// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.

namespace WixToolset.Dtf.Compression
{
    using System;
    using System.IO;
    using System.Diagnostics.CodeAnalysis;

    /// <summary>
    /// Stream context used to extract a single file from an archive into a memory stream.
    /// </summary>
    [SuppressMessage("Microsoft.Design", "CA1001:TypesThatOwnDisposableFieldsShouldBeDisposable")]
    public class BasicUnpackStreamContext : IUnpackStreamContext
    {
        private Stream archiveStream;
        private Stream fileStream;

        /// <summary>
        /// Creates a new BasicExtractStreamContext that reads from the specified archive stream.
        /// </summary>
        /// <param name="archiveStream">Archive stream to read from.</param>
        public BasicUnpackStreamContext(Stream archiveStream)
        {
            this.archiveStream = archiveStream;
        }

        /// <summary>
        /// Gets the stream for the extracted file, or null if no file was extracted.
        /// </summary>
        public Stream FileStream
        {
            get
            {
                return this.fileStream;
            }
        }

        /// <summary>
        /// Opens the archive stream for reading. Returns a DuplicateStream instance,
        /// so the stream may be virtually opened multiple times.
        /// </summary>
        /// <param name="archiveNumber">The archive number to open (ignored; 0 is assumed).</param>
        /// <param name="archiveName">The name of the archive being opened.</param>
        /// <param name="compressionEngine">Instance of the compression engine doing the operations.</param>
        /// <returns>A stream from which archive bytes are read.</returns>
        public Stream OpenArchiveReadStream(int archiveNumber, string archiveName, CompressionEngine compressionEngine)
        {
            return new DuplicateStream(this.archiveStream);
        }

        /// <summary>
        /// Does *not* close the stream. The archive stream should be managed by
        /// the code that invokes the archive extraction.
        /// </summary>
        /// <param name="archiveNumber">The archive number of the stream to close.</param>
        /// <param name="archiveName">The name of the archive being closed.</param>
        /// <param name="stream">The stream being closed.</param>
        public void CloseArchiveReadStream(int archiveNumber, string archiveName, Stream stream)
        {
            // Do nothing.
        }

        /// <summary>
        /// Opens a stream for writing extracted file bytes. The returned stream is a MemoryStream
        /// instance, so the file is extracted straight into memory.
        /// </summary>
        /// <param name="path">Path of the file within the archive.</param>
        /// <param name="fileSize">The uncompressed size of the file to be extracted.</param>
        /// <param name="lastWriteTime">The last write time of the file.</param>
        /// <returns>A stream where extracted file bytes are to be written.</returns>
        public Stream OpenFileWriteStream(string path, long fileSize, DateTime lastWriteTime)
        {
            this.fileStream = new MemoryStream(new byte[fileSize], 0, (int) fileSize, true, true);
            return this.fileStream;
        }

        /// <summary>
        /// Does *not* close the file stream. The file stream is saved in memory so it can
        /// be read later.
        /// </summary>
        /// <param name="path">Path of the file within the archive.</param>
        /// <param name="stream">The file stream to be closed.</param>
        /// <param name="attributes">The attributes of the extracted file.</param>
        /// <param name="lastWriteTime">The last write time of the file.</param>
        public void CloseFileWriteStream(string path, Stream stream, FileAttributes attributes, DateTime lastWriteTime)
        {
            // Do nothing.
        }
    }
}