using System;
using System.Device.Gpio;

namespace GPIORaspberryPI4;

public sealed class DigitalInput : IDigitalInput
{
    private readonly GpioController _gpio;
    private readonly int _pin;
    private readonly bool _activeLow;
    private bool _disposed;

    public int Pin => _pin;

    public bool IsActive => Read();

    public DigitalInput(int pin, bool pullUp = true, bool activeLow = true)
    {
        _pin = pin;
        _activeLow = activeLow;

        _gpio = new GpioController();

        var mode = pullUp ? PinMode.InputPullUp : PinMode.Input;

        _gpio.OpenPin(_pin, mode);
    }

    public bool Read()
    {
        ThrowIfDisposed();

        var value = _gpio.Read(_pin);

        return _activeLow
            ? value == PinValue.Low
            : value == PinValue.High;
    }

    private void ThrowIfDisposed()
    {
        if (_disposed)
            throw new ObjectDisposedException(nameof(DigitalInput));
    }

    public void Dispose()
    {
        if (_disposed)
            return;

        if (_gpio.IsPinOpen(_pin))
            _gpio.ClosePin(_pin);

        _gpio.Dispose();
        _disposed = true;
    }
}