// License: GPL. Copyright 2007 by Immanuel Scholz and others
package org.openstreetmap.josm.command;

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

import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import javax.swing.JLabel;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.MutableTreeNode;

import org.openstreetmap.josm.data.coor.LatLon;
import org.openstreetmap.josm.data.osm.Node;
import org.openstreetmap.josm.data.osm.OsmPrimitive;
import org.openstreetmap.josm.data.osm.visitor.AllNodesVisitor;
import org.openstreetmap.josm.tools.ImageProvider;

/**
 * MoveCommand moves a set of OsmPrimitives along the map. It can be moved again
 * to collect several MoveCommands into one command.
 *
 * @author imi
 */
public class MoveCommand extends Command {
    /**
     * The objects that should be moved.
     */
    private Collection<Node> nodes = new LinkedList<Node>();
    /**
     * x difference movement. Coordinates are in northern/eastern
     */
    private double x;
    /**
     * y difference movement. Coordinates are in northern/eastern
     */
    private double y;

    /**
     * Small helper for holding the interesting part of the old data state of the
     * objects.
     */
    public static class OldState {
        LatLon latlon;
        boolean modified;
    }

    /**
     * List of all old states of the objects.
     */
    private List<OldState> oldState = new LinkedList<OldState>();


    public MoveCommand(OsmPrimitive osm, double x, double y) {
        this(Collections.singleton(osm), x, y);
    }
    /**
     * Create a MoveCommand and assign the initial object set and movement vector.
     */
    public MoveCommand(Collection<OsmPrimitive> objects, double x, double y) {
        super();
        this.x = x;
        this.y = y;
        this.nodes = AllNodesVisitor.getAllNodes(objects);
        for (Node n : this.nodes) {
            OldState os = new OldState();
            os.latlon = new LatLon(n.getCoor());
            os.modified = n.isModified();
            oldState.add(os);
        }
    }

    /**
     * Move the same set of objects again by the specified vector. The vectors
     * are added together and so the resulting will be moved to the previous
     * vector plus this one.
     *
     * The move is immediately executed and any undo will undo both vectors to
     * the original position the objects had before first moving.
     */
    public void moveAgain(double x, double y) {
        for (Node n : nodes) {
            n.setEastNorth(n.getEastNorth().add(x, y));
        }
        this.x += x;
        this.y += y;
    }

    @Override public boolean executeCommand() {
        for (Node n : nodes) {
            // in case #3892 happens again
            //
            assert n!= null : tr("null detected in node list");
            assert n.getEastNorth() != null : tr("unexpected null value for n.getEastNorth(). id of n is", n.getUniqueId());
            n.setEastNorth(n.getEastNorth().add(x, y));
            n.setModified(true);
        }
        return true;
    }

    @Override public void undoCommand() {
        Iterator<OldState> it = oldState.iterator();
        for (Node n : nodes) {
            OldState os = it.next();
            n.setCoor(os.latlon);
            n.setModified(os.modified);
        }
    }

    @Override public void fillModifiedData(Collection<OsmPrimitive> modified, Collection<OsmPrimitive> deleted, Collection<OsmPrimitive> added) {
        for (OsmPrimitive osm : nodes) {
            modified.add(osm);
        }
    }

    @Override public MutableTreeNode description() {
        return new DefaultMutableTreeNode(new JLabel(trn("Move {0} node", "Move {0} nodes", nodes.size(), nodes.size()), ImageProvider.get("data", "node"), JLabel.HORIZONTAL));
    }

    public Collection<Node> getMovedNodes() {
        return nodes;
    }
}