RaspberryIO_26/Unosquare.RaspberryIO/Pi.cs

using System;
using System.Threading.Tasks;

using Swan;
using Swan.DependencyInjection;

using Unosquare.RaspberryIO.Abstractions;
using Unosquare.RaspberryIO.Camera;
using Unosquare.RaspberryIO.Computer;

namespace Unosquare.RaspberryIO {
  /// <summary>
  /// Our main character. Provides access to the Raspberry Pi's GPIO, system and board information and Camera.
  /// </summary>
  public static class Pi {
    private const String MissingDependenciesMessage = "You need to load a valid assembly (WiringPi or PiGPIO).";
    private static readonly Object SyncLock = new Object();
    private static Boolean _isInit;
    private static SystemInfo? _info;

    /// <summary>
    /// Initializes static members of the <see cref="Pi" /> class.
    /// </summary>
    static Pi() {
      lock(SyncLock) {
        Camera = CameraController.Instance;
        PiDisplay = DsiDisplay.Instance;
        Audio = AudioSettings.Instance;
        Bluetooth = Bluetooth.Instance;
      }
    }

    /// <summary>
    /// Provides information on this Raspberry Pi's CPU and form factor.
    /// </summary>
    public static SystemInfo Info => _info ??= SystemInfo.Instance;

    /// <summary>
    /// Provides access to the Raspberry Pi's GPIO as a collection of GPIO Pins.
    /// </summary>
    public static IGpioController Gpio => ResolveDependency<IGpioController>();

    /// <summary>
    /// Provides access to the 2-channel SPI bus.
    /// </summary>
    public static ISpiBus Spi => ResolveDependency<ISpiBus>();

    /// <summary>
    /// Provides access to the functionality of the i2c bus.
    /// </summary>
    public static II2CBus I2C => ResolveDependency<II2CBus>();

    /// <summary>
    /// Provides access to timing functionality.
    /// </summary>
    public static ITiming Timing => ResolveDependency<ITiming>();

    /// <summary>
    /// Provides access to threading functionality.
    /// </summary>
    public static IThreading Threading => ResolveDependency<IThreading>();

    /// <summary>
    /// Provides access to the official Raspberry Pi Camera.
    /// </summary>
    public static CameraController Camera {
      get;
    }

    /// <summary>
    /// Provides access to the official Raspberry Pi 7-inch DSI Display.
    /// </summary>
    public static DsiDisplay PiDisplay {
      get;
    }

    /// <summary>
    /// Provides access to Raspberry Pi ALSA sound card driver.
    /// </summary>
    public static AudioSettings Audio {
      get;
    }

    /// <summary>
    /// Provides access to Raspberry Pi Bluetooth driver.
    /// </summary>
    public static Bluetooth Bluetooth {
      get;
    }

    /// <summary>
    /// Restarts the Pi. Must be running as SU.
    /// </summary>
    /// <returns>The process result.</returns>
    public static Task<ProcessResult> RestartAsync() => ProcessRunner.GetProcessResultAsync("reboot");

    /// <summary>
    /// Restarts the Pi. Must be running as SU.
    /// </summary>
    /// <returns>The process result.</returns>
    public static ProcessResult Restart() => RestartAsync().GetAwaiter().GetResult();

    /// <summary>
    /// Halts the Pi. Must be running as SU.
    /// </summary>
    /// <returns>The process result.</returns>
    public static Task<ProcessResult> ShutdownAsync() => ProcessRunner.GetProcessResultAsync("halt");

    /// <summary>
    /// Halts the Pi. Must be running as SU.
    /// </summary>
    /// <returns>The process result.</returns>
    public static ProcessResult Shutdown() => ShutdownAsync().GetAwaiter().GetResult();

    /// <summary>
    /// Initializes an Abstractions implementation.
    /// </summary>
    /// <typeparam name="T">An implementation of <see cref="IBootstrap"/>.</typeparam>
    public static void Init<T>() where T : IBootstrap {
      lock(SyncLock) {
        if(_isInit) {
          return;
        }

        Activator.CreateInstance<T>().Bootstrap();
        _isInit = true;
      }
    }

    private static T ResolveDependency<T>() where T : class {
      if(!_isInit) {
        throw new InvalidOperationException($"You must first initialize {nameof(Pi)} referencing a valid {nameof(IBootstrap)} implementation.");
      }

      return DependencyContainer.Current.CanResolve<T>() ? DependencyContainer.Current.Resolve<T>() : throw new InvalidOperationException(MissingDependenciesMessage);
    }
  }
}