001// License: GPL. For details, see LICENSE file.
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.Objects;
017import java.util.Set;
018
019import javax.swing.JOptionPane;
020
021import org.openstreetmap.josm.Main;
022import org.openstreetmap.josm.command.ChangeCommand;
023import org.openstreetmap.josm.command.ChangeNodesCommand;
024import org.openstreetmap.josm.command.Command;
025import org.openstreetmap.josm.command.DeleteCommand;
026import org.openstreetmap.josm.command.SequenceCommand;
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;
042import org.openstreetmap.josm.tools.UserCancelException;
043
044/**
045 * Merges a collection of nodes into one node.
046 *
047 * The "surviving" node will be the one with the lowest positive id.
048 * (I.e. it was uploaded to the server and is the oldest one.)
049 *
050 * However we use the location of the node that was selected *last*.
051 * The "surviving" node will be moved to that location if it is
052 * different from the last selected node.
053 *
054 * @since 422
055 */
056public class MergeNodesAction extends JosmAction {
057
058    /**
059     * Constructs a new {@code MergeNodesAction}.
060     */
061    public MergeNodesAction() {
062        super(tr("Merge Nodes"), "mergenodes", tr("Merge nodes into the oldest one."),
063                Shortcut.registerShortcut("tools:mergenodes", tr("Tool: {0}", tr("Merge Nodes")), KeyEvent.VK_M, Shortcut.DIRECT), true);
064        putValue("help", ht("/Action/MergeNodes"));
065    }
066
067    @Override
068    public void actionPerformed(ActionEvent event) {
069        if (!isEnabled())
070            return;
071        Collection<OsmPrimitive> selection = getLayerManager().getEditDataSet().getAllSelected();
072        List<Node> selectedNodes = OsmPrimitive.getFilteredList(selection, Node.class);
073
074        if (selectedNodes.size() == 1) {
075            List<Node> nearestNodes = Main.map.mapView.getNearestNodes(
076                    Main.map.mapView.getPoint(selectedNodes.get(0)), selectedNodes, OsmPrimitive::isUsable);
077            if (nearestNodes.isEmpty()) {
078                new Notification(
079                        tr("Please select at least two nodes to merge or one node that is close to another node."))
080                        .setIcon(JOptionPane.WARNING_MESSAGE)
081                        .show();
082                return;
083            }
084            selectedNodes.addAll(nearestNodes);
085        }
086
087        Node targetNode = selectTargetNode(selectedNodes);
088        Node targetLocationNode = selectTargetLocationNode(selectedNodes);
089        Command cmd = mergeNodes(Main.getLayerManager().getEditLayer(), selectedNodes, targetNode, targetLocationNode);
090        if (cmd != null) {
091            Main.main.undoRedo.add(cmd);
092            Main.getLayerManager().getEditLayer().data.setSelected(targetNode);
093        }
094    }
095
096    /**
097     * Select the location of the target node after merge.
098     *
099     * @param candidates the collection of candidate nodes
100     * @return the coordinates of this node are later used for the target node
101     */
102    public static Node selectTargetLocationNode(List<Node> candidates) {
103        int size = candidates.size();
104        if (size == 0)
105            throw new IllegalArgumentException("empty list");
106        if (size == 1) // to avoid division by 0 in mode 2
107            return candidates.get(0);
108
109        switch (Main.pref.getInteger("merge-nodes.mode", 0)) {
110        case 0:
111            return candidates.get(size - 1);
112        case 1:
113            double east1 = 0, north1 = 0;
114            for (final Node n : candidates) {
115                EastNorth en = n.getEastNorth();
116                east1 += en.east();
117                north1 += en.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 || n.getId() < targetNode.getId()) {
164                        targetNode = n;
165                    }
166                } else if (oldestNode == null || n.getId() < oldestNode.getId()) {
167                    oldestNode = n;
168                }
169            }
170            lastNode = n;
171        }
172        if (targetNode == null) {
173            targetNode = oldestNode != null ? oldestNode : lastNode;
174        }
175        return targetNode;
176    }
177
178
179    /**
180     * Fixes the parent ways referring to one of the nodes.
181     *
182     * Replies null, if the ways could not be fixed, i.e. because a way would have to be deleted
183     * which is referred to by a relation.
184     *
185     * @param nodesToDelete the collection of nodes to be deleted
186     * @param targetNode the target node the other nodes are merged to
187     * @return a list of commands; null, if the ways could not be fixed
188     */
189    protected static List<Command> fixParentWays(Collection<Node> nodesToDelete, Node targetNode) {
190        List<Command> cmds = new ArrayList<>();
191        Set<Way> waysToDelete = new HashSet<>();
192
193        for (Way w: OsmPrimitive.getFilteredList(OsmPrimitive.getReferrer(nodesToDelete), Way.class)) {
194            List<Node> newNodes = new ArrayList<>(w.getNodesCount());
195            for (Node n: w.getNodes()) {
196                if (!nodesToDelete.contains(n) && !n.equals(targetNode)) {
197                    newNodes.add(n);
198                } else if (newNodes.isEmpty() || !newNodes.get(newNodes.size()-1).equals(targetNode)) {
199                    // make sure we collapse a sequence of deleted nodes
200                    // to exactly one occurrence of the merged target node
201                    newNodes.add(targetNode);
202                }
203                // else: drop the node
204            }
205            if (newNodes.size() < 2) {
206                if (w.getReferrers().isEmpty()) {
207                    waysToDelete.add(w);
208                } else {
209                    ButtonSpec[] options = new ButtonSpec[] {
210                            new ButtonSpec(
211                                    tr("Abort Merging"),
212                                    ImageProvider.get("cancel"),
213                                    tr("Click to abort merging nodes"),
214                                    null /* no special help topic */
215                            )
216                    };
217                    HelpAwareOptionPane.showOptionDialog(
218                            Main.parent,
219                            tr("Cannot merge nodes: Would have to delete way {0} which is still used by {1}",
220                                DefaultNameFormatter.getInstance().formatAsHtmlUnorderedList(w),
221                                DefaultNameFormatter.getInstance().formatAsHtmlUnorderedList(w.getReferrers(), 20)),
222                            tr("Warning"),
223                            JOptionPane.WARNING_MESSAGE,
224                            null, /* no icon */
225                            options,
226                            options[0],
227                            ht("/Action/MergeNodes#WaysToDeleteStillInUse")
228                    );
229                    return null;
230                }
231            } else if (newNodes.size() < 2 && w.getReferrers().isEmpty()) {
232                waysToDelete.add(w);
233            } else {
234                cmds.add(new ChangeNodesCommand(w, newNodes));
235            }
236        }
237        if (!waysToDelete.isEmpty()) {
238            cmds.add(new DeleteCommand(waysToDelete));
239        }
240        return cmds;
241    }
242
243    /**
244     * Merges the nodes in {@code nodes} at the specified node's location. Uses the dataset
245     * managed by {@code layer} as reference.
246     * @param layer layer the reference data layer. Must not be null
247     * @param nodes the collection of nodes. Ignored if null
248     * @param targetLocationNode this node's location will be used for the target node
249     * @throws IllegalArgumentException if {@code layer} is null
250     */
251    public static void doMergeNodes(OsmDataLayer layer, Collection<Node> nodes, Node targetLocationNode) {
252        if (nodes == null) {
253            return;
254        }
255        Set<Node> allNodes = new HashSet<>(nodes);
256        allNodes.add(targetLocationNode);
257        Node target;
258        if (nodes.contains(targetLocationNode) && !targetLocationNode.isNew()) {
259            target = targetLocationNode; // keep existing targetLocationNode as target to avoid unnecessary changes (see #2447)
260        } else {
261            target = selectTargetNode(allNodes);
262        }
263
264        Command cmd = mergeNodes(layer, nodes, target, targetLocationNode);
265        if (cmd != null) {
266            Main.main.undoRedo.add(cmd);
267            layer.data.setSelected(target);
268        }
269    }
270
271    /**
272     * Merges the nodes in {@code nodes} at the specified node's location. Uses the dataset
273     * managed by {@code layer} as reference.
274     *
275     * @param layer layer the reference data layer. Must not be null.
276     * @param nodes the collection of nodes. Ignored if null.
277     * @param targetLocationNode this node's location will be used for the targetNode.
278     * @return The command necessary to run in order to perform action, or {@code null} if there is nothing to do
279     * @throws IllegalArgumentException if {@code layer} is null
280     */
281    public static Command mergeNodes(OsmDataLayer layer, Collection<Node> nodes, Node targetLocationNode) {
282        if (nodes == null) {
283            return null;
284        }
285        Set<Node> allNodes = new HashSet<>(nodes);
286        allNodes.add(targetLocationNode);
287        return mergeNodes(layer, nodes, selectTargetNode(allNodes), targetLocationNode);
288    }
289
290    /**
291     * Merges the nodes in <code>nodes</code> onto one of the nodes. Uses the dataset
292     * managed by <code>layer</code> as reference.
293     *
294     * @param layer layer the reference data layer. Must not be null.
295     * @param nodes the collection of nodes. Ignored if null.
296     * @param targetNode the target node the collection of nodes is merged to. Must not be null.
297     * @param targetLocationNode this node's location will be used for the targetNode.
298     * @return The command necessary to run in order to perform action, or {@code null} if there is nothing to do
299     * @throws IllegalArgumentException if layer is null
300     */
301    public static Command mergeNodes(OsmDataLayer layer, Collection<Node> nodes, Node targetNode, Node targetLocationNode) {
302        CheckParameterUtil.ensureParameterNotNull(layer, "layer");
303        CheckParameterUtil.ensureParameterNotNull(targetNode, "targetNode");
304        if (nodes == null) {
305            return null;
306        }
307
308        try {
309            TagCollection nodeTags = TagCollection.unionOfAllPrimitives(nodes);
310
311            // the nodes we will have to delete
312            //
313            Collection<Node> nodesToDelete = new HashSet<>(nodes);
314            nodesToDelete.remove(targetNode);
315
316            // fix the ways referring to at least one of the merged nodes
317            //
318            List<Command> wayFixCommands = fixParentWays(nodesToDelete, targetNode);
319            if (wayFixCommands == null) {
320                return null;
321            }
322            List<Command> cmds = new LinkedList<>(wayFixCommands);
323
324            // build the commands
325            //
326            if (!targetNode.equals(targetLocationNode)) {
327                LatLon targetLocationCoor = targetLocationNode.getCoor();
328                if (!Objects.equals(targetNode.getCoor(), targetLocationCoor)) {
329                    Node newTargetNode = new Node(targetNode);
330                    newTargetNode.setCoor(targetLocationCoor);
331                    cmds.add(new ChangeCommand(targetNode, newTargetNode));
332                }
333            }
334            cmds.addAll(CombinePrimitiveResolverDialog.launchIfNecessary(nodeTags, nodes, Collections.singleton(targetNode)));
335            if (!nodesToDelete.isEmpty()) {
336                cmds.add(new DeleteCommand(nodesToDelete));
337            }
338            return new SequenceCommand(/* for correct i18n of plural forms - see #9110 */
339                    trn("Merge {0} node", "Merge {0} nodes", nodes.size(), nodes.size()), cmds);
340        } catch (UserCancelException ex) {
341            Main.trace(ex);
342            return null;
343        }
344    }
345
346    @Override
347    protected void updateEnabledState() {
348        updateEnabledStateOnCurrentSelection();
349    }
350
351    @Override
352    protected void updateEnabledState(Collection<? extends OsmPrimitive> selection) {
353        if (selection == null || selection.isEmpty()) {
354            setEnabled(false);
355            return;
356        }
357        boolean ok = true;
358        for (OsmPrimitive osm : selection) {
359            if (!(osm instanceof Node)) {
360                ok = false;
361                break;
362            }
363        }
364        setEnabled(ok);
365    }
366}