package org.apache.samoa.streams.fs;

/*
 * #%L
 * SAMOA
 * %%
 * Copyright (C) 2014 - 2015 Apache Software Foundation
 * %%
 * 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.
 * #L%
 */

import java.io.File;
import java.io.FileInputStream;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

/**
 * Source for FileStream for local files
 * 
 * @author Casey
 */
public class LocalFileStreamSource implements FileStreamSource {
  /**
	 * 
	 */
  private static final long serialVersionUID = 3986511547525870698L;

  private transient InputStream fileStream;
  private List<String> filePaths;
  private int currentIndex;

  public LocalFileStreamSource() {
    this.currentIndex = -1;
  }

  public void init(String path, String ext) {
    this.filePaths = new ArrayList<>();
    File fileAtPath = new File(path);
    if (fileAtPath.isDirectory()) {
      File[] filesInDir = fileAtPath.listFiles(new FileExtensionFilter(ext));
      for (File aFilesInDir : filesInDir) {
        filePaths.add(aFilesInDir.getAbsolutePath());
      }
    }
    else {
      this.filePaths.add(path);
    }
    this.currentIndex = -1;
  }

  public void reset() throws IOException {
    this.currentIndex = -1;
    this.closeFileStream();
  }

  private void closeFileStream() {
    if (fileStream != null) {
      try {
        fileStream.close();
      } catch (IOException ioe) {
        ioe.printStackTrace();
      }
    }
  }

  public InputStream getNextInputStream() {
    this.closeFileStream();

    if (this.currentIndex >= (this.filePaths.size() - 1))
      return null;

    this.currentIndex++;
    String filePath = this.filePaths.get(currentIndex);

    File file = new File(filePath);
    try {
      fileStream = new FileInputStream(file);
    } catch (IOException ioe) {
      this.closeFileStream();
      throw new RuntimeException("Failed opening file:" + filePath, ioe);
    }

    return fileStream;
  }

  public InputStream getCurrentInputStream() {
    return fileStream;
  }

  protected int getFilePathListSize() {
    if (filePaths != null)
      return filePaths.size();
    return 0;
  }

  protected String getFilePathAt(int index) {
    if (filePaths != null && filePaths.size() > index)
      return filePaths.get(index);
    return null;
  }

  private class FileExtensionFilter implements FilenameFilter {
    private String extension;

    FileExtensionFilter(String ext) {
      extension = ext;
    }

    @Override
    public boolean accept(File dir, String name) {
      File f = new File(dir, name);
      if (extension == null)
        return f.isFile();
      else
        return f.isFile() && name.toLowerCase().endsWith("." + extension);
    }
  }
}