/*
 ***************************************************************************************
 *  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.epl.agg.factory;

import com.espertech.esper.client.EventType;
import com.espertech.esper.client.hook.AggregationFunctionFactory;
import com.espertech.esper.epl.agg.access.AggregationAccessor;
import com.espertech.esper.epl.agg.access.AggregationAgent;
import com.espertech.esper.epl.agg.access.AggregationStateKey;
import com.espertech.esper.epl.agg.aggregator.AggregationMethod;
import com.espertech.esper.epl.agg.service.AggregationMethodFactory;
import com.espertech.esper.epl.agg.service.AggregationStateFactory;
import com.espertech.esper.epl.agg.service.AggregationValidationUtil;
import com.espertech.esper.epl.expression.baseagg.ExprAggregateNodeBase;
import com.espertech.esper.epl.expression.core.ExprEvaluator;
import com.espertech.esper.epl.expression.core.ExprValidationException;
import com.espertech.esper.epl.expression.methodagg.ExprMethodAggUtil;
import com.espertech.esper.epl.expression.methodagg.ExprPlugInAggNode;

public class AggregationMethodFactoryPlugIn implements AggregationMethodFactory {
    protected final ExprPlugInAggNode parent;
    protected final AggregationFunctionFactory aggregationFunctionFactory;
    protected final Class aggregatedValueType;

    public AggregationMethodFactoryPlugIn(ExprPlugInAggNode parent, AggregationFunctionFactory aggregationFunctionFactory, Class aggregatedValueType) {
        this.parent = parent;
        this.aggregationFunctionFactory = aggregationFunctionFactory;
        this.aggregatedValueType = aggregatedValueType;
    }

    public Class getResultType() {
        return aggregationFunctionFactory.getValueType();
    }

    public boolean isAccessAggregation() {
        return false;
    }

    public AggregationStateKey getAggregationStateKey(boolean isMatchRecognize) {
        throw new IllegalStateException("Not an access aggregation function");
    }

    public AggregationStateFactory getAggregationStateFactory(boolean isMatchRecognize) {
        throw new IllegalStateException("Not an access aggregation function");
    }

    public AggregationAccessor getAccessor() {
        throw new IllegalStateException("Not an access aggregation function");
    }

    public AggregationMethod make() {

        AggregationMethod method = aggregationFunctionFactory.newAggregator();
        if (!parent.isDistinct()) {
            return method;
        }
        return AggregationMethodFactoryUtil.makeDistinctAggregator(method, false);
    }

    public ExprAggregateNodeBase getAggregationExpression() {
        return parent;
    }

    public void validateIntoTableCompatible(AggregationMethodFactory intoTableAgg) throws ExprValidationException {
        AggregationValidationUtil.validateAggregationType(this, intoTableAgg);
    }

    public AggregationAgent getAggregationStateAgent() {
        return null;
    }

    public ExprEvaluator getMethodAggregationEvaluator(boolean join, EventType[] typesPerStream) throws ExprValidationException {
        return ExprMethodAggUtil.getDefaultEvaluator(parent.getPositionalParams(), join, typesPerStream);
    }
}