//
// $Id$
//
// Nenya library - tools for developing networked games
// Copyright (C) 2002-2007 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.tile;

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

import java.lang.ref.SoftReference;
import java.util.Map;

import com.google.common.collect.Maps;

import com.samskivert.io.PersistenceException;

import com.threerings.media.image.ImageManager;

/**
 * The tile manager provides a simplified interface for retrieving and caching tiles. Tiles can be
 * loaded in two different ways. An application can load a tileset by hand, specifying the path to
 * the tileset image and all of the tileset metadata necessary for extracting the image tiles, or
 * it can provide a tileset repository which loads up tilesets using whatever repository mechanism
 * is implemented by the supplied repository. In the latter case, tilesets are loaded by a unique
 * identifier.
 * 
 * <p> Loading tilesets by hand is intended for things like toolbar icons or games with a single
 * set of tiles (think Stratego, for example). Loading tilesets from a repository supports games
 * with vast numbers of tiles to which more tiles may be added on the fly (think the tiles for an
 * isometric-display graphical MUD).
 */
public class TileManager
{
    /**
     * Creates a tile manager and provides it with a reference to the image manager from which it
     * will load tileset images.
     * 
     * @param imgr the image manager via which the tile manager will decode and cache images.
     */
    public TileManager (ImageManager imgr)
    {
        _imgr = imgr;
        _defaultProvider = new IMImageProvider(_imgr, (String)null);
    }

    /**
     * Loads up a tileset from the specified image with the specified metadata parameters.
     */
    public UniformTileSet loadTileSet (String imgPath, int width, int height)
    {
        return loadCachedTileSet("", imgPath, width, height);
    }

    /**
     * Loads up a tileset from the specified image (located in the specified resource set) with
     * the specified metadata parameters.
     */
    public UniformTileSet loadTileSet (String rset, String imgPath, int width, int height)
    {
        return loadTileSet(getImageProvider(rset), rset, imgPath, width, height);
    }

    /**
     */
    public UniformTileSet loadTileSet (
        ImageProvider improv, String improvKey, String imgPath,
        int width, int height)
    {
        UniformTileSet uts = loadCachedTileSet(improvKey, imgPath, width, height);
        uts.setImageProvider(improv);
        return uts;
    }

    /**
     * Returns an image provider that will load images from the specified
     * resource set.
     */
    public ImageProvider getImageProvider (String rset)
    {
        return new IMImageProvider(_imgr, rset);
    }

    /**
     * Used to load and cache tilesets loaded via {@link #loadTileSet}.
     */
    protected UniformTileSet loadCachedTileSet (String bundle, String imgPath, int width,
        int height)
    {
        String key = bundle + "::" + imgPath;
        SoftReference<UniformTileSet> ref = _handcache.get(key);
        UniformTileSet uts = (ref == null) ? null : ref.get();
        if (uts == null) {
            uts = new UniformTileSet();
            uts.setImageProvider(_defaultProvider);
            uts.setImagePath(imgPath);
            uts.setWidth(width);
            uts.setHeight(height);
            _handcache.put(key, new SoftReference<UniformTileSet>(uts));
        }
        return uts;
    }

    /**
     * Clears any cached tilesets.
     */
    public void clearCache ()
    {
        _handcache = Maps.newHashMap();
    }

    /**
     * Sets the tileset repository that will be used by the tile manager when tiles are requested
     * by tileset id.
     */
    public void setTileSetRepository (TileSetRepository setrep)
    {
        _setrep = setrep;
    }

    /**
     * Returns the tileset repository currently in use.
     */
    public TileSetRepository getTileSetRepository ()
    {
        return _setrep;
    }

    /**
     * Returns the tileset with the specified id. Tilesets are fetched from the tileset repository
     * supplied via {@link #setTileSetRepository}, and are subsequently cached.
     * 
     * @param tileSetId the unique identifier for the desired tileset.
     * 
     * @exception NoSuchTileSetException thrown if no tileset exists with the specified id or if
     * an underlying error occurs with the tileset repository's persistence mechanism.
     */
    public TileSet getTileSet (int tileSetId)
        throws NoSuchTileSetException
    {
        // make sure we have a repository configured
        if (_setrep == null) {
            throw new NoSuchTileSetException(tileSetId);
        }

        try {
            return _setrep.getTileSet(tileSetId);
        } catch (PersistenceException pe) {
            log.warning("Failure loading tileset", "id", tileSetId, "error", pe);
            throw new NoSuchTileSetException(tileSetId);
        }
    }

    /**
     * Returns the tileset with the specified name.
     * 
     * @throws NoSuchTileSetException if no tileset with the specified name is available via our
     * configured tile set repository.
     */
    public TileSet getTileSet (String name)
        throws NoSuchTileSetException
    {
        // make sure we have a repository configured
        if (_setrep == null) {
            throw new NoSuchTileSetException(name);
        }

        try {
            return _setrep.getTileSet(name);
        } catch (PersistenceException pe) {
            log.warning("Failure loading tileset", "name", name, "error", pe);
            throw new NoSuchTileSetException(name);
        }
    }

    /**
     * Returns the {@link Tile} object with the specified fully qualified tile id.
     * 
     * @see TileUtil#getFQTileId
     */
    public Tile getTile (int fqTileId)
        throws NoSuchTileSetException
    {
        return getTile(TileUtil.getTileSetId(fqTileId), TileUtil.getTileIndex(fqTileId), null);
    }

    /**
     * Returns the {@link Tile} object with the specified fully qualified tile id. The supplied
     * colorizer will be used to recolor the tile.
     * 
     * @see TileUtil#getFQTileId
     */
    public Tile getTile (int fqTileId, TileSet.Colorizer rizer)
        throws NoSuchTileSetException
    {
        return getTile(TileUtil.getTileSetId(fqTileId), TileUtil.getTileIndex(fqTileId), rizer);
    }

    /**
     * Returns the {@link Tile} object from the specified tileset at the specified index.
     * 
     * @param tileSetId the tileset id.
     * @param tileIndex the index of the tile to be retrieved.
     * 
     * @return the tile object.
     */
    public Tile getTile (int tileSetId, int tileIndex, TileSet.Colorizer rizer)
        throws NoSuchTileSetException
    {
        TileSet set = getTileSet(tileSetId);
        return set.getTile(tileIndex, rizer);
    }

    /** The entity through which we decode and cache images. */
    protected ImageManager _imgr;

    /** A cache of tilesets that have been loaded by hand. */
    protected Map<String, SoftReference<UniformTileSet>> _handcache = Maps.newHashMap();

    /** The tile set repository. */
    protected TileSetRepository _setrep;

    /** Used to load tileset images from the default resource source. */
    protected ImageProvider _defaultProvider;
}