/* FileOps -- Utility class for file operations

  Digital Image Library servlet components

  Copyright (C) 2001, 2002 Robert Casties (robcast@mail.berlios.de)

  This program is free software; you can redistribute  it and/or modify it
  under  the terms of  the GNU General  Public License as published by the
  Free Software Foundation;  either version 2 of the  License, or (at your
  option) any later version.
   
  Please read license.txt for the full details. A copy of the GPL
  may be found at http://www.gnu.org/copyleft/lgpl.html

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

*/

package digilib.io;

import java.io.*;
import java.util.*;

import digilib.*;

public class FileOps {

	private Utils util = null;
	public static String[] fileTypes =
		{
			"jpg",
			"image/jpeg",
			"jpeg",
			"image/jpeg",
			"jp2",
			"image/jp2",
			"png",
			"image/png",
			"gif",
			"image/gif",
			"tif",
			"image/tiff",
			"tiff",
			"image/tiff" };

	public static String[] fileExtensions =
		{ "jpg", "jpeg", "jp2", "png", "gif", "tif", "tiff" };

	public FileOps() {
		util = new Utils();
	}

	public FileOps(Utils u) {
		util = u;
	}

	public void setUtils(Utils u) {
		util = u;
	}

	/**
	 *  get the mime type for a file format (by extension)
	 */
	public static String mimeForFile(File f) {
		String fn = f.getName();
		for (int i = 0; i < fileTypes.length; i += 2) {
			if (fn.toLowerCase().endsWith(fileTypes[i])) {
				return fileTypes[i + 1];
			}
		}
		return null;
	}

	public static Iterator getImageExtensionIterator() {
		return Arrays.asList(fileExtensions).iterator();
	}

	/**
	 * convert a string with a list of pathnames into an array of strings
	 * using the system's path separator string
	 */
	public static String[] pathToArray(String paths) {
		// split list into directories
		StringTokenizer dirs =
			new StringTokenizer(paths, File.pathSeparator);
		int n = dirs.countTokens();
		if (n < 1) {
			return null;
		}
		// add directories into array
		String[] pathArray = new String[n];
		for (int i = 0; i < n; i++) {
			String s = dirs.nextToken();
			// make shure the dir name ends with a directory separator
			if (s.endsWith(File.separator)) {
				pathArray[i] = s;
			} else {
				pathArray[i] = s + File.separator;
			}
		}
		return pathArray;
	}

	/**
	 *  get a filehandle for a file or directory name
	 *    returns File number n if fn is directory (starts with 1)
	 */
	public File getFile(String fn, int n) throws FileOpException {
		util.dprintln(4, "getFile (" + fn + ", " + n + ")");

		File f = new File(fn);
		// if fn is a file name then return file
		if (f.isFile()) {
			return f;
		}
		// if fn is a directory name then open directory
		if (f.isDirectory()) {
			File[] fl = f.listFiles(new ImageFileFilter());
			Arrays.sort(fl);
			if ((n > 0) && (n <= fl.length)) {
				return fl[n - 1];
			}
		}
		throw new FileOpException("Unable to find file: " + fn);
	}

	/**
	 *  get the number of files in a directory
	 *    (almost the same as getFile)
	 *  returns 0 in case of problems
	 */
	public int getNumFiles(String fn) throws FileOpException {
		util.dprintln(4, "getNumFiles (" + fn + ")");

		File f = new File(fn);
		// if fn is a file name then return 1
		if (f.isFile()) {
			return 1;
		}
		// if fn is a directory name then return the number of files
		if (f.isDirectory()) {
			return f.listFiles(new ImageFileFilter()).length;
		}
		// then fn must be something strange...
		return 0;
	}

	/**
	 *  get a filehandle for a file or directory name out of a list
	 *    dirs is a list of base directories, fn is the appended file/dirname
	 *    searches dirs until fn exists (backwards if fwd is false)
	 *    returns File number n if fn is directory (starts with 1)
	 */
	public File getFileVariant(String[] dirs, String fn, int n, boolean fwd)
		throws FileOpException {
		util.dprintln(
			4,
			"getVariantFile (" + dirs + ", " + fn + ", " + n + ")");

		File f = null;
		int nvar = dirs.length;

		for (int i = 0; i < nvar; i++) {
			try {
				f = getFile(dirs[(fwd) ? i : (nvar - i - 1)] + fn, n);
			} catch (FileOpException e) {
				f = null;
			}
			if (f != null) {
				return f;
			}
		}
		throw new FileOpException("Unable to find file: " + fn);
	}

	/**
	 *  get the number of files in a directory
	 *    (almost the same as getFileVariant)
	 *  returns 0 in case of problems
	 */
	public int getNumFilesVariant(String[] dirs, String fn, boolean fwd)
		throws FileOpException {
		util.dprintln(4, "getNumFilesVariant (" + dirs + ", " + fn + ")");

		int nf = 0;
		int nvar = dirs.length;

		for (int i = 0; i < nvar; i++) {
			try {
				nf = getNumFiles(dirs[(fwd) ? i : (nvar - i - 1)] + fn);
			} catch (FileOpException e) {
				nf = 0;
			}
			if (nf > 0) {
				return nf;
			}
		}
		return 0;
	}

	/**
	 *  FileFilter for image types (helper class for getFile)
	 */
	static class ImageFileFilter implements FileFilter {

		public boolean accept(File f) {
			if (f.isFile()) {
				return (mimeForFile(f) != null);
			} else {
				return false;
			}
		}
	}

}