/*
 * (c) Copyright 2007-2011 by Volker Bergmann. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, is permitted under the terms of the
 * GNU General Public License.
 *
 * For redistributing this software or a derivative work under a license other
 * than the GPL-compatible Free Software License as defined by the Free
 * Software Foundation or approved by OSI, you must first obtain a commercial
 * license to this software product from Volker Bergmann.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * WITHOUT A WARRANTY OF ANY KIND. ALL EXPRESS OR IMPLIED CONDITIONS,
 * REPRESENTATIONS AND WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE
 * HEREBY EXCLUDED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

package org.databene.benerator.primitive;

import org.databene.benerator.*;
import org.databene.benerator.wrapper.NonNullGeneratorWrapper;
import org.databene.benerator.wrapper.ProductWrapper;
import org.databene.commons.CollectionUtil;
import org.databene.commons.ArrayFormat;

import java.util.Set;
import java.util.TreeSet;

/**
 * Generates unique strings of fixed length.<br/>
 * <br/>
 * Created: 15.11.2007 14:07:49
 * @author Volker Bergmann
 */
public class UniqueFixedLengthStringGenerator extends NonNullGeneratorWrapper<int[], String> {

    public static final Set<Character> DEFAULT_CHAR_SET
            = CollectionUtil.toSet('0', '1', '2', '3', '4', '5', '6', '7', '8', '9');
    private static final int DEFAULT_LENGTH = 4;
    private static final boolean DEFAULT_ORDERED = false;

    private char[] digitSymbols;
    private int length;
    private boolean ordered;
    
    public UniqueFixedLengthStringGenerator() {
        this(DEFAULT_CHAR_SET, DEFAULT_LENGTH, DEFAULT_ORDERED);
    }

    public UniqueFixedLengthStringGenerator(Set<Character> chars, int length, boolean ordered) {
    	super(null);
        this.digitSymbols = CollectionUtil.toCharArray(new TreeSet<Character>(chars));
        this.length = length;
        this.ordered = ordered;
    }

    // Generator interface ---------------------------------------------------------------------------------------------

	public Class<String> getGeneratedType() {
	    return String.class;
    }

    @Override
    public synchronized void init(GeneratorContext context) {
    	assertNotInitialized();
    	if (ordered)
    		setSource(new IncrementalIntsGenerator(digitSymbols.length, length));
    	else
    		setSource(new UniqueIntsGenerator(digitSymbols.length, length));
        super.init(context);
    }
    
	public String generate() {
		ProductWrapper<int[]> wrapper = generateFromSource();
		if (wrapper == null)
			return null;
		int[] ordinals = wrapper.unwrap();
		char[] buffer = new char[length];
		for (int i = 0; i < length; i++)
			buffer[i] = digitSymbols[ordinals[i]];
        return new String(buffer);
    }

    @Override
    public String toString() {
        return getClass().getSimpleName() + "[length=" + length + ", charset=" +
                ArrayFormat.formatChars(",", digitSymbols) + ']'; 
    }

}