using LibreHardwareMonitor.Hardware;

namespace ChromeboxFanControl;

public enum CpuTempAggregation
{
    AverageCore,
    MaxCore
}

/// <summary>
/// CPU temperature via LibreHardwareMonitor only (no fan sensors).
/// </summary>
public sealed class CpuTempReader : IDisposable
{
    private readonly Computer _computer = new()
    {
        IsCpuEnabled = true,
        IsMotherboardEnabled = true
    };
    private bool _open;

    public CpuTempReader()
    {
        _computer.Open();
        _open = true;
    }

    public void Dispose()
    {
        if (!_open)
            return;
        _computer.Close();
        _open = false;
    }

    /// <summary>Returns null if no reading available.</summary>
    public double? ReadCpuTemp(CpuTempAggregation mode)
    {
        foreach (var hw in _computer.Hardware)
        {
            hw.Update();
            foreach (var sh in hw.SubHardware)
                sh.Update();
        }

        var coreTemps = new List<double>();
        foreach (var hw in _computer.Hardware)
        {
            CollectCoreTemps(hw, coreTemps);
            foreach (var sh in hw.SubHardware)
                CollectCoreTemps(sh, coreTemps);
        }

        if (coreTemps.Count > 0)
        {
            return mode == CpuTempAggregation.MaxCore
                ? coreTemps.Max()
                : coreTemps.Average();
        }

        // Fallback: any CPU temperature sensor
        var any = new List<double>();
        foreach (var hw in _computer.Hardware)
        {
            CollectAnyCpuTemp(hw, any);
            foreach (var sh in hw.SubHardware)
                CollectAnyCpuTemp(sh, any);
        }

        if (any.Count == 0)
            return null;
        return mode == CpuTempAggregation.MaxCore ? any.Max() : any.Average();
    }

    private static readonly string[] CoreTempPatterns =
    [
        "Core", "Package", "Tctl", "Tdie", "CCD", "CPU Package",
        "Core Average", "Core Max", "Core #"
    ];

    private static void CollectCoreTemps(IHardware hw, List<double> list)
    {
        foreach (var s in hw.Sensors)
        {
            if (s.SensorType != SensorType.Temperature || !s.Value.HasValue)
                continue;
            var name = s.Name;
            if (CoreTempPatterns.Any(p => name.Contains(p, StringComparison.OrdinalIgnoreCase)))
                list.Add(s.Value.Value);
        }
    }

    private static void CollectAnyCpuTemp(IHardware hw, List<double> list)
    {
        foreach (var s in hw.Sensors)
        {
            if (s.SensorType == SensorType.Temperature && s.Value.HasValue)
                list.Add(s.Value.Value);
        }
    }
}