using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using ICSharpCode.SharpZipLib.Core;
using ICSharpCode.SharpZipLib.Zip;
using System.IO;


namespace Fab2ApprovalSystem.Misc
{
    /// <summary>
    /// 
    /// </summary>
    public class Zipper
    {

        
        /// <summary>
        /// Compresses the files in the nominated folder, and creates a zip file on disk named as outPathname.
        /// </summary>
        /// <param name="outPathname"></param>
        /// <param name="folderName"></param>
        public void CreateZip(string outPathname, string folderName) {
            // TODO Try and Catch block
            Directory.CreateDirectory(Path.GetDirectoryName(outPathname));

            FileStream fsOut = File.Create(outPathname);
            ZipOutputStream zipStream = new ZipOutputStream(fsOut);

            zipStream.SetLevel(3); //0-9, 9 being the highest level of compression

            //zipStream.Password = password;  // optional. Null is the same as not setting. Required if using AES.

            // This setting will strip the leading part of the folder path in the entries, to
            // make the entries relative to the starting folder.
            // To include the full path for each entry up to the drive root, assign folderOffset = 0.
            int folderOffset = folderName.Length + (folderName.EndsWith("\\") ? 0 : 1);

            CompressFolder(folderName, zipStream, folderOffset);

            zipStream.IsStreamOwner = true; // Makes the Close also Close the underlying stream
            zipStream.Close();
        }

        /// <summary>
        /// Recurses down the folder structure
        /// </summary>
        /// <param name="path"></param>
        /// <param name="zipStream"></param>
        /// <param name="folderOffset"></param>
        private void CompressFolder(string path, ZipOutputStream zipStream, int folderOffset)
        {
            // TODO Try and Catch block
            string[] files = Directory.GetFiles(path);

            foreach (string filename in files)
            {

                FileInfo fi = new FileInfo(filename);

                string entryName = filename.Substring(folderOffset); // Makes the name in zip based on the folder
                entryName = ZipEntry.CleanName(entryName); // Removes drive from name and fixes slash direction
                ZipEntry newEntry = new ZipEntry(entryName);
                newEntry.DateTime = fi.LastWriteTime; // Note the zip format stores 2 second granularity

                // Specifying the AESKeySize triggers AES encryption. Allowable values are 0 (off), 128 or 256.
                // A password on the ZipOutputStream is required if using AES.
                //   newEntry.AESKeySize = 256;

                // To permit the zip to be unpacked by built-in extractor in WinXP and Server2003, WinZip 8, Java, and other older code,
                // you need to do one of the following: Specify UseZip64.Off, or set the Size.
                // If the file may be bigger than 4GB, or you do not need WinXP built-in compatibility, you do not need either,
                // but the zip will be in Zip64 format which not all utilities can understand.
                //   zipStream.UseZip64 = UseZip64.Off;
                newEntry.Size = fi.Length;

                zipStream.PutNextEntry(newEntry);

                // Zip the file in buffered chunks
                // the "using" will close the stream even if an exception occurs
                byte[] buffer = new byte[4096];
                using (FileStream streamReader = File.OpenRead(filename))
                {
                    StreamUtils.Copy(streamReader, zipStream, buffer);
                }
                zipStream.CloseEntry();
            }
            string[] folders = Directory.GetDirectories(path);
            foreach (string folder in folders)
            {
                CompressFolder(folder, zipStream, folderOffset);
            }
        }

        

    }
}