/*
    * Copyright (C) 2008 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.plexus.metadata.ann;
  
  import java.lang.reflect.InvocationHandler;
  import java.lang.reflect.Method;
  import java.net.URL;
  import java.net.URLClassLoader;
  import java.util.Arrays;
  import java.util.Map;
  
  import org.objectweb.asm.Type;
  
  /**
   * @author Eugene Kuleshov
   */
  public class AnnInvocationHandler implements InvocationHandler {
      private final Ann ann;
      private final ClassLoader cl;
      private final Class<?> c;
  
      public AnnInvocationHandler(Ann ann, ClassLoader cl, Class<?> c) {
          this.ann = ann;
          this.cl = cl;
          this.c = c;
      }
  
      public Object invoke(Object proxy, Method m, Object[] args) throws Throwable {
          String name = m.getName();
  
          if ("toString".equals(name)) {
              StringBuilder sb = new StringBuilder(ann.getType());
              sb.append("[");
              String sep = "";
              for (Map.Entry<String, Object> e : ann.getParams().entrySet()) {
                  // TODO conversion for class, array, enum, and annotation types
                  sb.append(sep).append(e.getKey()).append("=").append(e.getValue());
                  sep = "; ";
              }
              sb.append("]");
              return sb.toString();
          }
  
          Object value = ann.getParams().get(name);
          if (value != null) {
              if (value instanceof Type) {
                  String className = ((Type) value).getClassName();
                  try {
                      return Class.forName(className, false, cl);
                  } catch (ClassNotFoundException ex) {
                      if (cl instanceof URLClassLoader) {
                          URL[] urls = ((URLClassLoader) cl).getURLs();
                          throw new RuntimeException(
                                  "Unable to load class " + className + " from " + Arrays.toString(urls), ex);
                      }
                      throw new RuntimeException("Unable to load class " + className + " from " + cl, ex);
                  }
              }
              // TODO conversion for class, array, enum, and annotation types
              return value;
          } else {
              Method am = c.getDeclaredMethod(m.getName(), m.getParameterTypes());
              return am.getDefaultValue();
          }
      }
  }