package filesystem;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.io.*;
import java.nio.channels.*;

/**
 * Utilities class to allow various commonly used file operations.
 * 
 * @author ablackbu
 * @version 11-27-10
 */
public class FSUtil {

	// singelton
	private static FSUtil instance;

	// true if the operation is copy
	private boolean isCopy;

	// the clipboard for copy/cut/paste
	private File clipBoard;

	private FSUtil() {
		isCopy = false;
		clipBoard = null;
	}

	/**
	 * Public access for the singleton.
	 * 
	 * @return the singleton object.
	 */
	public static FSUtil getInstance() {
		if (instance == null) {
			instance = new FSUtil();
		}
		return instance;
	}

	/**
	 * Renames the given file to the given name.
	 * 
	 * @param file
	 *            the file which will be renamed
	 * @param name
	 *            the new name
	 * @return true if successful else false
	 */
	public boolean rename(File file, String name) {
		String pathToFile = file.getAbsolutePath();
		String oldFileName = file.getName();
		int endingIndex = pathToFile.length() - (oldFileName.length());
		pathToFile = pathToFile.substring(0, endingIndex);
		
		// Destination directory
		File dir = new File(pathToFile);

		// Move file to new directory
		return file.renameTo(new File(dir, name));
	}

	/**
	 * Sets the current file onto the clipboard for pasting. Will copy on paste.
	 * 
	 * @param file
	 *            file to copy
	 */
	public void copy(File file) {
		isCopy = true;
		clipBoard = file;
	}

	/**
	 * Sets the current file onto the clipboard for pasting. Will move on paste.
	 * 
	 * @param file
	 *            file to cut
	 */
	public void cut(File file) {
		isCopy = false;
		clipBoard = file;
	}

	/**
	 * Moves or Copies the clipboard to the given directory.
	 * 
	 * @param file
	 *            directory to paste into
	 * @return true if successful else false
	 */
	public boolean paste(File file) {
		
		if (clipBoard == null)
			return false;
		
		String fullFileName = fileNameSetter(file);
		
		if (isCopy) { // make copy
			try {
				File f = new File(file.getPath() + "/"
						+ fullFileName);
				
				copyFile(clipBoard, f);
			} catch (IOException e) {
				e.printStackTrace();
			}
			return true;
		} else { // move
			return move(clipBoard, file.getAbsolutePath());
		}
	}

	/**
	 * Mutator method for the clipboard.
	 * 
	 * @param f
	 *            file to set the clipboard to.
	 */
	public void setClipboard(File f) {
		clipBoard = f;
	}

	/**
	 * Method to check if the clipboard is set.
	 * 
	 * @return true if clipboard is null
	 */
	public boolean isClipBoardEmpty() {
		if (clipBoard == null)
			return true;
		return false;
	}

	/**
	 * Copy backend which does the actual copying.
	 * 
	 * @param in
	 *            input file
	 * @param out
	 *            output file
	 * @throws IOException
	 */
	private void copyFile(File in, File out) throws IOException {
		FileChannel inChannel = new FileInputStream(in).getChannel();
		FileChannel outChannel = new FileOutputStream(out).getChannel();
		try {
			inChannel.transferTo(0, inChannel.size(), outChannel);
		} catch (IOException e) {
			e.printStackTrace();
			throw e;
		} finally {
			if (inChannel != null)
				inChannel.close();
			if (outChannel != null)
				outChannel.close();
		}
	}

	/**
	 * Delete the file to the recycle bin/trash based on OS
	 * 
	 * note currently on windows this is does not move to the recycle bin
	 * because the recycle bin does not have a specific area on the FS.
	 * 
	 * @param the
	 *            file to be "deleted"
	 * @return true if successful, else false
	 */
	public boolean delete(File file) {
		String fileName = file.getName();
		if (FSInfo.getInstance().getOS().equals("Linux")) {
			try {
				BufferedWriter out = new BufferedWriter(
						new FileWriter(FSInfo.getInstance().getHomeDir()
								.toString()
								+ "/.local/share/Trash/info/"
								+ fileName
								+ ".trashinfo"));

				Calendar calendar = new GregorianCalendar();
				int year = calendar.get(Calendar.YEAR);
				int month = calendar.get(Calendar.MONTH);
				int day = calendar.get(Calendar.DAY_OF_MONTH);
				int hour = calendar.get(Calendar.HOUR);
				if (calendar.get(Calendar.AM_PM) == Calendar.PM)
					hour += 12;
				int minute = calendar.get(Calendar.MINUTE);
				int second = calendar.get(Calendar.SECOND);

				out.write("[Trash Info]\n");
				out.write("Path=" + file.getAbsolutePath() + "\n");
				out.write("DeletionDate=" + year + "-" + month + "-" + day
						+ "T" + hour + ":" + minute + ":" + second);
				out.close();
			} catch (IOException e) {
				System.err.println("Duplicate files in trash.");
				e.getStackTrace();
			}

			move(file, FSInfo.getInstance().getHomeDir().toString()
					+ "/.local/share/Trash/files");

		} else if (FSInfo.getInstance().getOS().equals("Windows")) {
			System.err.println("Windows");
			file.delete(); // TODO send to recycle bin
		} else if (FSInfo.getInstance().getOS().equals("OS X")) {
			System.err.println("OS X");
			move(file, "~/.Trash");
		} else {
			return false;
		}
		return true;
	}

	/**
	 * Moves the given file to the given path.
	 * 
	 * @param file
	 *            the file to move
	 * @param path
	 *            the path to move the file to
	 * @return true if successful, else false
	 */
	public boolean move(File file, String path) {
		// Destination directory
		File dir = new File(path);

		// Move file to new directory
		return file.renameTo(new File(dir, file.getName()));
	}
	
	/**
	 * 
	 * @param dir
	 * @return
	 */
	private String fileNameSetter(File dir) {
	
		File f = new File(dir.getAbsolutePath() + "/" + clipBoard.getName());
		
		try {
			if(f.createNewFile())
				return  clipBoard.getName();
		} catch (IOException e) {
			e.printStackTrace();
		}
		
		
		int dotPos = clipBoard.getName().lastIndexOf('.');
		String extension = clipBoard.getName().substring(dotPos);
		String name = clipBoard.getName().substring(0, dotPos);
		String cpString = " (copy)";
		
		String fullFileName = name + cpString + extension;
		
		return fileNameSetter(dir, fullFileName);
	}
	
	/**
	 * 
	 * @param dir
	 * @return the fileName
	 */
	private String fileNameSetter(File dir, String fileName) {
		
		File f = new File(dir.getAbsolutePath() + "/"  + fileName);
		
		try {
			if(f.createNewFile())
				return  f.getName();
		} catch (IOException e) {
			e.printStackTrace();
		}	
		
		int dotPos = fileName.lastIndexOf('.');
		String extension = fileName.substring(dotPos);
		String name  = fileName.substring(0, dotPos);
		int counter = 2;
		
		String fullFileName = name + counter + extension;
		
		return fileNameSetter(dir, fullFileName, counter);		
	}
	
	/**
	 * 
	 * @param dir
	 * @param fileName
	 * @param counter
	 * @return
	 */
	private String fileNameSetter(File dir, String fileName, int counter) {
		counter++;
		File f = new File(dir.getAbsolutePath() + "/"  + fileName);
		
		try {
			if(f.createNewFile())
				return  f.getName();
		} catch (IOException e) {
			e.printStackTrace();
		}	
		
		int dotPos = fileName.lastIndexOf('.');
		String extension = fileName.substring(dotPos);
		String name  = fileName.substring(0, dotPos-1);
		
		String fullFileName = name + counter + extension;
		
		return fileNameSetter(dir, fullFileName, counter);
	}	
}