pdf");
-        AppServices.moveToActiveWindowScreen(window, 800, 450);
-        File file = fileChooser.showSaveDialog(window);
-        if(file != null) {
-            try(Document document = new Document()) {
-                document.setMargins(36, 36, 48, 36);
-                PdfWriter.getInstance(document, new FileOutputStream(file));
-                document.open();
-
-                Font titleFont = FontFactory.getFont(FontFactory.HELVETICA_BOLD, 16, Color.BLACK);
-                Chunk title = new Chunk("Output descriptor for " + walletName, titleFont);
-                document.add(title);
-
-                UREncoder urEncoder = new UREncoder(ur, 2000, 10, 0);
-                String fragment = urEncoder.nextPart();
-                if(urEncoder.isSinglePart()) {
-                    Image image = Image.getInstance(SwingFXUtils.fromFXImage(getQrCode(fragment), null), Color.WHITE);
-                    document.add(image);
-                }
-
-                Font descriptorFont = FontFactory.getFont(FontFactory.COURIER, 14, Color.BLACK);
-                Paragraph descriptor = new Paragraph(outputDescriptor, descriptorFont);
-                document.add(descriptor);
-            } catch(Exception e) {
-                log.error("Error creating descriptor PDF", e);
-                AppServices.showErrorDialog("Error creating PDF", e.getMessage());
-            }
-        }
-    }
 }

src/main/java/com/sparrowwallet/sparrow/control/QRDisplayDialog.java

@@ -244,11 +244,11 @@ public class QRDisplayDialog extends Dialog<UR> {
                 legacy.setGraphic(getGlyph(FontAwesome5.Glyph.BAN));
             }
         }
+    }
 
-        private Glyph getGlyph(FontAwesome5.Glyph glyphName) {
+    protected static Glyph getGlyph(FontAwesome5.Glyph glyphName) {
         Glyph glyph = new Glyph(FontAwesome5.FONT_NAME, glyphName);
         glyph.setFontSize(11);
         return glyph;
     }
-    }
 }

src/main/java/com/sparrowwallet/sparrow/glyphfont/FontAwesome5.java

@@ -38,6 +38,7 @@ public class FontAwesome5 extends GlyphFont {
         FEATHER_ALT('\uf56b'),
         FILE_CSV('\uf6dd'),
         FILE_IMPORT('\uf56f'),
+        FILE_PDF('\uf1c1'),
         HAND_HOLDING('\uf4bd'),
         HAND_HOLDING_MEDICAL('\ue05c'),
         HAND_HOLDING_WATER('\uf4c1'),

src/main/java/com/sparrowwallet/sparrow/io/PdfUtils.java

@@ -0,0 +1,75 @@
+package com.sparrowwallet.sparrow.io;
+
+import com.google.zxing.BarcodeFormat;
+import com.google.zxing.WriterException;
+import com.google.zxing.client.j2se.MatrixToImageConfig;
+import com.google.zxing.client.j2se.MatrixToImageWriter;
+import com.google.zxing.common.BitMatrix;
+import com.google.zxing.qrcode.QRCodeWriter;
+import com.lowagie.text.*;
+import com.lowagie.text.Font;
+import com.lowagie.text.Image;
+import com.lowagie.text.pdf.PdfWriter;
+import com.sparrowwallet.hummingbird.UR;
+import com.sparrowwallet.hummingbird.UREncoder;
+import com.sparrowwallet.sparrow.AppServices;
+import javafx.embed.swing.SwingFXUtils;
+import javafx.stage.FileChooser;
+import javafx.stage.Stage;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.awt.*;
+import java.io.*;
+
+public class PdfUtils {
+    private static final Logger log = LoggerFactory.getLogger(PdfUtils.class);
+
+    private static final int QR_WIDTH = 480;
+    private static final int QR_HEIGHT = 480;
+
+    public static void saveOutputDescriptor(String walletName, String outputDescriptor, UR ur) {
+        Stage window = new Stage();
+        FileChooser fileChooser = new FileChooser();
+        fileChooser.setTitle("Save PDF");
+        fileChooser.setInitialFileName(walletName + ".pdf");
+        AppServices.moveToActiveWindowScreen(window, 800, 450);
+        File file = fileChooser.showSaveDialog(window);
+        if(file != null) {
+            try(Document document = new Document()) {
+                document.setMargins(36, 36, 48, 36);
+                PdfWriter.getInstance(document, new FileOutputStream(file));
+                document.open();
+
+                Font titleFont = FontFactory.getFont(FontFactory.HELVETICA_BOLD, 16, Color.BLACK);
+                Chunk title = new Chunk("Output descriptor for " + walletName, titleFont);
+                document.add(title);
+
+                UREncoder urEncoder = new UREncoder(ur, 2000, 10, 0);
+                String fragment = urEncoder.nextPart();
+                if(urEncoder.isSinglePart()) {
+                    Image image = Image.getInstance(SwingFXUtils.fromFXImage(getQrCode(fragment), null), Color.WHITE);
+                    document.add(image);
+                }
+
+                Font descriptorFont = FontFactory.getFont(FontFactory.COURIER, 14, Color.BLACK);
+                Paragraph descriptor = new Paragraph(outputDescriptor, descriptorFont);
+                document.add(descriptor);
+            } catch(Exception e) {
+                log.error("Error creating descriptor PDF", e);
+                AppServices.showErrorDialog("Error creating PDF", e.getMessage());
+            }
+        }
+    }
+
+    private static javafx.scene.image.Image getQrCode(String fragment) throws IOException, WriterException {
+        QRCodeWriter qrCodeWriter = new QRCodeWriter();
+        BitMatrix qrMatrix = qrCodeWriter.encode(fragment, BarcodeFormat.QR_CODE, QR_WIDTH, QR_HEIGHT);
+
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        MatrixToImageWriter.writeToStream(qrMatrix, "PNG", baos, new MatrixToImageConfig());
+
+        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
+        return new javafx.scene.image.Image(bais);
+    }
+}

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

@@ -0,0 +1,90 @@
+package com.sparrowwallet.sparrow.wallet;
+
+import com.sparrowwallet.drongo.wallet.Wallet;
+import com.sparrowwallet.hummingbird.UR;
+import com.sparrowwallet.sparrow.AppServices;
+import com.sparrowwallet.sparrow.glyphfont.FontAwesome5;
+import com.sparrowwallet.sparrow.io.PdfUtils;
+import javafx.scene.Node;
+import javafx.scene.control.*;
+import javafx.scene.layout.HBox;
+import javafx.scene.layout.Priority;
+import org.controlsfx.glyphfont.Glyph;
+
+public class MultisigBackupDialog extends Dialog<String> {
+    private final Wallet wallet;
+    private final String descriptor;
+    private final UR ur;
+
+    private final TextArea textArea;
+
+    public MultisigBackupDialog(Wallet wallet, String descriptor, UR ur) {
+        this.wallet = wallet;
+        this.descriptor = descriptor;
+        this.ur = ur;
+
+        setTitle("Backup Multisig Wallet?");
+
+        DialogPane dialogPane = new MultisigBackupDialogPane();
+        dialogPane.setHeaderText("To restore this multisig wallet, you need at least " + wallet.getDefaultPolicy().getNumSignaturesRequired() + " seeds and ALL of the xpubs!\n" +
+                "It is recommended to backup either this wallet file, or the wallet output descriptor.\n\n" +
+                "The wallet output descriptor contains all the xpubs and is shown below.\n" +
+                "Alternatively, use the Export button below to export the Sparrow wallet file.");
+        setDialogPane(dialogPane);
+
+        dialogPane.getStyleClass().addAll("alert", "warning");
+
+        HBox hbox = new HBox();
+        this.textArea = new TextArea(descriptor);
+        this.textArea.setMaxWidth(Double.MAX_VALUE);
+        this.textArea.setWrapText(true);
+        this.textArea.getStyleClass().add("fixed-width");
+        this.textArea.setEditable(false);
+        hbox.getChildren().add(textArea);
+        HBox.setHgrow(this.textArea, Priority.ALWAYS);
+
+        dialogPane.setContent(hbox);
+        dialogPane.getStylesheets().add(AppServices.class.getResource("general.css").toExternalForm());
+        AppServices.setStageIcon(dialogPane.getScene().getWindow());
+
+        dialogPane.getStyleClass().add("text-input-dialog");
+        dialogPane.getButtonTypes().add(ButtonType.OK);
+
+        final ButtonType qrButtonType = new javafx.scene.control.ButtonType("Save PDF...", ButtonBar.ButtonData.LEFT);
+        dialogPane.getButtonTypes().add(qrButtonType);
+
+        dialogPane.setPrefWidth(700);
+        dialogPane.setPrefHeight(350);
+        AppServices.moveToActiveWindowScreen(this);
+    }
+
+    private class MultisigBackupDialogPane extends DialogPane {
+        @Override
+        protected Node createButton(ButtonType buttonType) {
+            Node button;
+            if(buttonType.getButtonData() == ButtonBar.ButtonData.LEFT) {
+                Button pdfButton = new Button(buttonType.getText());
+                pdfButton.setGraphicTextGap(5);
+                pdfButton.setGraphic(getGlyph(FontAwesome5.Glyph.FILE_PDF));
+
+                final ButtonBar.ButtonData buttonData = buttonType.getButtonData();
+                ButtonBar.setButtonData(pdfButton, buttonData);
+                pdfButton.setOnAction(event -> {
+                    PdfUtils.saveOutputDescriptor(wallet.getFullDisplayName(), descriptor, ur);
+                });
+
+                button = pdfButton;
+            } else {
+                button = super.createButton(buttonType);
+            }
+
+            return button;
+        }
+
+        private Glyph getGlyph(FontAwesome5.Glyph glyphName) {
+            Glyph glyph = new Glyph(FontAwesome5.FONT_NAME, glyphName);
+            glyph.setFontSize(11);
+            return glyph;
+        }
+    }
+}

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

@@ -217,7 +217,16 @@ public class SettingsController extends WalletFormController implements Initiali
         apply.setOnAction(event -> {
             revert.setDisable(true);
             apply.setDisable(true);
+            boolean addressChange = ((SettingsWalletForm)walletForm).isAddressChange();
             saveWallet(false, false);
+
+            Wallet wallet = walletForm.getWallet();
+            if(wallet.getPolicyType() == PolicyType.MULTI && wallet.getDefaultPolicy().getNumSignaturesRequired() < wallet.getKeystores().size() && addressChange) {
+                String outputDescriptor = OutputDescriptor.getOutputDescriptor(wallet, KeyPurpose.DEFAULT_PURPOSES, null).toString(true);
+                CryptoOutput cryptoOutput = getCryptoOutput(wallet);
+                MultisigBackupDialog dialog = new MultisigBackupDialog(wallet, outputDescriptor, cryptoOutput.toUR());
+                dialog.showAndWait();
+            }
         });
 
         setFieldsFromWallet(walletForm.getWallet());
@@ -325,18 +334,8 @@ public class SettingsController extends WalletFormController implements Initiali
         }
 
         OutputDescriptor outputDescriptor = OutputDescriptor.getOutputDescriptor(walletForm.getWallet(), KeyPurpose.DEFAULT_PURPOSES, null);
-        List<ScriptExpression> scriptExpressions = getScriptExpressions(walletForm.getWallet().getScriptType());
+        CryptoOutput cryptoOutput = getCryptoOutput(walletForm.getWallet());
-
+        if(cryptoOutput == null) {
-        CryptoOutput cryptoOutput;
-        if(walletForm.getWallet().getPolicyType() == PolicyType.SINGLE) {
-            cryptoOutput = new CryptoOutput(scriptExpressions, getCryptoHDKey(walletForm.getWallet().getKeystores().get(0)));
-        } else if(walletForm.getWallet().getPolicyType() == PolicyType.MULTI) {
-            List<CryptoHDKey> cryptoHDKeys = walletForm.getWallet().getKeystores().stream().map(this::getCryptoHDKey).collect(Collectors.toList());
-            MultiKey multiKey = new MultiKey(walletForm.getWallet().getDefaultPolicy().getNumSignaturesRequired(), null, cryptoHDKeys);
-            List<ScriptExpression> multiScriptExpressions = new ArrayList<>(scriptExpressions);
-            multiScriptExpressions.add(ScriptExpression.SORTED_MULTISIG);
-            cryptoOutput = new CryptoOutput(multiScriptExpressions, multiKey);
-        } else {
             AppServices.showErrorDialog("Unsupported Wallet Policy", "Cannot show a descriptor for this wallet.");
             return;
         }
@@ -346,6 +345,23 @@ public class SettingsController extends WalletFormController implements Initiali
         qrDisplayDialog.showAndWait();
     }
 
+    private CryptoOutput getCryptoOutput(Wallet wallet) {
+        List<ScriptExpression> scriptExpressions = getScriptExpressions(wallet.getScriptType());
+
+        CryptoOutput cryptoOutput = null;
+        if(wallet.getPolicyType() == PolicyType.SINGLE) {
+            cryptoOutput = new CryptoOutput(scriptExpressions, getCryptoHDKey(wallet.getKeystores().get(0)));
+        } else if(wallet.getPolicyType() == PolicyType.MULTI) {
+            List<CryptoHDKey> cryptoHDKeys = wallet.getKeystores().stream().map(this::getCryptoHDKey).collect(Collectors.toList());
+            MultiKey multiKey = new MultiKey(wallet.getDefaultPolicy().getNumSignaturesRequired(), null, cryptoHDKeys);
+            List<ScriptExpression> multiScriptExpressions = new ArrayList<>(scriptExpressions);
+            multiScriptExpressions.add(ScriptExpression.SORTED_MULTISIG);
+            cryptoOutput = new CryptoOutput(multiScriptExpressions, multiKey);
+        }
+
+        return cryptoOutput;
+    }
+
     private List<ScriptExpression> getScriptExpressions(ScriptType scriptType) {
         if(scriptType == ScriptType.P2PK) {
             return List.of(ScriptExpression.PUBLIC_KEY);