/*
    * $Id: DefinitionModel.java 1305937 2012-03-27 18:15:15Z nlebas $
    *
    * 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.tiles.template;
  
  import java.io.IOException;
  import java.util.Deque;
  
  import org.apache.tiles.Attribute;
  import org.apache.tiles.Definition;
  import org.apache.tiles.access.TilesAccess;
  import org.apache.tiles.autotag.core.runtime.ModelBody;
  import org.apache.tiles.autotag.core.runtime.annotation.Parameter;
  import org.apache.tiles.mgmt.MutableTilesContainer;
  import org.apache.tiles.request.Request;
  
  /**
   * <p>
   * <strong>Create a definition at runtime. </strong>
   * </p>
   * <p>
   * Create a new definition at runtime. Newly created definition will be
   * available across the entire request.
   * </p>
   *
   * @version $Rev: 1305937 $ $Date: 2012-03-28 05:15:15 +1100 (Wed, 28 Mar 2012) $
   * @since 2.2.0
   */
  public class DefinitionModel {
  
      /**
       * Executes the operation.
       *
       * @param name The name of the definition to create. If not specified, an
       * anonymous definition will be created.
       * @param template The template of this definition.
       * @param role A comma-separated list of roles. If present, the definition
       * will be rendered only if the current user belongs to one of the roles.
       * @param extendsParam The definition name that this definition extends.
       * @param preparer The preparer to use to invoke before the definition is
       * rendered.
       * @param request The request.
       * @param modelBody The body.
       * @throws IOException If something goes wrong.
       * @since 2.2.0
       */
      public void execute(String name, String template, String role,
              @Parameter(name = "extends") String extendsParam, String preparer,
              Request request, ModelBody modelBody) throws IOException {
          Deque<Object> composeStack = ComposeStackUtil
                  .getComposeStack(request);
          Definition definition = createDefinition(name, template, role,
                  extendsParam, preparer);
          composeStack.push(definition);
          modelBody.evaluateWithoutWriting();
          MutableTilesContainer container = (MutableTilesContainer) TilesAccess
                  .getCurrentContainer(request);
          definition = (Definition) composeStack.pop();
          registerDefinition(definition, container, composeStack, request);
      }
  
      /**
       * Creates the definition to store.
       *
       * @param name The name of the definition to create. If not specified, an
       * anonymous definition will be created.
       * @param template The template of this definition.
       * @param role A comma-separated list of roles. If present, the definition
       * will be rendered only if the current user belongs to one of the roles.
       * @param extendsParam The definition name that this definition extends.
       * @param preparer The preparer to use to invoke before the definition is
       * rendered.
       * @return The created definition.
       */
      private Definition createDefinition(String name, String template,
              String role, String extendsParam, String preparer) {
          Definition definition = new Definition();
          definition.setName(name);
          Attribute templateAttribute = Attribute
                  .createTemplateAttribute(template);
          templateAttribute.setRole(role);
         definition.setTemplateAttribute(templateAttribute);
         definition.setExtends(extendsParam);
         definition.setPreparer(preparer);
         return definition;
     }
 
     /**
      * Registers a definition in the container.
      *
      * @param definition The definition to register.
      * @param container The container into which the definition will be
      * registered.
      * @param composeStack The compose stack,
      * @param request The request.
      */
     private void registerDefinition(Definition definition,
             MutableTilesContainer container, Deque<Object> composeStack,
             Request request) {
         container.register(definition, request);
 
         if (composeStack.isEmpty()) {
             return;
         }
 
         Object obj = composeStack.peek();
         if (obj instanceof Attribute) {
             Attribute attribute = (Attribute) obj;
             attribute.setValue(definition.getName());
             if (attribute.getRenderer() == null) {
                 attribute.setRenderer("definition");
             }
         }
     }
 }