001//License: GPL. For details, see LICENSE file.. See LICENSE file for details.
002package org.openstreetmap.josm.actions;
003
004import static org.openstreetmap.josm.gui.help.HelpUtil.ht;
005import static org.openstreetmap.josm.tools.I18n.tr;
006import static org.openstreetmap.josm.tools.I18n.trn;
007
008import java.awt.event.ActionEvent;
009import java.awt.event.KeyEvent;
010import java.util.ArrayList;
011import java.util.Collection;
012import java.util.Collections;
013import java.util.HashSet;
014import java.util.LinkedList;
015import java.util.List;
016import java.util.Set;
017
018import javax.swing.JOptionPane;
019
020import org.openstreetmap.josm.Main;
021import org.openstreetmap.josm.command.ChangeCommand;
022import org.openstreetmap.josm.command.ChangeNodesCommand;
023import org.openstreetmap.josm.command.Command;
024import org.openstreetmap.josm.command.DeleteCommand;
025import org.openstreetmap.josm.command.SequenceCommand;
026import org.openstreetmap.josm.corrector.UserCancelException;
027import org.openstreetmap.josm.data.coor.EastNorth;
028import org.openstreetmap.josm.data.coor.LatLon;
029import org.openstreetmap.josm.data.osm.Node;
030import org.openstreetmap.josm.data.osm.OsmPrimitive;
031import org.openstreetmap.josm.data.osm.TagCollection;
032import org.openstreetmap.josm.data.osm.Way;
033import org.openstreetmap.josm.gui.DefaultNameFormatter;
034import org.openstreetmap.josm.gui.HelpAwareOptionPane;
035import org.openstreetmap.josm.gui.HelpAwareOptionPane.ButtonSpec;
036import org.openstreetmap.josm.gui.Notification;
037import org.openstreetmap.josm.gui.conflict.tags.CombinePrimitiveResolverDialog;
038import org.openstreetmap.josm.gui.layer.OsmDataLayer;
039import org.openstreetmap.josm.tools.CheckParameterUtil;
040import org.openstreetmap.josm.tools.ImageProvider;
041import org.openstreetmap.josm.tools.Shortcut;
042
043/**
044 * Merges a collection of nodes into one node.
045 *
046 * The "surviving" node will be the one with the lowest positive id.
047 * (I.e. it was uploaded to the server and is the oldest one.)
048 *
049 * However we use the location of the node that was selected *last*.
050 * The "surviving" node will be moved to that location if it is
051 * different from the last selected node.
052 *
053 * @since 422
054 */
055public class MergeNodesAction extends JosmAction {
056
057    /**
058     * Constructs a new {@code MergeNodesAction}.
059     */
060    public MergeNodesAction() {
061        super(tr("Merge Nodes"), "mergenodes", tr("Merge nodes into the oldest one."),
062                Shortcut.registerShortcut("tools:mergenodes", tr("Tool: {0}", tr("Merge Nodes")), KeyEvent.VK_M, Shortcut.DIRECT), true);
063        putValue("help", ht("/Action/MergeNodes"));
064    }
065
066    @Override
067    public void actionPerformed(ActionEvent event) {
068        if (!isEnabled())
069            return;
070        Collection<OsmPrimitive> selection = getCurrentDataSet().getAllSelected();
071        List<Node> selectedNodes = OsmPrimitive.getFilteredList(selection, Node.class);
072
073        if (selectedNodes.size() == 1) {
074            List<Node> nearestNodes = Main.map.mapView.getNearestNodes(
075                    Main.map.mapView.getPoint(selectedNodes.get(0)), selectedNodes, OsmPrimitive.isUsablePredicate);
076            if (nearestNodes.isEmpty()) {
077                new Notification(
078                        tr("Please select at least two nodes to merge or one node that is close to another node."))
079                        .setIcon(JOptionPane.WARNING_MESSAGE)
080                        .show();
081                return;
082            }
083            selectedNodes.addAll(nearestNodes);
084        }
085
086        Node targetNode = selectTargetNode(selectedNodes);
087        Node targetLocationNode = selectTargetLocationNode(selectedNodes);
088        Command cmd = mergeNodes(Main.main.getEditLayer(), selectedNodes, targetNode, targetLocationNode);
089        if (cmd != null) {
090            Main.main.undoRedo.add(cmd);
091            Main.main.getEditLayer().data.setSelected(targetNode);
092        }
093    }
094
095    /**
096     * Select the location of the target node after merge.
097     *
098     * @param candidates the collection of candidate nodes
099     * @return the coordinates of this node are later used for the target node
100     */
101    public static Node selectTargetLocationNode(List<Node> candidates) {
102        int size = candidates.size();
103        if (size == 0)
104            throw new IllegalArgumentException("empty list");
105
106        switch (Main.pref.getInteger("merge-nodes.mode", 0)) {
107        case 0:
108            Node targetNode = candidates.get(size - 1);
109            for (final Node n : candidates) { // pick last one
110                targetNode = n;
111            }
112            return targetNode;
113        case 1:
114            double east1 = 0, north1 = 0;
115            for (final Node n : candidates) {
116                east1 += n.getEastNorth().east();
117                north1 += n.getEastNorth().north();
118            }
119
120            return new Node(new EastNorth(east1 / size, north1 / size));
121        case 2:
122            final double[] weights = new double[size];
123
124            for (int i = 0; i < size; i++) {
125                final LatLon c1 = candidates.get(i).getCoor();
126                for (int j = i + 1; j < size; j++) {
127                    final LatLon c2 = candidates.get(j).getCoor();
128                    final double d = c1.distance(c2);
129                    weights[i] += d;
130                    weights[j] += d;
131                }
132            }
133
134            double east2 = 0, north2 = 0, weight = 0;
135            for (int i = 0; i < size; i++) {
136                final EastNorth en = candidates.get(i).getEastNorth();
137                final double w = weights[i];
138                east2 += en.east() * w;
139                north2 += en.north() * w;
140                weight += w;
141            }
142
143            return new Node(new EastNorth(east2 / weight, north2 / weight));
144        default:
145            throw new IllegalStateException("unacceptable merge-nodes.mode");
146        }
147    }
148
149    /**
150     * Find which node to merge into (i.e. which one will be left)
151     *
152     * @param candidates the collection of candidate nodes
153     * @return the selected target node
154     */
155    public static Node selectTargetNode(Collection<Node> candidates) {
156        Node oldestNode = null;
157        Node targetNode = null;
158        Node lastNode = null;
159        for (Node n : candidates) {
160            if (!n.isNew()) {
161                // Among existing nodes, try to keep the oldest used one
162                if (!n.getReferrers().isEmpty()) {
163                    if (targetNode == null) {
164                        targetNode = n;
165                    } else if (n.getId() < targetNode.getId()) {
166                        targetNode = n;
167                    }
168                } else if (oldestNode == null) {
169                    oldestNode = n;
170                } else if (n.getId() < oldestNode.getId()) {
171                    oldestNode = n;
172                }
173            }
174            lastNode = n;
175        }
176        if (targetNode == null) {
177            targetNode = (oldestNode != null ? oldestNode : lastNode);
178        }
179        return targetNode;
180    }
181
182
183    /**
184     * Fixes the parent ways referring to one of the nodes.
185     *
186     * Replies null, if the ways could not be fixed, i.e. because a way would have to be deleted
187     * which is referred to by a relation.
188     *
189     * @param nodesToDelete the collection of nodes to be deleted
190     * @param targetNode the target node the other nodes are merged to
191     * @return a list of commands; null, if the ways could not be fixed
192     */
193    protected static List<Command> fixParentWays(Collection<Node> nodesToDelete, Node targetNode) {
194        List<Command> cmds = new ArrayList<>();
195        Set<Way> waysToDelete = new HashSet<>();
196
197        for (Way w: OsmPrimitive.getFilteredList(OsmPrimitive.getReferrer(nodesToDelete), Way.class)) {
198            List<Node> newNodes = new ArrayList<>(w.getNodesCount());
199            for (Node n: w.getNodes()) {
200                if (! nodesToDelete.contains(n) && !n.equals(targetNode)) {
201                    newNodes.add(n);
202                } else if (newNodes.isEmpty()) {
203                    newNodes.add(targetNode);
204                } else if (!newNodes.get(newNodes.size()-1).equals(targetNode)) {
205                    // make sure we collapse a sequence of deleted nodes
206                    // to exactly one occurrence of the merged target node
207                    newNodes.add(targetNode);
208                } else {
209                    // drop the node
210                }
211            }
212            if (newNodes.size() < 2) {
213                if (w.getReferrers().isEmpty()) {
214                    waysToDelete.add(w);
215                } else {
216                    ButtonSpec[] options = new ButtonSpec[] {
217                            new ButtonSpec(
218                                    tr("Abort Merging"),
219                                    ImageProvider.get("cancel"),
220                                    tr("Click to abort merging nodes"),
221                                    null /* no special help topic */
222                            )
223                    };
224                    HelpAwareOptionPane.showOptionDialog(
225                            Main.parent,
226                            tr("Cannot merge nodes: Would have to delete way {0} which is still used by {1}",
227                                DefaultNameFormatter.getInstance().formatAsHtmlUnorderedList(w),
228                                DefaultNameFormatter.getInstance().formatAsHtmlUnorderedList(w.getReferrers())),
229                            tr("Warning"),
230                            JOptionPane.WARNING_MESSAGE,
231                            null, /* no icon */
232                            options,
233                            options[0],
234                            ht("/Action/MergeNodes#WaysToDeleteStillInUse")
235                    );
236                    return null;
237                }
238            } else if(newNodes.size() < 2 && w.getReferrers().isEmpty()) {
239                waysToDelete.add(w);
240            } else {
241                cmds.add(new ChangeNodesCommand(w, newNodes));
242            }
243        }
244        if (!waysToDelete.isEmpty()) {
245            cmds.add(new DeleteCommand(waysToDelete));
246        }
247        return cmds;
248    }
249
250    /**
251     * Merges the nodes in {@code nodes} at the specified node's location. Uses the dataset
252     * managed by {@code layer} as reference.
253     * @param layer layer the reference data layer. Must not be null
254     * @param nodes the collection of nodes. Ignored if null
255     * @param targetLocationNode this node's location will be used for the target node
256     * @throws IllegalArgumentException thrown if {@code layer} is null
257     */
258    public static void doMergeNodes(OsmDataLayer layer, Collection<Node> nodes, Node targetLocationNode) {
259        if (nodes == null) {
260            return;
261        }
262        Set<Node> allNodes = new HashSet<>(nodes);
263        allNodes.add(targetLocationNode);
264        Node target;
265        if (nodes.contains(targetLocationNode) && !targetLocationNode.isNew()) {
266            target = targetLocationNode; // keep existing targetLocationNode as target to avoid unnecessary changes (see #2447)
267        } else {
268            target = selectTargetNode(allNodes);
269        }
270
271        Command cmd = mergeNodes(layer, nodes, target, targetLocationNode);
272        if (cmd != null) {
273            Main.main.undoRedo.add(cmd);
274            getCurrentDataSet().setSelected(target);
275        }
276    }
277
278    /**
279     * Merges the nodes in {@code nodes} at the specified node's location. Uses the dataset
280     * managed by {@code layer} as reference.
281     *
282     * @param layer layer the reference data layer. Must not be null.
283     * @param nodes the collection of nodes. Ignored if null.
284     * @param targetLocationNode this node's location will be used for the targetNode.
285     * @return The command necessary to run in order to perform action, or {@code null} if there is nothing to do
286     * @throws IllegalArgumentException thrown if {@code layer} is null
287     */
288    public static Command mergeNodes(OsmDataLayer layer, Collection<Node> nodes, Node targetLocationNode) {
289        if (nodes == null) {
290            return null;
291        }
292        Set<Node> allNodes = new HashSet<>(nodes);
293        allNodes.add(targetLocationNode);
294        return mergeNodes(layer, nodes, selectTargetNode(allNodes), targetLocationNode);
295    }
296
297    /**
298     * Merges the nodes in <code>nodes</code> onto one of the nodes. Uses the dataset
299     * managed by <code>layer</code> as reference.
300     *
301     * @param layer layer the reference data layer. Must not be null.
302     * @param nodes the collection of nodes. Ignored if null.
303     * @param targetNode the target node the collection of nodes is merged to. Must not be null.
304     * @param targetLocationNode this node's location will be used for the targetNode.
305     * @return The command necessary to run in order to perform action, or {@code null} if there is nothing to do
306     * @throws IllegalArgumentException thrown if layer is null
307     */
308    public static Command mergeNodes(OsmDataLayer layer, Collection<Node> nodes, Node targetNode, Node targetLocationNode) {
309        CheckParameterUtil.ensureParameterNotNull(layer, "layer");
310        CheckParameterUtil.ensureParameterNotNull(targetNode, "targetNode");
311        if (nodes == null) {
312            return null;
313        }
314
315        try {
316            TagCollection nodeTags = TagCollection.unionOfAllPrimitives(nodes);
317            List<Command> resultion = CombinePrimitiveResolverDialog.launchIfNecessary(nodeTags, nodes, Collections.singleton(targetNode));
318            List<Command> cmds = new LinkedList<>();
319
320            // the nodes we will have to delete
321            //
322            Collection<Node> nodesToDelete = new HashSet<>(nodes);
323            nodesToDelete.remove(targetNode);
324
325            // fix the ways referring to at least one of the merged nodes
326            //
327            Collection<Way> waysToDelete = new HashSet<>();
328            List<Command> wayFixCommands = fixParentWays(
329                    nodesToDelete,
330                    targetNode);
331            if (wayFixCommands == null) {
332                return null;
333            }
334            cmds.addAll(wayFixCommands);
335
336            // build the commands
337            //
338            if (!targetNode.equals(targetLocationNode)) {
339                LatLon targetLocationCoor = targetLocationNode.getCoor();
340                if (!targetNode.getCoor().equals(targetLocationCoor)) {
341                    Node newTargetNode = new Node(targetNode);
342                    newTargetNode.setCoor(targetLocationCoor);
343                    cmds.add(new ChangeCommand(targetNode, newTargetNode));
344                }
345            }
346            cmds.addAll(resultion);
347            if (!nodesToDelete.isEmpty()) {
348                cmds.add(new DeleteCommand(nodesToDelete));
349            }
350            if (!waysToDelete.isEmpty()) {
351                cmds.add(new DeleteCommand(waysToDelete));
352            }
353            return new SequenceCommand(/* for correct i18n of plural forms - see #9110 */
354                    trn("Merge {0} node", "Merge {0} nodes", nodes.size(), nodes.size()), cmds);
355        } catch (UserCancelException ex) {
356            return null;
357        }
358    }
359
360    @Override
361    protected void updateEnabledState() {
362        if (getCurrentDataSet() == null) {
363            setEnabled(false);
364        } else {
365            updateEnabledState(getCurrentDataSet().getAllSelected());
366        }
367    }
368
369    @Override
370    protected void updateEnabledState(Collection<? extends OsmPrimitive> selection) {
371        if (selection == null || selection.isEmpty()) {
372            setEnabled(false);
373            return;
374        }
375        boolean ok = true;
376        for (OsmPrimitive osm : selection) {
377            if (!(osm instanceof Node)) {
378                ok = false;
379                break;
380            }
381        }
382        setEnabled(ok);
383    }
384}