using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using SharpCompress.Common;
using SharpCompress.Common.Zip;
using SharpCompress.Common.Zip.Headers;
using SharpCompress.Compressors.Deflate;
using SharpCompress.IO;
using SharpCompress.Readers;
using SharpCompress.Readers.Zip;
using SharpCompress.Writers;
using SharpCompress.Writers.Zip;

namespace SharpCompress.Archives.Zip
{
    public class ZipArchive : AbstractWritableArchive<ZipArchiveEntry, ZipVolume>
    {
#nullable disable
        private readonly SeekableZipHeaderFactory headerFactory;
#nullable enable

        /// <summary>
        /// Gets or sets the compression level applied to files added to the archive,
        /// if the compression method is set to deflate
        /// </summary>
        public CompressionLevel DeflateCompressionLevel { get; set; }

        /// <summary>
        /// Constructor with a SourceStream able to handle FileInfo and Streams.
        /// </summary>
        /// <param name="srcStream"></param>
        /// <param name="options"></param>
        internal ZipArchive(SourceStream srcStream)
            : base(ArchiveType.Zip, srcStream)
        {
            headerFactory = new SeekableZipHeaderFactory(srcStream.ReaderOptions.Password, srcStream.ReaderOptions.ArchiveEncoding);
        }

        /// <summary>
        /// Constructor expects a filepath to an existing file.
        /// </summary>
        /// <param name="filePath"></param>
        /// <param name="readerOptions"></param>
        public static ZipArchive Open(string filePath, ReaderOptions? readerOptions = null)
        {
            filePath.CheckNotNullOrEmpty(nameof(filePath));
            return Open(new FileInfo(filePath), readerOptions ?? new ReaderOptions());
        }

        /// <summary>
        /// Constructor with a FileInfo object to an existing file.
        /// </summary>
        /// <param name="fileInfo"></param>
        /// <param name="readerOptions"></param>
        public static ZipArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null)
        {
            fileInfo.CheckNotNull(nameof(fileInfo));
            return new ZipArchive(new SourceStream(fileInfo, i => ZipArchiveVolumeFactory.GetFilePart(i, fileInfo), readerOptions ?? new ReaderOptions()));
        }

        /// <summary>
        /// Constructor with all file parts passed in
        /// </summary>
        /// <param name="fileInfos"></param>
        /// <param name="readerOptions"></param>
        public static ZipArchive Open(IEnumerable<FileInfo> fileInfos, ReaderOptions? readerOptions = null)
        {
            fileInfos.CheckNotNull(nameof(fileInfos));
            FileInfo[] files = fileInfos.ToArray();
            return new ZipArchive(new SourceStream(files[0], i => i < files.Length ? files[i] : null, readerOptions ?? new ReaderOptions()));
        }

        /// <summary>
        /// Constructor with all stream parts passed in
        /// </summary>
        /// <param name="streams"></param>
        /// <param name="readerOptions"></param>
        public static ZipArchive Open(IEnumerable<Stream> streams, ReaderOptions? readerOptions = null)
        {
            streams.CheckNotNull(nameof(streams));
            Stream[] strms = streams.ToArray();
            return new ZipArchive(new SourceStream(strms[0], i => i < strms.Length ? strms[i] : null, readerOptions ?? new ReaderOptions()));
        }

        /// <summary>
        /// Takes a seekable Stream as a source
        /// </summary>
        /// <param name="stream"></param>
        /// <param name="readerOptions"></param>
        public static ZipArchive Open(Stream stream, ReaderOptions? readerOptions = null)
        {
            stream.CheckNotNull(nameof(stream));
            return new ZipArchive(new SourceStream(stream, i => null, readerOptions ?? new ReaderOptions()));
        }

        public static bool IsZipFile(string filePath, string? password = null)
        {
            return IsZipFile(new FileInfo(filePath), password);
        }

        public static bool IsZipFile(FileInfo fileInfo, string? password = null)
        {
            if (!fileInfo.Exists)
            {
                return false;
            }
            using (Stream stream = fileInfo.OpenRead())
            {
                return IsZipFile(stream, password);
            }
        }

        public static bool IsZipFile(Stream stream, string? password = null)
        {
            StreamingZipHeaderFactory headerFactory = new StreamingZipHeaderFactory(password, new ArchiveEncoding());
            try
            {
                ZipHeader? header = headerFactory.ReadStreamHeader(stream).FirstOrDefault(x => x.ZipHeaderType != ZipHeaderType.Split);
                if (header is null)
                {
                    return false;
                }
                return Enum.IsDefined(typeof(ZipHeaderType), header.ZipHeaderType);
            }
            catch (CryptographicException)
            {
                return true;
            }
            catch
            {
                return false;
            }
        }

        public static bool IsZipMulti(Stream stream, string? password = null)
        {
            StreamingZipHeaderFactory headerFactory = new StreamingZipHeaderFactory(password, new ArchiveEncoding());
            try
            {
                ZipHeader? header = headerFactory.ReadStreamHeader(stream).FirstOrDefault(x => x.ZipHeaderType != ZipHeaderType.Split);
                if (header is null)
                {
                    if (stream.CanSeek) //could be multipart. Test for central directory - might not be z64 safe
                    {
                        SeekableZipHeaderFactory z = new SeekableZipHeaderFactory(password, new ArchiveEncoding());
                        var x = z.ReadSeekableHeader(stream).FirstOrDefault();
                        return x?.ZipHeaderType == ZipHeaderType.DirectoryEntry;
                    }
                    else
                        return false;
                }
                return Enum.IsDefined(typeof(ZipHeaderType), header.ZipHeaderType);
            }
            catch (CryptographicException)
            {
                return true;
            }
            catch
            {
                return false;
            }
        }

        protected override IEnumerable<ZipVolume> LoadVolumes(SourceStream srcStream)
        {
            base.SrcStream.LoadAllParts(); //request all streams
            base.SrcStream.Position = 0;

            List<Stream> streams = base.SrcStream.Streams.ToList();
            if (streams.Count > 1) //test part 2 - true = multipart not split
            {
                streams[1].Position += 4; //skip the POST_DATA_DESCRIPTOR to prevent an exception
                bool isZip = IsZipFile(streams[1], ReaderOptions.Password);
                streams[1].Position -= 4;
                if (isZip)
                {
                    base.SrcStream.IsVolumes = true;

                    var tmp = streams[0]; //arcs as zip, z01 ... swap the zip the end
                    streams.RemoveAt(0);
                    streams.Add(tmp);

                    //streams[0].Position = 4; //skip the POST_DATA_DESCRIPTOR to prevent an exception
                    return streams.Select(a => new ZipVolume(a, ReaderOptions));
                }
            }

            //split mode or single file
            return new ZipVolume(base.SrcStream, ReaderOptions).AsEnumerable();
        }

        internal ZipArchive()
            : base(ArchiveType.Zip)
        {
        }

        protected override IEnumerable<ZipArchiveEntry> LoadEntries(IEnumerable<ZipVolume> volumes)
        {
            var vols = volumes.ToArray();
            foreach (ZipHeader h in headerFactory.ReadSeekableHeader(vols.Last().Stream))
            {
                if (h != null)
                {
                    switch (h.ZipHeaderType)
                    {
                        case ZipHeaderType.DirectoryEntry:
                        {
                            DirectoryEntryHeader deh = (DirectoryEntryHeader)h;
                            Stream s;
                            if (deh.RelativeOffsetOfEntryHeader + deh.CompressedSize > vols[deh.DiskNumberStart].Stream.Length)
                            {
                                var v = vols.Skip(deh.DiskNumberStart).ToArray();
                                s = new SourceStream(v[0].Stream, i => i < v.Length ? v[i].Stream : null, new ReaderOptions() { LeaveStreamOpen = true });
                            }
                            else
                                s = vols[deh.DiskNumberStart].Stream;
                            yield return new ZipArchiveEntry(this, new SeekableZipFilePart(headerFactory, deh, s));
                        }
                        break;
                        case ZipHeaderType.DirectoryEnd:
                        {
                            byte[] bytes = ((DirectoryEndHeader)h).Comment ?? Array.Empty<byte>();
                            volumes.Last().Comment = ReaderOptions.ArchiveEncoding.Decode(bytes);
                            yield break;
                        }
                    }
                }
            }
        }

        public void SaveTo(Stream stream)
        {
            SaveTo(stream, new WriterOptions(CompressionType.Deflate));
        }

        protected override void SaveTo(Stream stream, WriterOptions options,
                                       IEnumerable<ZipArchiveEntry> oldEntries,
                                       IEnumerable<ZipArchiveEntry> newEntries)
        {
            using (var writer = new ZipWriter(stream, new ZipWriterOptions(options)))
            {
                foreach (var entry in oldEntries.Concat(newEntries)
                                                .Where(x => !x.IsDirectory))
                {
                    using (var entryStream = entry.OpenEntryStream())
                    {
                        writer.Write(entry.Key, entryStream, entry.LastModifiedTime);
                    }
                }
            }
        }

        protected override ZipArchiveEntry CreateEntryInternal(string filePath, Stream source, long size, DateTime? modified,
                                                               bool closeStream)
        {
            return new ZipWritableArchiveEntry(this, source, filePath, size, modified, closeStream);
        }

        public static ZipArchive Create()
        {
            return new ZipArchive();
        }

        protected override IReader CreateReaderForSolidExtraction()
        {
            var stream = Volumes.Single().Stream;
            stream.Position = 0;
            return ZipReader.Open(stream, ReaderOptions);
        }
    }
}
