/*
 ***************************************************************************************
 *  Copyright (C) 2006 EsperTech, Inc. All rights reserved.                            *
 *  http://www.espertech.com/esper                                                     *
 *  http://www.espertech.com                                                           *
 *  ---------------------------------------------------------------------------------- *
 *  The software in this package is published under the terms of the GPL license       *
 *  a copy of which has been included with this distribution in the license.txt file.  *
 ***************************************************************************************
 */
package com.espertech.esper.event.vaevent;

import com.espertech.esper.client.EventBean;
import com.espertech.esper.client.EventPropertyGetter;
import com.espertech.esper.util.NullableObject;

/**
 * Strategy for merging update properties using all declared property's values.
 */
public class UpdateStrategyDeclared extends UpdateStrategyBase {
    /**
     * Ctor.
     *
     * @param spec the specification
     */
    public UpdateStrategyDeclared(RevisionSpec spec) {
        super(spec);
    }

    public void handleUpdate(boolean isBaseEventType,
                             RevisionStateMerge revisionState,
                             RevisionEventBeanMerge revisionEvent,
                             RevisionTypeDesc typesDesc) {
        EventBean underlyingEvent = revisionEvent.getUnderlyingFullOrDelta();

        // Previously-seen full event
        if (isBaseEventType) {
            // If delta types don't add properties, simply set the overlay to null
            NullableObject<Object>[] changeSetValues;
            if (!spec.isDeltaTypesAddProperties()) {
                changeSetValues = null;
            } else {
                // If delta types do add properties, set a new overlay
                changeSetValues = revisionState.getOverlays();
                if (changeSetValues == null) {
                    changeSetValues = new NullableObject[spec.getChangesetPropertyNames().length];
                } else {
                    changeSetValues = arrayCopy(changeSetValues);   // preserve the last revisions
                }

                // reset properties not contributed by any delta, leaving all delta-contributed properties in place
                boolean[] changesetPropertyDeltaContributed = spec.getChangesetPropertyDeltaContributed();
                for (int i = 0; i < changesetPropertyDeltaContributed.length; i++) {
                    // if contributed then leave the value, else override
                    if (!changesetPropertyDeltaContributed[i]) {
                        changeSetValues[i] = null;
                    }
                }
            }
            revisionState.setOverlays(changeSetValues);
            revisionState.setBaseEventUnderlying(underlyingEvent);
        } else {
            // Delta event to existing full event merge
            NullableObject<Object>[] changeSetValues = revisionState.getOverlays();

            if (changeSetValues == null) {
                changeSetValues = new NullableObject[spec.getChangesetPropertyNames().length];
            } else {
                changeSetValues = arrayCopy(changeSetValues);   // preserve the last revisions
            }

            // apply all properties of the delta event
            int[] indexes = typesDesc.getChangesetPropertyIndex();
            EventPropertyGetter[] getters = typesDesc.getChangesetPropertyGetters();
            for (int i = 0; i < indexes.length; i++) {
                int index = indexes[i];
                Object value = getters[i].get(underlyingEvent);
                changeSetValues[index] = new NullableObject<Object>(value);
            }

            revisionState.setOverlays(changeSetValues);
        }
    }
}