using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using DotNetty.Buffers;
using DotNetty.Codecs;
using DotNetty.Transport.Channels;
using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using HybirdFrameworkEntity;

namespace Module.Socket.Tool
{
    public class CustomFrameDecoder4 : ByteToMessageDecoder
    {
        private readonly IByteBuffer[] delimiters;
        private readonly bool stripDelimiter;
        private readonly bool failFast;

        public CustomFrameDecoder4(IByteBuffer[] delimiters, bool stripDelimiter, bool failFast)
        {
            this.delimiters = delimiters;
            this.stripDelimiter = stripDelimiter;
            this.failFast = failFast;
        }

        protected override void Decode(IChannelHandlerContext ctx, IByteBuffer buffer, List<object> output)
        {

            // 查找分隔符
            IByteBuffer delimiter = FindDelimiter(buffer);
            if (delimiter != null)
            {
                int delimiterIndex = IndexOf(buffer, delimiter);//分隔符索引
                int frameLengthIndex = delimiterIndex + delimiter.Capacity;//帧长度索引

                if (delimiterIndex > 0)
                {
                    buffer.SkipBytes(delimiterIndex);
                    return;
                }

                if (buffer.ReadableBytes < frameLengthIndex + 2)
                {
                    // 数据不足，等待更多数据
                    return;
                }

                // 读取长度字段
                int frameLength = buffer.GetUnsignedShortLE(buffer.ReaderIndex + frameLengthIndex);
                int totalFrameLength = delimiterIndex + delimiter.Capacity + 2 + frameLength;

                if (buffer.ReadableBytes < totalFrameLength)
                {
                    // 数据不足，等待更多数据
                    return;
                }

                byte[] bytes = new byte[totalFrameLength];
                buffer.ReadBytes(bytes);

                {
                    string input = ctx.Channel.RemoteAddress.ToString();

                    // 正则表达式匹配IPv4地址和端口号  
                    string pattern = @"\[(::ffff:)?(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})\]:(\d+)";
                    Match match = Regex.Match(input, pattern);

                    // 获取IP地址（不包括IPv6前缀）  
                    string ipAddress = match.Groups[2].Value;
                    // 获取端口号  
                    string port = match.Groups[3].Value;


                    int checksum = 0;
                    for (int i = 6; i < bytes.Count() - 1; i++)//这里有校验域所以减一
                    {
                        checksum += bytes[i];
                    }

                    // 取校验和的低8位  
                    //byte b1 = (byte)(checksum & 0xFF);
                    //byte b2 = bytes[bytes.Count() - 1];
                    if (bytes[bytes.Count() - 1] == (byte)(checksum & 0xFF))
                    {
                        var info = bytes[4];
                        if ((info & (1 << 1)) != 0)//AES加密
                        {
                            //这里要解密
                            List<byte> byteList = bytes.ToList();
                            byteList.Remove(8);
                            byteList.Remove(8);//移除前面两个长度
                            bytes = byteList.ToArray();
                            
                            new Decode().decode(ipAddress, port, bytes);
                        }
                        else //不加密
                        {
                            new Decode().decode(ipAddress, port, bytes);
                        }
                    }
                    //ctx.Channel.WriteAndFlushAsync(bytes);
                }
                output.Add(bytes);
            }
        }

        private IByteBuffer FindDelimiter(IByteBuffer buffer)
        {
            foreach (IByteBuffer delimiter in delimiters)
            {
                int delimiterIndex = IndexOf(buffer, delimiter);
                if (delimiterIndex >= 0)
                {
                    return delimiter;
                }
            }
            return null;
        }

        private static int IndexOf(IByteBuffer haystack, IByteBuffer needle)
        {
            for (int i = haystack.ReaderIndex; i < haystack.WriterIndex; i++)
            {
                int num = i;
                int j;
                for (j = 0; j < needle.Capacity && haystack.GetByte(num) == needle.GetByte(j); j++)
                {
                    num++;
                    if (num == haystack.WriterIndex && j != needle.Capacity - 1)
                    {
                        return -1;
                    }
                }

                if (j == needle.Capacity)
                {
                    return i - haystack.ReaderIndex;
                }
            }

            return -1;
        }

    }

}