﻿using System;
using System.Data;
using System.IO;
using System.Linq;
using ICSharpCode.SharpZipLib.Core;
using ICSharpCode.SharpZipLib.Zip;
using System.Data.OleDb;

namespace ExcelExportFiles
{
    public static class ZipFileManager
    {
        public static void Extract(string archiveFileNameIn, string outFolder)
        {
            ZipFile zf = null;
            try
            {
                FileStream fs = File.OpenRead(archiveFileNameIn);
                zf = new ZipFile(fs);
                foreach (ZipEntry zipEntry in zf)
                {
                    if (!zipEntry.IsFile)
                    {
                        continue;           // Ignore directories
                    }

                    String entryFileName = zipEntry.Name;
                    // to remove the folder from the entry:- entryFileName = Path.GetFileName(entryFileName);
                    // Optionally match entrynames against a selection list here to skip as desired.
                    // The unpacked length is available in the zipEntry.Size property.

                    byte[] buffer = new byte[4096];     // 4K is optimum
                    Stream zipStream = zf.GetInputStream(zipEntry);

                    // Manipulate the output filename here as desired.
                    String fullZipToPath = Path.Combine(outFolder, entryFileName);
                    string directoryName = Path.GetDirectoryName(fullZipToPath);
                    if (directoryName.Length > 0)
                    {
                        Directory.CreateDirectory(directoryName);
                    }

                    // Unzip file in buffered chunks. This is just as fast as unpacking to a buffer the full size
                    // of the file, but does not waste memory.
                    // The "using" will close the stream even if an exception occurs.
                    using (FileStream streamWriter = File.Create(fullZipToPath))
                    {
                        StreamUtils.Copy(zipStream, streamWriter, buffer);
                    }
                }
            }
            finally
            {
                if (zf != null)
                {
                    zf.IsStreamOwner = true; // Makes close also shut the underlying stream
                    zf.Close(); // Ensure we release resources
                }

            }
        }
    }
}