using System;
using System.Runtime.InteropServices;

namespace Unosquare.RaspberryIO.Native {
  public partial class WiringPi {
    #region WiringPi - I2C Library Calls

    /// <summary>
    /// Simple device read. Some devices present data when you read them without having to do any register transactions.
    /// </summary>
    /// <param name="fd">The fd.</param>
    /// <returns>The result</returns>
    [DllImport(WiringPiLibrary, EntryPoint = "wiringPiI2CRead", SetLastError = true)]
    public static extern Int32 WiringPiI2CRead(Int32 fd);

    /// <summary>
    /// These read an 8-bit value from the device register indicated.
    /// </summary>
    /// <param name="fd">The fd.</param>
    /// <param name="reg">The reg.</param>
    /// <returns>The result</returns>
    [DllImport(WiringPiLibrary, EntryPoint = "wiringPiI2CReadReg8", SetLastError = true)]
    public static extern Int32 WiringPiI2CReadReg8(Int32 fd, Int32 reg);

    /// <summary>
    /// These read a 16-bit value from the device register indicated.
    /// </summary>
    /// <param name="fd">The fd.</param>
    /// <param name="reg">The reg.</param>
    /// <returns>The result</returns>
    [DllImport(WiringPiLibrary, EntryPoint = "wiringPiI2CReadReg16", SetLastError = true)]
    public static extern Int32 WiringPiI2CReadReg16(Int32 fd, Int32 reg);

    /// <summary>
    /// Simple device write. Some devices accept data this way without needing to access any internal registers.
    /// </summary>
    /// <param name="fd">The fd.</param>
    /// <param name="data">The data.</param>
    /// <returns>The result</returns>
    [DllImport(WiringPiLibrary, EntryPoint = "wiringPiI2CWrite", SetLastError = true)]
    public static extern Int32 WiringPiI2CWrite(Int32 fd, Int32 data);

    /// <summary>
    /// These write an 8-bit data value into the device register indicated.
    /// </summary>
    /// <param name="fd">The fd.</param>
    /// <param name="reg">The reg.</param>
    /// <param name="data">The data.</param>
    /// <returns>The result</returns>
    [DllImport(WiringPiLibrary, EntryPoint = "wiringPiI2CWriteReg8", SetLastError = true)]
    public static extern Int32 WiringPiI2CWriteReg8(Int32 fd, Int32 reg, Int32 data);

    /// <summary>
    /// These write a 16-bit data value into the device register indicated.
    /// </summary>
    /// <param name="fd">The fd.</param>
    /// <param name="reg">The reg.</param>
    /// <param name="data">The data.</param>
    /// <returns>The result</returns>
    [DllImport(WiringPiLibrary, EntryPoint = "wiringPiI2CWriteReg16", SetLastError = true)]
    public static extern Int32 WiringPiI2CWriteReg16(Int32 fd, Int32 reg, Int32 data);

    /// <summary>
    /// This initialises the I2C system with your given device identifier.
    /// The ID is the I2C number of the device and you can use the i2cdetect program to find this out. wiringPiI2CSetup()
    /// will work out which revision Raspberry Pi you have and open the appropriate device in /dev.
    /// The return value is the standard Linux filehandle, or -1 if any error – in which case, you can consult errno as usual.
    /// E.g. the popular MCP23017 GPIO expander is usually device Id 0x20, so this is the number you would pass into wiringPiI2CSetup().
    /// </summary>
    /// <param name="devId">The dev identifier.</param>
    /// <returns>The result</returns>
    [DllImport(WiringPiLibrary, EntryPoint = "wiringPiI2CSetup", SetLastError = true)]
    public static extern Int32 WiringPiI2CSetup(Int32 devId);

    #endregion

  }
}