/*
    * Copyright (c) 2006-present the original author or authors.
    *
    * 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.codehaus.gmaven.adapter.impl;
  
  import java.util.Map;
  
  import javax.annotation.Nullable;
  
  import groovy.lang.Binding;
  import groovy.lang.GroovyClassLoader;
  import groovy.lang.GroovyCodeSource;
  import groovy.lang.GroovyShell;
  import org.codehaus.gmaven.adapter.ClassSource;
  import org.codehaus.gmaven.adapter.ResourceLoader;
  import org.codehaus.gmaven.adapter.ScriptExecutor;
  import org.codehaus.groovy.control.CompilerConfiguration;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import static com.google.common.base.Preconditions.checkNotNull;
  
  /**
   * Default {@link ScriptExecutor} implementation.
   *
   * @since 2.0
   */
  public class ScriptExecutorImpl
      implements ScriptExecutor
  {
    private final Logger log = LoggerFactory.getLogger(getClass());
  
    private final GroovyRuntimeImpl runtime;
  
    ScriptExecutorImpl(final GroovyRuntimeImpl runtime) {
      this.runtime = checkNotNull(runtime);
    }
  
    @Override
    @Nullable
    public Object execute(final ClassSource classSource,
                          final ClassLoader classLoader,
                          final ResourceLoader resourceLoader,
                          final Map<String, Object> context,
                          final @Nullable Map<String, Object> options)
        throws Exception
    {
      checkNotNull(classSource);
      checkNotNull(classLoader);
      checkNotNull(resourceLoader);
      checkNotNull(context);
  
      log.trace("Execute; class-source: {}, class-loader: {}, resource-loader: {}, context: {}",
          classSource, classLoader, resourceLoader, context);
  
      GroovyClassLoader gcl = runtime.createGroovyClassLoader(classLoader, resourceLoader);
  
      CompilerConfiguration cc = new CompilerConfiguration();
  
      // TODO: How, if at all, do we want to expose compiler configuration customizations?
  
      Binding binding = runtime.createBinding(context);
      GroovyShell shell = new GroovyShell(gcl, binding, cc);
  
      if (options != null) {
        configureOptions(shell, options);
      }
  
      GroovyCodeSource codeSource = runtime.createGroovyCodeSource(classSource);
      try {
        return shell.evaluate(codeSource);
      }
      finally {
        gcl.clearCache();
      }
    }
  
    private void configureOptions(final GroovyShell shell, final Map<String, Object> options) {
      // TODO
    }
  }