using System;
using System.Collections.Concurrent;
using System.ComponentModel;
using System.IO.Ports;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json;
using TeamAAS.Communication.Attributes;
using TeamAAS.Communication.Base;
using TeamAAS.Communication.Interfaces;
using TeamAAS.Communication.Enums;

namespace TeamAAS.Communication.Devices
{
    [Communication("串口", "基础通讯", "RS232/RS485 串口通讯")]
    public class SerialCommunication : BindableCommunicationBase
    {
        [JsonIgnore]
        private SerialPort _serial;
        private readonly ConcurrentQueue<string> _received = new ConcurrentQueue<string>();
        [JsonIgnore]
        private readonly StringBuilder _receiveBuffer = new StringBuilder();
        [JsonIgnore]
        private System.Threading.Timer _reconnectTimer;
        [JsonIgnore]
        private volatile bool _hasConnectedOnce;
        [JsonIgnore]
        private volatile bool _manualDisconnect;
        [JsonIgnore]
        private volatile bool _isReconnecting;

        private string _portName = "COM1";
        [Category("II.客户端配置"), DisplayName("1.端口名称"), Description("串口名称，如 COM1")]
        [TypeConverter(typeof(ComPortListConverter))]
        public string PortName
        {
            get { return _portName; }
            set { if (SetProperty(ref _portName, value)) Notify(nameof(EndpointUrl)); }
        }

        private BaudRates _baudRate = BaudRates.BR_9600;
        [Category("II.客户端配置"), DisplayName("2.波特率"), Description("串口波特率")]
        public BaudRates BaudRate
        {
            get { return _baudRate; }
            set { if (SetProperty(ref _baudRate, value)) Notify(nameof(EndpointUrl)); }
        }

        private Parity _parity = Parity.None;
        [Category("II.客户端配置"), DisplayName("3.校验位"), Description("串口校验位")]
        public Parity Parity
        {
            get { return _parity; }
            set { SetProperty(ref _parity, value); }
        }

        private StopBits _stopBits = StopBits.One;
        [Category("II.客户端配置"), DisplayName("4.停止位"), Description("串口停止位")]
        public StopBits StopBits
        {
            get { return _stopBits; }
            set { SetProperty(ref _stopBits, value); }
        }

        private int _dataBits = 8;
        [Category("II.客户端配置"), DisplayName("5.数据位"), Description("串口数据位")]
        public int DataBits
        {
            get { return _dataBits; }
            set { SetProperty(ref _dataBits, value); }
        }


        private Terminator _terminator = Terminator.None;
        [Category("III.数据格式"), DisplayName("1.结束符"), Description("发送时自动附加、接收时自动去除的结束符")]
        public Terminator Terminator
        {
            get { return _terminator; }
            set { SetProperty(ref _terminator, value); }
        }

        private DataEncoding _dataEncoding = DataEncoding.Default;
        [Category("III.数据格式"), DisplayName("2.编码格式"), Description("收发数据的编码格式")]
        public DataEncoding DataEncoding
        {
            get { return _dataEncoding; }
            set { SetProperty(ref _dataEncoding, value); }
        }
        [Browsable(false)]
        public override string EndpointUrl
        {
            get { return $"serial://{PortName}?baud={BaudRate}"; }
            set
            {
                if (!string.IsNullOrWhiteSpace(value) && value.StartsWith("serial://"))
                {
                    var uri = new Uri(value);
                    PortName = uri.Host;
                }
            }
        }

        [JsonIgnore, Browsable(false)]
        public override bool IsConnected => (_serial != null && _serial.IsOpen);

        public override event Action<object, bool> ConnectChangedEvent;
        public override event Action<object, string> DataReceivedEvent;

        public override void Connect()
        {
            Disconnect();
            _serial = new SerialPort(PortName, (int)BaudRate, Parity, DataBits, StopBits);
            _serial.Encoding = GetEncoding();
            _serial.DataReceived += Serial_DataReceived;
            _serial.Open();
            _manualDisconnect = false;
            _hasConnectedOnce = true;
            StopReconnectTimer();
            ConnectChangedEvent?.Invoke(this, true);
            Notify(nameof(IsConnected));
        }

        public override Task ConnectAsync()
        {
            return Task.Run(() => Connect());
        }

        public override void Disconnect()
        {
            StopReconnectTimer();
            _manualDisconnect = true;
            if (_serial != null)
            {
                try { _serial.Close(); } catch { }
                _serial.Dispose();
                _serial = null;
            }

            ConnectChangedEvent?.Invoke(this, false);
            Notify(nameof(IsConnected));
        }

        public override void Dispose()
        {
            Disconnect();
        }

        private void Serial_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            try
            {
                var sp = sender as SerialPort;
                if (sp == null) return;
                var text = sp.ReadExisting();
                if (!string.IsNullOrEmpty(text))
                {
                    _receiveBuffer.Append(text);
                    FlushReceivedMessages(_receiveBuffer);
                }
            }
            catch
            {
                if (_hasConnectedOnce && !_manualDisconnect)
                    StartAutoReconnect();
            }
        }


        /// <summary>
        /// 获取编码
        /// </summary>
        public Encoding GetEncoding()
        {
            switch (DataEncoding)
            {
                case DataEncoding.ASCII: return Encoding.ASCII;
                case DataEncoding.UTF7: return Encoding.UTF7;
                case DataEncoding.UTF8: return Encoding.UTF8;
                case DataEncoding.UTF32: return Encoding.UTF32;
                case DataEncoding.Unicode: return Encoding.Unicode;
                case DataEncoding.BigEndianUnicode: return Encoding.BigEndianUnicode;
                case DataEncoding.GB2312: return Encoding.GetEncoding("gb2312");
                default: return Encoding.Default;
            }
        }

        /// <summary>
        /// 获取结束符字符串
        /// </summary>
        public string GetTerminatorString()
        {
            switch (Terminator)
            {
                case Terminator.CR: return "\r";
                case Terminator.LF: return "\n";
                case Terminator.CRLF: return "\r\n";
                case Terminator.None:
                default: return string.Empty;
            }
        }

        /// <summary>
        /// 去除数据尾部结束符
        /// </summary>
        public string TrimTerminator(string text)
        {
            if (string.IsNullOrEmpty(text)) return text;
            var term = GetTerminatorString();
            if (string.IsNullOrEmpty(term)) return text;
            return text.EndsWith(term) ? text.Substring(0, text.Length - term.Length) : text;
        }

        /// <summary>
        /// 按结束符分帧：收到完整结束符才触发接收事件；无结束符时直接触发
        /// </summary>
        private void FlushReceivedMessages(StringBuilder receiveBuffer)
        {
            var term = GetTerminatorString();
            if (string.IsNullOrEmpty(term))
            {
                if (receiveBuffer.Length > 0)
                {
                    var text = receiveBuffer.ToString();
                    receiveBuffer.Clear();
                    _received.Enqueue(text);
                    DataReceivedEvent?.Invoke(this, text);
                }
                return;
            }

            string content = receiveBuffer.ToString();
            int idx;
            while ((idx = content.IndexOf(term, StringComparison.Ordinal)) >= 0)
            {
                var msg = content.Substring(0, idx);
                content = content.Substring(idx + term.Length);
                _received.Enqueue(msg);
                DataReceivedEvent?.Invoke(this, msg);
            }
            receiveBuffer.Clear();
            receiveBuffer.Append(content);
        }


        /// <summary>
        /// 自动重连：初始化连接成功过，掉线后每5秒尝试连接一次
        /// </summary>
        private void StartAutoReconnect()
        {
            if (_reconnectTimer != null) return;
            if (_serial != null)
            {
                try { _serial.Close(); } catch { }
                _serial.Dispose();
                _serial = null;
            }
            ConnectChangedEvent?.Invoke(this, false);
            Notify(nameof(IsConnected));
            _reconnectTimer = new System.Threading.Timer(ReconnectTimer_Elapsed, null, TimeSpan.FromSeconds(5), TimeSpan.FromSeconds(5));
        }

        private void ReconnectTimer_Elapsed(object state)
        {
            if (_manualDisconnect) { StopReconnectTimer(); return; }
            if (_isReconnecting) return;
            _isReconnecting = true;
            try
            {
                if (_serial != null)
                {
                    try { _serial.Close(); } catch { }
                    _serial.Dispose();
                    _serial = null;
                }
                var serial = new SerialPort(PortName, (int)BaudRate, Parity, DataBits, StopBits);
                serial.Encoding = GetEncoding();
                serial.DataReceived += Serial_DataReceived;
                try
                {
                    serial.Open();
                    _serial = serial;
                    StopReconnectTimer();
                    ConnectChangedEvent?.Invoke(this, true);
                    Notify(nameof(IsConnected));
                }
                catch
                {
                    try { serial.Dispose(); } catch { }
                }
            }
            finally
            {
                _isReconnecting = false;
            }
        }

        private void StopReconnectTimer()
        {
            var t = _reconnectTimer;
            _reconnectTimer = null;
            if (t != null) { try { t.Dispose(); } catch { } }
        }


        public void Send(string text)
        {
            if (_serial == null || !_serial.IsOpen)
                throw new InvalidOperationException("串口未连接。");

            _serial.Write((text ?? string.Empty) + GetTerminatorString());
        }

        public override object ReadValue(string address)
        {
            _received.TryDequeue(out var text);
            return text;
        }

        public override Task<object> ReadValueAsync(string address)
        {
            return Task.FromResult(ReadValue(address));
        }

        public override void WriteValue(string address, object value)
        {
            Send(value?.ToString() ?? string.Empty);
        }

        public override Task WriteValueAsync(string address, object value)
        {
            Send(value?.ToString() ?? string.Empty);
            return Task.CompletedTask;
        }
    }
}