using Edge.Core.Parser.BinaryParser.Util;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Abstractions;
using PetroChinaOnlineWatchPlugin.MessageEntity.Outgoing;
using System;
using System.Diagnostics;
using System.Net;
using System.Net.Sockets;

namespace PetroChinaOnlineWatchPlugin
{
    internal class HeartBeatUdpProxy
    {
        public event EventHandler OnDataReceived;
        public static HeartBeatUdpProxy Default => instance;
        private static readonly HeartBeatUdpProxy instance = new HeartBeatUdpProxy();

        private int heartBeatUdpPortNumber = 0;
        private UdpClient heartBeatUdpClient;
        private ILogger logger = NullLogger.Instance;
        private string localIpAddresses = string.Empty;
        private string broadcastIpAddresses = string.Empty;
        private AppConfigV1 appConfig;

        public bool Start(AppConfigV1 appConfig, ILogger logger)
        {
            this.appConfig = appConfig;
            this.logger = logger;
            heartBeatUdpPortNumber = appConfig.HeartBeatPortNumber;
            // setup heartBeat UdpClient
            heartBeatUdpClient = new UdpClient(new IPEndPoint(IPAddress.Any, heartBeatUdpPortNumber))
            { EnableBroadcast = true };
            heartBeatUdpClient.BeginReceive(Udp_DataReceived, null);

            GetLocalIp();

            return true;
        }

        public void Udp_SendData()
        {
            try
            {
                var outHeartBeat = new HeartBeatOut()
                {
                    IpAddress = localIpAddresses,
                    Port = ConnectionController.Default.TcpListenPort,
                    Subnet = appConfig.LocalSubnet,
                    Node = appConfig.LocalNode
                };
                byte[] heartBeatRawDataToSend = Parser.Default.Serialize(outHeartBeat);
                logger.LogTrace($"Udp Outgoing--->: 0x{heartBeatRawDataToSend.ToHexLogString()}");
                heartBeatUdpClient.Send(heartBeatRawDataToSend, heartBeatRawDataToSend.Length,
                    broadcastIpAddresses, heartBeatUdpPortNumber);
            }
            catch (Exception ex)
            {
                logger.LogError($"Exception in Udp_SendData(...):\r\n{ex}");
            }
        }

        private void Udp_DataReceived(IAsyncResult ar)
        {
            try
            {
                // IFSF always have 10 bytes heartbeat:  ip0.ip1.ip2,ip3,port(2 bytes),4 ifsf standard bytes
                var broadcastHeartBeatReceiveEP = new IPEndPoint(IPAddress.Any, 0);
                byte[] heartBeatBytes = heartBeatUdpClient.EndReceive(ar, ref broadcastHeartBeatReceiveEP);
                logger.LogTrace($"Udp Incoming--->: 0x{heartBeatBytes.ToHexLogString()}");
                dynamic heartBeat = Parser.Default.Deserialize(heartBeatBytes);
                logger.LogTrace($"HeartBeatIncoming--->: {heartBeat.ToString()}");

                if (heartBeat.Subnet == appConfig.RemoteSubnet && heartBeat.Node == appConfig.RemoteNode)
                {
                    logger.LogTrace($"Received heart beat from IpAddress:Port, {heartBeat.ToString()}");
                    if (!ConnectionController.Default.TcpClientInstance.Connected)
                        OnDataReceived?.Invoke(this, new UdpDataEventArgs() { IpAddress = heartBeat.IpAddress, Port = heartBeat.Port });
                }
            }
            catch (Exception ex)
            {
                logger.LogError($"Exception in Udp_DataReceived(...):\r\n{ex}");
            }
            finally
            {
                heartBeatUdpClient.BeginReceive(Udp_DataReceived, null);
            }
        }

        private void GetLocalIp()
        {
            try
            {
                //var localIpAddresses = NetworkInterface.GetAllNetworkInterfaces()
                //    .Where(i => i.SupportsMulticast && i.Supports(NetworkInterfaceComponent.IPv4))
                //    .SelectMany(i => i.GetIPProperties().UnicastAddresses)
                //    .Select(ad => ad.Address)
                //    .Where(ad => ad.AddressFamily == AddressFamily.InterNetwork);
                //logger.LogInformation("Local ip addresses are: " + localIpAddresses.Select(i => i.ToString())
                //    .Aggregate((acc, n) => acc + ", " + n));
                var cmd = new Process();
                cmd.StartInfo.FileName = "ipconfig.exe";
                cmd.StartInfo.RedirectStandardOutput = true;
                cmd.StartInfo.RedirectStandardInput = true;
                cmd.StartInfo.UseShellExecute = false;
                cmd.StartInfo.CreateNoWindow = true;

                cmd.Start();
                string info = cmd.StandardOutput.ReadToEnd();
                cmd.WaitForExit();
                cmd.Close();

                info = info.Substring(info.IndexOf(appConfig.NetworkConnections));
                string ipFlag = "IPv4 Address. . . . . . . . . . . : ";
                int index = info.IndexOf(ipFlag);
                if (index > 0)
                {
                    info = info?.Substring(index + ipFlag.Length);
                }
                else
                {
                    ipFlag = "IPv4 地址 . . . . . . . . . . . . : ";
                    info = info?.Substring(info.IndexOf(ipFlag) + ipFlag.Length);
                }
                localIpAddresses = info?.Split("\r\n")[0];
                logger.LogInformation($"Local ip addresses is: {localIpAddresses}");
                ipFlag = "Subnet Mask . . . . . . . . . . . : ";
                index = info.IndexOf(ipFlag);
                if (index > 0)
                {
                    info = info?.Substring(index + ipFlag.Length);
                }
                else
                {
                    ipFlag = "子网掩码  . . . . . . . . . . . . : ";
                    info = info?.Substring(info.IndexOf(ipFlag) + ipFlag.Length);
                }
                string subnetMask = info?.Split("\r\n")[0];
                logger.LogInformation($"Local subnet mask is: {subnetMask}");
                broadcastIpAddresses = GetBroadcastIpAddresses(localIpAddresses, subnetMask);
                logger.LogInformation($"Broadcast ip addresses is: {broadcastIpAddresses}");
            }
            catch (Exception ex)
            {
                logger.LogError($"Exception in GetLocalIp(...):\r\n{ex}");
            }
        }

        private string GetBroadcastIpAddresses(string ipAddress, string subnetMask)
        {
            byte[] ipBuffer = IpAddress2Bytes(ipAddress);
            byte[] smBuffer = IpAddress2Bytes(subnetMask);
            return $"{ipBuffer[0] | Negate(smBuffer[0])}.{ipBuffer[1] | Negate(smBuffer[1])}." +
                $"{ipBuffer[2] | Negate(smBuffer[2])}.{ipBuffer[3] | Negate(smBuffer[3])}";
        }

        private byte Negate(byte value)
        {
            int first = value >> 7;
            if (first == 1)
            {
                value = (byte)(value & 0x7F);
                value = (byte)(~value & 0x7F);
            }
            else
            {
                value = (byte)(~value);
            }
            return value;
        }

        private byte[] IpAddress2Bytes(string ipAddress)
        {
            byte[] buffer = new byte[4];
            int i = 0;
            foreach (string item in ipAddress.Split('.'))
            {
                buffer[i++] = byte.Parse(item);
            }
            return buffer;
        }
    }

    public class UdpDataEventArgs : EventArgs
    {
        public string IpAddress { get; set; }
        public int Port { get; set; }
    }
}