/******************************************************************************
 * 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.internal;

import org.eclipse.sapphire.ElementHandle;
import org.eclipse.sapphire.Event;
import org.eclipse.sapphire.Listener;
import org.eclipse.sapphire.LocalizableText;
import org.eclipse.sapphire.Property;
import org.eclipse.sapphire.RequiredConstraintService;
import org.eclipse.sapphire.Text;
import org.eclipse.sapphire.Value;
import org.eclipse.sapphire.modeling.CapitalizationType;
import org.eclipse.sapphire.modeling.Status;
import org.eclipse.sapphire.services.ServiceCondition;
import org.eclipse.sapphire.services.ServiceContext;
import org.eclipse.sapphire.services.ValidationService;

/**
 * @author <a href="mailto:konstantin.komissarchik@oracle.com">Konstantin Komissarchik</a>
 */

public final class RequiredConstraintValidationService extends ValidationService
{
    @Text( "{0} must be specified" )
    private static LocalizableText message;
    
    static
    {
        LocalizableText.init( RequiredConstraintValidationService.class );
    }

    private Property property;
    private RequiredConstraintService requiredConstraintService;
    private Listener listener;
    
    @Override
    protected void initValidationService()
    {
        this.property = context( Property.class );
        this.requiredConstraintService = this.property.service( RequiredConstraintService.class );
        
        this.listener = new Listener()
        {
            @Override
            public void handle( final Event event )
            {
                refresh();
            }
        };
        
        this.requiredConstraintService.attach( this.listener );
    }

    @Override
    protected Status compute()
    {
        if( ! this.requiredConstraintService.required() || check() )
        {
            return Status.createOkStatus();
        }
        else
        {
            String msg = message.format( this.property.definition().getLabel( true, CapitalizationType.NO_CAPS, false ) );
            msg = this.property.definition().getLocalizationService().transform( msg, CapitalizationType.FIRST_WORD_ONLY, false );
            return Status.createErrorStatus( msg );
        }
    }
    
    protected boolean check()
    {
        if( this.property instanceof Value )
        {
            return ( ( (Value<?>) this.property ).text() != null );
        }
        else if( this.property instanceof ElementHandle )
        {
            return ( ( (ElementHandle<?>) this.property ).content() != null );
        }
        
        throw new IllegalStateException();
    }

    @Override
    public void dispose()
    {
        super.dispose();
        
        if( this.listener != null )
        {
            this.requiredConstraintService.detach( this.listener );
        }
    }

    public static final class Condition extends ServiceCondition
    {
        @Override
        public boolean applicable( final ServiceContext context )
        {
            final Property property = context.find( Property.class );
            return ( property != null && property.service( RequiredConstraintService.class ) != null );
        }
    }

}