/*
 * Copyright 2008 the original author or authors.
 *
 * 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.
 */
package org.mockftpserver.fake.filesystem;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * File system entry representing a file
 *
 * @author Chris Mair
 * @version $Revision$ - $Date$
 */
public class FileEntry extends AbstractFileSystemEntry {

    private static final byte[] EMPTY = new byte[0];

    private byte[] bytes = EMPTY;
    private ByteArrayOutputStream out;

    /**
     * Construct a new instance without setting its path
     */
    public FileEntry() {
    }

    /**
     * Construct a new instance with the specified value for its path
     *
     * @param path - the value for path
     */
    public FileEntry(String path) {
        super(path);
    }

    /**
     * Construct a new instance with the specified path and file contents
     *
     * @param path     - the value for path
     * @param contents - the contents of the file, as a String
     */
    public FileEntry(String path, String contents) {
        super(path);
        setContents(contents);
    }

    /**
     * Return false to indicate that this entry represents a file
     *
     * @return false
     */
    public boolean isDirectory() {
        return false;
    }

    /**
     * Return the size of this file
     *
     * @return the file size in bytes
     */
    public long getSize() {
        return getCurrentBytes().length;
    }

    /**
     * Set the contents of the file represented by this entry
     *
     * @param contents - the String whose bytes are used as the contents
     */
    public void setContents(String contents) {
        byte[] newBytes = (contents != null) ? contents.getBytes() : EMPTY;
        setContentsInternal(newBytes);
    }

    /**
     * Set the contents of the file represented by this entry
     *
     * @param contents - the byte[] used as the contents
     */
    public void setContents(byte[] contents) {
        // Copy the bytes[] to guard against subsequent modification of the source array
        byte[] newBytes = EMPTY;
        if (contents != null) {
            newBytes = new byte[contents.length];
            System.arraycopy(contents, 0, newBytes, 0, contents.length);
        }
        setContentsInternal(newBytes);
    }

    /**
     * Create and return an InputStream for reading the contents of the file represented by this entry
     *
     * @return an InputStream
     */
    public InputStream createInputStream() {
        return new ByteArrayInputStream(getCurrentBytes());
    }

    /**
     * Create and return an OutputStream for writing the contents of the file represented by this entry
     *
     * @param append - true if the OutputStream should append to any existing contents false if
     *               any existing contents should be overwritten
     * @return an OutputStream
     * @throws FileSystemException - if an error occurs creating or initializing the OutputStream
     */
    public OutputStream createOutputStream(boolean append) {
        // If appending and we already have an OutputStream, then continue to use it
        if (append && out != null) {
            return out;
        }

        out = new ByteArrayOutputStream();
        byte[] initialContents = (append) ? bytes : EMPTY;
        try {
            out.write(initialContents);
        }
        catch (IOException e) {
            throw new FileSystemException(getPath(), null, e);
        }
        return out;
    }

    /**
     * Return a new FileSystemEntry that is a clone of this object, except having the specified path
     *
     * @param path - the new path value for the cloned file system entry
     * @return a new FileSystemEntry that has all the same values as this object except for its path
     */
    public FileSystemEntry cloneWithNewPath(String path) {
        FileEntry clone = new FileEntry(path);
        clone.setLastModified(getLastModified());
        clone.setOwner(getOwner());
        clone.setGroup(getGroup());
        clone.setPermissions(getPermissions());
        clone.setContents(getCurrentBytes());
        return clone;
    }

    //-------------------------------------------------------------------------
    // Internal Helper Methods
    //-------------------------------------------------------------------------

    /**
     * @return the current contents of this file entry as a byte[]
     */
    private byte[] getCurrentBytes() {
        return (out != null) ? out.toByteArray() : bytes;
    }

    /**
     * Set the contents of the file represented by this entry
     *
     * @param contents - the byte[] used as the contents
     */
    private void setContentsInternal(byte[] contents) {
        this.bytes = contents;

        // Get rid of any OutputStream
        this.out = null;
    }

    /**
     * @see java.lang.Object#toString()
     */
    public String toString() {
        return "File['" + getPath() + "' size=" + getSize() + " lastModified=" + getLastModified() + " owner="
                + getOwner() + " group=" + getGroup() + " permissions=" + getPermissions() + "]";
    }

}