// License: GPL. Copyright 2007 by Martijn van Oosterhout and others
package org.openstreetmap.josm.data.osm;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.io.XmlWriter;
import org.openstreetmap.josm.io.XmlWriter.OsmWriterInterface;
import java.io.PrintWriter;
import java.util.Map;
import java.util.Map.Entry;
import java.util.HashMap;
import java.util.Collections;
import java.util.Collection;



/**
 * Represents a single changeset in JOSM. For now its only used during
 * upload but in the future we may do more.
 *
 */
public final class Changeset /*extends OsmPrimitive*/ implements OsmWriterInterface {
    /**
     * The key/value list for this primitive.
     */
    public Map<String, String> keys;

    public long id = 0;

    /**
     * User that created this changeset, as specified by the server.
     * Never changed by JOSM.
     */
    public User user = null;

    /**
     * Time of last modification to this object. This is not set by JOSM but
     * read from the server and delivered back to the server unmodified.
     */
    public String end_timestamp = null;

    /**
     * Time of first modification to this object. This is not set by JOSM but
     * read from the server and delivered back to the server unmodified.
     */
    public String start_timestamp = null;

        private void addTags(PrintWriter out) {
                if (this.keys != null) {
                        for (Entry<String, String> e : this.keys.entrySet())
                                out.println("    <tag k='"+ XmlWriter.encode(e.getKey()) +
                                                "' v='"+XmlWriter.encode(e.getValue())+ "' />");
                }
        }

    public final void header(PrintWriter out) {
            out.print("<osm version='");
                out.print(Main.pref.get("osm-server.version", "0.6"));
                out.println("' generator='JOSM'>");
    }
    public final void write(PrintWriter out) {
        out.print("  <changeset");
        if (id != 0)
            out.print(" id="+id);
        if (this.user != null) {
            out.print(" user='"+XmlWriter.encode(this.user.name)+"'");
        }
        out.println(">\n");
        addTags( out );
        out.println("  </changeset>");
    }
    public final void footer(PrintWriter out) {
        out.println("</osm>");
    }

    /******************************************************
     * This tag stuff is copied from OsmPrimitive. Perhaps a changeset
     * really is a primitive, but it's not right now. Perhaps it should
     * be...
     ******************************************************/

    /**
     * Set the given value to the given key
     * @param key The key, for which the value is to be set.
     * @param value The value for the key.
     */
    public final void put(String key, String value) {
        if (value == null)
            remove(key);
        else {
            if (keys == null)
                keys = new HashMap<String, String>();
            keys.put(key, value);
        }
    }
    /**
     * Remove the given key from the list.
     */
    public final void remove(String key) {
        if (keys != null) {
            keys.remove(key);
            if (keys.isEmpty())
                keys = null;
        }
    }

    public final String get(String key) {
        return keys == null ? null : keys.get(key);
    }

    public final Collection<Entry<String, String>> entrySet() {
        if (keys == null)
            return Collections.emptyList();
        return keys.entrySet();
    }

    public final Collection<String> keySet() {
        if (keys == null)
            return Collections.emptyList();
        return keys.keySet();
    }
}