using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
using System.Threading.Tasks;
using System.Xml;
using Rssdp.Infrastructure;

namespace Rssdp
{
    /// <summary>
    /// Base class representing the common details of a (root or embedded) device, either to be published or that has been located.
    /// </summary>
    /// <remarks>
    /// <para>Do not derive new types directly from this class. New device classes should derive from either <see cref="SsdpRootDevice"/> or <see cref="SsdpEmbeddedDevice"/>.</para>
    /// </remarks>
    /// <seealso cref="SsdpRootDevice"/>
    /// <seealso cref="SsdpEmbeddedDevice"/>
    public abstract class SsdpDevice
    {

        #region Fields

        private string _Udn;
        private string _DeviceType;
        private string _DeviceTypeNamespace;
        private int _DeviceVersion;

        private IList<SsdpDevice> _Devices;

        #endregion

        #region Events

        /// <summary>
        /// Raised when a new child device is added.
        /// </summary>
        /// <seealso cref="AddDevice"/>
        /// <seealso cref="DeviceAdded"/>
        public event EventHandler<DeviceEventArgs> DeviceAdded;

        /// <summary>
        /// Raised when a child device is removed.
        /// </summary>
        /// <seealso cref="RemoveDevice"/>
        /// <seealso cref="DeviceRemoved"/>
        public event EventHandler<DeviceEventArgs> DeviceRemoved;

        #endregion

        #region Constructors

        /// <summary>
        /// Derived type constructor, allows constructing a device with no parent. Should only be used from derived types that are or inherit from <see cref="SsdpRootDevice"/>.
        /// </summary>
        protected SsdpDevice()
        {
            _DeviceTypeNamespace = SsdpConstants.UpnpDeviceTypeNamespace;
            _DeviceType = SsdpConstants.UpnpDeviceTypeBasicDevice;
            _DeviceVersion = 1;

            _Devices = new List<SsdpDevice>();
            this.Devices = new ReadOnlyCollection<SsdpDevice>(_Devices);
        }

        #endregion

        public SsdpRootDevice ToRootDevice()
        {
            var device = this;

            var rootDevice = device as SsdpRootDevice;
            if (rootDevice == null)
                rootDevice = ((SsdpEmbeddedDevice)device).RootDevice;

            return rootDevice;
        }
        
        #region Public Properties

        #region UPnP Device Description Properties

        /// <summary>
        /// Sets or returns the core device type (not including namespace, version etc.). Required.
        /// </summary>
        /// <remarks><para>Defaults to the UPnP basic device type.</para></remarks>
        /// <seealso cref="DeviceTypeNamespace"/>
        /// <seealso cref="DeviceVersion"/>
        /// <seealso cref="FullDeviceType"/>
        public string DeviceType
        {
            get
            {
                return _DeviceType;
            }
            set
            {
                _DeviceType = value;
            }
        }

        public string DeviceClass { get; set; }

        /// <summary>
        /// Sets or returns the namespace for the <see cref="DeviceType"/> of this device. Optional, but defaults to UPnP schema so should be changed if <see cref="DeviceType"/> is not a UPnP device type.
        /// </summary>
        /// <remarks><para>Defaults to the UPnP standard namespace.</para></remarks>
        /// <seealso cref="DeviceType"/>
        /// <seealso cref="DeviceVersion"/>
        /// <seealso cref="FullDeviceType"/>
        public string DeviceTypeNamespace
        {
            get
            {
                return _DeviceTypeNamespace;
            }
            set
            {
                _DeviceTypeNamespace = value;
            }
        }

        /// <summary>
        /// Sets or returns the version of the device type. Optional, defaults to 1.
        /// </summary>
        /// <remarks><para>Defaults to a value of 1.</para></remarks>
        /// <seealso cref="DeviceType"/>
        /// <seealso cref="DeviceTypeNamespace"/>
        /// <seealso cref="FullDeviceType"/>
        public int DeviceVersion
        {
            get
            {
                return _DeviceVersion;
            }
            set
            {
                _DeviceVersion = value;
            }
        }

        /// <summary>
        /// Returns the full device type string.
        /// </summary>
        /// <remarks>
        /// <para>The format used is urn:<see cref="DeviceTypeNamespace"/>:device:<see cref="DeviceType"/>:<see cref="DeviceVersion"/></para>
        /// </remarks>
        public string FullDeviceType
        {
            get
            {
                return String.Format("urn:{0}:{3}:{1}:{2}",
                this.DeviceTypeNamespace ?? String.Empty,
                this.DeviceType ?? String.Empty,
                this.DeviceVersion,
                this.DeviceClass ?? "device");
            }
        }

        /// <summary>
        /// Sets or returns the universally unique identifier for this device (without the uuid: prefix). Required.
        /// </summary>
        /// <remarks>
        /// <para>Must be the same over time for a specific device instance (i.e. must survive reboots).</para>
        /// <para>For UPnP 1.0 this can be any unique string. For UPnP 1.1 this should be a 128 bit number formatted in a specific way, preferably generated using the time and MAC based algorithm. See section 1.1.4 of http://upnp.org/specs/arch/UPnP-arch-DeviceArchitecture-v1.1.pdf for details.</para>
        /// <para>Technically this library implements UPnP 1.0, so any value is allowed, but we advise using UPnP 1.1 compatible values for good behaviour and forward compatibility with future versions.</para>
        /// </remarks>
        public string Uuid { get; set; }

        /// <summary>
        /// Returns (or sets*) a unique device name for this device. Optional, not recommended to be explicitly set.
        /// </summary>
        /// <remarks>
        /// <para>* In general you should not explicitly set this property. If it is not set (or set to null/empty string) the property will return a UDN value that is correct as per the UPnP specification, based on the other device properties.</para>
        /// <para>The setter is provided to allow for devices that do not correctly follow the specification (when we discover them), rather than to intentionally deviate from the specification.</para>
        /// <para>If a value is explicitly set, it is used verbatim, and so any prefix (such as uuid:) must be provided in the value.</para>
        /// </remarks>
        public string Udn
        {
            get
            {
                if (String.IsNullOrEmpty(_Udn) && !String.IsNullOrEmpty(this.Uuid))
                    return "uuid:" + this.Uuid;
                else
                    return _Udn;
            }
            set
            {
                _Udn = value;
            }
        }

        /// <summary>
        /// Sets or returns a friendly/display name for this device on the network. Something the user can identify the device/instance by, i.e Lounge Main Light. Required.
        /// </summary>
        /// <remarks><para>A short description for the end user. </para></remarks>
        public string FriendlyName { get; set; }

        /// <summary>
        /// Sets or returns the name of the manufacturer of this device. Required.
        /// </summary>
        public string Manufacturer { get; set; }

        /// <summary>
        /// Sets or returns a URL to the manufacturers web site. Optional.
        /// </summary>
        public Uri ManufacturerUrl { get; set; }

        /// <summary>
        /// Sets or returns a description of this device model. Recommended.
        /// </summary>
        /// <remarks><para>A long description for the end user.</para></remarks>
        public string ModelDescription { get; set; }

        /// <summary>
        /// Sets or returns the name of this model. Required.
        /// </summary>
        public string ModelName { get; set; }

        /// <summary>
        /// Sets or returns the number of this model. Recommended.
        /// </summary>
        public string ModelNumber { get; set; }

        /// <summary>
        /// Sets or returns a URL to a web page with details of this device model. Optional.
        /// </summary>
        /// <remarks>
        /// <para>Optional. May be relative to base URL.</para>
        /// </remarks>
        public Uri ModelUrl { get; set; }

        /// <summary>
        /// Sets or returns the serial number for this device. Recommended.
        /// </summary>
        public string SerialNumber { get; set; }

        /// <summary>
        /// Sets or returns the universal product code of the device, if any. Optional.
        /// </summary>
        /// <remarks>
        /// <para>If not blank, must be exactly 12 numeric digits.</para>
        /// </remarks>
        public string Upc { get; set; }

        /// <summary>
        /// Sets or returns the URL to a web page that can be used to configure/manager/use the device. Recommended.
        /// </summary>
        /// <remarks>
        /// <para>May be relative to base URL. </para>
        /// </remarks>
        public Uri PresentationUrl { get; set; }

        #endregion

        /// <summary>
        /// Returns a read-only enumerable set of <see cref="SsdpDevice"/> objects representing children of this device. Child devices are optional.
        /// </summary>
        /// <seealso cref="AddDevice"/>
        /// <seealso cref="RemoveDevice"/>
        public IList<SsdpDevice> Devices
        {
            get;
            private set;
        }

        #endregion

        #region Public Methods

        /// <summary>
        /// Adds a child device to the <see cref="Devices"/> collection.
        /// </summary>
        /// <param name="device">The <see cref="SsdpEmbeddedDevice"/> instance to add.</param>
        /// <remarks>
        /// <para>If the device is already a member of the <see cref="Devices"/> collection, this method does nothing.</para>
        /// <para>Also sets the <see cref="SsdpEmbeddedDevice.RootDevice"/> property of the added device and all descendant devices to the relevant <see cref="SsdpRootDevice"/> instance.</para>
        /// </remarks>
        /// <exception cref="System.ArgumentNullException">Thrown if the <paramref name="device"/> argument is null.</exception>
        /// <exception cref="System.InvalidOperationException">Thrown if the <paramref name="device"/> is already associated with a different <see cref="SsdpRootDevice"/> instance than used in this tree. Can occur if you try to add the same device instance to more than one tree. Also thrown if you try to add a device to itself.</exception>
        /// <seealso cref="DeviceAdded"/>
        public void AddDevice(SsdpEmbeddedDevice device)
        {
            if (device == null) throw new ArgumentNullException("device");
            if (device.RootDevice != null && device.RootDevice != this.ToRootDevice()) throw new InvalidOperationException("This device is already associated with a different root device (has been added as a child in another branch).");
            if (device == this) throw new InvalidOperationException("Can't add device to itself.");

            bool wasAdded = false;
            lock (_Devices)
            {
                device.RootDevice = this.ToRootDevice();
                _Devices.Add(device);
                wasAdded = true;
            }

            if (wasAdded)
                OnDeviceAdded(device);
        }

        /// <summary>
        /// Removes a child device from the <see cref="Devices"/> collection.
        /// </summary>
        /// <param name="device">The <see cref="SsdpEmbeddedDevice"/> instance to remove.</param>
        /// <remarks>
        /// <para>If the device is not a member of the <see cref="Devices"/> collection, this method does nothing.</para>
        /// <para>Also sets the <see cref="SsdpEmbeddedDevice.RootDevice"/> property to null for the removed device and all descendant devices.</para>
        /// </remarks>
        /// <exception cref="System.ArgumentNullException">Thrown if the <paramref name="device"/> argument is null.</exception>
        /// <seealso cref="DeviceRemoved"/>
        public void RemoveDevice(SsdpEmbeddedDevice device)
        {
            if (device == null) throw new ArgumentNullException("device");

            bool wasRemoved = false;
            lock (_Devices)
            {
                wasRemoved = _Devices.Remove(device);
                if (wasRemoved)
                {
                    device.RootDevice = null;
                }
            }

            if (wasRemoved)
                OnDeviceRemoved(device);
        }

        /// <summary>
        /// Raises the <see cref="DeviceAdded"/> event.
        /// </summary>
        /// <param name="device">The <see cref="SsdpEmbeddedDevice"/> instance added to the <see cref="Devices"/> collection.</param>
        /// <seealso cref="AddDevice"/>
        /// <seealso cref="DeviceAdded"/>		
        protected virtual void OnDeviceAdded(SsdpEmbeddedDevice device)
        {
            var handlers = this.DeviceAdded;
            if (handlers != null)
                handlers(this, new DeviceEventArgs(device));
        }

        /// <summary>
        /// Raises the <see cref="DeviceRemoved"/> event.
        /// </summary>
        /// <param name="device">The <see cref="SsdpEmbeddedDevice"/> instance removed from the <see cref="Devices"/> collection.</param>
        /// <seealso cref="RemoveDevice"/>
        /// <see cref="DeviceRemoved"/>
        protected virtual void OnDeviceRemoved(SsdpEmbeddedDevice device)
        {
            var handlers = this.DeviceRemoved;
            if (handlers != null)
                handlers(this, new DeviceEventArgs(device));
        }

        #endregion

    }
}