/*
 * Copyright 2010 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.jbpm.process.builder.dialect.java;

import java.util.HashMap;
import java.util.Map;
import java.util.Set;

import org.drools.compiler.compiler.AnalysisResult;
import org.drools.compiler.compiler.BoundIdentifiers;
import org.drools.compiler.compiler.ReturnValueDescr;
import org.drools.compiler.rule.builder.PackageBuildContext;
import org.drools.mvel.java.JavaDialect;
import org.jbpm.process.builder.ProcessBuildContext;
import org.jbpm.process.builder.ReturnValueEvaluatorBuilder;
import org.jbpm.process.core.ContextResolver;
import org.jbpm.process.instance.impl.ReturnValueConstraintEvaluator;

public class JavaReturnValueEvaluatorBuilder extends AbstractJavaProcessBuilder
        implements
        ReturnValueEvaluatorBuilder {

    /*
     * (non-Javadoc)
     * 
     * @see org.drools.semantics.java.builder.ConsequenceBuilder#buildConsequence(org.drools.semantics.java.builder.BuildContext, org.drools.semantics.java.builder.BuildUtils, RuleDescr)
     */
    public void build(final PackageBuildContext context,
            final ReturnValueConstraintEvaluator constraintNode,
            final ReturnValueDescr descr,
            final ContextResolver contextResolver) {

        final String className = getClassName(context);

        AnalysisResult analysis = getAnalysis(context, descr);

        if (analysis == null) {
            // not possible to get the analysis results
            return;
        }

        buildReturnValueEvaluator(context,
                constraintNode,
                descr,
                contextResolver,
                className,
                analysis);
    }

    protected String getClassName(PackageBuildContext context) {
        return "returnValueEvaluator" + context.getNextId();
    }

    protected AnalysisResult getAnalysis(final PackageBuildContext context,
            final ReturnValueDescr descr) {

        JavaDialect dialect = (JavaDialect) context.getDialect("java");

        Map<String, Class<?>> variables = new HashMap<String, Class<?>>();
        BoundIdentifiers boundIdentifiers = new BoundIdentifiers(variables, context);
        AnalysisResult analysis = dialect.analyzeBlock(context,
                descr,
                descr.getText(),
                boundIdentifiers);
        return analysis;
    }

    protected void buildReturnValueEvaluator(final PackageBuildContext context,
            final ReturnValueConstraintEvaluator constraintNode,
            final ReturnValueDescr descr,
            final ContextResolver contextResolver,
            String className,
            AnalysisResult analysis) {

        Set<String> identifiers = analysis.getBoundIdentifiers().getGlobals().keySet();

        final Map map = createVariableContext(className,
                descr.getText(),
                (ProcessBuildContext) context,
                (String[]) identifiers.toArray(new String[identifiers.size()]),
                analysis.getNotBoundedIdentifiers(),
                contextResolver);

        map.put("text", descr.getText());

        generateTemplates("returnValueEvaluatorMethod",
                "returnValueEvaluatorInvoker",
                (ProcessBuildContext) context,
                className,
                map,
                constraintNode,
                descr);

        collectTypes("JavaReturnValue", analysis, (ProcessBuildContext) context);
    }
}
