/*
    * 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.configuration.internal;
  
  import org.codehaus.plexus.component.configurator.ComponentConfigurationException;
  import org.codehaus.plexus.component.configurator.ConfigurationListener;
  import org.codehaus.plexus.component.configurator.converters.composite.ObjectWithFieldsConverter;
  import org.codehaus.plexus.component.configurator.converters.lookup.ConverterLookup;
  import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluationException;
  import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluator;
  import org.codehaus.plexus.component.configurator.expression.TypeAwareExpressionEvaluator;
  import org.codehaus.plexus.configuration.PlexusConfiguration;
  import org.eclipse.sisu.plexus.CompositeBeanHelper;
  
  /**
   * An enhanced {@link ObjectWithFieldsConverter} leveraging the {@link TypeAwareExpressionEvaluator}
   * interface.
   */
  class EnhancedConfigurationConverter extends ObjectWithFieldsConverter {
      protected Object fromExpression(
              final PlexusConfiguration configuration, final ExpressionEvaluator evaluator, final Class<?> type)
              throws ComponentConfigurationException {
          String value = configuration.getValue();
          try {
              Object result = null;
              if (null != value && value.length() > 0) {
                  if (evaluator instanceof TypeAwareExpressionEvaluator) {
                      result = ((TypeAwareExpressionEvaluator) evaluator).evaluate(value, type);
                  } else {
                      result = evaluator.evaluate(value);
                  }
              }
              if (null == result && configuration.getChildCount() == 0) {
                  value = configuration.getAttribute("default-value");
                  if (null != value && value.length() > 0) {
                      if (evaluator instanceof TypeAwareExpressionEvaluator) {
                          result = ((TypeAwareExpressionEvaluator) evaluator).evaluate(value, type);
                      } else {
                          result = evaluator.evaluate(value);
                      }
                  }
              }
              failIfNotTypeCompatible(result, type, configuration);
              return result;
          } catch (final ExpressionEvaluationException e) {
              final String reason = String.format(
                      "Cannot evaluate expression '%s' for configuration entry '%s'", value, configuration.getName());
  
              throw new ComponentConfigurationException(configuration, reason, e);
          }
      }
  
      public Object fromConfiguration(
              final ConverterLookup lookup,
              final PlexusConfiguration configuration,
              final Class<?> type,
              final Class<?> enclosingType,
              final ClassLoader loader,
              final ExpressionEvaluator evaluator,
              final ConfigurationListener listener)
              throws ComponentConfigurationException {
          final Object value = fromExpression(configuration, evaluator, type);
          if (type.isInstance(value)) {
              return value;
          }
          try {
              final Class<?> implType = getClassForImplementationHint(type, configuration, loader);
              if (null == value && implType.isInterface() && configuration.getChildCount() == 0) {
                  return null; // nothing to process
              }
              final Object bean = instantiateObject(implType);
              if (null == value) {
                  processConfiguration(lookup, bean, loader, configuration, evaluator, listener);
              } else {
                  new CompositeBeanHelper(lookup, loader, evaluator, listener).setDefault(bean, value, configuration);
              }
              return bean;
          } catch (final ComponentConfigurationException e) {
              if (null == e.getFailedConfiguration()) {
                  e.setFailedConfiguration(configuration);
              }
              throw e;
          }
     }
 }