using ICSharpCode.SharpZipLib.Checksum;

namespace MiaoYu.Core.Zips;

/// <summary>
/// 压缩 zip  https://www.cnblogs.com/xielong/p/6165550.html
/// </summary>
public class Zip
{
    public Zip(string strFile, string strZip)
    {
        var len = strFile.Length;
        var strLen = strFile[len - 1];
        if (strFile[strFile.Length - 1] != Path.DirectorySeparatorChar)
        {
            strFile += Path.DirectorySeparatorChar;
        }

        using var outStream = new ZipOutputStream(File.Create(strZip));
        try
        {
            outStream.SetLevel(6);
            Execute(strFile, outStream, strFile);
        }
        finally
        {
            outStream.Finish();
            outStream.Close();
        }
    }

    private void Execute(string strFile, ZipOutputStream outStream, string staticFile)
    {
        if (strFile[strFile.Length - 1] != Path.DirectorySeparatorChar)
        {
            strFile += Path.DirectorySeparatorChar;
        }

        var crc = new Crc32();
        //获取指定目录下所有文件和子目录文件名称
        var filenames = Directory.GetFileSystemEntries(strFile);
        //遍历文件
        foreach (var file in filenames)
        {
            if (Directory.Exists(file))
            {
                Execute(file, outStream, staticFile);
            }
            //否则，直接压缩文件
            else
            {
                //打开文件
                using var fs = File.OpenRead(file);
                //定义缓存区对象
                var buffer = new byte[fs.Length];
                //通过字符流，读取文件
                fs.Read(buffer, 0, buffer.Length);
                //得到目录下的文件（比如:D:\Debug1\test）,test
                var tempFile = file.Substring(staticFile.LastIndexOf("\\", StringComparison.Ordinal) + 1);
                var entry = new ZipEntry(tempFile) { DateTime = DateTime.Now, Size = fs.Length };

                crc.Reset();
                crc.Update(buffer);
                entry.Crc = crc.Value;
                outStream.PutNextEntry(entry);
                //写文件
                outStream.Write(buffer, 0, buffer.Length);
                fs.Close();
            }
        }
    }

    /// <summary>
    /// 解压
    /// </summary>
    /// <param name="zipFile">压缩包文件名</param>
    /// <param name="targetPath">解压缩目标路径</param>
    public static string UnZip(string zipFile, string targetPath)
    {
        var directoryName = targetPath;
        if (!Directory.Exists(directoryName)) Directory.CreateDirectory(directoryName); //生成解压目录   
        var currentDirectory = directoryName;
        var data = new byte[2048];
        var size = 2048;

        ZipEntry zipEntry = null;
        var theEntry = string.Empty;

        using var s = new ZipInputStream(File.OpenRead(zipFile));
        while ((zipEntry = s.GetNextEntry()) != null)
        {
            if (zipEntry.IsDirectory)
            {
                // 该结点是目录
                if (!Directory.Exists(currentDirectory + zipEntry.Name))
                    Directory.CreateDirectory(currentDirectory + zipEntry.Name);
                //保存路径名
                if (!string.IsNullOrEmpty(zipEntry.Name) && zipEntry.Name.Contains("/"))
                    theEntry = zipEntry.Name.Substring(0, zipEntry.Name.IndexOf('/'));
            }
            else
            {
                if (string.IsNullOrWhiteSpace(zipEntry.Name)) continue;

                //解压文件到指定的目录
                using var streamWriter = File.Create(currentDirectory + zipEntry.Name);
                while (true)
                {
                    size = s.Read(data, 0, data.Length);
                    if (size <= 0) break;
                    streamWriter.Write(data, 0, size);
                }

                streamWriter.Close();
            }
        }

        s.Close();
        return "/" + theEntry; //返回压缩文件的路径
    }
}