using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using System.Net.Http.Headers;

namespace Rssdp
{
	/// <summary>
	/// Represents a discovered device, containing basic information about the device and the location of it's full device description document. Also provides convenience methods for retrieving the device description document.
	/// </summary>
	/// <seealso cref="SsdpDevice"/>
	/// <seealso cref="Rssdp.Infrastructure.ISsdpDeviceLocator"/>
	public sealed class DiscoveredSsdpDevice
	{

		#region Fields

		private DateTimeOffset _AsAt;

		#endregion

		#region Public Properties

		/// <summary>
		/// Sets or returns the type of notification, being either a uuid, device type, service type or upnp:rootdevice.
		/// </summary>
		public string NotificationType { get; set; }

		/// <summary>
		/// Sets or returns the universal service name (USN) of the device.
		/// </summary>
		public string Usn { get; set; }

		/// <summary>
		/// Sets or returns a URL pointing to the device description document for this device.
		/// </summary>
		public Uri DescriptionLocation { get; set; }

		/// <summary>
		/// Sets or returns the length of time this information is valid for (from the <see cref="AsAt"/> time).
		/// </summary>
		public TimeSpan CacheLifetime { get; set; }

		/// <summary>
		/// Sets or returns the date and time this information was received.
		/// </summary>
		public DateTimeOffset AsAt
		{
			get { return _AsAt; }
			set
			{
				if (_AsAt != value)
				{
					_AsAt = value;
				}
			}
		}

		/// <summary>
		/// Returns the headers from the SSDP device response message
		/// </summary>
		public HttpHeaders ResponseHeaders { get; set; }

		#endregion

		#region Public Methods

		/// <summary>
		/// Returns true if this device information has expired, based on the current date/time, and the <see cref="CacheLifetime"/> &amp; <see cref="AsAt"/> properties.
		/// </summary>
		/// <returns></returns>
		public bool IsExpired()
		{
			return this.CacheLifetime == TimeSpan.Zero || this.AsAt.Add(this.CacheLifetime) <= DateTimeOffset.Now;
		}

		#endregion

		#region Overrides

		/// <summary>
		/// Returns the device's <see cref="Usn"/> value.
		/// </summary>
		/// <returns>A string containing the device's universal service name.</returns>
		public override string ToString()
		{
			return this.Usn;
		}

		#endregion
	}
}