/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.drill.exec.expr.fn;

import java.io.StringWriter;
import java.util.Map;

import org.codehaus.janino.Java;
import org.codehaus.janino.Java.ClassDeclaration;
import org.codehaus.janino.Java.MethodDeclarator;
import org.codehaus.janino.util.Traverser;

import com.google.common.collect.Maps;


public class MethodGrabbingVisitor{
  static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(MethodGrabbingVisitor.class);

  private Class<?> c;
  private Map<String, String> methods = Maps.newHashMap();
  private ClassFinder classFinder = new ClassFinder();
  private boolean captureMethods = false;

  private MethodGrabbingVisitor(Class<?> c) {
    super();
    this.c = c;
  }

  public class ClassFinder extends Traverser{

    @Override
    public void traverseClassDeclaration(ClassDeclaration cd) {
//      logger.debug("Traversing: {}", cd.getClassName());
      boolean prevCapture = captureMethods;
      captureMethods = c.getName().equals(cd.getClassName());
      super.traverseClassDeclaration(cd);
      captureMethods = prevCapture;
    }

    @Override
    public void traverseMethodDeclarator(MethodDeclarator md) {
//      logger.debug(c.getName() + ": Found {}, include {}", md.name, captureMethods);

      if(captureMethods){
        StringWriter writer = new StringWriter();
        ModifiedUnparseVisitor v = new ModifiedUnparseVisitor(writer);
//        UnparseVisitor v = new UnparseVisitor(writer);

        md.accept(v);
        v.close();
        writer.flush();
        methods.put(md.name, writer.getBuffer().toString());
      }
    }
  }


  public static Map<String, String> getMethods(Java.CompilationUnit cu, Class<?> c){
    MethodGrabbingVisitor visitor = new MethodGrabbingVisitor(c);
    cu.getPackageMemberTypeDeclarations()[0].accept(visitor.classFinder.comprehensiveVisitor());
    return visitor.methods;
  }

}
