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(Main.map.mapView.getPoint(selectedNodes.get(0)), selectedNodes, OsmPrimitive.isUsablePredicate);
075            if (nearestNodes.isEmpty()) {
076                new Notification(
077                        tr("Please select at least two nodes to merge or one node that is close to another node."))
078                        .setIcon(JOptionPane.WARNING_MESSAGE)
079                        .show();
080                return;
081            }
082            selectedNodes.addAll(nearestNodes);
083        }
084
085        Node targetNode = selectTargetNode(selectedNodes);
086        Node targetLocationNode = selectTargetLocationNode(selectedNodes);
087        Command cmd = mergeNodes(Main.main.getEditLayer(), selectedNodes, targetNode, targetLocationNode);
088        if (cmd != null) {
089            Main.main.undoRedo.add(cmd);
090            Main.main.getEditLayer().data.setSelected(targetNode);
091        }
092    }
093
094    /**
095     * Select the location of the target node after merge.
096     *
097     * @param candidates the collection of candidate nodes
098     * @return the coordinates of this node are later used for the target node
099     */
100    public static Node selectTargetLocationNode(List<Node> candidates) {
101        int size = candidates.size();
102        if (size == 0)
103            throw new IllegalArgumentException("empty list");
104
105        switch (Main.pref.getInteger("merge-nodes.mode", 0)) {
106        case 0:
107            Node targetNode = candidates.get(size - 1);
108            for (final Node n : candidates) { // pick last one
109                targetNode = n;
110            }
111            return targetNode;
112        case 1:
113            double east1 = 0, north1 = 0;
114            for (final Node n : candidates) {
115                east1 += n.getEastNorth().east();
116                north1 += n.getEastNorth().north();
117            }
118
119            return new Node(new EastNorth(east1 / size, north1 / size));
120        case 2:
121            final double[] weights = new double[size];
122
123            for (int i = 0; i < size; i++) {
124                final LatLon c1 = candidates.get(i).getCoor();
125                for (int j = i + 1; j < size; j++) {
126                    final LatLon c2 = candidates.get(j).getCoor();
127                    final double d = c1.distance(c2);
128                    weights[i] += d;
129                    weights[j] += d;
130                }
131            }
132
133            double east2 = 0, north2 = 0, weight = 0;
134            for (int i = 0; i < size; i++) {
135                final EastNorth en = candidates.get(i).getEastNorth();
136                final double w = weights[i];
137                east2 += en.east() * w;
138                north2 += en.north() * w;
139                weight += w;
140            }
141
142            return new Node(new EastNorth(east2 / weight, north2 / weight));
143        default:
144            throw new RuntimeException("unacceptable merge-nodes.mode");
145        }
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 != targetNode) {
201                    newNodes.add(n);
202                } else if (newNodes.isEmpty()) {
203                    newNodes.add(targetNode);
204                } else if (newNodes.get(newNodes.size()-1) != targetNode) {
205                    // make sure we collapse a sequence of deleted nodes
206                    // to exactly one occurrence of the merged target node
207                    //
208                    newNodes.add(targetNode);
209                } else {
210                    // drop the node
211                }
212            }
213            if (newNodes.size() < 2) {
214                if (w.getReferrers().isEmpty()) {
215                    waysToDelete.add(w);
216                } else {
217                    ButtonSpec[] options = new ButtonSpec[] {
218                            new ButtonSpec(
219                                    tr("Abort Merging"),
220                                    ImageProvider.get("cancel"),
221                                    tr("Click to abort merging nodes"),
222                                    null /* no special help topic */
223                            )
224                    };
225                    HelpAwareOptionPane.showOptionDialog(
226                            Main.parent,
227                            tr("Cannot merge nodes: Would have to delete way {0} which is still used by {1}",
228                                DefaultNameFormatter.getInstance().formatAsHtmlUnorderedList(w),
229                                DefaultNameFormatter.getInstance().formatAsHtmlUnorderedList(w.getReferrers())),
230                            tr("Warning"),
231                            JOptionPane.WARNING_MESSAGE,
232                            null, /* no icon */
233                            options,
234                            options[0],
235                            ht("/Action/MergeNodes#WaysToDeleteStillInUse")
236                    );
237                    return null;
238                }
239            } else if(newNodes.size() < 2 && w.getReferrers().isEmpty()) {
240                waysToDelete.add(w);
241            } else {
242                cmds.add(new ChangeNodesCommand(w, newNodes));
243            }
244        }
245        if (!waysToDelete.isEmpty()) {
246            cmds.add(new DeleteCommand(waysToDelete));
247        }
248        return cmds;
249    }
250
251    /**
252     * Merges the nodes in {@code nodes} at the specified node's location. Uses the dataset
253     * managed by {@code layer} as reference.
254     * @param layer layer the reference data layer. Must not be null
255     * @param nodes the collection of nodes. Ignored if null
256     * @param targetLocationNode this node's location will be used for the target node
257     * @throws IllegalArgumentException thrown if {@code layer} is null
258     */
259    public static void doMergeNodes(OsmDataLayer layer, Collection<Node> nodes, Node targetLocationNode) {
260        if (nodes == null) {
261            return;
262        }
263        Set<Node> allNodes = new HashSet<>(nodes);
264        allNodes.add(targetLocationNode);
265        Node target;
266        if (nodes.contains(targetLocationNode) && !targetLocationNode.isNew()) {
267            target = targetLocationNode; // keep existing targetLocationNode as target to avoid unnecessary changes (see #2447)
268        } else {
269            target = selectTargetNode(allNodes);
270        }
271
272        Command cmd = mergeNodes(layer, nodes, target, targetLocationNode);
273        if (cmd != null) {
274            Main.main.undoRedo.add(cmd);
275            getCurrentDataSet().setSelected(target);
276        }
277    }
278
279    /**
280     * Merges the nodes in {@code nodes} at the specified node's location. Uses the dataset
281     * managed by {@code layer} as reference.
282     *
283     * @param layer layer the reference data layer. Must not be null.
284     * @param nodes the collection of nodes. Ignored if null.
285     * @param targetLocationNode this node's location will be used for the targetNode.
286     * @return The command necessary to run in order to perform action, or {@code null} if there is nothing to do
287     * @throws IllegalArgumentException thrown if {@code layer} is null
288     */
289    public static Command mergeNodes(OsmDataLayer layer, Collection<Node> nodes, Node targetLocationNode) {
290        if (nodes == null) {
291            return null;
292        }
293        Set<Node> allNodes = new HashSet<>(nodes);
294        allNodes.add(targetLocationNode);
295        return mergeNodes(layer, nodes, selectTargetNode(allNodes), targetLocationNode);
296    }
297
298    /**
299     * Merges the nodes in <code>nodes</code> onto one of the nodes. Uses the dataset
300     * managed by <code>layer</code> as reference.
301     *
302     * @param layer layer the reference data layer. Must not be null.
303     * @param nodes the collection of nodes. Ignored if null.
304     * @param targetNode the target node the collection of nodes is merged to. Must not be null.
305     * @param targetLocationNode this node's location will be used for the targetNode.
306     * @return The command necessary to run in order to perform action, or {@code null} if there is nothing to do
307     * @throws IllegalArgumentException thrown if layer is null
308     */
309    public static Command mergeNodes(OsmDataLayer layer, Collection<Node> nodes, Node targetNode, Node targetLocationNode) {
310        CheckParameterUtil.ensureParameterNotNull(layer, "layer");
311        CheckParameterUtil.ensureParameterNotNull(targetNode, "targetNode");
312        if (nodes == null) {
313            return null;
314        }
315
316        try {
317            TagCollection nodeTags = TagCollection.unionOfAllPrimitives(nodes);
318            List<Command> resultion = CombinePrimitiveResolverDialog.launchIfNecessary(nodeTags, nodes, Collections.singleton(targetNode));
319            LinkedList<Command> cmds = new LinkedList<>();
320
321            // the nodes we will have to delete
322            //
323            Collection<Node> nodesToDelete = new HashSet<>(nodes);
324            nodesToDelete.remove(targetNode);
325
326            // fix the ways referring to at least one of the merged nodes
327            //
328            Collection<Way> waysToDelete = new HashSet<>();
329            List<Command> wayFixCommands = fixParentWays(
330                    nodesToDelete,
331                    targetNode);
332            if (wayFixCommands == null) {
333                return null;
334            }
335            cmds.addAll(wayFixCommands);
336
337            // build the commands
338            //
339            if (targetNode != targetLocationNode) {
340                LatLon targetLocationCoor = targetLocationNode.getCoor();
341                if (!targetNode.getCoor().equals(targetLocationCoor)) {
342                    Node newTargetNode = new Node(targetNode);
343                    newTargetNode.setCoor(targetLocationCoor);
344                    cmds.add(new ChangeCommand(targetNode, newTargetNode));
345                }
346            }
347            cmds.addAll(resultion);
348            if (!nodesToDelete.isEmpty()) {
349                cmds.add(new DeleteCommand(nodesToDelete));
350            }
351            if (!waysToDelete.isEmpty()) {
352                cmds.add(new DeleteCommand(waysToDelete));
353            }
354            return new SequenceCommand(/* for correct i18n of plural forms - see #9110 */
355                    trn("Merge {0} node", "Merge {0} nodes", nodes.size(), nodes.size()), cmds);
356        } catch (UserCancelException ex) {
357            return null;
358        }
359    }
360
361    @Override
362    protected void updateEnabledState() {
363        if (getCurrentDataSet() == null) {
364            setEnabled(false);
365        } else {
366            updateEnabledState(getCurrentDataSet().getAllSelected());
367        }
368    }
369
370    @Override
371    protected void updateEnabledState(Collection<? extends OsmPrimitive> selection) {
372        if (selection == null || selection.isEmpty()) {
373            setEnabled(false);
374            return;
375        }
376        boolean ok = true;
377        for (OsmPrimitive osm : selection) {
378            if (!(osm instanceof Node)) {
379                ok = false;
380                break;
381            }
382        }
383        setEnabled(ok);
384    }
385}