using System.Text;
using System.IO.Ports;

namespace DeviceCommand.Base
{
    public class Serial_Port
    {
        public string PortName { get; set; } = "COM1";
        public int BaudRate { get; set; } = 9600;
        public int DataBits { get; set; } = 8;
        public StopBits StopBits { get; set; } = StopBits.One;
        public Parity Parity { get; set; } = Parity.None;
        public int ReadTimeout { get; set; } = 3000;
        public int WriteTimeout { get; set; } = 3000;
        public SerialPort _SerialPort { get; set; } = new SerialPort();

        public Serial_Port CreateDevice(string portName, int baudRate, int dataBits = 8, StopBits stopBits = StopBits.One, Parity parity = Parity.None, int readTimeout = 3000, int writeTimeout = 3000)
        {
            PortName = portName;
            BaudRate = baudRate;
            DataBits = dataBits;
            StopBits = stopBits;
            Parity = parity;
            ReadTimeout = readTimeout;
            WriteTimeout = writeTimeout;
            return this;
        }

        public static void ChangeDeviceConfig(Serial_Port serialPort, string PortName, int BaudRate, int dataBits = 8, StopBits stopBits = StopBits.One, Parity parity = Parity.None, int ReadTimeout = 3000, int WriteTimeout = 3000)
        {
            serialPort.PortName = PortName;
            serialPort.BaudRate = BaudRate;
            serialPort.DataBits = dataBits;
            serialPort.StopBits = stopBits;
            serialPort.Parity = parity;
            if (ReadTimeout > 0) serialPort.ReadTimeout = ReadTimeout;
            if (WriteTimeout > 0) serialPort.WriteTimeout = WriteTimeout;
        }

        public static async Task<bool> ConnectAsync(Serial_Port serialPort, CancellationToken ct = default)
        {
            if (serialPort._SerialPort.PortName != serialPort.PortName
                || serialPort._SerialPort.BaudRate != serialPort.BaudRate
                || serialPort._SerialPort.Parity != serialPort.Parity
                || serialPort._SerialPort.DataBits != serialPort.DataBits
                || serialPort._SerialPort.StopBits != serialPort.StopBits
                || serialPort._SerialPort.ReadTimeout != serialPort.ReadTimeout
                || serialPort._SerialPort.WriteTimeout != serialPort.WriteTimeout)
            {
                serialPort._SerialPort.Close();
                serialPort._SerialPort.PortName = serialPort.PortName;
                serialPort._SerialPort.BaudRate = serialPort.BaudRate;
                serialPort._SerialPort.Parity = serialPort.Parity;
                serialPort._SerialPort.DataBits = serialPort.DataBits;
                serialPort._SerialPort.StopBits = serialPort.StopBits;
                serialPort._SerialPort.ReadTimeout = serialPort.ReadTimeout;
                serialPort._SerialPort.WriteTimeout = serialPort.WriteTimeout;
                serialPort._SerialPort.Open();
            }
            else if (!serialPort._SerialPort.IsOpen)
            {
                serialPort._SerialPort.Open();
            }
            return true;
        }

        public static void Close(Serial_Port serialPort)
        {
            if (serialPort._SerialPort.IsOpen) serialPort._SerialPort.Close();
        }

        public static async Task SendAsync(Serial_Port serialPort, byte[] bytes, CancellationToken ct = default)
        {
            if (!serialPort._SerialPort.IsOpen) return;
            var timeoutMs = serialPort.WriteTimeout;
            if (timeoutMs <= 0)
            {
                serialPort._SerialPort.Write(bytes, 0, bytes.Length);
                return;
            }
            var sendTask = Task.Run(() => serialPort._SerialPort.Write(bytes, 0, bytes.Length), ct);
            var timeoutTask = Task.Delay(timeoutMs, ct);
            var completedTask = await Task.WhenAny(sendTask, timeoutTask);
            if (completedTask == timeoutTask) throw new TimeoutException($"串口通讯异常：写入操作在 {timeoutMs} ms内未完成");
            await sendTask;
        }

        public static async Task SendAsync(Serial_Port serialPort, string str, CancellationToken ct = default)
        {
            if (!serialPort._SerialPort.IsOpen) return;
            byte[] bytes = Encoding.UTF8.GetBytes(str);
            await SendAsync(serialPort, bytes, ct);
        }

        public static async Task<byte[]> ReadAsync(Serial_Port serialPort, byte[] buffer, CancellationToken ct = default)
        {
            if (!serialPort._SerialPort.IsOpen) return null;
            var timeoutMs = serialPort.ReadTimeout;
            var readTask = ReadByte(serialPort, buffer, ct);
            if (timeoutMs <= 0) return await readTask;
            var timeoutTask = Task.Delay(timeoutMs, ct);
            var completedTask = await Task.WhenAny(readTask, timeoutTask);
            if (completedTask == timeoutTask) throw new TimeoutException($"串口通讯异常：读取操作在 {timeoutMs} ms内未完成");
            return await readTask;
        }

        public static async Task<byte[]> ReadByte(Serial_Port serialPort, byte[] buffer, CancellationToken ct)
        {
            int bytesRead = 0;
            while (bytesRead < buffer.Length)
            {
                if (serialPort._SerialPort.BytesToRead > 0)
                {
                    bytesRead += serialPort._SerialPort.Read(buffer, bytesRead, buffer.Length - bytesRead);
                }
            }
            return buffer;
        }

        public static async Task<string> ReadAsync(Serial_Port serialPort, string delimiter = "\n", CancellationToken ct = default)
        {
            if (!serialPort._SerialPort.IsOpen) return null;
            var timeoutMs = serialPort.ReadTimeout;
            var readTask = ReadDefaultString(serialPort, delimiter, ct);
            if (timeoutMs <= 0) return await readTask;
            var timeoutTask = Task.Delay(timeoutMs, ct);
            var completedTask = await Task.WhenAny(readTask, timeoutTask);
            if (completedTask == timeoutTask) throw new TimeoutException($"串口通讯异常：读取操作在 {timeoutMs} ms内未完成");
            return await readTask;
        }

        private static async Task<string> ReadDefaultString(Serial_Port serialPort, string delimiter, CancellationToken ct)
        {
            delimiter ??= "\n";
            MemoryStream memoryStream = new();
            byte[] buffer = new byte[2048];
            string data = string.Empty;
            await Task.Run(() =>
            {
                while (true)
                {
                    if (ct.IsCancellationRequested) return;
                    if (serialPort._SerialPort.BytesToRead > 0)
                    {
                        int bytesRead = serialPort._SerialPort.Read(buffer, 0, buffer.Length);
                        memoryStream.Write(buffer, 0, bytesRead);
                        data = Encoding.UTF8.GetString(memoryStream.ToArray());
                        int lineEndIndex = data.IndexOf(delimiter);
                        if (lineEndIndex >= 0)
                        {
                            data = data.Substring(0, lineEndIndex).Trim();
                            return;
                        }
                    }
                }
            }, ct);
            return data;
        }
    }
}