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

import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map.Entry;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.data.osm.DataSet;
import org.openstreetmap.josm.data.osm.DataSource;
import org.openstreetmap.josm.data.osm.Relation;
import org.openstreetmap.josm.data.osm.RelationMember;
import org.openstreetmap.josm.data.osm.Node;
import org.openstreetmap.josm.data.osm.OsmPrimitive;
import org.openstreetmap.josm.data.osm.Changeset;
import org.openstreetmap.josm.data.osm.Way;
import org.openstreetmap.josm.data.osm.visitor.Visitor;

/**
 * Save the dataset into a stream as osm intern xml format. This is not using any
 * xml library for storing.
 * @author imi
 */
public class OsmWriter extends XmlWriter implements Visitor {

    /**
     * The counter for new created objects. Starting at -1 and goes down.
     */
    private long newIdCounter = -1;
    /**
     * All newly created ids and their primitive that uses it. This is a back reference
     * map to allow references to use the correnct primitives.
     */
    public HashMap<OsmPrimitive, Long> usedNewIds = new HashMap<OsmPrimitive, Long>();

    private final boolean osmConform;
    private final Changeset changeset;

    public abstract static class Osm implements OsmWriterInterface {
        public void header(PrintWriter out) {
            out.print("<osm version='");
            out.print(Main.pref.get("osm-server.version", "0.5"));
            out.println("' generator='JOSM'>");
        }
        public void footer(PrintWriter out) {
            out.println("</osm>");
        }
    }

    // simple helper to write the object's class to the out stream
    private Visitor typeWriteVisitor = new Visitor() {
        public void visit(Node n) { out.print("node"); }
        public void visit(Way w) { out.print("way"); }
        public void visit(Relation e) { out.print("relation"); }
    };

    /**
     * An output writer for function output that writes everything of the given dataset into
     * the xml
     */
    public static final class All extends Osm {
        private final DataSet ds;
        private final boolean osmConform;

        /**
         * Construct an writer function
         * @param osmConform <code>true</code>, if the xml should be 100% osm conform. In this
         *      case, not all information can be retrieved later (as example, modified state
         *      is lost and id's remain 0 instead of decrementing from -1)
         */
        public All(DataSet ds, boolean osmConform) {
            this.ds = ds;
            this.osmConform = osmConform;
        }

        public void write(PrintWriter out) {
            Visitor writer = new OsmWriter(out, osmConform, null);
            for (Node n : ds.nodes)
                if (shouldWrite(n))
                    writer.visit(n);
            for (Way w : ds.ways)
                if (shouldWrite(w))
                    writer.visit(w);
            for (Relation e : ds.relations)
                if (shouldWrite(e))
                    writer.visit(e);
        }

        private boolean shouldWrite(OsmPrimitive osm) {
            return osm.id != 0 || !osm.deleted;
        }

        @Override public void header(PrintWriter out) {
            super.header(out);
            for (DataSource s : ds.dataSources) {
                out.println("  <bounds minlat='"
                + s.bounds.min.lat()+"' minlon='"
                + s.bounds.min.lon()+"' maxlat='"
                + s.bounds.max.lat()+"' maxlon='"
                + s.bounds.max.lon()
                +"' origin='"+XmlWriter.encode(s.origin)+"' />");
            }
        }
    }

    /**
     * An output writer for functino output that writes only one specific primitive into
     * the xml
     */
    public static final class Single extends Osm {
        private final OsmPrimitive osm;
        private final boolean osmConform;
        private final Changeset changeset;

        public Single(OsmPrimitive osm, boolean osmConform, Changeset changeset) {
            this.osm = osm;
            this.osmConform = osmConform;
            this.changeset = changeset;
        }

        public void write(PrintWriter out) {
            osm.visit(new OsmWriter(out, osmConform, changeset));
        }
    }

    public OsmWriter(PrintWriter out, boolean osmConform, Changeset changeset) {
        super(out);
        this.osmConform = osmConform;
        this.changeset = changeset;
    }

    public void visit(Node n) {
        if (n.incomplete) return;
        addCommon(n, "node");
        out.print(" lat='"+n.coor.lat()+"' lon='"+n.coor.lon()+"'");
        addTags(n, "node", true);
    }

    public void visit(Way w) {
        if (w.incomplete) return;
        addCommon(w, "way");
        out.println(">");
        for (Node n : w.nodes)
            out.println("    <nd ref='"+getUsedId(n)+"' />");
        addTags(w, "way", false);
    }

    public void visit(Relation e) {
        if (e.incomplete) return;
        addCommon(e, "relation");
        out.println(">");
        for (RelationMember em : e.members) {
            out.print("    <member type='");
            em.member.visit(typeWriteVisitor);
            out.println("' ref='"+getUsedId(em.member)+"' role='" +
                XmlWriter.encode(em.role) + "' />");
        }
        addTags(e, "relation", false);
    }


    /**
     * Return the id for the given osm primitive (may access the usedId map)
     */
    private long getUsedId(OsmPrimitive osm) {
        if (osm.id != 0)
            return osm.id;
        if (usedNewIds.containsKey(osm))
            return usedNewIds.get(osm);
        usedNewIds.put(osm, newIdCounter);
        return osmConform ? 0 : newIdCounter--;
    }

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

    /**
     * Add the common part as the form of the tag as well as the XML attributes
     * id, action, user, and visible.
     */
    private void addCommon(OsmPrimitive osm, String tagname) {
        out.print("  <"+tagname+" id='"+getUsedId(osm)+"'");
        if (!osmConform) {
            String action = null;
            if (osm.deleted)
                action = "delete";
            else if (osm.modified)
                action = "modify";
            if (action != null)
                out.print(" action='"+action+"'");
        }
        if (osm.timestamp != null) {
            out.print(" timestamp='"+osm.timestamp+"'");
        }
        // user and visible added with 0.4 API
        if (osm.user != null) {
            out.print(" user='"+XmlWriter.encode(osm.user.name)+"'");
        }
        out.print(" visible='"+osm.visible+"'");
        if (osm.version != -1)
            out.print(" version='"+osm.version+"'");
        if (this.changeset != null && this.changeset.id != 0)
            out.print(" changeset='"+this.changeset.id+"'" );
    }
}