// Copyright 2011, 2012 Tony Garnock-Jones <tonygarnockjones@gmail.com>.
//
// This file is part of Hop.
//
// Hop is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Hop is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
// License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Hop.  If not, see <http://www.gnu.org/licenses/>.
//
package hop;

import java.io.Flushable;
import java.io.IOException;
import java.lang.ref.WeakReference;
import java.util.*;

/**
 */
public class NodeContainer implements Flushable {
    public String _name;
    public Map<String, WeakReference<Node>> _directory;

    public NodeContainer() {
        this(UUID.randomUUID().toString());
    }

    public NodeContainer(String name) {
        _name = name;
        _directory = new Hashtable<String, WeakReference<Node>>();
    }

    public String getName() {
        return _name;
    }

    public synchronized boolean bind(String name, Node n) {
        WeakReference<Node> ref = _directory.get(name);
        if (ref != null && ref.get() != null) {
            return false;
        }
        ref = new WeakReference<Node>(n);
        _directory.put(name, ref);
        return true;
    }

    public synchronized boolean unbind(String name) {
        if (!_directory.containsKey(name))
            return false;
        _directory.remove(name);
        return true;
    }

    public void flush() throws IOException {
        ArrayList<Flushable> fs = new ArrayList<Flushable>();
        synchronized (this) {
            for (Map.Entry<String, WeakReference<Node>> e : _directory.entrySet()) {
                Node n = e.getValue().get();
                if (n instanceof Flushable) {
                    fs.add((Flushable) n);
                }
            }
        }
        for (Flushable f : fs) {
            f.flush();
        }
    }

    public void flush(String name) throws IOException {
        Flushable f;
        synchronized (this) {
            WeakReference<Node> ref = _directory.get(name);
            if (ref == null) return;
            Node n = ref.get();
            if (n == null) return;
            if (!(n instanceof Flushable)) return;
            f = ((Flushable) n);
        }
        f.flush();
    }

    public synchronized void unbindReferencesTo(Node n) {
        for (Map.Entry<String, WeakReference<Node>> e : _directory.entrySet()) {
            if (e.getValue().get() == n) {
                _directory.remove(e.getKey());
            }
        }
    }

    public synchronized Node lookup(String name) {
        WeakReference<Node> r = _directory.get(name);
        return (r == null) ? null : r.get();
    }

    public boolean post(String sink, Object name, Object message, Object token) {
        return send(sink, SexpMessage.post(name, message, token));
    }

    public boolean send(String name, Object message) {
        Node n = lookup(name);
        if (n == null) {
            System.err.println("Warning: sending to nonexistent node " + name + "; message " + message);
            return false;
        }
        n.handle(message);
        return true;
    }
}