using System;
using System.IO.Ports;
using System.Threading.Tasks;

namespace ASTM_D7896_Tester.Services
{
    public class FiveHalfDmmService : IDisposable
    {
        private SerialPort _serialPort;
        private bool _disposed;

        public FiveHalfDmmService(string portName, int baudRate = 115200)
        {
            _serialPort = new SerialPort(portName, baudRate, Parity.None, 8, StopBits.One);
            _serialPort.ReadTimeout = 2000;
            _serialPort.WriteTimeout = 1000;
            _serialPort.NewLine = "\n";
        }

        public void Open()
        {
            if (!_serialPort.IsOpen)
                _serialPort.Open();
        }

        public void Close()
        {
            if (_serialPort.IsOpen)
                _serialPort.Close();
        }

        public bool IsOpen => _serialPort?.IsOpen == true;

        private async Task<string> QueryAsync(string command)
        {
            if (!_serialPort.IsOpen) throw new InvalidOperationException("串口未打开");
            // 使用 Task.Run 避免阻塞 UI 线程
            var tcs = new TaskCompletionSource<string>();
            Task.Run(() =>
            {
                try
                {
                    _serialPort.WriteLine(command);
                    string result = _serialPort.ReadLine();
                    tcs.SetResult(result);
                }
                catch (Exception ex)
                {
                    tcs.SetException(ex);
                }
            });
            return await tcs.Task;
        }

        private async Task SendCommandAsync(string command)
        {
            if (!_serialPort.IsOpen) throw new InvalidOperationException("串口未打开");
            await Task.Run(() => _serialPort.WriteLine(command));
        }

        /// <summary>
        /// 配置为高速直流电压测量（FAST 分辨率）
        /// </summary>
        public async Task ConfigureHighSpeedDcvAsync()
        {
            await SendCommandAsync("CONFigure:VOLTage:DC AUTO");
            await SendCommandAsync("SENSe:VOLTage:DC:RESolution FAST");
            await SendCommandAsync("TRIGger:SOURce BUS");   // 使用软件触发
            await SendCommandAsync("TRIGger:DELay:AUTO OFF");
            await SendCommandAsync("TRIGger:DELay 0");
        }

        /// <summary>
        /// 预置采样点数并进入等待触发状态
        /// </summary>
        public async Task PrepareBatchAsync(int sampleCount)
        {
            await SendCommandAsync($"SAMPle:COUNt {sampleCount}");
            await SendCommandAsync("INITiate");
        }

        /// <summary>
        /// 发送触发信号（*TRG）
        /// </summary>
        public async Task TriggerAsync()
        {
            await SendCommandAsync("*TRG");
        }

        /// <summary>
        /// 获取批量采集结果（在 PrepareBatchAsync 和 TriggerAsync 之后调用）
        /// </summary>
        public async Task<double[]> FetchBatchAsync()
        {
            string response = await QueryAsync("FETCh?");
            string[] parts = response.Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
            double[] values = new double[parts.Length];
            for (int i = 0; i < parts.Length; i++)
            {
                if (!double.TryParse(parts[i], System.Globalization.NumberStyles.Float,
                        System.Globalization.CultureInfo.InvariantCulture, out values[i]))
                    throw new Exception($"解析失败: {parts[i]}");
            }
            return values;
        }

        /// <summary>
        /// 单次读取电压（用于实时监控）
        /// </summary>
        public async Task<double> ReadVoltageAsync()
        {
            string resp = await QueryAsync("MEASure:VOLTage:DC?");
            if (double.TryParse(resp, System.Globalization.NumberStyles.Float,
                    System.Globalization.CultureInfo.InvariantCulture, out double value))
                return value;
            throw new Exception($"无效响应: {resp}");
        }

        public void Dispose()
        {
            if (!_disposed)
            {
                Close();
                _serialPort?.Dispose();
                _disposed = true;
            }
        }
    }
}