using System;
using System.IO;
using System.Threading;

namespace Capnp.Net.Runtime.Tests
{
    class FluctStream : Stream
    {
        readonly Stream _baseStream;
        readonly Random _rng = new Random();
        
        public FluctStream(Stream baseStream)
        {
            _baseStream = baseStream;
        }

        public override bool CanRead => _baseStream.CanRead;

        public override bool CanSeek => false;

        public override bool CanWrite => _baseStream.CanWrite;

        public override long Length => _baseStream.Length;

        public override long Position
        {
            get => _baseStream.Position;
            set => throw new NotImplementedException();
        }

        public override void Flush() => _baseStream.Flush();

        public override int Read(byte[] buffer, int offset, int count)
        {
            int n = _rng.Next(0, 8);
            if (n >= 7)
                Thread.Sleep(n - 7);
            return _baseStream.Read(buffer, offset, count);
        }

        public override long Seek(long offset, SeekOrigin origin) => throw new NotImplementedException();

        public override void SetLength(long value) => throw new NotImplementedException();

        public override void Write(byte[] buffer, int offset, int count)
        {
            _baseStream.Write(buffer, offset, count);
        }
    }
}