/*
    * Copyright 2006-2012 smartics, Kronseder & Reiner GmbH
    *
    * 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 de.smartics.maven.plugin.buildmetadata.data;
  
  import java.lang.reflect.Field;
  import java.util.Map;
  
  import org.apache.commons.beanutils.ConvertUtils;
  import org.apache.maven.execution.MavenSession;
  import org.apache.maven.execution.RuntimeInformation;
  import org.apache.maven.plugin.MojoExecutionException;
  import org.apache.maven.project.MavenProject;
  
  import de.smartics.maven.plugin.buildmetadata.common.ScmInfo;
  
  /**
   * Configuration instance to create instances of {@link MetaDataProvider}.
   *
   * @author <a href="mailto:robert.reiner@smartics.de">Robert Reiner</a>
   * @version $Revision:591 $
   */
  public final class MetaDataProviderBuilder
  {
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    // --- members --------------------------------------------------------------
  
    /**
     * The Maven project.
     */
    private final MavenProject project;
  
    /**
     * The Maven session instance.
     */
    private final MavenSession session;
  
    /**
     * The runtime information of the Maven instance being executed for the build.
     */
    private final RuntimeInformation runtime;
  
    /**
     * The information for the SCM provided to the build plugin.
     */
    private final ScmInfo scmInfo;
  
    // ****************************** Initializer *******************************
  
    // ****************************** Constructors ******************************
  
    /**
     * Default constructor.
     *
     * @param project the Maven project.
     * @param session the Maven session instance.
     * @param runtime the runtime information of the Maven instance being executed
     *          for the build.
     * @param scmInfo the information for the SCM provided to the build plugin.
     */
    public MetaDataProviderBuilder(final MavenProject project,
        final MavenSession session, final RuntimeInformation runtime,
        final ScmInfo scmInfo)
    {
      this.project = project;
      this.session = session;
      this.runtime = runtime;
      this.scmInfo = scmInfo;
    }
  
    // ****************************** Inner Classes *****************************
  
    // ********************************* Methods ********************************
  
    // --- init -----------------------------------------------------------------
  
    // --- get&set --------------------------------------------------------------
  
    // --- business -------------------------------------------------------------
  
    /**
     * Creates a configured instance of the {@link MetaDataProvider} interface.
     *
     * @param config the configuration for the build.
    * @return the created instance.
    * @throws MojoExecutionException if the instance cannot be created.
    */
   public MetaDataProvider build(final Provider config)
     throws MojoExecutionException
   {
     final MetaDataProvider instance = create(config.getType());
     initialize(instance, config.getProperties());
     return instance;
   }
 
   @SuppressWarnings("unchecked")
   private MetaDataProvider create(final String metaDataProviderClassName)
     throws MojoExecutionException
   {
     try
     {
       final Class<? extends MetaDataProvider> metaDataProviderClass =
           (Class<? extends MetaDataProvider>) Class
               .forName(metaDataProviderClassName);
       final MetaDataProvider instance = metaDataProviderClass.newInstance();
       return instance;
     }
     catch (final Exception e)
     {
       throw new MojoExecutionException(
           "Cannot create instance for meta data provider class '"
               + metaDataProviderClassName + "'.", e);
     }
   }
 
   private void initialize(final MetaDataProvider instance,
       final Map<String, String> properties) throws MojoExecutionException
   {
     setNonNullProperty(instance, "project", project, MavenProject.class);
     setNonNullProperty(instance, "session", session, MavenSession.class);
     setNonNullProperty(instance, "runtime", runtime, RuntimeInformation.class);
     setNonNullProperty(instance, "scmInfo", scmInfo, ScmInfo.class);
 
     setProperties(instance, properties);
   }
 
   private void setNonNullProperty(final MetaDataProvider instance,
       final String propertyName, final Object propertyValue,
       final Class<?> propertyType) throws MojoExecutionException
   {
     if (propertyValue != null)
     {
       final Class<? extends MetaDataProvider> metaDataProviderClass =
           instance.getClass();
       try
       {
         final Field field = findField(metaDataProviderClass, propertyName);
         final Class<?> type = field.getType();
         if (type.isAssignableFrom(propertyType))
         {
           field.setAccessible(true);
           field.set(instance, propertyValue);
         }
       }
       catch (final NoSuchFieldException e)
       {
         // OK, no such field, so we do not set it.
       }
       catch (final Exception e)
       {
         throw new MojoExecutionException("Cannot set property '" + propertyName
                                          + "' for the instance of class '"
                                          + metaDataProviderClass.getName()
                                          + "'.", e);
       }
     }
   }
 
   private Field findField(final Class<?> type, final String propertyName)
     throws NoSuchFieldException
   {
     try
     {
       return type.getDeclaredField(propertyName);
     }
     catch (final NoSuchFieldException e)
     {
       if (type.getSuperclass().equals(Object.class))
       {
         throw e;
       }
     }
     return findField(type.getSuperclass(), propertyName);
   }
 
   private void setProperties(final MetaDataProvider instance,
       final Map<String, String> properties) throws MojoExecutionException
   {
     if (properties != null && !properties.isEmpty())
     {
       for (final Map.Entry<String, String> entry : properties.entrySet())
       {
         final String propertyName = entry.getKey();
         if (!Provider.RUN_AT_BUILD_POINT.equals(propertyName))
         {
           final String propertyValue = entry.getValue();
           setProperty(instance, propertyName, propertyValue);
         }
       }
     }
   }
 
   private void setProperty(final MetaDataProvider instance,
       final String propertyName, final String propertyValue)
     throws MojoExecutionException
   {
     final Class<? extends MetaDataProvider> metaDataProviderClass =
         instance.getClass();
 
     try
     {
       final Field field = findField(metaDataProviderClass, propertyName);
       field.setAccessible(true);
       final Class<?> type = field.getType();
       final Object typedPropertyValue =
           ConvertUtils.convert(propertyValue, type);
       field.set(instance, typedPropertyValue);
     }
     catch (final Exception e)
     {
       throw new MojoExecutionException(
           "Cannot set property '" + propertyName + "' to value '"
               + propertyValue + "' for the instance of class '"
               + metaDataProviderClass.getName() + "'.", e);
     }
   }
 
   // --- object basics --------------------------------------------------------
 
 }