/*******************************************************************************
 * 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
 *******************************************************************************/
/*
 * 16.8.2006
 */
package org.simantics.utils.datastructures;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

/**
 * MapList is a data structure with map on left side and arraylist on right side.
 * <p>
 * 
 * @author Toni Kalajainen
 */
public class MapList<L, R> {

    @SuppressWarnings("rawtypes")
    public static final MapList EMPTY_MAPLIST = new MapList() {
        private static final String IMMUTABLE_MSG = "Cannot modify immutable empty MapList";

        @Override
        public void add(Object key) {
            throw new UnsupportedOperationException(IMMUTABLE_MSG);
        }
        @Override
        public void add(Object key, int index, Object value) {
            throw new UnsupportedOperationException(IMMUTABLE_MSG);
        }
        @Override
        public void add(Object key, Object value) {
            throw new UnsupportedOperationException(IMMUTABLE_MSG);
        }
        @Override
        public void addAll(Object key, Collection values) {
            throw new UnsupportedOperationException(IMMUTABLE_MSG);
        }
        @Override
        public void clear() {
            throw new UnsupportedOperationException(IMMUTABLE_MSG);
        }
        @Override
        public boolean remove(Object key) {
            throw new UnsupportedOperationException(IMMUTABLE_MSG);
        }
        public boolean remove(Object key, Object value) {
            throw new UnsupportedOperationException(IMMUTABLE_MSG);
        }
    };

    @SuppressWarnings("unchecked")
    public static <L, R> MapList<L, R> emptyMapList() {
        return EMPTY_MAPLIST;
    }

    protected Map<L, List<R>> lists;

    public MapList() {
    	lists = new HashMap<L, List<R>>();
    }
    
    @SuppressWarnings("unchecked")
	public MapList( Class<?> mapClass ) {
    	try {
			lists = (Map<L, List<R>>) mapClass.newInstance();
		} catch (InstantiationException e) {
			throw new RuntimeException( e );
		} catch (IllegalAccessException e) {
			throw new RuntimeException( e );
		}
    }

    public MapList(MapList<L, R> copyFrom) {
        for (Entry<L, List<R>> e : copyFrom.lists.entrySet())
            lists.put( e.getKey(), new ArrayList<R>(e.getValue()) );
    }

	public static <L, R> MapList<L, R> use( Map<L, List<R>> map ) {
		MapList<L, R> result = new MapList<L, R>();
		result.lists = map;
		return result;
	}
    
    public void add(L key) {
        getOrCreateList(key);
    }

    public void add(L key, R value)
    {
        List<R> list = getOrCreateList(key);
        list.add(value);
    }

    public void add(L key, int index, R value)
    {
        ArrayList<R> list = getOrCreateList(key);
        list.add(index, value);
    }

	public void addAll(L key, Collection<R> values) {
		ArrayList<R> list = getOrCreateList(key);
		list.addAll(values);
	}
    
    private ArrayList<R> getOrCreateList(L key)
    {
        ArrayList<R> list = (ArrayList<R>) lists.get(key);
        if (list==null) {
            list = new ArrayList<R>(1);
            lists.put(key, list);
        }
        return list;
    }

    private List<R> getList(L key)
    {
        return lists.get(key);
    }

    public boolean remove(L key, R value)
    {
        List<R> list = getList(key);
        if (list==null) return false;
        boolean result = list.remove(value);
        if (list.size()==0)
            lists.remove(key);
        return result;
    }

    public boolean remove(L key)
    {
        List<R> list = getList(key);
        if (list==null) return false;
        lists.remove(key);
        return true;
    }

    public void clear()
    {
        lists.clear();
    }

    public L[] getKeys(L[] list)
    {
        return lists.keySet().toArray(list);
    }

    public Set<L> getKeys()
    {
        return lists.keySet();
    }

    public int getKeySize() {
        return lists.size();
    }

    public boolean containsKey(L key)
    {
        return lists.containsKey(key);
    }

    public boolean contains(L key, R obj)
    {
        List<R> l = lists.get(key);
        if (l==null) return false;
        return l.contains(obj);

    }

    public R[] getValues(L key, R[] list)
    {
        List<R> l = lists.get(key);
        if (l==null) return null;
        return l.toArray(list);
    }

    /**
     * @param key
     *            the key to get values for
     * @param list
     *            the list to fill with existing values for specified key. Fills
     *            this array with at maximum as many values as there is room for
     *            in the array even if there are more values available in the
     *            maplist for the specified key.
     * @return the amount of values existing for the key. May be smaller or
     *         larger than the size of the provided list. If smaller, only the
     *         first array indexes will be filled with data and if larger, all
     *         array indexes will be filled with data.
     */
    public int getAtMostValues(L key, R[] list)
    {
        List<R> l = lists.get(key);
        if (l==null) return 0;
        int valueCount = l.size();
        int size = Math.min(valueCount, list.length);
        for (int i = 0; i < size; ++i)
            list[i] = l.get(i);
        return valueCount;
    }

    /**
     * Returns a the internal list values for the specified key. The list is
     * valid as long as it contains elements. The list should not be modified
     * but the return value of this method does not enforce it like
     * {@link #getValues(Object)} does. Use this method when you know you will
     * not risk a 3rd party modifying the returned list and you want to avoid
     * the cost of extra memory allocation through
     * {@link Collections#unmodifiableList(List)}.
     * 
     * @param key
     *            the key to look values for
     * @return empty unmodifiable list if there is no list with the specified
     *         key, otherwise an unmodifiable version of the stored list
     */
    public List<R> getValuesUnsafe(L key)
    {
        List<R> l = lists.get(key);
        return l != null ? l : Collections.<R>emptyList();
    }

    /**
     * Returns a read-only reference to the values. The list is valid as long as
     * it contains elements.
     * 
     * @param key
     * @return empty unmodifiable list if there is no list with the specified key,
     *         otherwise an unmodifiable version of the stored list
     */
    public List<R> getValues(L key)
    {
        List<R> l = lists.get(key);
        if (l==null) return Collections.emptyList();
        return Collections.unmodifiableList(l);
    }

    /**
     * Returns a copy of the values
     * 
     * @param key
     * @return empty unmodifiable list if there is no list with the specified key,
     *         otherwise a copy of the stored list
     */
    public List<R> getValuesSnapshot(L key)
    {
        List<R> l = lists.get(key);
        if (l==null) return Collections.emptyList();
        return new ArrayList<R>(l);
    }
    
    public List<R> getAllValuesSnapshot() 
    {
        return getAllValuesSnapshot(null);
    }

    public List<R> getAllValuesSnapshot(List<R> result) 
    {
        if (result == null)
            result = new ArrayList<R>();
        for (List<R> right : lists.values()) {
            result.addAll(right);
        }
        return result;
    }

    public boolean isEmpty() {
        return lists.isEmpty();
    }

    /**
     * Makes _this_ maplist immutable.
     */
    public void makeImmutable() {
        for (Entry<L, List<R>> e : lists.entrySet())
            lists.put(e.getKey(), Collections.unmodifiableList(e.getValue()));
        lists = Collections.unmodifiableMap(lists);
    }

}