Add missing drop handler

ugs-platform/ugs-platform-plugin-designer/src/main/java/com/willwinder/ugs/nbp/designer/gui/DropHandler.java

@@ -0,0 +1,128 @@
+/*
+    Copyright 2024 Will Winder
+
+    This file is part of Universal Gcode Sender (UGS).
+
+    UGS is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    UGS is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with UGS.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.willwinder.ugs.nbp.designer.gui;
+
+import com.willwinder.ugs.nbp.designer.actions.ToolImportAction;
+import static com.willwinder.ugs.nbp.designer.actions.ToolImportAction.FILE_NAME_EXTENSION_FILTERS;
+import com.willwinder.ugs.nbp.designer.logic.ControllerFactory;
+import com.willwinder.ugs.nbp.lib.lookup.CentralLookup;
+import com.willwinder.universalgcodesender.model.BackendAPI;
+import com.willwinder.universalgcodesender.utils.ThreadHelper;
+import org.apache.commons.lang3.StringUtils;
+
+import java.awt.datatransfer.DataFlavor;
+import java.awt.datatransfer.Transferable;
+import java.awt.datatransfer.UnsupportedFlavorException;
+import java.awt.dnd.DnDConstants;
+import java.awt.dnd.DropTargetDragEvent;
+import java.awt.dnd.DropTargetDropEvent;
+import java.awt.dnd.DropTargetEvent;
+import java.awt.dnd.DropTargetListener;
+import java.io.File;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Optional;
+
+/**
+ * Listens for drag'n'drop of known file types and imports it via the {@link ToolImportAction}.
+ *
+ * @author Joacim Breiler
+ */
+public class DropHandler implements DropTargetListener {
+    private static Optional<String> getFilename(DataFlavor stringFlavor, Transferable transferable) {
+        try {
+            String filename = (String) transferable.getTransferData(stringFlavor);
+            if (hasCorrectExtension(filename)) {
+                return Optional.of(filename);
+            }
+        } catch (UnsupportedFlavorException | IOException e) {
+            // Never mind...
+        }
+
+        return Optional.empty();
+    }
+
+    private static boolean hasCorrectExtension(String filename) {
+        return Arrays.stream(FILE_NAME_EXTENSION_FILTERS)
+                .flatMap(s -> Arrays.stream(s.getExtensions()))
+                .anyMatch(extension -> StringUtils.endsWithIgnoreCase(filename, extension));
+    }
+
+    private Optional<String> getFilename(DropTargetDragEvent dtde) {
+        DataFlavor stringFlavor = DataFlavor.stringFlavor;
+        if (!dtde.isDataFlavorSupported(stringFlavor)) {
+            return Optional.empty();
+        }
+
+        Transferable transferable = dtde.getTransferable();
+        return getFilename(stringFlavor, transferable);
+    }
+
+    private Optional<String> getFilename(DropTargetDropEvent dtde) {
+        DataFlavor stringFlavor = DataFlavor.stringFlavor;
+        if (!dtde.isDataFlavorSupported(stringFlavor)) {
+            return Optional.empty();
+        }
+
+        dtde.acceptDrop(DnDConstants.ACTION_COPY);
+        Transferable transferable = dtde.getTransferable();
+        return getFilename(stringFlavor, transferable);
+    }
+
+    @Override
+    public void dragEnter(DropTargetDragEvent dtde) {
+        Optional<String> filename = getFilename(dtde);
+        if (filename.isEmpty()) {
+            dtde.rejectDrag();
+            return;
+        }
+
+        dtde.acceptDrag(DnDConstants.ACTION_COPY);
+    }
+
+    @Override
+    public void dragOver(DropTargetDragEvent dtde) {
+        dragEnter(dtde);
+    }
+
+    @Override
+    public void dropActionChanged(DropTargetDragEvent dtde) {
+        // Not used
+    }
+
+    @Override
+    public void dragExit(DropTargetEvent dte) {
+        // Not used
+    }
+
+    @Override
+    public void drop(DropTargetDropEvent dtde) {
+        Optional<String> filename = getFilename(dtde);
+        if (filename.isEmpty()) {
+            dtde.dropComplete(false);
+            return;
+        }
+
+        ThreadHelper.invokeLater(() -> {
+            File file = filename.map(File::new).get();
+            ToolImportAction.readDesign(ControllerFactory.getController(), CentralLookup.getDefault().lookup(BackendAPI.class), file);
+            dtde.dropComplete(true);
+        });
+    }
+}