using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Pcie8586Probe.Hardware;
using Pcie8586Probe.Models;
using SSPCTester.Devices.Config;
using SSPCTester.Devices.Interfaces;
using DriverInputRange = Pcie8586Probe.Models.InputRange;

namespace SSPCTester.Devices.Drivers.Real;

/// <summary>PCIe8586 高速采集卡适配器。原生句柄仅由 IDigitizer 持有。</summary>
public sealed class Pcie8586Daq : IDaq, IDisposable
{
    private readonly DaqOptions _options;
    private readonly ILogger<Pcie8586Daq> _logger;
    private readonly IDigitizer _digitizer;
    private readonly SemaphoreSlim _operationLock = new(1, 1);
    private bool _connected;

    public Pcie8586Daq(IOptions<DeviceOptions> options, ILogger<Pcie8586Daq> logger)
        : this(options.Value.Daq, logger, new Pcie8586Digitizer())
    {
    }

    internal Pcie8586Daq(DaqOptions options, ILogger<Pcie8586Daq> logger, IDigitizer digitizer)
    {
        _options = options;
        _logger = logger;
        _digitizer = digitizer;
    }

    public bool IsConnected => _connected && _digitizer.IsOpen;
    public string DisplayName => "PCIe8586 高速采集卡";
    public event EventHandler<bool>? ConnectionChanged;
    public event EventHandler<CurveSample>? SampleReceived;

    public async Task<IReadOnlyList<DaqDeviceDescriptor>> EnumerateDevicesAsync(CancellationToken ct = default)
    {
        try
        {
            var devices = await _digitizer.EnumerateDevicesAsync(ct);
            return devices.Select(x => new DaqDeviceDescriptor(
                x.LogicalId, x.PhysicalId, x.Description, x.IsSimulated)).ToArray();
        }
        catch (DllNotFoundException ex)
        {
            throw new InvalidOperationException("找不到 ACTS1000_64.dll。请安装厂商驱动并将 x64 运行库放到程序目录。", ex);
        }
        catch (BadImageFormatException ex)
        {
            throw new InvalidOperationException("ACTS1000_64.dll 位数不匹配，程序和运行库必须都是 x64。", ex);
        }
    }

    public async Task<bool> ConnectAsync(CancellationToken ct = default)
    {
        await _operationLock.WaitAsync(ct);
        try
        {
            if (IsConnected) return true;
            var devices = await EnumerateDevicesAsync(ct);
            var selected = devices.SingleOrDefault(x => x.LogicalId == _options.LogicalDeviceId)
                ?? throw new InvalidOperationException($"未发现逻辑 ID {_options.LogicalDeviceId} 的 PCIe8586。");
            await _digitizer.OpenAsync(
                new DeviceInfo(selected.LogicalId, selected.PhysicalId, selected.Description, selected.IsSimulated), ct);
            _connected = true;
            ConnectionChanged?.Invoke(this, true);
            return true;
        }
        finally
        {
            _operationLock.Release();
        }
    }

    public async Task DisconnectAsync()
    {
        await _operationLock.WaitAsync();
        try
        {
            await _digitizer.StopAsync();
            await _digitizer.CloseAsync();
            if (_connected)
            {
                _connected = false;
                ConnectionChanged?.Invoke(this, false);
            }
        }
        finally
        {
            _operationLock.Release();
        }
    }

    public async Task<CurveData> CaptureAroundActionAsync(
        DaqActionCaptureRequest request,
        Func<CancellationToken, Task> action,
        CancellationToken ct = default)
    {
        ValidateOptions(requireOutputVoltage: true);
        await _operationLock.WaitAsync(ct);
        try
        {
            if (!IsConnected) await ConnectWithoutLockAsync(ct);
            var config = CreateDriverConfig();
            await _digitizer.ConfigureAsync(config, ct);

            int preSamples = Math.Max(1, (int)Math.Round(config.SampleRateHz * request.PreTriggerMs / 1_000.0));
            int postSamples = Math.Max(1, (int)Math.Round(config.SampleRateHz * request.PostTriggerMs / 1_000.0));
            int targetSamples = checked(preSamples + postSamples);
            var collected = Enumerable.Range(0, config.ChannelCount)
                .Select(_ => new List<double>(targetSamples)).ToArray();
            bool actionInvoked = false;
            int triggerIndex = 0;
            var preTriggerTimeout = TimeSpan.FromMilliseconds(Math.Max(3_000, request.PreTriggerMs * 5));
            using var acquisitionCts = CancellationTokenSource.CreateLinkedTokenSource(ct);
            acquisitionCts.CancelAfter(preTriggerTimeout);

            try
            {
                await foreach (var block in _digitizer.StartAcquisitionAsync(acquisitionCts.Token))
                {
                    if (!actionInvoked)
                    {
                        int take = Math.Min(preSamples - collected[0].Count, block.SamplesPerChannel);
                        for (int channel = 0; channel < config.ChannelCount; channel++)
                            collected[channel].AddRange(block.Channels[channel].AsSpan(0, take).ToArray());
                        if (collected[0].Count >= preSamples)
                        {
                            triggerIndex = collected[0].Count;
                            actionInvoked = true;
                            acquisitionCts.CancelAfter(Timeout.InfiniteTimeSpan);
                            await action(ct);
                        }
                        // 动作发生在本次 DMA 读取完成之后；当前块未使用余量仍属于动作前数据，必须丢弃。
                        continue;
                    }

                    int remaining = targetSamples - collected[0].Count;
                    int postTake = Math.Min(remaining, block.SamplesPerChannel);
                    for (int channel = 0; channel < config.ChannelCount; channel++)
                        collected[channel].AddRange(block.Channels[channel].AsSpan(0, postTake).ToArray());
                    if (collected[0].Count >= targetSamples) break;
                }
            }
            catch (OperationCanceledException ex) when (!ct.IsCancellationRequested && !actionInvoked)
            {
                string message =
                    $"PCIe8586 did not provide enough pre-trigger samples within {preTriggerTimeout.TotalMilliseconds:F0}ms; control action was not executed. " +
                    $"sampleRate={config.SampleRateHz:F0}Hz, channels={config.ChannelCount}, " +
                    $"preTrigger={request.PreTriggerMs:F1}ms, postTrigger={request.PostTriggerMs:F1}ms, " +
                    $"samples={collected[0].Count}/{preSamples}.";
                _logger.LogWarning(message);
                throw new InvalidOperationException(message, ex);
            }
            finally
            {
                await _digitizer.StopAsync();
            }

            if (!actionInvoked)
                throw new InvalidOperationException(
                    $"PCIe8586 acquisition ended before enough pre-trigger samples were collected; control action was not executed. " +
                    $"sampleRate={config.SampleRateHz:F0}Hz, channels={config.ChannelCount}, " +
                    $"preTrigger={request.PreTriggerMs:F1}ms, postTrigger={request.PostTriggerMs:F1}ms, " +
                    $"samples={collected[0].Count}/{preSamples}.");
            if (collected[0].Count < targetSamples)
                throw new InvalidOperationException("PCIe8586 采集提前结束，后置波形不完整。");

            return BuildCurve(collected.Select(x => x.ToArray()).ToArray(), config.SampleRateHz, triggerIndex);
        }
        finally
        {
            _operationLock.Release();
        }
    }

    public async Task<CurveData> CaptureAsync(
        int[] channels, int sampleRateHz, double durationSec, CancellationToken ct = default)
    {
        double preMs = Math.Max(1, durationSec * 1_000 * 0.2);
        double postMs = Math.Max(1, durationSec * 1_000 - preMs);
        return await CaptureAroundActionAsync(
            new DaqActionCaptureRequest(preMs, postMs, true), _ => Task.CompletedTask, ct);
    }

    public async Task<double[]> ReadInstantAsync(int[] channels, CancellationToken ct = default)
    {
        var curve = await CaptureAroundActionAsync(
            new DaqActionCaptureRequest(1, 2, true), _ => Task.CompletedTask, ct);
        return channels.Select(channel =>
        {
            var data = curve.EngineeringChannels.SingleOrDefault(x => x.PhysicalChannel == channel);
            return data?.Samples.Average() ?? double.NaN;
        }).ToArray();
    }

    public void ValidateOptions(bool requireOutputVoltage)
    {
        if (_options.ChannelCount is not (1 or 2 or 4 or 8))
            throw new InvalidOperationException("PCIe8586 启用通道数只能为 1、2、4 或 8。");
        if (_options.ClockDivider < 1)
            throw new InvalidOperationException("PCIe8586 时钟分频必须大于 0。");
        if (_options.PreTriggerMs <= 0 || _options.PostTriggerMs <= 0)
            throw new InvalidOperationException("前置和后置采集窗口必须大于 0。");

        var enabled = _options.Channels.Where(x => x.PhysicalChannel < _options.ChannelCount).ToArray();
        foreach (var channel in enabled.Where(x => ParseRole(x.Role) != DaqChannelRole.Unconfigured))
        {
            if (!channel.IsCalibrated)
                throw new InvalidOperationException($"PCIe8586 CH{channel.PhysicalChannel}（{channel.Name}）尚未标定。");
            if (!double.IsFinite(channel.Scale) || channel.Scale == 0 || !double.IsFinite(channel.Offset))
                throw new InvalidOperationException($"PCIe8586 CH{channel.PhysicalChannel} 标定比例或偏置无效。");
        }

        if (requireOutputVoltage &&
            enabled.Count(x => ParseRole(x.Role) == DaqChannelRole.OutputVoltage && x.IsCalibrated) != 1)
            throw new InvalidOperationException("曲线测试必须配置且只能配置一个已标定的“输出电压”通道。");
    }

    private async Task ConnectWithoutLockAsync(CancellationToken ct)
    {
        var devices = await EnumerateDevicesAsync(ct);
        var selected = devices.SingleOrDefault(x => x.LogicalId == _options.LogicalDeviceId)
            ?? throw new InvalidOperationException($"未发现逻辑 ID {_options.LogicalDeviceId} 的 PCIe8586。");
        await _digitizer.OpenAsync(
            new DeviceInfo(selected.LogicalId, selected.PhysicalId, selected.Description, selected.IsSimulated), ct);
        _connected = true;
        ConnectionChanged?.Invoke(this, true);
    }

    private AcquisitionConfig CreateDriverConfig() => new(
        _options.ChannelCount,
        string.Equals(_options.InputRange, "PlusMinus1V", StringComparison.OrdinalIgnoreCase)
            ? DriverInputRange.PlusMinus1V
            : DriverInputRange.PlusMinus5V,
        _options.ClockDivider,
        AcquisitionMode.Continuous,
        10_000);

    private CurveData BuildCurve(double[][] cardVolts, double sampleRateHz, int triggerIndex)
    {
        var engineering = new List<CurveChannelData>();
        for (int channel = 0; channel < cardVolts.Length; channel++)
        {
            var cfg = _options.Channels.FirstOrDefault(x => x.PhysicalChannel == channel)
                ?? new DaqChannelOptions { PhysicalChannel = channel, Name = $"CH{channel}" };
            var role = ParseRole(cfg.Role);
            var values = cardVolts[channel].Select(x => x * cfg.Scale + cfg.Offset).ToArray();
            engineering.Add(new CurveChannelData(
                channel, role, cfg.Name, UnitFor(role), cfg.Scale, cfg.Offset, values));
        }

        var voltage = engineering.Single(x => x.Role == DaqChannelRole.OutputVoltage).Samples;
        var current = engineering.SingleOrDefault(x => x.Role == DaqChannelRole.OutputCurrent)?.Samples;
        if (voltage.Length > 0)
        {
            int sample = Math.Clamp(triggerIndex, 0, voltage.Length - 1);
            SampleReceived?.Invoke(this, new CurveSample(
                sample / sampleRateHz,
                voltage[sample],
                current is { Length: > 0 } ? current[Math.Min(sample, current.Length - 1)] : 0));
        }
        return new CurveData
        {
            SampleRateHz = (int)Math.Round(sampleRateHz),
            TriggerSampleIndex = triggerIndex,
            TriggerTimeSec = triggerIndex / sampleRateHz,
            Voltage = voltage,
            Current = current,
            EngineeringChannels = engineering
        };
    }

    internal static DaqChannelRole ParseRole(string? role) =>
        Enum.TryParse<DaqChannelRole>(role, true, out var value) ? value : DaqChannelRole.Unconfigured;

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

    public void Dispose()
    {
        try { DisconnectAsync().GetAwaiter().GetResult(); } catch { }
        _digitizer.Dispose();
        _operationLock.Dispose();
    }
}