/*
 * Copyright 2016 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.kie.dmn.core.ast;

import org.kie.dmn.api.core.DMNResult;
import org.kie.dmn.core.api.DMNExpressionEvaluator;
import org.kie.dmn.core.api.EvaluatorResult;
import org.kie.dmn.core.api.EvaluatorResult.ResultType;
import org.kie.dmn.api.core.event.DMNRuntimeEventManager;
import org.kie.dmn.feel.FEEL;
import org.kie.dmn.feel.lang.CompiledExpression;
import org.kie.dmn.feel.lang.ast.FunctionDefNode;
import org.kie.dmn.feel.lang.impl.CompiledExpressionImpl;

/**
 * An evaluator for DMN Literal Expressions
 */
public class DMNLiteralExpressionEvaluator
        implements DMNExpressionEvaluator {
    private CompiledExpression expression;

    public DMNLiteralExpressionEvaluator(CompiledExpression expression) {
        this.expression = expression;
    }

    public boolean isFunctionDefinition() {
        return ((CompiledExpressionImpl)expression).getExpression() instanceof FunctionDefNode;
    }

    public CompiledExpression getExpression() {
        return this.expression;
    }

    @Override
    public EvaluatorResult evaluate(DMNRuntimeEventManager dmrem, DMNResult result) {
        // in case an exception is thrown, the parent node will report it
        Object val = FEEL.newInstance().evaluate( expression, result.getContext().getAll() );
        return new EvaluatorResultImpl( val, ResultType.SUCCESS );
    }
}