/*
    * 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.resolver.internal.ant.types;
  
  import org.apache.maven.model.Model;
  import org.apache.tools.ant.Project;
  import org.codehaus.plexus.interpolation.reflection.ReflectionValueExtractor;
  
  /**
   */
  class ModelValueExtractor {
  
      private static final String PREFIX_PROPERTIES = "properties.";
  
      private final String prefix;
  
      private final Project project;
  
      private final Model model;
  
      ModelValueExtractor(String prefix, Model model, Project project) {
          if (model == null) {
              throw new IllegalArgumentException("reference to Maven POM has not been specified");
          }
          if (project == null) {
              throw new IllegalArgumentException("reference to Ant project has not been specified");
          }
          if (prefix == null || prefix.length() <= 0) {
              prefix = "pom.";
          } else if (!prefix.endsWith(".")) {
              prefix += '.';
          }
          this.prefix = prefix;
          this.model = model;
          this.project = project;
      }
  
      public Project getProject() {
          return project;
      }
  
      public boolean isApplicable(String expression) {
          return expression.startsWith(prefix);
      }
  
      public Object getValue(String expression) {
          if (expression.startsWith(prefix)) {
              String expr = expression.substring(prefix.length());
              try {
                  if (expr.startsWith(PREFIX_PROPERTIES)) {
                      String key = expr.substring(PREFIX_PROPERTIES.length());
                      return model.getProperties().getProperty(key);
                  }
  
                  return ReflectionValueExtractor.evaluate(expr, model, false);
              } catch (Exception e) {
                  project.log("Could not retrieve '" + expression + "' from POM: " + e.getMessage(), e, Project.MSG_WARN);
                  return null;
              }
          } else {
              return null;
          }
      }
  }