using System;
using System.Collections.Generic;
using System.Text;
using System.Threading.Tasks;

namespace Rssdp
{
	/// <summary>
	/// Event arguments for the <see cref="Rssdp.Infrastructure.SsdpDeviceLocatorBase.DeviceUnavailable"/> event.
	/// </summary>
	public sealed class DeviceUnavailableEventArgs : EventArgs
	{

		#region Fields

		private readonly DiscoveredSsdpDevice _DiscoveredDevice;
		private readonly bool _Expired;

		#endregion

		#region Constructors

		/// <summary>
		/// Full constructor.
		/// </summary>
		/// <param name="discoveredDevice">A <see cref="DiscoveredSsdpDevice"/> instance representing the device that has become unavailable.</param>
		/// <param name="expired">A boolean value indicating whether this device is unavailable because it expired, or because it explicitly sent a byebye notification.. See <see cref="Expired"/> for more detail.</param>
		/// <exception cref="System.ArgumentNullException">Thrown if the <paramref name="discoveredDevice"/> parameter is null.</exception>
		public DeviceUnavailableEventArgs(DiscoveredSsdpDevice discoveredDevice, bool expired) 
		{
			if (discoveredDevice == null) throw new ArgumentNullException("discoveredDevice");

			_DiscoveredDevice = discoveredDevice;
			_Expired = expired;
		}

		#endregion

		#region Public Properties

		/// <summary>
		/// Returns true if the device is considered unavailable because it's cached information expired before a new alive notification or search result was received. Returns false if the device is unavailable because it sent an explicit notification of it's unavailability.
		/// </summary>
		public bool Expired
		{
			get { return _Expired; }
		}

		/// <summary>
		/// A reference to a <see cref="Rssdp.DiscoveredSsdpDevice"/> instance containing the discovery details of the removed device.
		/// </summary>
		public DiscoveredSsdpDevice DiscoveredDevice
		{
			get { return _DiscoveredDevice; }
		} 

		#endregion
	}
}