/*
    * Copyright 2013 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.properties.config.transfer.filesystem;
  
  import java.io.BufferedOutputStream;
  import java.io.File;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.OutputStream;
  import java.util.Properties;
  
  import org.apache.commons.io.FileUtils;
  import org.apache.commons.io.IOUtils;
  
  import de.smartics.properties.api.config.domain.Property;
  import de.smartics.properties.api.config.domain.PropertyLocation;
  import de.smartics.properties.api.config.domain.PropertyProvider;
  import de.smartics.properties.api.config.domain.key.ConfigurationKey;
  import de.smartics.properties.api.config.transfer.PropertySink;
  import de.smartics.properties.api.config.transfer.TransferException;
  import de.smartics.properties.spi.config.domain.key.ConfigurationKeyContextManager;
  import de.smartics.util.io.FileFunction;
  import de.smartics.util.lang.Arg;
  
  /**
   * Writes properties to a folder.
   */
  public final class FileSystemPropertySink implements PropertySink
  {
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    // --- members --------------------------------------------------------------
  
    /**
     * The name of the folder the properties definitions are written to.
     */
    private final File targetFolder;
  
    /**
     * The format the property definition files will be written to.
     */
    private final PropertiesFormat outputFormat;
  
    // ****************************** Initializer *******************************
  
    // ****************************** Constructors ******************************
  
    /**
     * Convenience constructor to create native properties files.
     *
     * @param targetFolder the name of the folder the properties definitions are
     *          written to.
     */
    public FileSystemPropertySink(final File targetFolder)
    {
      this(targetFolder, PropertiesFormat.NATIVE);
    }
  
    /**
     * Default constructor.
     *
     * @param targetFolder the name of the folder the properties definitions are
     *          written to.
     * @param outputFormat the format the property definition files will be
     *          written to.
     * @throws NullPointerException if {@code targetFolder} or
     *           {@code outputFormat} is <code>null</code>.
     */
    public FileSystemPropertySink(final File targetFolder,
        final PropertiesFormat outputFormat) throws NullPointerException
    {
      this.targetFolder = Arg.checkNotNull("targetFolder", targetFolder);
      this.outputFormat = Arg.checkNotNull("outputFormat", outputFormat);
    }
  
    // ****************************** Inner Classes *****************************
  
    // ********************************* Methods ********************************
  
    // --- init -----------------------------------------------------------------
  
    // --- get&set --------------------------------------------------------------
  
    // --- business -------------------------------------------------------------
 
   @Override
   public void clear() throws TransferException
   {
     try
     {
       FileUtils.cleanDirectory(targetFolder);
     }
     catch (final IOException e)
     {
       final ConfigurationKey<?> key =
           ConfigurationKeyContextManager.INSTANCE.context()
               .configurationKeyFactory().createDefaultKey();
       throw new TransferException(new TransferMessageBean(
           TransferFileCode.FAILED_TO_CLEAN, e, key, targetFolder));
     }
   }
 
   // TODO: Not yet transactional ...
   @Override
   public void write(final PropertyProvider provider) throws TransferException
   {
     final PropertyLocation location = provider.getSourceId();
     final ConfigurationKey<?> key = provider.getConfigurationKey();
 
     final Properties properties = createProperties(provider);
 
     writeProperties(key, location, properties);
   }
 
   private Properties createProperties(final PropertyProvider provider)
   {
     final Properties properties = new Properties();
     for (final Property property : provider.getProperties())
     {
       final String name = property.getName();
       final String value = property.getValue();
       properties.setProperty(name, value);
     }
     return properties;
   }
 
   private void writeProperties(final ConfigurationKey<?> key,
       final PropertyLocation location, final Properties properties)
   {
     // FIXME: translate location to a valid filename path
     final String path = location.getPath();
     final File propertiesFile = createFile(path);
     OutputStream out = null;
     try
     {
       final File parentDir = propertiesFile.getParentFile();
       FileFunction.provideDirectory(parentDir);
 
       out = new BufferedOutputStream(new FileOutputStream(propertiesFile));
 
       final String comments = key.toString();
       if (outputFormat == PropertiesFormat.XML)
       {
         properties.storeToXML(out, comments);
       }
       else
       {
         properties.store(out, comments);
       }
     }
     catch (final IOException e)
     {
       throw new TransferException(new TransferMessageBean(
           TransferFileCode.FAILED_TO_TRANSFER, e, key, targetFolder));
     }
     finally
     {
       IOUtils.closeQuietly(out);
     }
   }
 
   private File createFile(final String path)
   {
     final String adjustedPath = outputFormat.adjustPath(path);
     return new File(targetFolder, adjustedPath);
   }
 
   // TODO: Not yet transactional ...
   @Override
   public void write(final Iterable<PropertyProvider> providers)
     throws TransferException
   {
     for (final PropertyProvider provider : providers)
     {
       write(provider);
     }
   }
 
   /**
    * {@inheritDoc}
    * <p>
    * This is a no-op.
    * </p>
    */
   @Override
   public void close() throws TransferException
   {
   }
 
   // --- object basics --------------------------------------------------------
 
 }