using System;
using System.IO;
using System.Text;
using System.Linq;
using System.Collections.Generic;

namespace AniNIX.Shared {

    public class DirHandle : IDisposable {

        // Internal representations of the directory.
        private FileSystemWatcher _dirHandle = new FileSystemWatcher();
        private String _path; 

        /// <summary>
        /// Create a new DirHandle
        /// </summary>
        /// <param name=path>The path to watch</param>
        /// <param name=filter>Optional filter to control files by -- accepts regex</param>
        public DirHandle(String path, String filter = "*.*") {
            this._path=path;
            _dirHandle.Path = path;
            _dirHandle.NotifyFilter = NotifyFilters.LastWrite;
            _dirHandle.Filter = filter;
            _dirHandle.NotifyFilter = NotifyFilters.LastWrite | NotifyFilters.Security | NotifyFilters.DirectoryName | NotifyFilters.FileName | NotifyFilters.Size;
            _dirHandle.EnableRaisingEvents = false;
        }

        /// <summary>
        /// Wait until the directory changes
        /// </summary>
        public void HoldForChange() {
            _dirHandle.WaitForChanged(WatcherChangeTypes.Changed);
            return;
        }

        /// <summary>
        /// Get a list of files in the path.
        /// </summary>
        /// <returns>A List of strings</returns>
        public List<String> ListContents() {
            return new List<String>(Directory.GetFiles(@_path));
        }

        /// <summary>
        /// Get the path of the newest file.
        /// </summary>
        /// <returns>A List of strings</returns>
        public String GetNewest() {
           try {
                return this.SortedListOfFiles()[0].FullName.Trim();
            } catch (Exception e) {
                e.ToString();
                return null;
            }
        }

        /// <summary>
        /// Get the path of the oldest file
        /// </summary>
        /// <returns>A List of strings</returns>
        public String GetOldest() {
            try {
                FileInfo[] files = this.SortedListOfFiles();
                return files[files.Length-1].FullName.Trim();
            } catch (Exception e) {
                e.ToString();
                return null;
            }
 
        }

        /// <summary>
        /// Sorts the list of files from newest to oldest.
        /// </summary>
        /// <returns>A List of strings</returns>
        private FileInfo[] SortedListOfFiles() {
            return (new DirectoryInfo(@_path)).GetFiles().OrderByDescending(p => p.CreationTime).ToArray();
        }

        /* IDisposable */

        /// <summary>
        /// Clean up this FileStream, implementing IDisposable
        /// </summary>
        public void Dispose() {
            this.Dispose(true);
            GC.SuppressFinalize(this);
        }
        /// <summary>
        /// Force the GarbageCollector to Dispose if programmer does not
        /// </summary>
        ~DirHandle() {
            Dispose(false);
            ReportMessage.Log(Verbosity.Error,"Programmer forgot to dispose of DirHandle. Marking for Garbage Collector");
        }

        // This bool indicates whether we have disposed of this Raven
        public bool _isDisposed = false;

        /// <summary>
        /// Dispose of this FileHandle's resources responsibly.
        /// </summary>
        private void Dispose(bool disposing) {
            if (!_isDisposed) {
                if (disposing) {
                    _path = null;
                }
                if ( _dirHandle != null) {
                    _dirHandle.Dispose();
                }
            }
            this._isDisposed = true;
        }

    }
}