/*
 * Copyright (C) 2007, Robin Rosenberg <robin.rosenberg@dewire.com>
 * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials provided
 *   with the distribution.
 *
 * - Neither the name of the Git Development Community nor the
 *   names of its contributors may be used to endorse or promote
 *   products derived from this software without specific prior
 *   written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.spearce.jgit.treewalk;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

import org.spearce.jgit.errors.IncorrectObjectTypeException;
import org.spearce.jgit.lib.FileMode;
import org.spearce.jgit.lib.Repository;
import org.spearce.jgit.util.FS;

/**
 * Working directory iterator for standard Java IO.
 * <p>
 * This iterator uses the standard <code>java.io</code> package to read the
 * specified working directory as part of a {@link TreeWalk}.
 */
public class FileTreeIterator extends WorkingTreeIterator {
	private final File directory;

	/**
	 * Create a new iterator to traverse the given directory and its children.
	 * 
	 * @param root
	 *            the starting directory. This directory should correspond to
	 *            the root of the repository.
	 */
	public FileTreeIterator(final File root) {
		directory = root;
		init(entries());
	}

	/**
	 * Create a new iterator to traverse a subdirectory.
	 * 
	 * @param p
	 *            the parent iterator we were created from.
	 * @param root
	 *            the subdirectory. This should be a directory contained within
	 *            the parent directory.
	 */
	protected FileTreeIterator(final FileTreeIterator p, final File root) {
		super(p);
		directory = root;
		init(entries());
	}

	@Override
	public AbstractTreeIterator createSubtreeIterator(final Repository repo)
			throws IncorrectObjectTypeException, IOException {
		return new FileTreeIterator(this, ((FileEntry) current()).file);
	}

	private Entry[] entries() {
		final File[] all = directory.listFiles();
		if (all == null)
			return EOF;
		final Entry[] r = new Entry[all.length];
		for (int i = 0; i < r.length; i++)
			r[i] = new FileEntry(all[i]);
		return r;
	}

	/**
	 * Wrapper for a standard Java IO file
	 */
	static public class FileEntry extends Entry {
		final File file;

		private final FileMode mode;

		private long length = -1;

		private long lastModified;

		FileEntry(final File f) {
			file = f;

			if (f.isDirectory()) {
				if (new File(f, ".git").isDirectory())
					mode = FileMode.GITLINK;
				else
					mode = FileMode.TREE;
			} else if (FS.INSTANCE.canExecute(file))
				mode = FileMode.EXECUTABLE_FILE;
			else
				mode = FileMode.REGULAR_FILE;
		}

		@Override
		public FileMode getMode() {
			return mode;
		}

		@Override
		public String getName() {
			return file.getName();
		}

		@Override
		public long getLength() {
			if (length < 0)
				length = file.length();
			return length;
		}

		@Override
		public long getLastModified() {
			if (lastModified == 0)
				lastModified = file.lastModified();
			return lastModified;
		}

		@Override
		public InputStream openInputStream() throws IOException {
			return new FileInputStream(file);
		}

		/**
		 * Get the underlying file of this entry.
		 *
		 * @return the underlying file of this entry
		 */
		public File getFile() {
			return file;
		}
	}
}