/*

  * 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.resource.filesystem.heap;

 import java.io.File;

 import java.io.IOException;

 import java.net.MalformedURLException;

 import java.net.URL;

 import java.util.ArrayList;

 import java.util.Iterator;

 import java.util.List;

 import org.apache.commons.io.FileUtils;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 import de.smartics.properties.resource.domain.ArtifactId;

 import de.smartics.properties.resource.domain.ArtifactRef;

 import de.smartics.properties.resource.domain.ClassPathEnvironment;

 import de.smartics.properties.resource.heap.HeapException;

 import de.smartics.properties.resource.heap.ResourceHeap;

 import de.smartics.util.lang.Arg;

 /**

  * Provides an implementation of {@link ResourceHeap} based on a file system.

  */

 public final class FileSystemResourceHeap implements ResourceHeap

 {

   // ********************************* Fields *********************************

   // --- constants ------------------------------------------------------------

   /**

    * Reference to the logger for this class.

    */

   private static final Logger LOG = LoggerFactory

       .getLogger(FileSystemResourceHeap.class);

   // --- members --------------------------------------------------------------

   /**

    * The list of root folders to traverse.

    */

   private final List<File> rootFolders = new ArrayList<File>();

   /**

    * The artifact identifier to use for properties files encountered.

    */

   private ArtifactId defaultArtifactId = new ArtifactId.Builder()

       .withGroupId("unknown-group").withName("unknown")

       .withVersion("unknown-version").withArchiveType("properties").build();

   // ****************************** Initializer *******************************

   // ****************************** Constructors ******************************

   // ****************************** Inner Classes *****************************

   // ********************************* Methods ********************************

   // --- init -----------------------------------------------------------------

   // --- get&set --------------------------------------------------------------

   /**

    * Returns the artifact identifier to use for properties files encountered.

    *

    * @return the artifact identifier to use for properties files encountered.

    */

   public ArtifactId getDefaultArtifactId()

   {

     return defaultArtifactId;

   }

   /**

    * Sets the artifact identifier to use for properties files encountered.

    *

    * @param defaultArtifactId the artifact identifier to use for properties

    *          files encountered.

    */

   public void setDefaultArtifactId(final ArtifactId defaultArtifactId)

   {

     this.defaultArtifactId = defaultArtifactId;

   }

   // --- business -------------------------------------------------------------

   /**

    * Adds a root folder to check for property resources.

    *

    * @param rootFolder the folder to add as a root to check for property

    *          resources.

    * @throws NullPointerException if {@code rootFolder} is <code>null</code>.

    * @throws IllegalArgumentException if {@code rootFolder} is not a directory.

    */

   public void addRootFolder(final File rootFolder) throws NullPointerException,

     IllegalArgumentException

   {

     Arg.checkNotNull("rootFolder", rootFolder);

     if (!rootFolder.isDirectory())

     {

       throw new IllegalArgumentException(String.format("'%s' is not a folder.",

           rootFolder.getAbsolutePath()));

     }

     rootFolders.add(rootFolder);

   }

   @Override

   @SuppressWarnings("unchecked")

   public ClassPathEnvironment resolve() throws HeapException

   {

     final ClassPathEnvironment env = new ClassPathEnvironment();

     final String[] extensions =

         new String[] { "jar", "ear", "war", "sar", "properties" };

     for (final File rootFolder : rootFolders)

     {

       boolean containsPropertiesFile = false;

       for (final Iterator<File> files =

           FileUtils.iterateFiles(rootFolder, extensions, true); files.hasNext();)

       {

         final File file = files.next();

         if (!isPropertiesFile(file))

         {

           final ArtifactRef archiveArtifactRef = createArchiveArtifactRef(file);

           if (archiveArtifactRef != null)

           {

             env.addArchiveArtifactRef(archiveArtifactRef);

           }

         }

         else if (!containsPropertiesFile)

         {

           containsPropertiesFile = true;

           final ArtifactRef rootRef = createFolderRef(rootFolder);

           env.addAnyArtifactRef(rootRef);

         }

       }

     }

     return env;

   }

   private ArtifactRef createFolderRef(final File file)

   {

     try

     {

       return new ArtifactRef(defaultArtifactId, file.toURI().toURL());

     }

     catch (final MalformedURLException e)

     {

       LOG.debug("Cannot transform file '{}' to an URL: "

                 + e.getLocalizedMessage());

       return null;

     }

   }

   private boolean isPropertiesFile(final File file)

   {

     final String name = file.getName();

     final boolean isPropertiesFile = name.endsWith(".properties");

     return isPropertiesFile;

   }

   private static ArtifactRef createArchiveArtifactRef(final File archiveFile)

     throws HeapException

   {

     try

     {

       final ArtifactId id = readArtifactId(archiveFile);

       final URL url = archiveFile.toURI().toURL();

       if (id != null)

       {

         final ArtifactRef ref = new ArtifactRef(id, url);

         return ref;

       }

     }

     catch (final MalformedURLException e)

     {

       LOG.debug("Cannot transform file '{}' to an URL: "

                 + e.getLocalizedMessage());

     }

     catch (final IOException e)

     {

       throw new HeapException(new FileMessageBean(

           FileSystemResourceCode.FAILED_TO_READ_ARCHIVE_FILE, e, archiveFile));

     }

     return null;

   }

   private static ArtifactId readArtifactId(final File archiveFile)

     throws NullPointerException, IOException

   {

     final ArtifactIdGrabber grabber = ArtifactIdGrabber.createLazy(archiveFile);

     if (grabber.isDefinitionArchive())

     {

       final ArtifactId id = grabber.getArtifactId();

       return id;

     }

     return null;

   }

   // --- object basics --------------------------------------------------------

 }