using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using SSPCTester.Devices.Config;
using SSPCTester.Devices.Drivers.Real;
using SSPCTester.Devices.Interfaces;

namespace SSPCTester.Devices.Drivers.Mock;

/// <summary>
/// 模拟数据采集卡。
/// 生成逼真的电压上升 / 下降波形：V(t) = Vmax * (1 - exp(-t/τ)) + 噪声。
/// </summary>
public sealed class MockDaq : MockDeviceBase, IDaq
{
    private readonly Random _rng = new(1024);
    private readonly DaqOptions _opts;
    private double? _nextTriggerSec;

    /// <summary>满量程电压（V）。</summary>
    public double NominalVoltage { get; set; } = 5.0;

    /// <summary>满量程电流（A）。</summary>
    public double NominalCurrent { get; set; } = 1.0;

    /// <summary>开启延时（秒），用于模拟"控制信号 → 开始上升"的延时。</summary>
    public double OnDelaySec { get; set; } = 0.0003;

    /// <summary>关断延时（秒）。</summary>
    public double OffDelaySec { get; set; } = 0.0003;

    /// <summary>RC 时间常数（秒）。</summary>
    public double TauSec { get; set; } = 0.0005;

    /// <summary>下一次 CaptureAsync 的模式：true=上升曲线，false=下降曲线。</summary>
    public bool NextCaptureIsRising { get; set; } = true;

    public MockDaq(IOptions<DeviceOptions> options, ILogger<MockDaq> logger)
        : base(logger, "PCIe8586 高速采集卡 (Mock)")
    {
        _opts = options.Value.Daq;
    }

    public event EventHandler<CurveSample>? SampleReceived;

    public Task<IReadOnlyList<DaqDeviceDescriptor>> EnumerateDevicesAsync(CancellationToken ct = default) =>
        Task.FromResult<IReadOnlyList<DaqDeviceDescriptor>>(
            new[] { new DaqDeviceDescriptor(0, 0, "模拟 PCIe8586", true) });

    public async Task<CurveData> CaptureAsync(
        int[] channels, int sampleRateHz, double durationSec, CancellationToken ct = default)
    {
        ArgumentNullException.ThrowIfNull(channels);
        if (channels.Length == 0)
            throw new ArgumentException("At least one channel must be requested.", nameof(channels));
        if (sampleRateHz <= 0) throw new ArgumentOutOfRangeException(nameof(sampleRateHz));
        if (durationSec <= 0) throw new ArgumentOutOfRangeException(nameof(durationSec));

        // 模拟采集耗时（不全等比例，避免阻塞太久）
        int simulatedDelayMs = (int)Math.Min(durationSec * 1000.0 * 0.05, 400);
        await Task.Delay(simulatedDelayMs, ct).ConfigureAwait(false);

        int n = (int)Math.Round(sampleRateHz * durationSec);
        var cardVoltage = new double[n];
        var cardCurrent = new double[n];
        double dt = 1.0 / sampleRateHz;
        int channelCount = Math.Max(1, _opts.ChannelCount);
        var requestedChannels = channels.Distinct().ToArray();
        foreach (int channel in requestedChannels)
        {
            if (channel < 0 || channel >= channelCount)
                throw new ArgumentOutOfRangeException(
                    nameof(channels),
                    $"Requested channel {channel} is outside the configured PCIe8586 channel count {channelCount}.");
        }

        bool rising = NextCaptureIsRising;
        double delay = rising ? OnDelaySec : OffDelaySec;
        // 触发时刻设在 1/4 处，便于前后查看
        double triggerSec = _nextTriggerSec ?? durationSec * 0.25;
        _nextTriggerSec = null;

        for (int k = 0; k < n; k++)
        {
            double t = k * dt;
            double tRel = t - triggerSec - delay; // 相对于"开始上升/下降"的时间
            double voltage;
            if (rising)
            {
                voltage = tRel <= 0 ? 0 : NominalVoltage * (1 - Math.Exp(-tRel / TauSec));
            }
            else
            {
                voltage = tRel <= 0 ? NominalVoltage : NominalVoltage * Math.Exp(-tRel / TauSec);
            }
            voltage += NextGaussian() * NominalVoltage * 0.005;
            cardVoltage[k] = voltage;

            double current;
            if (rising)
                current = tRel <= 0 ? 0 : NominalCurrent * (1 - Math.Exp(-tRel / TauSec));
            else
                current = tRel <= 0 ? NominalCurrent : NominalCurrent * Math.Exp(-tRel / TauSec);
            current += NextGaussian() * NominalCurrent * 0.01;
            cardCurrent[k] = current;
        }

        return BuildCurve(cardVoltage, cardCurrent, sampleRateHz, triggerSec, triggerIndex: 0, requestedChannels[0]);
    }

    public Task<double[]> ReadInstantAsync(int[] channels, CancellationToken ct = default)
    {
        var result = new double[channels.Length];
        for (int k = 0; k < channels.Length; k++)
        {
            int physical = channels[k];
            var cfg = _opts.Channels.FirstOrDefault(x => x.PhysicalChannel == physical);
            var role = cfg is null
                ? DaqChannelRole.Unconfigured
                : Pcie8586Daq.ParseRole(cfg.Role);

            double cardValue = role switch
            {
                DaqChannelRole.OutputVoltage or DaqChannelRole.InputVoltage =>
                    NominalVoltage * (1 + (_rng.NextDouble() - 0.5) * 0.004),
                DaqChannelRole.OutputCurrent or DaqChannelRole.InputCurrent =>
                    NominalCurrent * (1 + (_rng.NextDouble() - 0.5) * 0.02),
                _ => 0
            };
            result[k] = ApplyCalibration(cardValue, cfg);
        }
        return Task.FromResult(result);
    }

    public async Task<CurveData> CaptureAroundActionAsync(
        DaqActionCaptureRequest request,
        Func<CancellationToken, Task> action,
        CancellationToken ct = default)
    {
        // Mock 下也遵循“先采前置窗口，再执行动作”的时序，避免与真卡行为不一致。
        await Task.Delay((int)Math.Max(1, request.PreTriggerMs * 0.2), ct).ConfigureAwait(false);

        double durationSec = (request.PreTriggerMs + request.PostTriggerMs) / 1_000.0;
        int sampleRate = _opts.SampleRateHz;
        NextCaptureIsRising = request.IsRising;
        await action(ct).ConfigureAwait(false);
        _nextTriggerSec = request.PreTriggerMs / 1_000.0;
        var curve = await CaptureAsync(Enumerable.Range(0, Math.Max(1, _opts.ChannelCount)).ToArray(), sampleRate, durationSec, ct).ConfigureAwait(false);
        int triggerIndex = (int)Math.Round(sampleRate * request.PreTriggerMs / 1_000.0);
        return new CurveData
        {
            SampleRateHz = curve.SampleRateHz,
            TriggerSampleIndex = triggerIndex,
            TriggerTimeSec = triggerIndex / (double)curve.SampleRateHz,
            Voltage = curve.Voltage,
            Current = curve.Current,
            EngineeringChannels = curve.EngineeringChannels
        };
    }

    private CurveData BuildCurve(
        double[] cardVoltage,
        double[] cardCurrent,
        int sampleRateHz,
        double triggerSec,
        int triggerIndex,
        int primaryPhysicalChannel)
    {
        var engineering = new List<CurveChannelData>();
        int channelCount = Math.Max(1, _opts.ChannelCount);
        for (int channel = 0; channel < channelCount; channel++)
        {
            var cfg = _opts.Channels.FirstOrDefault(x => x.PhysicalChannel == channel)
                ?? new DaqChannelOptions { PhysicalChannel = channel, Name = $"CH{channel}" };
            var role = Pcie8586Daq.ParseRole(cfg.Role);
            var source = role is DaqChannelRole.OutputCurrent or DaqChannelRole.InputCurrent
                ? cardCurrent
                : cardVoltage;
            var values = source.Select(x => ApplyCalibration(x, cfg)).ToArray();
            engineering.Add(new CurveChannelData(
                channel, role, cfg.Name, UnitFor(role), cfg.Scale, cfg.Offset, values));
        }

        var outputVoltage = engineering.Where(x => x.Role == DaqChannelRole.OutputVoltage).ToArray();
        var primary = outputVoltage.Length == 1
            ? outputVoltage[0]
            : engineering.FirstOrDefault(x => x.PhysicalChannel == primaryPhysicalChannel) ?? engineering.FirstOrDefault();
        var current = engineering.FirstOrDefault(x => x.Role == DaqChannelRole.OutputCurrent)?.Samples;

        return new CurveData
        {
            SampleRateHz = sampleRateHz,
            TriggerSampleIndex = triggerIndex,
            TriggerTimeSec = triggerSec,
            Voltage = primary?.Samples ?? Array.Empty<double>(),
            Current = current,
            EngineeringChannels = engineering
        };
    }

    private static double ApplyCalibration(double value, DaqChannelOptions? cfg) =>
        cfg is null ? value : value * cfg.Scale + cfg.Offset;

    private static string UnitFor(DaqChannelRole role) => role switch
    {
        DaqChannelRole.OutputVoltage or DaqChannelRole.InputVoltage => "V",
        DaqChannelRole.OutputCurrent or DaqChannelRole.InputCurrent => "A",
        _ => ""
    };

    /// <summary>由 ReadInstantAsync 衍生的"电流读数"接口（基础测试页用）。</summary>
    public (double volts, double amps) ReadVoltageCurrent(int channel, bool channelOn)
    {
        if (!channelOn) return (0.0, 0.0);
        double v = NominalVoltage * (1 + (_rng.NextDouble() - 0.5) * 0.004);
        double a = NominalCurrent * (1 + (_rng.NextDouble() - 0.5) * 0.02);
        return (v, a);
    }

    /// <summary>Box-Muller 生成高斯噪声。</summary>
    private double NextGaussian()
    {
        double u1 = 1.0 - _rng.NextDouble();
        double u2 = 1.0 - _rng.NextDouble();
        return Math.Sqrt(-2.0 * Math.Log(u1)) * Math.Cos(2.0 * Math.PI * u2);
    }

    /// <summary>仅用于编译期消除"事件未使用"警告。</summary>
    private void RaiseSample(CurveSample s) => SampleReceived?.Invoke(this, s);
}