// Copyright (C)2026, Philip Munts dba Munts Technologies.
//
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using IO.Objects.RemoteIO;
using System.Net.NetworkInformation;

namespace IO.Devices.M5Stack_Ultrasonic_I2C
{
  /// <summary>
  /// Encapsulates the M5 Stack Ultrasonic-I2C SONAR distance sensor module.
  /// </summary>
  public class Sensor : IO.Interfaces.Distance.Sensor
  {
    private readonly bool I2C_Clock_Stretch_Works;
    private readonly IO.Interfaces.I2C.Device dev;
    private readonly byte[] cmdbuf = { 1 };
    private byte[] respbuf = { 0, 0, 0 };

    /// <summary>
    /// Constructor for an M5 Stack Ultrasonic-I2C SONAR distance sensor object.
    /// </summary>
    /// <param name="bus">I<sup>2</sup>C bus controller.</param>
    /// <param name="addr">I<sup>2</sup>C slave address.</param>
    /// <param name="stretch">Indicates the I<sup>2</sup>C bus controller can
    /// properly handle I<sup>2</sup>C clock stretching.</param>
    /// <remarks>
    /// The M5 Stack Ultrasonic-I2C module pulls SCL low (i.e.I2C slave clock
    /// stretch) for 50 milliseconds after accepting the ping command.
    /// On Raspberry Pi's 1 to 4, which do not support I2C slave clock stretch,
    /// we have to wait it out with a safe margin before reading the echo
    /// response bytes.  The RP1 I/O Controller on Raspberry Pi 5 boards does
    /// support clock stretching.
    /// </remarks>
    public Sensor(IO.Interfaces.I2C.Bus bus, int addr = 0x57, bool stretch = false)
    {
      I2C_Clock_Stretch_Works = stretch;
      dev = new IO.Interfaces.I2C.Device(bus, addr);
    }

    /// <summary>
    /// Read-only property returning the distance in meters.
    /// </summary>
    public double meters
    {
      get
      {
        dev.Write(cmdbuf, cmdbuf.Length);
        System.Threading.Thread.Sleep(I2C_Clock_Stretch_Works ? 5 : 100);
        dev.Read(respbuf, respbuf.Length);
        float rawdist = respbuf[0] * 65536 + respbuf[1] * 256 + respbuf[2];
        return rawdist / 1.0E6;
      }
    }

    /// <summary>
    /// Read-only property returning the distance in centimeters.
    /// </summary>
    public double centimeters
    {
      get
      {
        return IO.Interfaces.Distance.Conversions.MetersToCentimeters(meters);
      }
    }

    /// <summary>
    /// Read-only property returning the distance in inches.
    /// </summary>
    public double inches
    {
      get
      {
        return IO.Interfaces.Distance.Conversions.MetersToInches(meters);
      }
    }
  }
}