using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace GCMM
{
    public static class ZipArchiveExtensions
    { //https://stackoverflow.com/a/14795752/2703239
        public static void ExtractToDirectory(this ZipArchive archive, string destinationDirectoryName, bool overwrite)
        {
            if (!overwrite)
            {
                archive.ExtractToDirectory(destinationDirectoryName);
                return;
            }

            DirectoryInfo di = Directory.CreateDirectory(destinationDirectoryName);
            string destinationDirectoryFullPath = di.FullName;

            foreach (ZipArchiveEntry file in archive.Entries)
            {
                string completeFileName = Path.GetFullPath(Path.Combine(destinationDirectoryFullPath, file.FullName));

                if (!completeFileName.StartsWith(destinationDirectoryFullPath, StringComparison.OrdinalIgnoreCase))
                {
                    throw new IOException("Trying to extract file outside of destination directory. See this link for more info: https://snyk.io/research/zip-slip-vulnerability");
                }

                if (file.Name == "")
                {// Assuming Empty for Directory
                    Directory.CreateDirectory(Path.GetDirectoryName(completeFileName));
                    continue;
                }
                file.ExtractToFile(completeFileName, true);
            }
        }
    }
}