using Lucene.Net.Store;
using Lucene.Net.Util;
using System;
using System.IO;

namespace Lucene.Net.Index
{
    /*
	 * Licensed to the Apache Software Foundation (ASF) under one or more
	 * contributor license agreements.  See the NOTICE file distributed with
	 * this work for additional information regarding copyright ownership.
	 * The ASF licenses this file to You 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.
	 */

    /// <summary>
    /// Command-line tool for extracting sub-files out of a compound file.
    /// </summary>
    public class CompoundFileExtractor
    {
        /// <summary>
        /// Prints the filename and size of each file within a given compound file.
        /// Add the -extract flag to extract files to the current working directory.
        /// In order to make the extracted version of the index work, you have to copy
        /// the segments file from the compound index into the directory where the extracted files are stored. </summary>
        /// <param name="args"> Usage: org.apache.lucene.index.IndexReader [-extract] &lt;cfsfile&gt; </param>
        public static void Main(string[] args)
        {
            string filename = null;
            bool extract = false;
            string dirImpl = null;

            int j = 0;
            while (j < args.Length)
            {
                string arg = args[j];
                if ("-extract".Equals(arg))
                {
                    extract = true;
                }
                else if ("-dir-impl".Equals(arg))
                {
                    if (j == args.Length - 1)
                    {
                        Console.WriteLine("ERROR: missing value for -dir-impl option");
                        Environment.Exit(1);
                    }
                    j++;
                    dirImpl = args[j];
                }
                else if (filename == null)
                {
                    filename = arg;
                }
                j++;
            }

            if (filename == null)
            {
                Console.WriteLine("Usage: org.apache.lucene.index.CompoundFileExtractor [-extract] [-dir-impl X] <cfsfile>");
                return;
            }

            Store.Directory dir = null;
            CompoundFileDirectory cfr = null;
            IOContext context = IOContext.READ;

            try
            {
                FileInfo file = new FileInfo(filename);
                string dirname = file.DirectoryName;
                filename = file.Name;
                if (dirImpl == null)
                {
                    dir = FSDirectory.Open(new DirectoryInfo(dirname));
                }
                else
                {
                    dir = CommandLineUtil.NewFSDirectory(dirImpl, new DirectoryInfo(dirname));
                }

                cfr = new CompoundFileDirectory(dir, filename, IOContext.DEFAULT, false);

                string[] files = cfr.ListAll();
                ArrayUtil.TimSort(files); // sort the array of filename so that the output is more readable

                for (int i = 0; i < files.Length; ++i)
                {
                    long len = cfr.FileLength(files[i]);

                    if (extract)
                    {
                        Console.WriteLine("extract " + files[i] + " with " + len + " bytes to local directory...");
                        using (IndexInput ii = cfr.OpenInput(files[i], context))
                        {

                            using (FileStream f = new FileStream(files[i], FileMode.Open, FileAccess.ReadWrite))
                            {

                                // read and write with a small buffer, which is more effective than reading byte by byte
                                byte[] buffer = new byte[1024];
                                int chunk = buffer.Length;
                                while (len > 0)
                                {
                                    int bufLen = (int)Math.Min(chunk, len);
                                    ii.ReadBytes(buffer, 0, bufLen);
                                    f.Write(buffer, 0, bufLen);
                                    len -= bufLen;
                                }

                            }
                        }
                    }
                    else
                    {
                        Console.WriteLine(files[i] + ": " + len + " bytes");
                    }
                }
            }
            catch (IOException ioe)
            {
                Console.WriteLine(ioe.ToString());
                Console.Write(ioe.StackTrace);
            }
            finally
            {
                try
                {
                    if (dir != null)
                    {
                        dir.Dispose();
                    }
                    if (cfr != null)
                    {
                        cfr.Dispose();
                    }
                }
                catch (IOException ioe)
                {
                    Console.WriteLine(ioe.ToString());
                    Console.Write(ioe.StackTrace);
                }
            }
        }
    }
}