using System;
using System.Runtime.InteropServices;

namespace Unosquare.RaspberryIO.Native {
  public partial class WiringPi {
    #region WiringPi - Serial Port

    /// <summary>
    /// This opens and initialises the serial device and sets the baud rate. It sets the port into “raw” mode (character at a time and no translations),
    /// and sets the read timeout to 10 seconds. The return value is the file descriptor or -1 for any error, in which case errno will be set as appropriate.
    /// The wiringSerial library is intended to provide simplified control – suitable for most applications, however if you need advanced control
    /// – e.g. parity control, modem control lines (via a USB adapter, there are none on the Pi’s on-board UART!) and so on,
    /// then you need to do some of this the old fashioned way.
    /// </summary>
    /// <param name="device">The device.</param>
    /// <param name="baud">The baud.</param>
    /// <returns>The result</returns>
    [DllImport(WiringPiLibrary, EntryPoint = "serialOpen", SetLastError = true)]
    public static extern Int32 SerialOpen(String device, Int32 baud);

    /// <summary>
    /// Closes the device identified by the file descriptor given.
    /// </summary>
    /// <param name="fd">The fd.</param>
    /// <returns>The result</returns>
    [DllImport(WiringPiLibrary, EntryPoint = "serialClose", SetLastError = true)]
    public static extern Int32 SerialClose(Int32 fd);

    /// <summary>
    /// Sends the single byte to the serial device identified by the given file descriptor.
    /// </summary>
    /// <param name="fd">The fd.</param>
    /// <param name="c">The c.</param>
    [DllImport(WiringPiLibrary, EntryPoint = "serialPutchar", SetLastError = true)]
    public static extern void SerialPutchar(Int32 fd, Byte c);

    /// <summary>
    /// Sends the nul-terminated string to the serial device identified by the given file descriptor.
    /// </summary>
    /// <param name="fd">The fd.</param>
    /// <param name="s">The s.</param>
    [DllImport(WiringPiLibrary, EntryPoint = "serialPuts", SetLastError = true)]
    public static extern void SerialPuts(Int32 fd, String s);

    /// <summary>
    /// Returns the number of characters available for reading, or -1 for any error condition,
    /// in which case errno will be set appropriately.
    /// </summary>
    /// <param name="fd">The fd.</param>
    /// <returns>The result</returns>
    [DllImport(WiringPiLibrary, EntryPoint = "serialDataAvail", SetLastError = true)]
    public static extern Int32 SerialDataAvail(Int32 fd);

    /// <summary>
    /// Returns the next character available on the serial device.
    /// This call will block for up to 10 seconds if no data is available (when it will return -1)
    /// </summary>
    /// <param name="fd">The fd.</param>
    /// <returns>The result</returns>
    [DllImport(WiringPiLibrary, EntryPoint = "serialGetchar", SetLastError = true)]
    public static extern Int32 SerialGetchar(Int32 fd);

    /// <summary>
    /// This discards all data received, or waiting to be send down the given device.
    /// </summary>
    /// <param name="fd">The fd.</param>
    [DllImport(WiringPiLibrary, EntryPoint = "serialFlush", SetLastError = true)]
    public static extern void SerialFlush(Int32 fd);

    #endregion
  }
}