source: trunk/src/org/expeditee/gio/DragAndDropManager.java@ 1097

package org.expeditee.gio;

import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.LinkedList;
import java.util.List;
import java.util.StringTokenizer;

import org.expeditee.core.Point;
import org.expeditee.gui.DisplayController;
import org.expeditee.importer.FileImporter;
import org.expeditee.importer.FilePathImporter;
import org.expeditee.importer.ImageImporter;
import org.expeditee.importer.TextImporter;
import org.expeditee.importer.pdfImporter;
import org.expeditee.items.Item;
import org.expeditee.items.Text;

/** TODO: Comment. cts16 */
public abstract class DragAndDropManager {
        
        /** The list of custom file importers registered with the DnD manager. */
        private List<FileImporter> _customFileImporters = new LinkedList<FileImporter>();

        /** The list of standard file importers registered with the DnD manager. */
        private List<FileImporter> _standardFileImporters = new LinkedList<FileImporter>();
        
        /** Standard constructor. */
        protected DragAndDropManager()
        {
                // Set up the standard file importers
                _standardFileImporters.add(new ImageImporter());
                _standardFileImporters.add(new pdfImporter());
                _standardFileImporters.add(new TextImporter());
                _standardFileImporters.add(new FilePathImporter()); // Filepath importer as last resort
        }

        /**
         * Adds a custom importer. If an importer competes with another importer for
         * handling the same file types, the importer that was added first will have
         * first serve.
         * 
         * @param importer
         *            The importer to add. Must not be null
         * 
         * @throws NullPointerException
         *             if importer is null.
         */
        public void addCustomFileImporter(FileImporter importer)
        {
                if (importer == null) throw new NullPointerException("importer");
                
                if (!_customFileImporters.contains(importer)) {
                        _customFileImporters.add(importer);
                }
        }

        /**
         * Removes a custom importer.
         * 
         * @param importer
         *            The importer to remove.
         * 
         * @throws NullPointerException
         *             if importer is null.
         */
        public void removeCustomFileImporter(FileImporter importer)
        {
                if (importer == null) throw new NullPointerException("importer");
                
                _customFileImporters.remove(importer);
        }

        /**
         * Imports a string into expeditee's current frame
         * 
         * @param text
         *            The text content.
         * 
         * @param expediteeDropPoint
         *            The location in the current expeditee frame of where to drop
         *            the text item.
         */
        public static Text importString(String text, Point expediteeDropPoint)
        {
                assert (DisplayController.getCurrentFrame() != null);
                assert (text != null && text.length() > 0);

                Text importedTextItem = new Text(DisplayController.getCurrentFrame().getNextItemID(), text);
                importedTextItem.setPosition(expediteeDropPoint);

                DisplayController.getCurrentFrame().addItem(importedTextItem);
                DisplayController.requestRefresh(true);

                return importedTextItem;
        }

        /** Imports a list of files into Expeditee's current frame. */
        public void importFileList(List<? extends File> files, Point expediteeDropPoint) throws IOException
        {
                Point currentPoint = new Point(expediteeDropPoint);

                 // import files one by one
                for (File fileToImport : files) {

                        Item lastItem = importFile(fileToImport, currentPoint);

                        if (lastItem == null) {
                                currentPoint.y += 30;
                        } else {
                                currentPoint.y += lastItem.getBoundsHeight();
                        }
                        // of the item that was created

                        // TODO: Better placement strategy
                        // if (currentPoint.y > (Browser._theBrowser.getHeight() - 20))
                        // currentPoint.y = Browser._theBrowser.getHeight() - 20;
                }
        }

        /**
         * Imports a file into Expeditee. Any custom importers registered get first attempt,
         * followed by the standard importers.
         * 
         * @param f
         *            The file to import.
         * 
         * @param expediteeDropPoint
         * 
         * @throws IOException
         */
        public Item importFile(File f, Point expediteeDropPoint) throws IOException
        {
                assert (f != null);

                // Check for custom importers first. They get preference to standard
                // importing routines...
                Item lastCreatedItem;
                if (null == (lastCreatedItem = performFileImport(_customFileImporters, f, expediteeDropPoint))) {
                        // Standard file importing
                        lastCreatedItem = performFileImport(_standardFileImporters, f, expediteeDropPoint);
                }
                
                return lastCreatedItem;
        }

        /**
         * Imports a single file into Expeditee's current frame. Importers are given the opportunity to
         * interpret the file in order of their addition to the list.
         */
        private Item performFileImport(List<FileImporter> importers, File f, Point expediteeDropPoint) throws IOException
        {
                for (FileImporter fi : importers) {
                        Item lastCreated = fi.importFile(f, expediteeDropPoint);
                        
                        if (lastCreated != null) return lastCreated;
                }

                return null;
        }
        
        /**
         * Converts a string formatted as a list of URIs into a list of Files.
         * 
         * Code adopted from SUN - java BUG ID 4899516 workaround for KDE/GNOME
         * Desktops
         * 
         * @param uriListString
         *            Formatted according to RFC 2483
         * 
         * @return The list of FILES in the uriListString. Never null.
         */
        protected List<File> textURIListToFileList(String uriListString)
        {
                List<File> fileList = new LinkedList<File>();

                for (StringTokenizer st = new StringTokenizer(uriListString, "\r\n"); st.hasMoreTokens();) {

                        String s = st.nextToken();

                        if (s.startsWith("#")) {
                                // the line is a comment (as per the RFC 2483)
                                continue;
                        }

                        try {

                                URI uri = new URI(s);
                                File file = new File(uri);
                                fileList.add(file);

                        } catch (URISyntaxException e) {
                                // malformed URI
                        } catch (IllegalArgumentException e) {
                                // the URI is not a valid 'file:' URI
                        }
                }

                return fileList;
        }
}