// License: GPL. Copyright 2007 by Immanuel Scholz and others
// Author: David Earl
package org.openstreetmap.josm.actions;

import static org.openstreetmap.josm.tools.I18n.tr;

import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;

import javax.swing.JOptionPane;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.data.osm.DataSet;
import org.openstreetmap.josm.data.osm.Node;
import org.openstreetmap.josm.data.osm.OsmPrimitive;
import org.openstreetmap.josm.data.osm.Relation;
import org.openstreetmap.josm.data.osm.RelationMember;
import org.openstreetmap.josm.data.osm.Way;
import org.openstreetmap.josm.data.osm.visitor.AbstractVisitor;
import org.openstreetmap.josm.tools.Shortcut;

public final class CopyAction extends JosmAction {

    private LinkedList<JosmAction> listeners;

    public CopyAction() {
        super(tr("Copy"), "copy",
                tr("Copy selected objects to paste buffer."),
                Shortcut.registerShortcut("system:copy", tr("Edit: {0}", tr("Copy")), KeyEvent.VK_C, Shortcut.GROUP_MENU), true);
        listeners = new LinkedList<JosmAction>();
    }

    @Override public void addListener(JosmAction a) {
        listeners.add(a);
    }

    public void actionPerformed(ActionEvent e) {
        if(isEmptySelection()) return;

        Main.pasteBuffer = copyData();
        Main.pasteSource = getEditLayer();
        Main.main.menu.paste.setEnabled(true); /* now we have a paste buffer we can make paste available */

        for(JosmAction a : listeners) {
            a.pasteBufferChanged(Main.pasteBuffer);
        }
    }

    public DataSet copyData() {
        /* New pasteBuffer - will be assigned to the global one at the end */
        final DataSet pasteBuffer = new DataSet();
        final HashMap<OsmPrimitive,OsmPrimitive> map = new HashMap<OsmPrimitive,OsmPrimitive>();
        /* temporarily maps old nodes to new so we can do a true deep copy */

        if(isEmptySelection()) return pasteBuffer;

        /* scan the selected objects, mapping them to copies; when copying a way or relation,
         * the copy references the copies of their child objects */
        new AbstractVisitor() {
            public void visit(Node n) {
                /* check if already in pasteBuffer - e.g. two ways are selected which share a node;
                 * or a way and a node in that way is selected, we'll see it twice, once via the
                 * way and once directly; and so on. */
                if (map.containsKey(n))
                    return;
                Node nnew = new Node(n);
                map.put(n, nnew);
                pasteBuffer.addPrimitive(nnew);
            }
            public void visit(Way w) {
                /* check if already in pasteBuffer - could have come from a relation, and directly etc. */
                if (map.containsKey(w))
                    return;
                Way wnew = new Way();
                wnew.cloneFrom(w);
                List<Node> nodes = new ArrayList<Node>();
                for (Node n : w.getNodes()) {
                    if (! map.containsKey(n)) {
                        n.visit(this);
                    }
                    nodes.add((Node)map.get(n));
                }
                wnew.setNodes(nodes);
                pasteBuffer.addPrimitive(wnew);
            }
            public void visit(Relation e) {
                if (map.containsKey(e))
                    return;
                Relation enew = new Relation(e);
                List<RelationMember> members = new ArrayList<RelationMember>();
                for (RelationMember m : e.getMembers()) {
                    if (! map.containsKey(m.getMember())) {
                        m.getMember().visit(this);
                    }
                    RelationMember mnew = new RelationMember(m.getRole(), map.get(m.getMember()));
                    members.add(mnew);
                }
                enew.setMembers(members);
                pasteBuffer.addPrimitive(enew);
            }
            public void visitAll() {
                for (OsmPrimitive osm : getCurrentDataSet().getSelected()) {
                    osm.visit(this);
                }
            }
        }.visitAll();

        return pasteBuffer;
    }

    @Override
    protected void updateEnabledState() {
        if (getCurrentDataSet() == null) {
            setEnabled(false);
        } else {
            updateEnabledState(getCurrentDataSet().getSelected());
        }
    }

    @Override
    protected void updateEnabledState(Collection<? extends OsmPrimitive> selection) {
        setEnabled(selection != null && !selection.isEmpty());
    }

    private boolean isEmptySelection() {
        Collection<OsmPrimitive> sel = getCurrentDataSet().getSelected();
        if (sel.isEmpty()) {
            JOptionPane.showMessageDialog(
                    Main.parent,
                    tr("Please select something to copy."),
                    tr("Information"),
                    JOptionPane.INFORMATION_MESSAGE
            );
            return true;
        }
        return false;
    }
}