// License: GPL. For details, see LICENSE file.
package s57;

import java.util.ArrayList;
import java.util.EnumMap;
import java.util.HashMap;
import java.util.ListIterator;

import s57.S57att.Att;
import s57.S57obj.Obj;
import s57.S57osm.KeyVal;
import s57.S57val.AttVal;

/**
 * @author Malcolm Herring
 */
public class S57map { // S57/OSM map generation methods
    // CHECKSTYLE.OFF: LineLength

    public static class MapBounds {
        public double minlat;
        public double minlon;
        public double maxlat;
        public double maxlon;
        public MapBounds() {
            minlat = Math.toRadians(90);
            minlon = Math.toRadians(180);
            maxlat = Math.toRadians(-90);
            maxlon = Math.toRadians(-180);
        }
    }

    public enum Nflag {
        ANON,    // Edge inner nodes
        ISOL,    // Node not part of Edge
        CONN,    // Edge first and last nodes
        TRNK, // Edge truncated polygon nodes
        DPTH    // Sounding nodes
    }

    public static class Snode {    // All coordinates in map
        public double lat;    // Latitude in radians
        public double lon;    // Longitude in radians
        public Nflag flg;        // Role of node
        public double val;    // Optional value

        public Snode() {
            flg = Nflag.ANON;
            lat = 0;
            lon = 0;
            val = 0;
        }

        public Snode(double ilat, double ilon) {
            flg = Nflag.ANON;
            lat = ilat;
            lon = ilon;
            val = 0;
        }

        public Snode(double ilat, double ilon, Nflag iflg) {
            lat = ilat;
            lon = ilon;
            flg = iflg;
            val = 0;
        }

        public Snode(double ilat, double ilon, double ival) {
            flg = Nflag.DPTH;
            lat = ilat;
            lon = ilon;
            val = ival;
        }
    }

    public static class Edge {        // A polyline segment
        public long first;    // First CONN node
        public long last;        // Last CONN node
        public ArrayList<Long> nodes; // Inner ANON nodes

        public Edge() {
            first = 0;
            last = 0;
            nodes = new ArrayList<>();
        }
    }

    public enum Rflag {
        UNKN, MASTER, SLAVE
    }

    public static class Reln {
        public long id;
        public Rflag reln;
        public Reln(long i, Rflag r) {
            id = i;
            reln = r;
        }
    }

    public static class RelTab extends ArrayList<Reln> {
        public RelTab() {
            super();
        }
    }

    public static class ObjTab extends HashMap<Integer, AttMap> {
        public ObjTab() {
            super();
        }
    }

    public static class ObjMap extends EnumMap<Obj, ObjTab> {
        public ObjMap() {
            super(Obj.class);
        }
    }

    public static class AttMap extends HashMap<Att, AttVal<?>> {
        public AttMap() {
            super();
        }
    }

    public static class NodeTab extends HashMap<Long, Snode> {
        public NodeTab() {
            super();
        }
    }

    public static class EdgeTab extends HashMap<Long, Edge> {
        public EdgeTab() {
            super();
        }
    }

    public static class FtrMap extends EnumMap<Obj, ArrayList<Feature>> {
        public FtrMap() {
            super(Obj.class);
        }
    }

    public static class FtrTab extends HashMap<Long, Feature> {
        public FtrTab() {
            super();
        }
    }

    public static class Prim {                // Spatial element
        public long id;                    // Snode ID for POINTs, Edge ID for LINEs & AREAs)
        public boolean forward;    // Direction of vector used (LINEs & AREAs)
        public boolean outer;        // Exterior/Interior boundary (AREAs)
        public boolean trunc;        // Cell limit truncation
        public Prim() {
            id = 0; forward = true; outer = true; trunc = false;
        }

        public Prim(long i) {
            id = i; forward = true; outer = true; trunc = false;
        }

        public Prim(long i, boolean o) {
            id = i; forward = true; outer = o; trunc = false;
        }

        public Prim(long i, boolean f, boolean o) {
            id = i; forward = f; outer = o; trunc = false;
        }

        public Prim(long i, boolean f, boolean o, boolean t) {
            id = i; forward = f; outer = o; trunc = t;
        }
    }

    public static class Comp {            // Composite spatial element
        public long ref;            // ID of Comp
        public int size;            // Number of Prims in this Comp
        public Comp(long r, int s) {
            ref = r;
            size = s;
        }
    }

    public enum Pflag {
        NOSP, POINT, LINE, AREA
    }

    public static class Geom {                            // Geometric structure of feature
        public Pflag prim;                        // Geometry type
        public ArrayList<Prim> elems;    // Ordered list of elements
        public int outers;                        // Number of outers
        public int inners;                        // Number of inners
        public ArrayList<Comp> comps;    // Ordered list of compounds
        public double area;                        // Area of feature
        public double length;                    // Length of feature
        public Snode centre;                    // Centre of feature
        public Geom(Pflag p) {
            prim = p;
            elems = new ArrayList<>();
            outers = inners = 0;
            comps = new ArrayList<>();
            area = 0;
            length = 0;
            centre = new Snode();
        }
    }

    public static class Feature {
        public long id;                // Ref for this feature
        public Rflag reln;        // Relationship status
        public Geom geom;            // Geometry data
        public Obj type;            // Feature type
        public AttMap atts;        // Feature attributes
        public RelTab rels;        // Related objects
        public ObjMap objs;        // Slave object attributes

        Feature() {
            id = 0;
            reln = Rflag.UNKN;
            geom = new Geom(Pflag.NOSP);
            type = Obj.UNKOBJ;
            atts = new AttMap();
            rels = new RelTab();
            objs = new ObjMap();
        }
    }

    public MapBounds bounds;
    public NodeTab nodes;
    public EdgeTab edges;
    public FtrMap features;
    public FtrTab index;
    public long xref;

    private long cref;
    private Feature feature;
    private Edge edge;
    private ArrayList<KeyVal<?>> osm;
    private boolean sea;

    public S57map(boolean s) {
        sea = s;
        nodes = new NodeTab();      // All nodes in map
        edges = new EdgeTab();      // All edges in map
        feature = new Feature();    // Current feature being built
        features = new FtrMap();    // All features in map, grouped by type
        index = new FtrTab();       // Feature look-up table
        bounds = new MapBounds();
        cref = 0x0000ffffffff0000L; // Compound reference generator
        xref = 0x0fff000000000000L; // Extras reference generator
    }

    // S57 map building methods

    public void newNode(long id, double lat, double lon, Nflag flag) {
        nodes.put(id, new Snode(Math.toRadians(lat), Math.toRadians(lon), flag));
        if (flag == Nflag.ANON) {
            edge.nodes.add(id);
        }
    }

    public void newNode(long id, double lat, double lon, double depth) {
        nodes.put(id, new Snode(Math.toRadians(lat), Math.toRadians(lon), depth));
    }

    public void newFeature(long id, Pflag p, long objl) {
        feature = new Feature();
        Obj obj = S57obj.decodeType(objl);
        feature.geom = new Geom(p);
        feature.type = obj;
        if (obj != Obj.UNKOBJ) {
            index.put(id, feature);
            feature.id = id;
        }
    }

    public void refObj(long id, int rind) {
        Rflag r = Rflag.UNKN;
        switch (rind) {
        case 1:
            r = Rflag.MASTER;
            break;
        case 2:
            r = Rflag.SLAVE;
            break;
        case 3:
            r = Rflag.UNKN;
            break;
        }
        feature.rels.add(new Reln(id, r));
    }

    public void endFeature() {

    }

    public void newAtt(long attl, String atvl) {
        Att att = S57att.decodeAttribute(attl);
        AttVal<?> val = S57val.decodeValue(atvl, att);
        feature.atts.put(att, val);
    }

    public void newPrim(long id, long ornt, long usag) {
        feature.geom.elems.add(new Prim(id, (ornt != 2), (usag != 2)));
    }

    public void addConn(long id, int topi) {
        if (topi == 1) {
            edge.first = id;
        } else {
            edge.last = id;
        }
    }

    public void newEdge(long id) {
        edge = new Edge();
        edges.put(id, edge);
    }

    public void endFile() {
        for (long id : index.keySet()) {
            Feature feature = index.get(id);
            sortGeom(feature);
            for (Reln reln : feature.rels) {
                Feature rel = index.get(reln.id);
                if (cmpGeoms(feature.geom, rel.geom)) {
                    switch (reln.reln) {
                    case SLAVE:
                        feature.reln = Rflag.MASTER;
                        break;
                    default:
                        feature.reln = Rflag.UNKN;
                        break;
                    }
                    rel.reln = reln.reln;
                } else {
                    reln.reln = Rflag.UNKN;
                }
            }
        }
        for (long id : index.keySet()) {
            Feature feature = index.get(id);
            if (feature.reln == Rflag.UNKN) {
                feature.reln = Rflag.MASTER;
            }
            if ((feature.type != Obj.UNKOBJ) && (feature.reln == Rflag.MASTER)) {
                if (features.get(feature.type) == null) {
                    features.put(feature.type, new ArrayList<Feature>());
                }
                features.get(feature.type).add(feature);
            }
        }
        for (long id : index.keySet()) {
            Feature feature = index.get(id);
            for (Reln reln : feature.rels) {
                Feature rel = index.get(reln.id);
                if (rel.reln == Rflag.SLAVE) {
                    if (feature.objs.get(rel.type) == null) {
                        feature.objs.put(rel.type, new ObjTab());
                    }
                    ObjTab tab = feature.objs.get(rel.type);
                    int ix = tab.size();
                    tab.put(ix, rel.atts);
                }
            }
        }
    }

    // OSM map building methods

    public void addNode(long id, double lat, double lon) {
        nodes.put(id, new Snode(Math.toRadians(lat), Math.toRadians(lon)));
        feature = new Feature();
        feature.id = id;
        feature.reln = Rflag.UNKN;
        feature.geom.prim = Pflag.POINT;
        feature.geom.elems.add(new Prim(id));
        edge = null;
        osm = new ArrayList<>();
    }

    public void addEdge(long id) {
        feature = new Feature();
        feature.id = id;
        feature.reln = Rflag.UNKN;
        feature.geom.prim = Pflag.LINE;
        feature.geom.elems.add(new Prim(id));
        edge = new Edge();
        osm = new ArrayList<>();
    }

    public void addToEdge(long node) {
        if (edge.first == 0) {
            edge.first = node;
            nodes.get(node).flg = Nflag.CONN;
        } else {
            if (edge.last != 0) {
                edge.nodes.add(edge.last);
            }
            edge.last = node;
        }
    }

    public void addArea(long id) {
        feature = new Feature();
        feature.id = id;
        feature.reln = Rflag.UNKN;
        feature.geom.prim = Pflag.AREA;
        edge = null;
        osm = new ArrayList<>();
    }

    public void addToArea(long id, boolean outer) {
        feature.geom.elems.add(new Prim(id, outer));
    }

    public void addTag(String key, String val) {
        feature.reln = Rflag.MASTER;
        String[] subkeys = key.split(":");
        if ((subkeys.length > 1) && subkeys[0].equals("seamark")) {
            Obj obj = S57obj.enumType(subkeys[1]);
            if ((subkeys.length > 2) && (obj != Obj.UNKOBJ)) {
                int idx = 0;
                Att att = Att.UNKATT;
                try {
                    idx = Integer.parseInt(subkeys[2]);
                    if (subkeys.length == 4) {
                        att = s57.S57att.enumAttribute(subkeys[3], obj);
                    }
                } catch (Exception e) {
                    att = S57att.enumAttribute(subkeys[2], obj);
                }
                ObjTab objs = feature.objs.get(obj);
                if (objs == null) {
                    objs = new ObjTab();
                    feature.objs.put(obj, objs);
                }
                AttMap atts = objs.get(idx);
                if (atts == null) {
                    atts = new AttMap();
                    objs.put(idx, atts);
                }
                AttVal<?> attval = S57val.convertValue(val, att);
                if (attval.val != null) {
                    if (att == Att.VALSOU) {
                        Snode node = nodes.get(feature.geom.elems.get(0).id);
                        node.val = (Double) attval.val;
                    }
                    atts.put(att, attval);
                }
            } else {
                if (subkeys[1].equals("type")) {
                    obj = S57obj.enumType(val);
                    feature.type = obj;
                    ObjTab objs = feature.objs.get(obj);
                    if (objs == null) {
                        objs = new ObjTab();
                        feature.objs.put(obj, objs);
                    }
                    AttMap atts = objs.get(0);
                    if (atts == null) {
                        atts = new AttMap();
                        objs.put(0, atts);
                    }
                    if ((obj == Obj.SOUNDG) && (feature.geom.prim == Pflag.POINT)) {
                        Snode node = nodes.get(feature.geom.elems.get(0).id);
                        node.flg = Nflag.DPTH;
                    }
                } else {
                    if (obj != Obj.UNKOBJ) {
                        if (val.equals("yes")) {
                            ObjTab objs = feature.objs.get(obj);
                            if (objs == null) {
                                objs = new ObjTab();
                                feature.objs.put(obj, objs);
                            }
                        }
                    } else {
                        Att att = S57att.enumAttribute(subkeys[1], Obj.UNKOBJ);
                        if (att != Att.UNKATT) {
                            AttVal<?> attval = S57val.convertValue(val, att);
                            if (attval.val != null)
                                feature.atts.put(att, attval);
                        }
                    }
                }
            }
        } else if (!sea) {
            S57osm.OSMtag(osm, key, val);
        }
    }

    public void tagsDone(long id) {
        switch (feature.geom.prim) {
        case POINT:
            Snode node = nodes.get(id);
            if ((node.flg != Nflag.CONN) && (node.flg != Nflag.DPTH) && (!feature.objs.isEmpty() || !osm.isEmpty())) {
                node.flg = Nflag.ISOL;
            }
            break;
        case LINE:
            edges.put(id, edge);
            nodes.get(edge.first).flg = Nflag.CONN;
            nodes.get(edge.last).flg = Nflag.CONN;
            if (edge.first == edge.last) {
                feature.geom.prim = Pflag.AREA;
            }
            break;
        case AREA:
            break;
        default:
            break;
        }
        if (sortGeom(feature) && !((edge != null) && (edge.last == 0))) {
            if (feature.type != Obj.UNKOBJ) {
                index.put(id, feature);
                if (features.get(feature.type) == null) {
                    features.put(feature.type, new ArrayList<Feature>());
                }
                features.get(feature.type).add(feature);
            }
            for (KeyVal<?> kvx : osm) {
                Feature base = new Feature();
                base.reln = Rflag.MASTER;
                base.geom = feature.geom;
                base.type = kvx.obj;
                ObjTab objs = new ObjTab();
                base.objs.put(kvx.obj, objs);
                AttMap atts = new AttMap();
                objs.put(0, atts);
                if (kvx.att != Att.UNKATT) {
                    atts.put(kvx.att, new AttVal<>(kvx.conv, kvx.val));
                }
                index.put(++xref, base);
                if (features.get(kvx.obj) == null) {
                    features.put(kvx.obj, new ArrayList<Feature>());
                }
                features.get(kvx.obj).add(base);
            }
            /*            if (!osm.isEmpty()) {
                if (feature.type == Obj.UNKOBJ) {
                    feature.type = osm.obj;
                    ObjTab objs = feature.objs.get(osm.obj);
                    if (objs == null) {
                        objs = new ObjTab();
                        feature.objs.put(osm.obj, objs);
                    }
                    AttMap atts = objs.get(0);
                    if (atts == null) {
                        atts = new AttMap();
                        objs.put(0, atts);
                    }
                    if (osm.att != Att.UNKATT) {
                        atts.put(osm.att, new AttVal<>(osm.conv, osm.val));
                    }
                } else {
                    Feature base = new Feature();
                    base.reln = Rflag.MASTER;
                    base.geom = feature.geom;
                    base.type = osm.obj;
                    ObjTab objs = new ObjTab();
                    base.objs.put(osm.obj, objs);
                    AttMap atts = new AttMap();
                    objs.put(0, atts);
                    if (osm.att != Att.UNKATT) {
                        atts.put(osm.att, new AttVal<>(osm.conv, osm.val));
                    }
                    index.put(++xref, base);
                    if (features.get(osm.obj) == null) {
                        features.put(osm.obj, new ArrayList<Feature>());
                    }
                    features.get(osm.obj).add(base);
                }
            }*/
        }
    }

    public void mapDone() {
        if (!sea) {
            S57box.bBox(this);
        }
    }

    // Utility methods

    public boolean sortGeom(Feature feature) {
        try {
            Geom sort = new Geom(feature.geom.prim);
            long first = 0;
            long last = 0;
            Comp comp = null;
            boolean next = true;
            feature.geom.length = 0;
            feature.geom.area = 0;
            if (feature.geom.elems.isEmpty()) {
                return false;
            }
            if (feature.geom.prim == Pflag.POINT) {
                feature.geom.centre = nodes.get(feature.geom.elems.get(0).id);
                return true;
            }
            Geom outer = new Geom(feature.geom.prim);
            Geom inner = new Geom(feature.geom.prim);
            for (Prim prim : feature.geom.elems) {
                if (prim.outer) {
                    outer.elems.add(prim);
                } else {
                    inner.elems.add(prim);
                }
            }
            boolean outin = true;
            int sweep = outer.elems.size();
            if (sweep == 0) {
                return false;
            }
            int prev = sweep;
            int top = 0;
            while (!outer.elems.isEmpty()) {
                Prim prim = outer.elems.remove(0);
                Edge edge = edges.get(prim.id);
                if (edge == null) {
                    return false;
                }
                if (next == true) {
                    next = false;
                    first = edge.first;
                    last = edge.last;
                    prim.forward = true;
                    sort.elems.add(prim);
                    if (prim.outer) {
                        sort.outers++;
                    } else {
                        sort.inners++;
                    }
                    comp = new Comp(cref++, 1);
                    sort.comps.add(comp);
                } else {
                    if (edge.first == last) {
                        sort.elems.add(prim);
                        last = edge.last;
                        prim.forward = true;
                        comp.size++;
                    } else if (edge.last == first) {
                        sort.elems.add(top, prim);
                        first = edge.first;
                        prim.forward = true;
                        comp.size++;
                    } else if (edge.last == last) {
                        sort.elems.add(prim);
                        last = edge.first;
                        prim.forward = false;
                        comp.size++;
                    } else if (edge.first == first) {
                        sort.elems.add(top, prim);
                        first = edge.last;
                        prim.forward = false;
                        comp.size++;
                    } else {
                        outer.elems.add(prim);
                    }
                }
                if (--sweep == 0) {
                    sweep = outer.elems.size();
                    if ((sweep == 0) || (sweep == prev)) {
                        if ((sort.prim == Pflag.AREA) && (first != last)) {
                            return false;
                        }
                        if (outin) {
                            if (sweep != 0) {
                                return false;
                            }
                            outer = inner;
                            outin = false;
                            sweep = outer.elems.size();
                        }
                        next = true;
                        top = sort.elems.size();
                    }
                    prev = sweep;
                }
            }
            if ((sort.prim == Pflag.LINE) && (sort.outers == 1) && (sort.inners == 0) && (first == last)) {
                sort.prim = Pflag.AREA;
            }
            feature.geom = sort;
            if (feature.geom.prim == Pflag.AREA) {
                int ie = 0;
                int ic = 0;
                while (ie < feature.geom.elems.size()) {
                    double area = calcArea(feature.geom, ic);
                    if (ie == 0)
                        feature.geom.area = Math.abs(area) * 3444 * 3444;
                    if (((ie == 0) && (area < 0.0)) || ((ie > 0) && (area >= 0.0))) {
                        ArrayList<Prim> tmp = new ArrayList<>();
                        for (int i = 0; i < feature.geom.comps.get(ic).size; i++) {
                            Prim p = feature.geom.elems.remove(ie);
                            p.forward = !p.forward;
                            tmp.add(0, p);
                        }
                        feature.geom.elems.addAll(ie, tmp);
                    }
                    ie += feature.geom.comps.get(ic).size;
                    ic++;
                }
            }
            feature.geom.length = calcLength(feature.geom);
            feature.geom.centre = calcCentroid(feature);
            return true;
        } catch (Exception e) {
            return false;
        }
    }

    public boolean cmpGeoms(Geom g1, Geom g2) {
        return ((g1.prim == g2.prim) && (g1.outers == g2.outers) && (g1.inners == g2.inners) && (g1.elems.size() == g2.elems.size()));
    }

    public class EdgeIterator {
        Edge edge;
        boolean forward;
        ListIterator<Long> it;

        public EdgeIterator(Edge e, boolean dir) {
            edge = e;
            forward = dir;
            it = null;
        }

        public boolean hasNext() {
            return (edge != null);
        }

        public long nextRef() {
            long ref = 0;
            if (forward) {
                if (it == null) {
                    ref = edge.first;
                    it = edge.nodes.listIterator();
                } else {
                    if (it.hasNext()) {
                        ref = it.next();
                    } else {
                        ref = edge.last;
                        edge = null;
                    }
                }
            } else {
                if (it == null) {
                    ref = edge.last;
                    it = edge.nodes.listIterator(edge.nodes.size());
                } else {
                    if (it.hasPrevious()) {
                        ref = it.previous();
                    } else {
                        ref = edge.first;
                        edge = null;
                    }
                }
            }
            return ref;
        }

        public Snode next() {
            return nodes.get(nextRef());
        }
    }

    public class GeomIterator {
        Geom geom;
        Prim prim;
        EdgeIterator eit;
        ListIterator<S57map.Prim> ite;
        ListIterator<Comp> itc;
        Comp comp;
        int ec;
        long lastref;

        public GeomIterator(Geom g) {
            geom = g;
            lastref = 0;
            ite = geom.elems.listIterator();
            itc = geom.comps.listIterator();
        }

        public boolean hasComp() {
            return (itc.hasNext());
        }

        public long nextComp() {
            comp = itc.next();
            ec = comp.size;
            lastref = 0;
            return comp.ref;
        }

        public boolean hasEdge() {
            return (ec > 0) && ite.hasNext();
        }

        public long nextEdge() {
            prim = ite.next();
            eit = new EdgeIterator(edges.get(prim.id), prim.forward);
            ec--;
            return prim.id;
        }

        public boolean hasNode() {
            return (eit.hasNext());
        }

        public long nextRef(boolean all) {
            long ref = eit.nextRef();
            if (!all && (ref == lastref)) {
                ref = eit.nextRef();
            }
            lastref = ref;
            return ref;
        }

        public long nextRef() {
            return nextRef(false);
        }

        public Snode next() {
            return nodes.get(nextRef());
        }
    }

    double calcArea(Geom geom, int comp) {
        Snode node;
        double lat, lon, llon, llat;
        lat = lon = llon = llat = 0;
        double sigma = 0;
        GeomIterator git = new GeomIterator(geom);
        for (int i = 0; i <= comp; i++) {
            if (git.hasComp()) {
                git.nextComp();
                while (git.hasEdge()) {
                    git.nextEdge();
                    while (git.hasNode()) {
                        node = git.next();
                        if (node == null)
                            continue;
                        llon = lon;
                        llat = lat;
                        lat = node.lat;
                        lon = node.lon;
                        sigma += (lon * Math.sin(llat)) - (llon * Math.sin(lat));
                    }
                }
                if (i != comp)
                    sigma = lat = lon = llon = llat = 0;
            }
        }
        return sigma / 2.0;
    }

    double calcLength(Geom geom) {
        Snode node;
        double lat, lon, llon, llat;
        lat = lon = llon = llat = 0;
        double sigma = 0;
        boolean first = true;
        GeomIterator git = new GeomIterator(geom);
        while (git.hasComp()) {
            git.nextComp();
            while (git.hasEdge()) {
                git.nextEdge();
                while (git.hasNode()) {
                    node = git.next();
                    if (first) {
                        first = false;
                        lat = node.lat;
                        lon = node.lon;
                    } else if (node != null) {
                        llat = lat;
                        llon = lon;
                        lat = node.lat;
                        lon = node.lon;
                        sigma += Math.acos(Math.sin(lat) * Math.sin(llat) + Math.cos(lat) * Math.cos(llat) * Math.cos(llon - lon));
                    }
                }
            }
        }
        return sigma * 3444;
    }

    Snode calcCentroid(Feature feature) {
        double lat, lon, slat, slon, llat, llon;
        llat = llon = lat = lon = slat = slon = 0;
        double sarc = 0;
        boolean first = true;
        switch (feature.geom.prim) {
        case POINT:
            return nodes.get(feature.geom.elems.get(0).id);
        case LINE:
            GeomIterator git = new GeomIterator(feature.geom);
            while (git.hasComp()) {
                git.nextComp();
                while (git.hasEdge()) {
                    git.nextEdge();
                    while (git.hasNode()) {
                        Snode node = git.next();
                        if (node == null) continue;
                        lat = node.lat;
                        lon = node.lon;
                        if (first) {
                            first = false;
                        } else {
                            sarc += Math.acos(Math.cos(lon - llon) * Math.cos(lat - llat));
                        }
                        llat = lat;
                        llon = lon;
                    }
                }
            }
            double harc = sarc / 2;
            sarc = 0;
            first = true;
            git = new GeomIterator(feature.geom);
            while (git.hasComp()) {
                git.nextComp();
                while (git.hasEdge()) {
                    git.nextEdge();
                    while (git.hasNode()) {
                        Snode node = git.next();
                        if (node == null) continue;
                        lat = node.lat;
                        lon = node.lon;
                        if (first) {
                            first = false;
                        } else {
                            sarc = Math.acos(Math.cos(lon - llon) * Math.cos(lat - llat));
                            if (sarc > harc)
                                break;
                        }
                        harc -= sarc;
                        llat = lat;
                        llon = lon;
                    }
                }
            }
            return new Snode(llat + ((lat - llat) * harc / sarc), llon + ((lon - llon) * harc / sarc));
        case AREA:
            git = new GeomIterator(feature.geom);
            while (git.hasComp()) {
                git.nextComp();
                while (git.hasEdge()) {
                    git.nextEdge();
                    while (git.hasNode()) {
                        Snode node = git.next();
                        lat = node.lat;
                        lon = node.lon;
                        if (first) {
                            first = false;
                        } else {
                            double arc = (Math.acos(Math.cos(lon - llon) * Math.cos(lat - llat)));
                            slat += ((lat + llat) / 2 * arc);
                            slon += ((lon + llon) / 2 * arc);
                            sarc += arc;
                        }
                        llon = lon;
                        llat = lat;
                    }
                }
            }
            return new Snode((sarc > 0.0 ? slat / sarc : 0.0), (sarc > 0.0 ? slon / sarc : 0.0));
        default:
        }
        return null;
    }

}