/*
    * 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.maven.shared.scriptinterpreter;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.PrintStream;
  import java.util.List;
  import java.util.Map;
  
  import bsh.Capabilities;
  import bsh.EvalError;
  import bsh.Interpreter;
  import bsh.TargetError;
  
  /**
   * Provides a facade to evaluate BeanShell scripts.
   *
   * @author Benjamin Bentmann
   */
  class BeanShellScriptInterpreter implements ScriptInterpreter {
  
      /** {@inheritDoc} */
      @Override
      public Object evaluateScript(
              String script,
              List<String> classPath,
              Map<String, ? extends Object> globalVariables,
              PrintStream scriptOutput)
              throws ScriptEvaluationException {
          PrintStream origOut = System.out;
          PrintStream origErr = System.err;
  
          try {
              Interpreter engine = new Interpreter();
  
              if (scriptOutput != null) {
                  System.setErr(scriptOutput);
                  System.setOut(scriptOutput);
                  engine.setErr(scriptOutput);
                  engine.setOut(scriptOutput);
              }
  
              if (!Capabilities.haveAccessibility()) {
                  try {
                      Capabilities.setAccessibility(true);
                  } catch (Exception e) {
                      if (scriptOutput != null) {
                          e.printStackTrace(scriptOutput);
                      }
                  }
              }
  
              if (classPath != null && !classPath.isEmpty()) {
                  for (String path : classPath) {
                      try {
                          engine.getClassManager()
                                  .addClassPath(new File(path).toURI().toURL());
                      } catch (IOException e) {
                          throw new RuntimeException("bad class path: " + path, e);
                      }
                  }
              }
  
              if (globalVariables != null) {
                  for (Map.Entry<String, ?> entry : globalVariables.entrySet()) {
                      try {
                          engine.set(entry.getKey(), entry.getValue());
                      } catch (EvalError e) {
                          throw new RuntimeException(e);
                      }
                  }
              }
  
              try {
                  return engine.eval(script);
              } catch (TargetError e) {
                  throw new ScriptEvaluationException(e.getTarget());
              } catch (ThreadDeath e) {
                  throw e;
              } catch (Throwable e) {
                  throw new ScriptEvaluationException(e);
              }
         } finally {
             System.setErr(origErr);
             System.setOut(origOut);
         }
     }
 }