add qr scanning support

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

@@ -0,0 +1,191 @@
+package com.sparrowwallet.sparrow.control;
+
+import com.github.sarxos.webcam.WebcamResolution;
+import com.sparrowwallet.drongo.Utils;
+import com.sparrowwallet.drongo.protocol.Base43;
+import com.sparrowwallet.drongo.protocol.Transaction;
+import com.sparrowwallet.drongo.psbt.PSBT;
+import com.sparrowwallet.sparrow.ur.ResultType;
+import com.sparrowwallet.sparrow.ur.UR;
+import com.sparrowwallet.sparrow.ur.URDecoder;
+import javafx.application.Platform;
+import javafx.beans.value.ChangeListener;
+import javafx.beans.value.ObservableValue;
+import javafx.scene.control.ButtonBar;
+import javafx.scene.control.ButtonType;
+import javafx.scene.control.Dialog;
+import javafx.scene.control.DialogPane;
+import javafx.scene.layout.StackPane;
+import org.controlsfx.tools.Borders;
+
+public class QRScanDialog extends Dialog<QRScanDialog.Result> {
+    private final URDecoder decoder;
+    private final WebcamService webcamService;
+
+    private boolean isUr;
+    private QRScanDialog.Result result;
+
+    public QRScanDialog() {
+        this.decoder = new URDecoder();
+
+        this.webcamService = new WebcamService(WebcamResolution.VGA);
+        WebcamView webcamView = new WebcamView(webcamService);
+
+        final DialogPane dialogPane = getDialogPane();
+
+        StackPane stackPane = new StackPane();
+        stackPane.getChildren().add(webcamView.getView());
+
+        dialogPane.setContent(Borders.wrap(stackPane).lineBorder().outerPadding(0).innerPadding(0).buildAll());
+
+        webcamService.resultProperty().addListener(new QRResultListener());
+        webcamService.setOnFailed(failedEvent -> {
+            Platform.runLater(() -> setResult(new Result(failedEvent.getSource().getException())));
+        });
+        webcamService.start();
+        setOnCloseRequest(event -> {
+            Platform.runLater(webcamService::cancel);
+        });
+
+        final ButtonType cancelButtonType = new javafx.scene.control.ButtonType("Cancel", ButtonBar.ButtonData.CANCEL_CLOSE);
+        dialogPane.getButtonTypes().addAll(cancelButtonType);
+        dialogPane.setPrefWidth(660);
+        dialogPane.setPrefHeight(550);
+
+        setResultConverter(dialogButton -> dialogButton != cancelButtonType ? result : null);
+    }
+
+    private class QRResultListener implements ChangeListener<com.google.zxing.Result> {
+        @Override
+        public void changed(ObservableValue<? extends com.google.zxing.Result> observable, com.google.zxing.Result oldValue, com.google.zxing.Result qrResult) {
+            if(result != null) {
+                Platform.runLater(() -> setResult(result));
+            }
+
+            //Try text first
+            String qrtext = qrResult.getText();
+            if(isUr || qrtext.toLowerCase().startsWith(UR.UR_PREFIX)) {
+                isUr = true;
+                decoder.receivePart(qrtext);
+
+                if(decoder.getResult() != null) {
+                    URDecoder.Result urResult = decoder.getResult();
+                    if(urResult.type == ResultType.SUCCESS) {
+                        if(urResult.ur.getType().equals(UR.BYTES_TYPE)) {
+                            try {
+                                PSBT psbt = new PSBT(urResult.ur.toBytes());
+                                result = new Result(psbt);
+                                return;
+                            } catch(Exception e) {
+                                //ignore, bytes not parsable as PSBT
+                            }
+
+                            try {
+                                Transaction transaction = new Transaction(urResult.ur.toBytes());
+                                result = new Result(transaction);
+                                return;
+                            } catch(Exception e) {
+                                //ignore, bytes not parsable as tx
+                            }
+
+                            result = new Result("Parsed UR of type " + urResult.ur.getType() + " was not a PSBT or transaction");
+                        } else {
+                            result = new Result("Cannot parse UR type of " + urResult.ur.getType());
+                        }
+                    } else {
+                        result = new Result(urResult.error);
+                    }
+                }
+            } else {
+                PSBT psbt;
+                Transaction transaction;
+                try {
+                    psbt = PSBT.fromString(qrtext);
+                    result = new Result(psbt);
+                    return;
+                } catch(Exception e) {
+                    //Ignore, not parseable as Base64 or hex
+                }
+
+                try {
+                    psbt = new PSBT(qrResult.getRawBytes());
+                    result = new Result(psbt);
+                    return;
+                } catch(Exception e) {
+                    //Ignore, not parseable as raw bytes
+                }
+
+                try {
+                    transaction = new Transaction(Utils.hexToBytes(qrtext));
+                    result = new Result(transaction);
+                    return;
+                } catch(Exception e) {
+                    //Ignore, not parseable as hex
+                }
+
+                try {
+                    transaction = new Transaction(qrResult.getRawBytes());
+                    result = new Result(transaction);
+                    return;
+                } catch(Exception e) {
+                    //Ignore, not parseable as raw bytes
+                }
+
+                //Try Base43 used by Electrum
+                byte[] base43 = Base43.decode(qrResult.getText());
+                try {
+                    psbt = new PSBT(base43);
+                    result = new Result(psbt);
+                    return;
+                } catch(Exception e) {
+                    //Ignore, not parseable as base43 decoded bytes
+                }
+
+                try {
+                    transaction = new Transaction(base43);
+                    result = new Result(transaction);
+                    return;
+                } catch(Exception e) {
+                    //Ignore, not parseable as base43 decoded bytes
+                }
+
+                result = new Result("Cannot parse QR code into a PSBT or transaction");
+            }
+        }
+    }
+
+    public static class Result {
+        public final Transaction transaction;
+        public final PSBT psbt;
+        public final String error;
+        public final Throwable exception;
+
+        public Result(Transaction transaction) {
+            this.transaction = transaction;
+            this.psbt = null;
+            this.error = null;
+            this.exception = null;
+        }
+
+        public Result(PSBT psbt) {
+            this.transaction = null;
+            this.psbt = psbt;
+            this.error = null;
+            this.exception = null;
+        }
+
+        public Result(String error) {
+            this.transaction = null;
+            this.psbt = null;
+            this.error = error;
+            this.exception = null;
+        }
+
+        public Result(Throwable exception) {
+            this.transaction = null;
+            this.psbt = null;
+            this.error = null;
+            this.exception = exception;
+        }
+    }
+}