/*
    * Copyright 2003 - 2013 The eFaps Team
    *
    * 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.
   *
   * Revision:        $Rev$
   * Last Changed:    $Date$
   * Last Changed By: $Author$
   */
  
  package org.efaps.update.schema.program.jasperreport;
  
  import groovy.lang.GroovyClassLoader;
  import groovyjarjarasm.asm.ClassVisitor;
  import groovyjarjarasm.asm.ClassWriter;
  
  import java.io.ByteArrayInputStream;
  import java.io.File;
  import java.io.Serializable;
  import java.io.UnsupportedEncodingException;
  import java.util.HashMap;
  import java.util.Map;
  
  import net.sf.jasperreports.compilers.JRGroovyCompiler;
  import net.sf.jasperreports.engine.DefaultJasperReportsContext;
  import net.sf.jasperreports.engine.JRException;
  import net.sf.jasperreports.engine.JasperReportsContext;
  import net.sf.jasperreports.engine.design.JRCompilationUnit;
  
  import org.codehaus.groovy.ast.ClassNode;
  import org.codehaus.groovy.control.CompilationFailedException;
  import org.codehaus.groovy.control.CompilationUnit;
  import org.codehaus.groovy.control.CompilerConfiguration;
  import org.codehaus.groovy.control.Phases;
  import org.efaps.admin.program.esjp.EFapsClassLoader;
  
  /**
   * Calculator compiler that uses groovy to compile expressions. It is used due
   * to the reason that the Classloader inside groovy must be set to use the
   * classpath from the maven targets.
   *
   * @author The eFaps Team
   * @version $Id$
   */
  public class JasperGroovyCompiler
      extends JRGroovyCompiler
  {
  
      /**
       *
       */
      public JasperGroovyCompiler()
      {
          this(DefaultJasperReportsContext.getInstance());
      }
  
      /**
       * @param _jasperReportsContext context to be used
       */
      public JasperGroovyCompiler(final JasperReportsContext _jasperReportsContext)
      {
          super(_jasperReportsContext);
      }
  
      /**
       * @see net.sf.jasperreports.compilers.JRGroovyCompiler#compileUnits(
       * net.sf.jasperreports.engine.design.JRCompilationUnit[],
       *      java.lang.String, java.io.File)
       * @param _units        compilation units for Jasper
       * @param _classpath    classpath
       * @param _tempDirFile  directory for the temporary files
       * @return null
       * @throws JRException on error during compilation
       */
      @Override
      protected String compileUnits(final JRCompilationUnit[] _units,
                                    final String _classpath,
                                    final File _tempDirFile)
          throws JRException
      {
          final CompilerConfiguration config = new CompilerConfiguration();
          config.setClasspath(_classpath);
          config.setVerbose(true);
          final GroovyClassLoader loader = new GroovyClassLoader(EFapsClassLoader.getInstance(), config, true);
          final CompilationUnit unit = new CompilationUnit(loader);
  
          for (int i = 0; i < _units.length; i++) {
              try {
                  unit.addSource("calculator_" + _units[i].getName(), new ByteArrayInputStream(_units[i].getSourceCode()
                                 .getBytes("UTF-8")));
             } catch (final UnsupportedEncodingException e) {
                 throw new JRException("Cannot add Source", e);
             }
         }
 
         final ClassCollector collector = new ClassCollector();
         unit.setClassgenCallback(collector);
         try {
             unit.compile(Phases.CLASS_GENERATION);
         } catch (final CompilationFailedException e) {
             throw new JRException("Errors were encountered when compiling report expressions class file:\n"
                             + e.toString());
         }
 
         if (collector.classes.size() < _units.length) {
             throw new JRException("Too few groovy class were generated.");
         } else if (collector.classCount > _units.length) {
             throw new JRException("Too many groovy classes were generated.\n"
                       + "Please make sure that you don't use Groovy features such as closures "
                       + "that are not supported by this report compiler.\n");
         }
 
         for (int i = 0; i < _units.length; i++) {
             _units[i].setCompileData((Serializable) collector.classes.get(_units[i].getName()));
         }
 
         return null;
     }
 
     /**
      * Class is a exact copy of the inner class of this parent class. This is
      * done due to private definition.
      */
     private static class ClassCollector extends CompilationUnit.ClassgenCallback
     {
         /**
          * Name to classes.
          */
         private final Map<String, Object> classes = new HashMap<String, Object>();
 
         /**
          * Count of classes.
          */
         private int classCount;
 
         /**
          * @see org.codehaus.groovy.control.CompilationUnit.ClassgenCallback#call(groovyjarjarasm.asm.ClassVisitor,
          * org.codehaus.groovy.ast.ClassNode)
          * @param _writer   writer
          * @param _node     node
          * @throws CompilationFailedException on error
          */
         @Override
         public void call(final ClassVisitor _writer,
                          final ClassNode _node)
         {
             this.classCount++;
             final String name = _node.getName();
             if (!this.classes.containsKey(name)) {
                 final byte[] bytes = ((ClassWriter) _writer).toByteArray();
                 this.classes.put(name, bytes);
             }
         }
     }
 }