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.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.data.coor.EastNorth;
027import org.openstreetmap.josm.data.coor.LatLon;
028import org.openstreetmap.josm.data.osm.Node;
029import org.openstreetmap.josm.data.osm.OsmPrimitive;
030import org.openstreetmap.josm.data.osm.TagCollection;
031import org.openstreetmap.josm.data.osm.Way;
032import org.openstreetmap.josm.gui.DefaultNameFormatter;
033import org.openstreetmap.josm.gui.HelpAwareOptionPane;
034import org.openstreetmap.josm.gui.HelpAwareOptionPane.ButtonSpec;
035import org.openstreetmap.josm.gui.Notification;
036import org.openstreetmap.josm.gui.conflict.tags.CombinePrimitiveResolverDialog;
037import org.openstreetmap.josm.gui.layer.OsmDataLayer;
038import org.openstreetmap.josm.tools.CheckParameterUtil;
039import org.openstreetmap.josm.tools.ImageProvider;
040import org.openstreetmap.josm.tools.Shortcut;
041import org.openstreetmap.josm.tools.UserCancelException;
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                }
209                // else: drop the node
210            }
211            if (newNodes.size() < 2) {
212                if (w.getReferrers().isEmpty()) {
213                    waysToDelete.add(w);
214                } else {
215                    ButtonSpec[] options = new ButtonSpec[] {
216                            new ButtonSpec(
217                                    tr("Abort Merging"),
218                                    ImageProvider.get("cancel"),
219                                    tr("Click to abort merging nodes"),
220                                    null /* no special help topic */
221                            )
222                    };
223                    HelpAwareOptionPane.showOptionDialog(
224                            Main.parent,
225                            tr("Cannot merge nodes: Would have to delete way {0} which is still used by {1}",
226                                DefaultNameFormatter.getInstance().formatAsHtmlUnorderedList(w),
227                                DefaultNameFormatter.getInstance().formatAsHtmlUnorderedList(w.getReferrers())),
228                            tr("Warning"),
229                            JOptionPane.WARNING_MESSAGE,
230                            null, /* no icon */
231                            options,
232                            options[0],
233                            ht("/Action/MergeNodes#WaysToDeleteStillInUse")
234                    );
235                    return null;
236                }
237            } else if (newNodes.size() < 2 && w.getReferrers().isEmpty()) {
238                waysToDelete.add(w);
239            } else {
240                cmds.add(new ChangeNodesCommand(w, newNodes));
241            }
242        }
243        if (!waysToDelete.isEmpty()) {
244            cmds.add(new DeleteCommand(waysToDelete));
245        }
246        return cmds;
247    }
248
249    /**
250     * Merges the nodes in {@code nodes} at the specified node's location. Uses the dataset
251     * managed by {@code layer} as reference.
252     * @param layer layer the reference data layer. Must not be null
253     * @param nodes the collection of nodes. Ignored if null
254     * @param targetLocationNode this node's location will be used for the target node
255     * @throws IllegalArgumentException if {@code layer} is null
256     */
257    public static void doMergeNodes(OsmDataLayer layer, Collection<Node> nodes, Node targetLocationNode) {
258        if (nodes == null) {
259            return;
260        }
261        Set<Node> allNodes = new HashSet<>(nodes);
262        allNodes.add(targetLocationNode);
263        Node target;
264        if (nodes.contains(targetLocationNode) && !targetLocationNode.isNew()) {
265            target = targetLocationNode; // keep existing targetLocationNode as target to avoid unnecessary changes (see #2447)
266        } else {
267            target = selectTargetNode(allNodes);
268        }
269
270        Command cmd = mergeNodes(layer, nodes, target, targetLocationNode);
271        if (cmd != null) {
272            Main.main.undoRedo.add(cmd);
273            getCurrentDataSet().setSelected(target);
274        }
275    }
276
277    /**
278     * Merges the nodes in {@code nodes} at the specified node's location. Uses the dataset
279     * managed by {@code layer} as reference.
280     *
281     * @param layer layer the reference data layer. Must not be null.
282     * @param nodes the collection of nodes. Ignored if null.
283     * @param targetLocationNode this node's location will be used for the targetNode.
284     * @return The command necessary to run in order to perform action, or {@code null} if there is nothing to do
285     * @throws IllegalArgumentException if {@code layer} is null
286     */
287    public static Command mergeNodes(OsmDataLayer layer, Collection<Node> nodes, Node targetLocationNode) {
288        if (nodes == null) {
289            return null;
290        }
291        Set<Node> allNodes = new HashSet<>(nodes);
292        allNodes.add(targetLocationNode);
293        return mergeNodes(layer, nodes, selectTargetNode(allNodes), targetLocationNode);
294    }
295
296    /**
297     * Merges the nodes in <code>nodes</code> onto one of the nodes. Uses the dataset
298     * managed by <code>layer</code> as reference.
299     *
300     * @param layer layer the reference data layer. Must not be null.
301     * @param nodes the collection of nodes. Ignored if null.
302     * @param targetNode the target node the collection of nodes is merged to. Must not be null.
303     * @param targetLocationNode this node's location will be used for the targetNode.
304     * @return The command necessary to run in order to perform action, or {@code null} if there is nothing to do
305     * @throws IllegalArgumentException if layer is null
306     */
307    public static Command mergeNodes(OsmDataLayer layer, Collection<Node> nodes, Node targetNode, Node targetLocationNode) {
308        CheckParameterUtil.ensureParameterNotNull(layer, "layer");
309        CheckParameterUtil.ensureParameterNotNull(targetNode, "targetNode");
310        if (nodes == null) {
311            return null;
312        }
313
314        try {
315            TagCollection nodeTags = TagCollection.unionOfAllPrimitives(nodes);
316            List<Command> resultion = CombinePrimitiveResolverDialog.launchIfNecessary(nodeTags, nodes, Collections.singleton(targetNode));
317            List<Command> cmds = new LinkedList<>();
318
319            // the nodes we will have to delete
320            //
321            Collection<Node> nodesToDelete = new HashSet<>(nodes);
322            nodesToDelete.remove(targetNode);
323
324            // fix the ways referring to at least one of the merged nodes
325            //
326            Collection<Way> waysToDelete = new HashSet<>();
327            List<Command> wayFixCommands = fixParentWays(
328                    nodesToDelete,
329                    targetNode);
330            if (wayFixCommands == null) {
331                return null;
332            }
333            cmds.addAll(wayFixCommands);
334
335            // build the commands
336            //
337            if (!targetNode.equals(targetLocationNode)) {
338                LatLon targetLocationCoor = targetLocationNode.getCoor();
339                if (!targetNode.getCoor().equals(targetLocationCoor)) {
340                    Node newTargetNode = new Node(targetNode);
341                    newTargetNode.setCoor(targetLocationCoor);
342                    cmds.add(new ChangeCommand(targetNode, newTargetNode));
343                }
344            }
345            cmds.addAll(resultion);
346            if (!nodesToDelete.isEmpty()) {
347                cmds.add(new DeleteCommand(nodesToDelete));
348            }
349            if (!waysToDelete.isEmpty()) {
350                cmds.add(new DeleteCommand(waysToDelete));
351            }
352            return new SequenceCommand(/* for correct i18n of plural forms - see #9110 */
353                    trn("Merge {0} node", "Merge {0} nodes", nodes.size(), nodes.size()), cmds);
354        } catch (UserCancelException ex) {
355            return null;
356        }
357    }
358
359    @Override
360    protected void updateEnabledState() {
361        if (getCurrentDataSet() == null) {
362            setEnabled(false);
363        } else {
364            updateEnabledState(getCurrentDataSet().getAllSelected());
365        }
366    }
367
368    @Override
369    protected void updateEnabledState(Collection<? extends OsmPrimitive> selection) {
370        if (selection == null || selection.isEmpty()) {
371            setEnabled(false);
372            return;
373        }
374        boolean ok = true;
375        for (OsmPrimitive osm : selection) {
376            if (!(osm instanceof Node)) {
377                ok = false;
378                break;
379            }
380        }
381        setEnabled(ok);
382    }
383}