/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.layer0.utils;

import java.util.HashMap;
import java.util.Map;

import org.simantics.db.Resource;

/**
 * Service that creates unique names for resources and
 * resource paths. 
 */
public class NameMap {

    int maxLength;
    Map<Resource, String> cache = new HashMap<Resource, String>();
    int curId = 0;
    
    public NameMap(int maxLength) {
        this.maxLength = maxLength;
    }
    
    protected boolean isValid(String name) {
        return true;
    }
    
    private static final int charA = 65;
    private static final int char0 = 48 - 26;
    
    public void clear() {
    	curId = 0;
    	cache.clear();
    }
    
    public String getName(Resource resource) {
        String ret = cache.get(resource);
        while(ret == null) {
            int id = curId++;
            byte[] c = new byte[5];
            c[0] = '@';
            for(int i=0;i<4;++i) {
                int lid = id%36;
                if(lid < 26)
                    c[4-i] = (byte)(charA + lid);
                else
                    c[4-i] = (byte)(char0 + lid);
                id /= 36;
            }                
            ret = new String(c);
            if(isValid(ret))
                cache.put(resource, ret);
            else
                ret = null;
        }
        return ret;
    }
    
    public static void main(String[] args) {
		NameMap m = new NameMap(24);
		for(int i=0;i<100;++i)
			System.out.println(m.getName(new Resource() {

				@Override
				public int getThreadHash() {
					return hashCode();
				}
				
				@Override
				public long getResourceId() {
					return 3;
				}

				@Override
				public Resource get() {
					return this;
				}

				@Override
				public boolean isPersistent() {
					return false;
				}
				
				@Override
				public int compareTo(Resource o) {
					// TODO Auto-generated method stub
					return 0;
				}

				@Override
				public boolean equalsResource(Resource other) {
					return equals(other);
				}
				
			}));
			
	}
    
    public String getName(Resource[] resources) {
        String ret = "";
        for(Resource r : resources)
            ret += getName(r);
        return ret;
    }
    
}