using SharpCompress.Archives;
using SharpCompress.Common;
using SharpCompress.Readers;
using SharpCompress.Writers;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using System.Web;

namespace IRaCIS.Core.Infrastructure.Extention
{
    /// <summary>
    /// 7z压缩
    /// </summary>
    public static class SevenZipCompressor
    {
        /// <summary>
        /// 将多个文件压缩到一个内存流中，可保存为zip文件，方便于web方式下载
        /// </summary>
        /// <param name="files">多个文件路径，文件或文件夹，或网络路径http/https</param>
        /// <param name="rootdir"></param>
        /// <returns>文件流</returns>
        public static MemoryStream ZipStream(List<string> files, string rootdir = "")
        {
            using var archive = CreateZipArchive(files, rootdir);
            var ms = new MemoryStream();
            archive.SaveTo(ms, new WriterOptions(CompressionType.Deflate)
            {
                LeaveStreamOpen = true,
                ArchiveEncoding = new ArchiveEncoding()
                {
                    Default = Encoding.UTF8
                }
            });
            return ms;
        }

        /// <summary>
        /// 压缩多个文件
        /// </summary>
        /// <param name="files">多个文件路径，文件或文件夹</param>
        /// <param name="zipFile">压缩到...</param>
        /// <param name="rootdir">压缩包内部根文件夹</param>
        /// <param name="archiveType"></param>
        public static void Zip(List<string> files, string zipFile, string rootdir = "", ArchiveType archiveType = ArchiveType.SevenZip)
        {
            using var archive = CreateZipArchive(files, rootdir, archiveType);
            archive.SaveTo(zipFile, new WriterOptions(CompressionType.Deflate)
            {
                LeaveStreamOpen = true,
                ArchiveEncoding = new ArchiveEncoding()
                {
                    Default = Encoding.UTF8
                }
            });
        }

        /// <summary>
        /// 解压文件，自动检测压缩包类型
        /// </summary>
        /// <param name="compressedFile">rar文件</param>
        /// <param name="dir">解压到...</param>
        /// <param name="ignoreEmptyDir">忽略空文件夹</param>
        public static void Decompress(string compressedFile, string dir = "", bool ignoreEmptyDir = true)
        {
            if (string.IsNullOrEmpty(dir))
            {
                dir = Path.GetDirectoryName(compressedFile);
            }

            using Stream stream = File.OpenRead(compressedFile);
            using var reader = ReaderFactory.Open(stream);
            while (reader.MoveToNextEntry())
            {
                if (ignoreEmptyDir)
                {
                    reader.WriteEntryToDirectory(dir, new ExtractionOptions()
                    {
                        ExtractFullPath = true,
                        Overwrite = true
                    });
                }
                else
                {
                    if (!reader.Entry.IsDirectory)
                    {
                        reader.WriteEntryToDirectory(dir, new ExtractionOptions()
                        {
                            ExtractFullPath = true,
                            Overwrite = true
                        });
                    }
                }
            }
        }

        /// <summary>
        /// 创建zip包
        /// </summary>
        /// <param name="files"></param>
        /// <param name="rootdir"></param>
        /// <param name="archiveType"></param>
        /// <returns></returns>
        private static IWritableArchive CreateZipArchive(List<string> files, string rootdir, ArchiveType archiveType = ArchiveType.SevenZip)
        {
            var archive = ArchiveFactory.Create(archiveType);
            var dic = GetFileEntryMaps(files);
            var remoteUrls = files.Distinct().Where(s => s.StartsWith("http")).Select(s =>
            {
                try
                {
                    return new Uri(s);
                }
                catch (UriFormatException)
                {
                    return null;
                }
            }).Where(u => u != null).ToList();
            foreach (var pair in dic)
            {
                archive.AddEntry(Path.Combine(rootdir, pair.Value), pair.Key);
            }

            if (!remoteUrls.Any())
            {
                return archive;
            }

            var streams = new ConcurrentDictionary<string, Stream>();
            using var httpClient = new HttpClient();
            Parallel.ForEach(remoteUrls, url =>
            {
                httpClient.GetAsync(url).ContinueWith(async t =>
                {
                    if (t.IsCompleted)
                    {
                        var res = await t;
                        if (res.IsSuccessStatusCode)
                        {
                            Stream stream = await res.Content.ReadAsStreamAsync();
                            streams[Path.Combine(rootdir, Path.GetFileName(HttpUtility.UrlDecode(url.AbsolutePath)))] = stream;
                        }
                    }
                }).Wait();
            });
            foreach (var kv in streams)
            {
                archive.AddEntry(kv.Key, kv.Value, true);
            }

            return archive;
        }

        /// <summary>
        /// 获取文件路径和zip-entry的映射
        /// </summary>
        /// <param name="files"></param>
        /// <returns></returns>
        private static Dictionary<string, string> GetFileEntryMaps(List<string> files)
        {
            var fileList = new List<string>();
            void GetFilesRecurs(string path)
            {
                //遍历目标文件夹的所有文件
                fileList.AddRange(Directory.GetFiles(path));

                //遍历目标文件夹的所有文件夹
                foreach (string directory in Directory.GetDirectories(path))
                {
                    GetFilesRecurs(directory);
                }
            }

            files.Where(s => !s.StartsWith("http")).ForEach(s =>
            {
                if (Directory.Exists(s))
                {
                    GetFilesRecurs(s);
                }
                else
                {
                    fileList.Add(s);
                }
            });
            if (!fileList.Any())
            {
                return new Dictionary<string, string>();
            }

            var dirname = new string(fileList.First().Substring(0, fileList.Min(s => s.Length)).TakeWhile((c, i) => fileList.All(s => s[i] == c)).ToArray());
            if (!Directory.Exists(dirname))
            {
                dirname = Directory.GetParent(dirname).FullName;
            }

            var dic = fileList.ToDictionary(s => s, s => s.Substring(dirname.Length));
            return dic;
        }
    }
}