/*
    * Copyright 2011, Aiki IT, FotoRenamer
    * <p/>
    * 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
    * <p/>
    * http://www.apache.org/licenses/LICENSE-2.0
    * <p/>
   * 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.aikiit.fotorenamer.image;
  
  import com.google.common.base.MoreObjects;
  import com.google.common.collect.Lists;
  import de.aikiit.fotorenamer.exception.InvalidDirectoryException;
  import de.aikiit.fotorenamer.exception.NoFilesFoundException;
  import de.aikiit.fotorenamer.gui.ProgressBar;
  import lombok.AccessLevel;
  import lombok.NoArgsConstructor;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  
  import javax.swing.*;
  import java.io.File;
  import java.io.IOException;
  import java.nio.file.Files;
  import java.util.List;
  import java.util.function.Consumer;
  import java.util.function.Predicate;
  
  import static de.aikiit.fotorenamer.util.LocalizationHelper.getBundleString;
  import static de.aikiit.fotorenamer.util.LocalizationHelper.getParameterizedBundleString;
  
  /**
   * Abstract class that handles image renaming and file handling.
   * <br>
   * The onliest abstract method generates a filename from a given file
   * and should be used to provide different strategies for image renaming.
   *
   * @author hirsch
   * @version 2011-03-22, 11:43
   */
  @NoArgsConstructor(access = AccessLevel.PRIVATE)
  abstract class AbstractImageRenamer implements Runnable {
  
      /**
       * The logger of this class.
       */
      private static final Logger LOG =
              LogManager.getLogger(AbstractImageRenamer.class);
  
      /**
       * The currently selected directory to work on.
       */
      private File currentDirectory = null;
      /**
       * The list of all relevant files in the current directory.
       */
      private List<File> imageList = null;
  
      /**
       * Progress bar for visual feedback of what's going on.
       */
      private ProgressBar progressBar = null;
      /**
       * Number of files that need processing.
       */
      private int amountOfFiles = 0;
  
      /**
       * Starts image processing on the given directory if it contains
       * relevant images. The strategy of renaming is defined by
       * subclasses implementation of @see #renameImage(File).
       *
       * @param directory Name of directory to work on.
       * @throws InvalidDirectoryException If there's a problem with
       *                                   the selected directory.
       * @throws NoFilesFoundException     If the selected directory is empty.
       */
      AbstractImageRenamer(final String directory)
              throws InvalidDirectoryException, NoFilesFoundException {
  
          if (directory == null) {
              throw new InvalidDirectoryException("null is not a directory");
          }
  
          this.currentDirectory = new File(directory);
          if (!this.currentDirectory.isDirectory()) {
              throw new InvalidDirectoryException(this.currentDirectory);
          }
  
          // retrieve relevant images in directory
          File[] files = this.currentDirectory.listFiles(
                  new ImageFilenameFilter());
         if (files == null || files.length == 0) {
             throw new NoFilesFoundException(this.currentDirectory);
         }
         this.imageList = Lists.newArrayList(files);
         this.amountOfFiles = this.imageList.size();
     }
 
     /**
      * Performs the actual/technical renaming.
      */
     private void renameFiles() {
         LOG.info("Starting to rename " + this.amountOfFiles + " files.");
 
         Consumer<File> consumer = file -> {
             // extract EXIF data and fetch target filename
             String targetFilename = renameImage(file);
 
             // update progress bar (names have a different length)
             progressBar.setProgress();
             progressBar.setText(file.getName());
             progressBar.updateUI();
 
             // TODO add second progressbar or counter for errors
             try {
                 Files.move(file.toPath(), new File(file.getParent(),
                         targetFilename).toPath());
             } catch (IOException e) {
                 LOG.error("Unable to rename '"
                         + file.getName() + "' to '"
                         + targetFilename + "'");
             }
         };
         Predicate<File> fileOnly = file -> file != null && file.isFile();
 
         this.imageList.parallelStream().filter(fileOnly).forEach(consumer);
     }
 
     /**
      * This method provides a strategy to rename image files when
      * iterating over a list of files.
      * It is called during image processing.
      *
      * @param imageFile Filename to renameFiles according to the subclass
      *                  implementation.
      * @return New filename for the given file.
      */
     protected abstract String renameImage(File imageFile);
 
     /**
      * Performs the renaming and updates the UI. All error handling is done in
      * other methods.
      *
      * @see #renameFiles()
      */
     public final void run() {
         String notification;
         this.progressBar = new ProgressBar(this.amountOfFiles);
 
         try {
             renameFiles();
         } catch (Exception e) {
             JOptionPane.showMessageDialog(null,
                     getParameterizedBundleString("fotorenamer.ui.rename.error", MoreObjects.firstNonNull(e.getMessage(), e.getClass().getSimpleName())),
                     getBundleString("fotorenamer.ui.rename.error.title"),
                     JOptionPane.ERROR_MESSAGE);
 
             this.amountOfFiles = 0;
         } finally {
             this.progressBar.dispose();
         }
 
         // show UI-notification
         switch (this.amountOfFiles) {
             case 0:
                 notification = getParameterizedBundleString("fotorenamer.ui.rename.success.message.none", this.currentDirectory.getName());
                 break;
             case 1:
                 notification = getParameterizedBundleString("fotorenamer.ui.rename.success.message.one", this.currentDirectory.getName());
                 break;
             default:
                 notification = getParameterizedBundleString("fotorenamer.ui.rename.success.message", this.amountOfFiles, this.currentDirectory.getName());
                 break;
         }
 
         notification += "\n\n";
         JOptionPane.showMessageDialog(null, notification, getBundleString("fotorenamer.ui.rename.success.title"),
                 JOptionPane.INFORMATION_MESSAGE);
     }
 }