namespace Supercell.Laser.Titan.DataStream
{
    using System;
    using System.IO;
    using System.IO.Compression;
    using System.Text;

    public class LogicCompressedString
    {
        private string m_string;
        public LogicCompressedString(string str) => m_string = str ?? string.Empty;
        public string GetString() => m_string;

        public static LogicCompressedString Decode(ByteStream stream)
        {
            if (stream == null || stream.IsAtEnd()) return null;
            int length = stream.ReadBytesLength();
            if (length <= 0) return new LogicCompressedString(string.Empty);
            byte[] bytes = stream.ReadBytes(length, 900000);
            if (bytes == null || bytes.Length == 0) return new LogicCompressedString(string.Empty);

            try
            {
                if (bytes.Length > 4 && (bytes[4] == 0x78 || bytes[4] == 0x58))
                {
                    using var ms = new MemoryStream(bytes, 4, bytes.Length - 4);
                    using var zlib = new ZLibStream(ms, CompressionMode.Decompress);
                    using var outMs = new MemoryStream();
                    zlib.CopyTo(outMs);
                    return new LogicCompressedString(Encoding.UTF8.GetString(outMs.ToArray()));
                }
                return new LogicCompressedString(Encoding.UTF8.GetString(bytes));
            }
            catch { return new LogicCompressedString(Encoding.UTF8.GetString(bytes)); }
        }

        public static void Encode(LogicCompressedString compStr, ByteStream stream)
        {
            if (stream == null) return;
            string str = compStr?.GetString();
            if (string.IsNullOrEmpty(str))
            {
                stream.WriteInt(-1);
                return;
            }
            byte[] rawBytes = Encoding.UTF8.GetBytes(str);
            try
            {
                using var outMs = new MemoryStream();
                outMs.WriteByte((byte)(rawBytes.Length >> 24));
                outMs.WriteByte((byte)(rawBytes.Length >> 16));
                outMs.WriteByte((byte)(rawBytes.Length >> 8));
                outMs.WriteByte((byte)rawBytes.Length);
                using (var zlib = new ZLibStream(outMs, CompressionLevel.Optimal, true))
                {
                    zlib.Write(rawBytes, 0, rawBytes.Length);
                }
                byte[] compressed = outMs.ToArray();
                stream.WriteBytes(compressed, compressed.Length);
            }
            catch { stream.WriteString(str); }
        }
    }
}