add coldcard single sig wallet import

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

@@ -770,6 +770,18 @@ public class AppController implements Initializable {
         if(optionalWallet.isPresent()) {
             Wallet wallet = optionalWallet.get();
             File walletFile = Storage.getWalletFile(wallet.getName());
+
+            if(walletFile.exists()) {
+                Alert alert = new Alert(Alert.AlertType.CONFIRMATION);
+                alert.setTitle("Existing wallet found");
+                alert.setHeaderText("Replace existing wallet?");
+                alert.setContentText("Wallet file " + wallet.getName() + " already exists");
+                Optional<ButtonType> result = alert.showAndWait();
+                if(result.isPresent() && result.get() == ButtonType.CANCEL) {
+                    return;
+                }
+            }
+
             Storage storage = new Storage(walletFile);
             Tab tab = addWalletTab(storage, wallet);
             tabs.getSelectionModel().select(tab);

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

@@ -28,7 +28,7 @@ public abstract class FileImportPane extends TitledDescriptionPane {
     private static final Logger log = LoggerFactory.getLogger(FileImportPane.class);
 
     private final FileImport importer;
-    private Button importButton;
+    protected Button importButton;
     private final SimpleStringProperty password = new SimpleStringProperty("");
 
     public FileImportPane(FileImport importer, String title, String description, String content, String imageUrl) {

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

@@ -0,0 +1,106 @@
+package com.sparrowwallet.sparrow.control;
+
+import com.google.common.io.ByteStreams;
+import com.google.gson.JsonParseException;
+import com.sparrowwallet.drongo.policy.Policy;
+import com.sparrowwallet.drongo.policy.PolicyType;
+import com.sparrowwallet.drongo.protocol.ScriptType;
+import com.sparrowwallet.drongo.wallet.Keystore;
+import com.sparrowwallet.drongo.wallet.Wallet;
+import com.sparrowwallet.sparrow.EventManager;
+import com.sparrowwallet.sparrow.event.WalletImportEvent;
+import com.sparrowwallet.sparrow.io.ImportException;
+import com.sparrowwallet.sparrow.io.KeystoreFileImport;
+import javafx.collections.FXCollections;
+import javafx.geometry.Insets;
+import javafx.geometry.Pos;
+import javafx.scene.Node;
+import javafx.scene.control.Button;
+import javafx.scene.control.ComboBox;
+import javafx.scene.control.Label;
+import javafx.scene.layout.HBox;
+import javafx.scene.layout.Priority;
+import javafx.scene.layout.Region;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+public class FileWalletKeystoreImportPane extends FileImportPane {
+    private static final Logger log = LoggerFactory.getLogger(FileWalletKeystoreImportPane.class);
+
+    private final KeystoreFileImport importer;
+    private String fileName;
+    private byte[] fileBytes;
+
+    public FileWalletKeystoreImportPane(KeystoreFileImport importer) {
+        super(importer, importer.getName(), "Wallet file import", importer.getKeystoreImportDescription(), "image/" + importer.getWalletModel().getType() + ".png");
+        this.importer = importer;
+    }
+
+    protected void importFile(String fileName, InputStream inputStream, String password) throws ImportException {
+        this.fileName = fileName;
+        try {
+            fileBytes = ByteStreams.toByteArray(inputStream);
+        } catch(IOException e) {
+            throw new ImportException("Could not read file", e);
+        }
+
+        setContent(getScriptTypeEntry());
+        setExpanded(true);
+        importButton.setDisable(true);
+    }
+
+    private void importWallet(ScriptType scriptType) throws ImportException {
+        ByteArrayInputStream bais = new ByteArrayInputStream(fileBytes);
+        Keystore keystore = importer.getKeystore(scriptType, bais, "");
+
+        Wallet wallet = new Wallet();
+        wallet.setName(fileName);
+        wallet.setPolicyType(PolicyType.SINGLE);
+        wallet.setScriptType(scriptType);
+        wallet.getKeystores().add(keystore);
+        wallet.setDefaultPolicy(Policy.getPolicy(PolicyType.SINGLE, scriptType, wallet.getKeystores(), null));
+
+        EventManager.get().post(new WalletImportEvent(wallet));
+    }
+
+    private Node getScriptTypeEntry() {
+        Label label = new Label("Script Type:");
+        ComboBox<ScriptType> scriptTypeComboBox = new ComboBox<>(FXCollections.observableArrayList(ScriptType.getAddressableScriptTypes(PolicyType.SINGLE)));
+        scriptTypeComboBox.setValue(ScriptType.P2WPKH);
+
+        Region region = new Region();
+        HBox.setHgrow(region, Priority.SOMETIMES);
+
+        Button importFileButton = new Button("Import");
+        importFileButton.setOnAction(event -> {
+            showHideLink.setVisible(true);
+            setExpanded(false);
+            try {
+                importWallet(scriptTypeComboBox.getValue());
+            } catch(ImportException e) {
+                log.error("Error importing file", e);
+                String errorMessage = e.getMessage();
+                if(e.getCause() instanceof JsonParseException) {
+                    errorMessage = "File was not in JSON format";
+                } else if(e.getCause() != null && e.getCause().getMessage() != null && !e.getCause().getMessage().isEmpty()) {
+                    errorMessage = e.getCause().getMessage();
+                }
+                setError("Import Error", errorMessage);
+                importButton.setDisable(false);
+            }
+        });
+
+        HBox contentBox = new HBox();
+        contentBox.setAlignment(Pos.CENTER_RIGHT);
+        contentBox.setSpacing(20);
+        contentBox.getChildren().addAll(label, scriptTypeComboBox, region, importFileButton);
+        contentBox.setPadding(new Insets(10, 30, 10, 30));
+        contentBox.setPrefHeight(60);
+
+        return contentBox;
+    }
+}

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

@@ -29,16 +29,22 @@ public class WalletImportDialog extends Dialog<Wallet> {
         stackPane.getChildren().add(anchorPane);
 
         ScrollPane scrollPane = new ScrollPane();
-        scrollPane.setPrefHeight(280);
+        scrollPane.setPrefHeight(320);
         scrollPane.setHbarPolicy(ScrollPane.ScrollBarPolicy.NEVER);
         anchorPane.getChildren().add(scrollPane);
         scrollPane.setFitToWidth(true);
         AnchorPane.setLeftAnchor(scrollPane, 0.0);
         AnchorPane.setRightAnchor(scrollPane, 0.0);
 
-        List<WalletImport> importers = List.of(new ColdcardMultisig(), new Electrum());
         Accordion importAccordion = new Accordion();
-        for(WalletImport importer : importers) {
+        List<KeystoreFileImport> keystoreImporters = List.of(new ColdcardSinglesig());
+        for(KeystoreFileImport importer : keystoreImporters) {
+            FileWalletKeystoreImportPane importPane = new FileWalletKeystoreImportPane(importer);
+            importAccordion.getPanes().add(importPane);
+        }
+
+        List<WalletImport> walletImporters = List.of(new ColdcardMultisig(), new Electrum());
+        for(WalletImport importer : walletImporters) {
             FileWalletImportPane importPane = new FileWalletImportPane(importer);
             importAccordion.getPanes().add(importPane);
         }
@@ -47,7 +53,7 @@ public class WalletImportDialog extends Dialog<Wallet> {
         final ButtonType cancelButtonType = new javafx.scene.control.ButtonType("Cancel", ButtonBar.ButtonData.CANCEL_CLOSE);
         dialogPane.getButtonTypes().addAll(cancelButtonType);
         dialogPane.setPrefWidth(500);
-        dialogPane.setPrefHeight(360);
+        dialogPane.setPrefHeight(400);
 
         setResultConverter(dialogButton -> dialogButton != cancelButtonType ? wallet : null);
     }