using System;
using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using Newtonsoft.Json;
using System.Threading.Tasks;

namespace UdpClientLib
{
    public class SingleUdpClient : NetworkClientBase, IDisposable
    {
        private readonly UdpClient _udpClient;
        private readonly Queue<Func<Task>> _sendQueue;
        private readonly SemaphoreSlim _sendSemaphore;
        private bool _disposed;
        private byte _counter = 1; // 1 ~ 255 범위의 카운터

        public string jsonResponse;

        public SingleUdpClient(string name, string serverIp, int serverPort)
        {
            Name = name;
            _serverEndPoint = new IPEndPoint(IPAddress.Parse(serverIp), serverPort);
            _sendQueue = new Queue<Func<Task>>();
            _sendSemaphore = new SemaphoreSlim(1, 1);

            _udpClient = new UdpClient();
            Console.WriteLine($"[{Name}] UDP 클라이언트 생성, 서버: {_serverEndPoint}");
        }

        public async Task RunAsync(CancellationToken cancellationToken)
        {
            Console.WriteLine($"[{Name}] 클라이언트 Task 시작");

            try
            {
                while (!cancellationToken.IsCancellationRequested)
                {
                    await ProcessSendQueueAsync();
                    await CheckForIncomingMessages();

                    await Task.Delay(10, cancellationToken);
                }
            }
            catch (OperationCanceledException)
            {
                Console.WriteLine($"[{Name}] 클라이언트 Task 정상 종료");
            }
            catch (Exception ex)
            {
                Console.WriteLine($"[{Name}] 클라이언트 Task 오류: {ex.Message}");
            }
        }

        private async Task ProcessSendQueueAsync()
        {
            await _sendSemaphore.WaitAsync();
            try
            {
                while (_sendQueue.Count > 0)
                {
                    var sendAction = _sendQueue.Dequeue();
                    await sendAction();
                }
            }
            finally
            {
                _sendSemaphore.Release();
            }
        }

        private async Task CheckForIncomingMessages()
        {
            try
            {
                if (_udpClient.Available > 0)
                {
                    var result = await _udpClient.ReceiveAsync();
                    jsonResponse = Encoding.UTF8.GetString(result.Buffer);
                    Console.WriteLine($"[{Name}] 수신: \"{jsonResponse}\" (from {result.RemoteEndPoint})");
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine($"[{Name}] 수신 오류: {ex.Message}");
            }
        }

        public Task SendMessageAsync(string message)
        {

            var tcs = new TaskCompletionSource<bool>();

            _sendQueue.Enqueue(async () =>
            {
                try
                {
                    byte[] data = Encoding.UTF8.GetBytes(message);
                    await _udpClient.SendAsync(data, data.Length, _serverEndPoint);
                    Console.WriteLine($"[{Name}] 메시지 전송: \"{message}\"");
                    tcs.SetResult(true);
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"[{Name}] 전송 실패: {ex.Message}");
                    tcs.SetException(ex);
                }
            });

            return tcs.Task;
        }
        public Task SendBytesAsync(byte[] data)
        {

            var tcs = new TaskCompletionSource<bool>();

            _sendQueue.Enqueue(async () =>
            {
                try
                {
                    String hexString = BitConverter.ToString(data).Replace("-", "");
                    byte[] packet = Encoding.UTF8.GetBytes(hexString);

                    await _udpClient.SendAsync(packet, packet.Length, _serverEndPoint);
                    Console.WriteLine($"[{Name}] 바이트 전송: {data.Length} bytes");

                    if (data.Length <= 20)
                    {
                        Console.WriteLine($"데이터: [{string.Join(", ", data)}]");
                    }

                    tcs.SetResult(true);
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"[{Name}] 바이트 전송 실패: {ex.Message}");
                    tcs.SetException(ex);
                }
            });

            return tcs.Task;
        }

        public Task SendFilledBytesAsync(Dictionary<int, byte> customValues = null)
        {
            // 기본값: 0000000058000000000000 (12바이트)
            byte[] data = { 0x00, 0x00, 0x00, 0x00, 0x58, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };

            data[11] = _counter;  // 마지막 바이트에 더하기

            if (customValues != null)
            {
                foreach (var kvp in customValues)
                {
                    int index = kvp.Key;
                    byte value = kvp.Value;

                    if (index >= 0 && index < data.Length)
                    {
                        data[index] = value;
                    }
                    else
                    {
                        throw new ArgumentOutOfRangeException(nameof(customValues),
                            $"인덱스 {index}는 유효하지 않습니다. (0 ~ {data.Length - 1} 범위)");
                    }
                }
            }

            // 카운터 증가 (255 다음엔 1로 되돌아감)
            _counter++;
            if (_counter > 255)
                _counter = 1;

            return SendBytesAsync(data);
        }

        // HTTP 요청 전송
        public Task SendHttpRequestAsync(HttpRequest request)
        {
            //string httpPacket = CreateHttpRequest(request);

            return SendMessageAsync($"{request.Method} {request.Path}\r\nContent-Type: application/json; charset=utf-8\r\n\r\n");
        }

        public Task SendGetRequestAsync(string path, Dictionary<string, string> headers = null)
            => SendHttpRequestAsync(new HttpRequest(HttpMethod.GET, path, headers));

        public Task SendPostRequestAsync(string path, object body = null, Dictionary<string, string> headers = null)
        {
            string jsonBody;

            if (body == null)
            {
                jsonBody = null;
            }
            else if (body is string str)
            {
                jsonBody = str;
            }
            else
            {
                jsonBody = JsonConvert.SerializeObject(body);
            }
            return SendHttpRequestAsync(new HttpRequest(HttpMethod.POST, path, headers, jsonBody));
        }

        public void Dispose()
        {
            if (!_disposed)
            {
                _udpClient?.Dispose();
                _disposed = true;
                Console.WriteLine($"[{Name}] UDP 클라이언트 종료");
            }
        }
    }
}