/*
 * 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.
 */

using System;
using System.Collections.Generic;

namespace Lucene.Net.Support
{
    /// <summary>
    /// Represents the methods to support some operations over files.
    /// </summary>
    public class FileSupport
    {
        /// <summary>
        /// Returns an array of abstract pathnames representing the files and directories of the specified path.
        /// </summary>
        /// <param name="path">The abstract pathname to list it childs.</param>
        /// <returns>An array of abstract pathnames childs of the path specified or null if the path is not a directory</returns>
        public static System.IO.FileInfo[] GetFiles(System.IO.FileInfo path)
        {
            if ((path.Attributes & System.IO.FileAttributes.Directory) > 0)
            {																 
                String[] fullpathnames = System.IO.Directory.GetFileSystemEntries(path.FullName);
                System.IO.FileInfo[] result = new System.IO.FileInfo[fullpathnames.Length];
                for (int i = 0; i < result.Length ; i++)
                    result[i] = new System.IO.FileInfo(fullpathnames[i]);
                return result;
            }
            else
                return null;
        }

        /// <summary>
        /// Returns a list of files in a give directory.
        /// </summary>
        /// <param name="fullName">The full path name to the directory.</param>
        /// <param name="indexFileNameFilter"></param>
        /// <returns>An array containing the files.</returns>
        public static System.String[] GetLuceneIndexFiles(System.String fullName, 
                                                          Lucene.Net.Index.IndexFileNameFilter indexFileNameFilter)
        {
            System.IO.DirectoryInfo dInfo = new System.IO.DirectoryInfo(fullName);
            List<string> list = new List<string>();
            foreach (System.IO.FileInfo fInfo in dInfo.GetFiles())
            {
                if (indexFileNameFilter.Accept(fInfo, fInfo.Name) == true)
                {
                    list.Add(fInfo.Name);
                }
            }
            return list.ToArray();
        }

        // Disable the obsolete warning since we must use FileStream.Handle
        // because Mono does not support FileSystem.SafeFileHandle at present.
#pragma warning disable 618

        /// <summary>
        /// Flushes the specified file stream. Ensures that all buffered
        /// data is actually written to the file system.
        /// </summary>
        /// <param name="fileStream">The file stream.</param>
        public static void Sync(System.IO.FileStream fileStream)
        {
            if (fileStream == null)
                throw new ArgumentNullException("fileStream");

            fileStream.Flush();

            //if (OS.IsWindows)
            //{
            //    if (!FlushFileBuffers(fileStream.Handle))
            //        throw new System.IO.IOException();
            //}
            //else if (OS.IsUnix)
            //{
            //    if (fsync(fileStream.Handle) != IntPtr.Zero)
            //    throw new System.IO.IOException();
            //}
            //else
            //{
            //    throw new NotImplementedException();
            //}
        }

#pragma warning restore 618

        //[System.Runtime.InteropServices.DllImport("libc")]
        //extern static IntPtr fsync(IntPtr fd);

        //[System.Runtime.InteropServices.DllImport("kernel32.dll")]
        //extern static bool FlushFileBuffers(IntPtr hFile);
    }
}