/*
    * Copyright 2013 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.openehealth.ipf.commons.core.extend.config;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import groovy.lang.GroovySystem;
  import groovy.lang.MetaClassRegistry;
  import groovy.lang.MetaMethod;
  import org.codehaus.groovy.reflection.CachedClass;
  import org.codehaus.groovy.runtime.m12n.ExtensionModule;
  import org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl;
  import org.openehealth.ipf.commons.core.config.OrderedConfigurer;
  import org.openehealth.ipf.commons.core.config.Registry;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Configurer used to autowire all classes implementing the
   * {@link org.openehealth.ipf.commons.core.extend.config.DynamicExtension}
   * interface using Groovy 2.x Extension Modules
   *
   * @author Christian Ohr
   *
   * @see DynamicExtension
   * @see DynamicExtensionModule
   */
  public class DynamicExtensionConfigurer<R extends Registry> extends
          OrderedConfigurer<DynamicExtension, R> {
  
      private static final Logger LOG = LoggerFactory.getLogger(DynamicExtensionConfigurer.class);
  
      public DynamicExtensionConfigurer() {
          setOrder(2);
      }
  
      @Override
      public void configure(DynamicExtension extension) throws Exception {
          if (extension != null) {
              LOG.info("Registering new extension module {} defined in class {}",
                      extension.getModuleName(), extension.getClass());
              ExtensionModule module = DynamicExtensionModule.newModule(extension);
              addExtensionMethods(module);
          }
      }
  
      public static void addExtensionMethods(ExtensionModule module) {
          MetaClassRegistry metaClassRegistry = GroovySystem.getMetaClassRegistry();
          ((MetaClassRegistryImpl) metaClassRegistry).getModuleRegistry().addModule(module);
          Map<CachedClass, List<MetaMethod>> classMap = new HashMap<>();
          for (MetaMethod metaMethod : module.getMetaMethods()){
              if (classMap.containsKey(metaMethod.getDeclaringClass())){
                  classMap.get(metaMethod.getDeclaringClass()).add(metaMethod);
              } else {
                  List<MetaMethod> methodList = new ArrayList<>();
                  methodList.add(metaMethod);
                  classMap.put(metaMethod.getDeclaringClass(), methodList);
              }
              if (metaMethod.isStatic()){
                  ((MetaClassRegistryImpl)metaClassRegistry).getStaticMethods().add(metaMethod);
              } else {
                  ((MetaClassRegistryImpl)metaClassRegistry).getInstanceMethods().add(metaMethod);
              }
              LOG.debug("registered method: {}", metaMethod);
          }
          for (Map.Entry<CachedClass, List<MetaMethod>> cachedClassEntry : classMap.entrySet()) {
              cachedClassEntry.getKey().addNewMopMethods(cachedClassEntry.getValue());
          }
      }
  
      @Override
      public Collection<DynamicExtension> lookup(Registry registry) {
          return registry.beans(DynamicExtension.class).values();
      }
  
  }