/******************************************************************************
 * Copyright (c) 2016 Oracle
 * 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:
 *    Konstantin Komissarchik - initial implementation and ongoing maintenance
 ******************************************************************************/

package org.eclipse.sapphire;

import org.eclipse.sapphire.services.Service;

/**
 * Converts an object to the specified type by delegating to available ConversionService and UniversalConversionService 
 * implementations. If object is null or is already of desired type, the object is returned unchanged.
 * 
 * <p>An implementation of this service is provided with Sapphire. This service is not intended to
 * be implemented by adopters.</p>
 * 
 * @author <a href="mailto:konstantin.komissarchik@oracle.com">Konstantin Komissarchik</a>
 */

public final class MasterConversionService extends Service
{
    /**
     * Converts an object to the specified type.
     * 
     * @param object the object to convert
     * @param type the desired type of a converted object
     * @return the converted object or null if could not be converted
     * @throws IllegalArgumentException if type is null
     */
    
    @SuppressWarnings( { "unchecked", "rawtypes" } )
    
    public <T> T convert( final Object object, final Class<T> type )
    {
        if( type == null )
        {
            throw new IllegalArgumentException();
        }
        
        if( object == null )
        {
            return null;
        }
        
        if( type.isInstance( object ) )
        {
            return type.cast( object );
        }
        
        T result = null;
        
        try
        {
            for( final ConversionService service : services( ConversionService.class ) )
            {
                if( service.source().isAssignableFrom( object.getClass() ) && type.isAssignableFrom( service.target() ) )
                {
                    try
                    {
                        result = type.cast( service.convert( object ) );
                    }
                    catch( ConversionException e )
                    {
                        throw e;
                    }
                    catch( Exception e )
                    {
                        Sapphire.service( LoggingService.class ).log( e );
                    }
                    
                    if( result != null )
                    {
                        break;
                    }
                }
            }
            
            if( result == null )
            {
                for( final UniversalConversionService service : services( UniversalConversionService.class ) )
                {
                    try
                    {
                        result = type.cast( service.convert( object, type ) );
                    }
                    catch( Exception e )
                    {
                        Sapphire.service( LoggingService.class ).log( e );
                    }
                    
                    if( result != null )
                    {
                        break;
                    }
                }
            }
        }
        catch( ConversionException e )
        {
            // If this exception is thrown, the conversion process should abort and null returned.
        }
            
        return result;
    }
    
}