/*******************************************************************************
 *
 * Copyright (c) 2004-2011 Oracle Corporation.
 *
 * 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:
 *
 *    Kohsuke Kawaguchi, Anton Kozak
 *
 *
 *******************************************************************************/ 

package hudson.matrix;

import com.thoughtworks.xstream.XStream;
import hudson.Util;
import hudson.util.RobustCollectionConverter;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.Arrays;
import org.apache.commons.collections.CollectionUtils;
import org.apache.commons.collections.ListUtils;

/**
 * List of {@link Axis}.
 *
 * @author Kohsuke Kawaguchi
 */
public class AxisList extends ArrayList<Axis> {

    public AxisList() {
    }

    public AxisList(Collection<? extends Axis> c) {
        super(c);
    }

    public AxisList(Axis... c) {
        this(Arrays.asList(c));
    }

    public Axis find(String name) {
        for (Axis a : this) {
            if (a.name.equals(name)) {
                return a;
            }
        }
        return null;
    }

    /**
     * Creates a subset of the list that only contains the type assignable to
     * the specified type.
     */
    public AxisList subList(Class<? extends Axis> subType) {
        return new AxisList(Util.filter(this, subType));
    }

    @Override
    public boolean add(Axis axis) {
        return axis != null && super.add(axis);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        if (!super.equals(o)) {
            return false;
        }
        AxisList axisList = (AxisList) o;

        return CollectionUtils.isEqualCollection(this, axisList);
    }

    @Override
    public int hashCode() {
        return ListUtils.hashCodeForList(this);
    }

    /**
     * List up all the possible combinations of this list.
     */
    public Iterable<Combination> list() {
        final int[] base = new int[size()];
        if (base.length == 0) {
            return Collections.<Combination>emptyList();
        }

        int b = 1;
        for (int i = size() - 1; i >= 0; i--) {
            base[i] = b;
            b *= get(i).size();
        }

        final int total = b;    // number of total combinations

        return new Iterable<Combination>() {
            public Iterator<Combination> iterator() {
                return new Iterator<Combination>() {
                    private int counter = 0;

                    public boolean hasNext() {
                        return counter < total;
                    }

                    public Combination next() {
                        String[] data = new String[size()];
                        int x = counter++;
                        for (int i = 0; i < data.length; i++) {
                            data[i] = get(i).value(x / base[i]);
                            x %= base[i];
                        }
                        assert x == 0;
                        return new Combination(AxisList.this, data);
                    }

                    public void remove() {
                        throw new UnsupportedOperationException();
                    }
                };
            }
        };
    }

    /**
     * {@link Converter} implementation for XStream.
     */
    public static final class ConverterImpl extends RobustCollectionConverter {

        public ConverterImpl(XStream xs) {
            super(xs);
        }

        @Override
        public boolean canConvert(Class type) {
            return type == AxisList.class;
        }

        @Override
        protected Object createCollection(Class type) {
            return new AxisList();
        }
    }
}