//
// $Id$
//
// Nenya library - tools for developing networked games
// Copyright (C) 2002-2010 Three Rings Design, Inc., All Rights Reserved
// http://www.threerings.net/code/nenya/
//
// This library is free software; you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License as published
// by the Free Software Foundation; either version 2.1 of the License, or
// (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

package com.threerings.media.util;

import java.util.ArrayList;
import java.util.List;

import java.awt.Graphics2D;

import static com.threerings.media.Log.log;

/**
 * Used to create a path that is a sequence of several other paths.
 */
public class PathSequence
    implements Path
{
    /**
     * Conveniently construct a path sequence with the two specified paths.
     */
    public PathSequence (Path first, Path second)
    {
        this(new ArrayList<Path>());
        _paths.add(first);
        _paths.add(second);
    }

    /**
     * Construct a path sequence with the list of paths.
     *
     * Note: Paths may be added to the end of the list while the pathable is still traversing
     * earlier paths!
     */
    public PathSequence (List<Path> paths)
    {
        _paths = paths;
    }

    /**
     * Add a new path to the end of our current list.
     */
    public void addPath (Path path)
    {
        _paths.add(path);
    }

    // documentation inherited from interface Path
    public void init (Pathable pable, long tickStamp)
    {
        _pable = pable;
        _pableRep = new DelegatingPathable(_pable) {
            @Override
            public void pathCompleted (long timeStamp) {
                long initStamp;
                // if we just finished a timed path, we can figure out how long ago it really
                // finished and init the next path at that time in the past.
                if (_curPath instanceof TimedPath) {
                    initStamp = _lastInit + ((TimedPath) _curPath)._duration;
                } else {
                    // we don't know
                    initStamp = timeStamp;
                }
                initNextPath(initStamp, timeStamp);
            }
        };
        initNextPath(tickStamp, tickStamp);
    }

    // documentation inherited from interface Path
    public boolean tick (Pathable pable, long tickStamp)
    {
        if (pable != _pable) {
            log.warning("PathSequence ticked with different path than it was inited with.");
        }
        return _curPath.tick(_pableRep, tickStamp);
    }

    // documentation inherited from interface Path
    public void fastForward (long timeDelta)
    {
        _lastInit += timeDelta;
        _curPath.fastForward(timeDelta);
    }

    // documentation inherited from interface Path
    public void paint (Graphics2D gfx)
    {
        // for now..
        _curPath.paint(gfx);
    }

    // documentation inherited from interface Path
    public void wasRemoved (Pathable pable)
    {
        if (_curPath != null) {
            _curPath.wasRemoved(_pableRep);
        }
    }

    /**
     * Initialize and start the next path in the sequence.
     */
    protected void initNextPath (long initStamp, long tickStamp)
    {
        if (_paths.size() == 0) {
            _pable.pathCompleted(tickStamp);

        } else {
            _curPath = _paths.remove(0);
            _lastInit = initStamp;

            _curPath.init(_pableRep, initStamp);
            _curPath.tick(_pableRep, tickStamp);
        }
    }

    /** The list of paths. */
    protected List<Path> _paths;

    /** The timestamp at which we last inited a path. */
    protected long _lastInit;

    /** The current path we're pathing. */
    protected Path _curPath;

    /** The pathable we're duping bigtime. */
    protected Pathable _pable;

    /** A fake pathable that we pass to the subpaths. */
    protected Pathable _pableRep;
}
