using System;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Threading;

namespace MultithreadingSample
{
    class FileCompressor
    {
        private const int BufferSize = 1 << 16;
        private readonly BlockingQueue<byte[]> _readingQueue = new BlockingQueue<byte[]>(8);
        //private readonly BlockingQueue<byte[]> _writingQueue = new BlockingQueue<byte[]>(8);

        public void Compress(string input, string output = null)
        {
            if (string.IsNullOrWhiteSpace(output))
            {
                output = input + ".gz";
            }

            try
            {
                using (var queue = new BlockingQueue<byte[]>(8))
                {
                    if (!File.Exists(input)) return;

                    Thread reader = new Thread(() =>
                    {
                        using (var inputStream = new FileStream(input, FileMode.Open))
                        {
                            var buffer = new byte[BufferSize];
                            while (inputStream.Read(buffer, 0, BufferSize) != 0)
                            {
                                _readingQueue.Enqueue(buffer.ToArray());
                            }
                        }
                    })
                    {
                        Name = "Reader"
                    };
                    reader.Start();

                    for (int i = 0; i < 7; i++)
                    {
                        Thread compressor = new Thread(() =>
                        {
                            using (var outputStream = new FileStream(output, FileMode.Create))
                            using (var gZipStream = new GZipStream(outputStream, CompressionMode.Compress))
                            {
                                while (true)
                                {
                                    gZipStream.Write(_readingQueue.Dequeue(), 0, BufferSize);
                                }
                            }
                        })
                        {
                            Name = "Compressor" + i
                        };
                        compressor.Start();
                    }
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
                throw;
            }
        }

        public void Decompress(string input)
        {

        }
    }
}