/*******************************************************************************
 * 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.g2d.diagram.impl;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

import org.simantics.utils.datastructures.MapList;

/**
 * @author Toni Kalajainen
 */
public class AbstractHandlerClass<Handler> implements Serializable {

    private static final long serialVersionUID = 4137854678128072467L;

    private final MapList<Class<?>, Handler> handlers = new MapList<Class<?>, Handler>();
    private final List<Handler> snapshot;
    private final int hash;

    public AbstractHandlerClass(Collection<Handler> contributions)
    {
        for (Handler c : contributions)
            _addClass(c.getClass(), c);
        this.handlers.makeImmutable();
        this.snapshot = Collections.unmodifiableList(new ArrayList<Handler>(contributions));
        this.hash = snapshot.hashCode();
    }

    private void _addClass(Class<?> clazz, Handler ec)
    {
        if (handlers.contains(clazz, ec)) return;
        handlers.add(clazz, ec);
        Class<?> superClazz = clazz.getSuperclass();
        if (superClazz!=null) _addClass(superClazz, ec);
        for (Class<?> interphase : clazz.getInterfaces())
            _addClass(interphase, ec);
    }

    /**
     * Get all interactors by class
     * @param clazz
     * @return collection
     */
    @SuppressWarnings("unchecked")
    public <R extends Handler> List<R> getItemsByClass(Class<R> clazz)
    {
        List<R> result = (List<R>) handlers.getValuesUnsafe(clazz);
        if (result!=null)
            return result;
        return Collections.emptyList();
    }

    /**
     * Get a single item by class.
     * (Convenience method)
     * 
     * @param <R>
     * @param clazz
     * @return the item
     * @throws RuntimeException if single interactor was not found
     */
    @SuppressWarnings("unchecked")
    public <R extends Handler> R getSingleItem(Class<R> clazz)
    {
        List<R> list = (List<R>) handlers.getValuesUnsafe(clazz);
        if (list==null || list.size()!=1)
            throw new RuntimeException("Invalid element class "+toString()+": One and only one "+clazz.getName()+" is expected, got " + (list != null ? list.size() : 0));
        return list.get(0);
    }

    /**
     * Get a single item by class.
     * (Convenience method)
     * 
     * @param <R>
     * @param clazz
     * @return the item or <code>null</code>
     * @throws RuntimeException if more than one items were found
     */
    @SuppressWarnings("unchecked")
    public <R extends Handler> R getAtMostOneItemOfClass(Class<R> clazz)
    {
        List<R> list = (List<R>) handlers.getValuesUnsafe(clazz);
        if (list==null || list.size()==0) return null;
        if (list.size()==1) return list.get(0);
        throw new RuntimeException("At most one was "+clazz.getName()+" expected in "+this.getClass().getName() + ", got " + list.size());
    }

    public <R extends Handler> R[] getAtMostItemsOfClass(Class<R> clazz, R[] result)
    {
        handlers.getAtMostValues(clazz, result);
        return result;
    }

    public List<Handler> getAll()
    {
        return snapshot;
    }

    public boolean contains(Handler handler)
    {
        return getAll().contains(handler);
    }

    @SuppressWarnings("unchecked")
    public <R extends Handler> boolean containsClass(Class<R> clazz)
    {
        List<R> list = (List<R>) handlers.getValuesUnsafe(clazz);
        if (list==null || list.size()==0) return false;
        return list.size()>0;
    }

    @Override
    public int hashCode() {
        return hash;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (!(obj instanceof AbstractHandlerClass<?>))
            return false;
        AbstractHandlerClass<?> other = (AbstractHandlerClass<?>) obj;
        return snapshot.equals(other.snapshot);
    }

}