import and export a wallet as an output descriptor in a text file

src/main/java/com/sparrowwallet/sparrow/AppController.java

@@ -978,6 +978,7 @@ public class AppController implements Initializable {
         List<WalletImport> walletImporters = List.of(new ColdcardSinglesig(), new ColdcardMultisig(),
                 new Electrum(),
                 new SpecterDesktop(),
+                new Descriptor(),
                 new CoboVaultSinglesig(), new CoboVaultMultisig(),
                 new PassportSinglesig(),
                 new KeystoneSinglesig(), new KeystoneMultisig(),

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

@@ -42,9 +42,9 @@ public class WalletExportDialog extends Dialog<Wallet> {
 
         List<WalletExport> exporters;
         if(wallet.getPolicyType() == PolicyType.SINGLE) {
-            exporters = List.of(new Electrum(), new SpecterDesktop(), new Sparrow());
+            exporters = List.of(new Electrum(), new Descriptor(), new SpecterDesktop(), new Sparrow());
         } else if(wallet.getPolicyType() == PolicyType.MULTI) {
-            exporters = List.of(new CaravanMultisig(), new ColdcardMultisig(), new CoboVaultMultisig(), new Electrum(), new KeystoneMultisig(), new PassportMultisig(), new SpecterDesktop(), new BlueWalletMultisig(), new SpecterDIY(), new Sparrow());
+            exporters = List.of(new CaravanMultisig(), new ColdcardMultisig(), new CoboVaultMultisig(), new Electrum(), new KeystoneMultisig(), new Descriptor(), new PassportMultisig(), new SpecterDesktop(), new BlueWalletMultisig(), new SpecterDIY(), new Sparrow());
         } else {
             throw new UnsupportedOperationException("Cannot export wallet with policy type " + wallet.getPolicyType());
         }

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

@@ -54,7 +54,7 @@ public class WalletImportDialog extends Dialog<Wallet> {
             importAccordion.getPanes().add(importPane);
         }
 
-        List<WalletImport> walletImporters = List.of(new CaravanMultisig(), new ColdcardMultisig(), new CoboVaultMultisig(), new Electrum(), new KeystoneMultisig(), new SpecterDesktop(), new BlueWalletMultisig(), new Sparrow());
+        List<WalletImport> walletImporters = List.of(new CaravanMultisig(), new ColdcardMultisig(), new CoboVaultMultisig(), new Electrum(), new KeystoneMultisig(), new Descriptor(), new SpecterDesktop(), new BlueWalletMultisig(), new Sparrow());
         for(WalletImport importer : walletImporters) {
             FileWalletImportPane importPane = new FileWalletImportPane(importer);
             importAccordion.getPanes().add(importPane);

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

@@ -0,0 +1,80 @@
+package com.sparrowwallet.sparrow.io;
+
+import com.sparrowwallet.drongo.OutputDescriptor;
+import com.sparrowwallet.drongo.wallet.Wallet;
+import com.sparrowwallet.drongo.wallet.WalletModel;
+
+import java.io.*;
+import java.nio.charset.StandardCharsets;
+import java.util.stream.Collectors;
+
+public class Descriptor implements WalletImport, WalletExport {
+
+    @Override
+    public String getName() {
+        return "Output Descriptor";
+    }
+
+    @Override
+    public WalletModel getWalletModel() {
+        return WalletModel.BITCOIN_CORE;
+    }
+
+    @Override
+    public void exportWallet(Wallet wallet, OutputStream outputStream) throws ExportException {
+        try {
+            OutputDescriptor outputDescriptor = OutputDescriptor.getOutputDescriptor(wallet);
+            String outputDescriptorString = outputDescriptor.toString(true);
+            outputStream.write(outputDescriptorString.getBytes(StandardCharsets.UTF_8));
+            outputStream.flush();
+        } catch(Exception e) {
+            throw new ExportException("Error writing output descriptor", e);
+        }
+    }
+
+    @Override
+    public String getWalletExportDescription() {
+        return "The output descriptor is a standardized description of the wallet compatible with Bitcoin Core, and can be used to create a watch-only copy using the Edit button on the Settings tab of a new Sparrow wallet.";
+    }
+
+    @Override
+    public String getExportFileExtension(Wallet wallet) {
+        return "txt";
+    }
+
+    @Override
+    public boolean isWalletExportScannable() {
+        return false;
+    }
+
+    @Override
+    public boolean walletExportRequiresDecryption() {
+        return false;
+    }
+
+    @Override
+    public boolean isEncrypted(File file) {
+        return false;
+    }
+
+    @Override
+    public String getWalletImportDescription() {
+        return "Import a file containing the output descriptor of a wallet. The output descriptor is a standardized description of the wallet compatible with Bitcoin Core.";
+    }
+
+    @Override
+    public Wallet importWallet(InputStream inputStream, String password) throws ImportException {
+        try {
+            String outputDescriptor = new BufferedReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8)).lines().collect(Collectors.joining("\n"));
+            OutputDescriptor descriptor = OutputDescriptor.getOutputDescriptor(outputDescriptor.trim());
+            return descriptor.toWallet();
+        } catch(Exception e) {
+            throw new ImportException("Error importing output descriptor", e);
+        }
+    }
+
+    @Override
+    public boolean isWalletImportScannable() {
+        return false;
+    }
+}