package org.openstreetmap.josm.command;

import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import org.openstreetmap.josm.data.osm.Key;
import org.openstreetmap.josm.data.osm.OsmPrimitive;

/**
 * Command that manipulate the key/value structure of several objects. Manages deletion,
 * adding and modify of values and keys.
 * 
 * @author imi
 */
public class ChangeKeyValueCommand implements Command {

	/**
	 * All primitives, that are affected with this command.
	 */
	private final List<OsmPrimitive> objects;
	/**
	 * The key that is subject to change.
	 */
	private final Key key;
	/**
	 * The key value. If it is <code>null</code>, delete all key references with the given
	 * key. Else, change the properties of all objects to the given value or create keys of
	 * those objects that do not have the key yet.
	 */
	private final String value;
	
	/**
	 * These are the old values of the objects to do a proper undo.
	 */
	private List<Map<Key, String>> oldProperties;
	
	/**
	 * These are the old modified states of the data.
	 */
	private List<Boolean> oldModified = new LinkedList<Boolean>();

	public ChangeKeyValueCommand(Collection<OsmPrimitive> objects, Key key, String value) {
		this.objects = new LinkedList<OsmPrimitive>(objects);
		this.key = key;
		this.value = value;
	}
	
	public void executeCommand() {
		// save old
		oldProperties = new LinkedList<Map<Key, String>>();
		for (OsmPrimitive osm : objects) {
			oldProperties.add(osm.keys == null ? null : new HashMap<Key, String>(osm.keys));
			oldModified.add(osm.modified);
			osm.modified = true;
		}

		if (value == null) {
			for (OsmPrimitive osm : objects) {
				if (osm.keys != null) {
					osm.keys.remove(key);
					if (osm.keys.isEmpty())
						osm.keys = null;
				}
			}
		} else {
			for (OsmPrimitive osm : objects) {
				if (osm.keys == null)
					osm.keys = new HashMap<Key, String>();
				osm.keys.put(key, value);
			}
		}
	}

	public void undoCommand() {
		Iterator<Map<Key, String>> it = oldProperties.iterator();
		Iterator<Boolean> itMod = oldModified.iterator();
		for (OsmPrimitive osm : objects) {
			osm.keys = it.next();
			osm.modified = itMod.next();
		}
	}

	public void fillModifiedData(Collection<OsmPrimitive> modified, Collection<OsmPrimitive> deleted, Collection<OsmPrimitive> added) {
		modified.addAll(objects);
	}

}