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

namespace Tango.Transport.Routing
{
    /// <summary>
    /// Represents a simple transport router.
    /// </summary>
    /// <seealso cref="Tango.Transport.ITransportRouter" />
    public class SimpleTransportRouter : ITransportRouter
    {
        /// <summary>
        /// Gets or sets the name of the transport component.
        /// </summary>
        public String ComponentName { get; set; }

        /// <summary>
        /// Occurs when component state changes.
        /// </summary>
        public event EventHandler<TransportComponentState> StateChanged;

        /// <summary>
        /// Gets the collection of <see cref="TransportRoutingChannel">channels</see>.
        /// </summary>
        public ObservableCollection<TransportRoutingChannel> Channels { get; private set; }

        private TransportComponentState _state;
        /// <summary>
        /// Gets the component state.
        /// </summary>
        public TransportComponentState State
        {
            get { return _state; }
            set { _state = value; StateChanged?.Invoke(this, State); }
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="SimpleTransportRouter"/> class.
        /// </summary>
        public SimpleTransportRouter()
        {
            Channels = new ObservableCollection<TransportRoutingChannel>();
            Channels.CollectionChanged += OnChannelsCollectionChanged;
            ComponentName = "Router";
        }

        /// <summary>
        /// Called when the <see cref="Channels"/> collection has changed.
        /// </summary>
        /// <param name="sender">The sender.</param>
        /// <param name="e">The <see cref="System.Collections.Specialized.NotifyCollectionChangedEventArgs"/> instance containing the event data.</param>
        protected virtual void OnChannelsCollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
        {
            //TODO: Do something here ?
        }

        /// <summary>
        /// Connects the transport component.
        /// </summary>
        /// <returns></returns>
        public Task Connect()
        {
            return Task.WhenAll(Channels.Select(x => x.Connect()));
        }

        /// <summary>
        /// Disconnects the transport component.
        /// </summary>
        /// <returns></returns>
        public Task Disconnect()
        {
            return Task.WhenAll(Channels.Select(x => x.Disconnect()));
        }

        /// <summary>
        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
        /// </summary>
        public void Dispose()
        {
            Channels.ToList().ForEach(x => x.Dispose());
        }
    }
}