using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using ICSharpCode.SharpZipLib.Checksum;
using ICSharpCode.SharpZipLib.Zip;

namespace Vote.Services.Tools
{
    /// <summary>
    /// 
    /// </summary>
    public class ZipHelper
    {

        /// <summary>
        /// 所有文件缓存
        /// </summary>
        List<string> files = new List<string>();
        /// <summary>
        /// 所有空目录缓存
        /// </summary>
        List<string> paths = new List<string>();
        /// <summary>
        /// 取得目录下所有文件及文件夹，分别存入files及paths
        /// </summary>
        /// <param name="rootPath">根目录</param>
        private void GetAllDirectories(string rootPath)
        {
            string[] subPaths = Directory.GetDirectories(rootPath);//得到所有子目录
            foreach (string path in subPaths)
            {
                GetAllDirectories(path);//对每一个字目录做与根目录相同的操作：即找到子目录并将当前目录的文件名存入List
            }
            string[] files = Directory.GetFiles(rootPath);
            foreach (string file in files)
            {
                this.files.Add(file);//将当前目录中的所有文件全名存入文件List
            }
            if (subPaths.Length == files.Length && files.Length == 0)//如果是空目录
            {
                this.paths.Add(rootPath);//记录空目录
            }
        }


        /// <summary>
        /// 压缩目录（包括子目录及所有文件）
        /// </summary>
        /// <param name="rootPath">要压缩的根目录</param>
        /// <param name="destinationPath">保存路径</param>
        /// <param name="compressLevel">压缩程度，范围0-9，数值越大，压缩程序越高</param>
        public void ZipFileFromDirectory(string rootPath, string destinationPath, int compressLevel)
        {
            this.files.Clear();
            GetAllDirectories(rootPath);

            string rootMark = rootPath + "\\";//得到当前路径的位置，以备压缩时将所压缩内容转变成相对路径。
            Crc32 crc = new Crc32();
            using ZipOutputStream outPutStream = new ZipOutputStream(System.IO.File.Create(destinationPath));
            outPutStream.SetLevel(compressLevel); // 0 - store only to 9 - means best compression
            foreach (string file in files)
            {
                using FileStream fileStream = System.IO.File.OpenRead(file);//打开压缩文件
                byte[] buffer = new byte[fileStream.Length];
                fileStream.Read(buffer, 0, buffer.Length);
                ZipEntry entry = new ZipEntry(file.Replace(rootMark, string.Empty));
                entry.DateTime = DateTime.Now;

                entry.Size = fileStream.Length;
                fileStream.Close();
                crc.Reset();
                crc.Update(buffer);
                entry.Crc = crc.Value;
                outPutStream.PutNextEntry(entry);
                outPutStream.Write(buffer, 0, buffer.Length);
            }

            this.files.Clear();

            foreach (string emptyPath in paths)
            {
                ZipEntry entry = new ZipEntry(emptyPath.Replace(rootMark, string.Empty) + "/");
                outPutStream.PutNextEntry(entry);
            }

            this.paths.Clear();
            outPutStream.Finish();
            outPutStream.Close();
            GC.Collect();
        }
        /// <summary>
        /// 压缩单个文件
        /// <param name="filepath">要压缩的文件路径</param>
        /// <param name="compressLevel">压缩程度，范围0-9，数值越大，压缩程序越高</param>
        /// <paramref name="dwgZipPath">输出zip文件路径</paramref>
        /// </summary>
        public bool ZipOneFile(string filepath, int compressLevel)
        {
            var r = false;
            try
            {
                var file = new FileInfo(filepath);
                var dwgZipPath = GetZipFileName(filepath);
                Crc32 crc = new Crc32();
                using ZipOutputStream outPutStream = new ZipOutputStream(System.IO.File.Create(dwgZipPath));
                outPutStream.SetLevel(compressLevel); // 0 - store only to 9 - means best compression 
                using FileStream fileStream = System.IO.File.OpenRead(filepath);//打开压缩文件
                byte[] buffer = new byte[fileStream.Length];
                fileStream.Read(buffer, 0, buffer.Length);
                ZipEntry entry = new ZipEntry(filepath.Replace(file.DirectoryName + "\\", string.Empty));
                entry.DateTime = DateTime.Now;
                entry.Size = fileStream.Length;
                fileStream.Close();
                crc.Reset();
                crc.Update(buffer);
                entry.Crc = crc.Value;
                outPutStream.PutNextEntry(entry);
                outPutStream.Write(buffer, 0, buffer.Length);
                this.files.Clear();
                this.paths.Clear();
                outPutStream.Finish();
                outPutStream.Close();
                GC.Collect();
                r = true;
            }
            catch (Exception ex)
            {
                r = false;
            }
            return r;
        }
        private string GetZipFileName(string filepath)
        {
            //if (System.IO.File.Exists(filepath + ".zip"))
            //{
            //    return GetZipFileName(filepath + ".zip");
            //}
            return filepath + ".zip";
        }

    }
}