using System.Collections.Generic;
using System.Linq;
using xCommons.Extensions;
using xExceptions.Constants;
using xPushService.Base;
using xPushService.Models;

namespace xPushService.Helpers {
    public class XPushServiceHelper {
        /// <summary>
        /// a collection of Hubs for Registring ...
        /// </summary>
        /// <returns></returns>
        private List<XHubDescriptor> hubs = new List<XHubDescriptor> ();

        /// <summary>
        /// add specified hub to provided hubs for registration ...
        /// </summary>
        /// <param name="route"></param>
        /// <typeparam name="TXHub"></typeparam>
        public void AddHub<TXHub> (string route) where TXHub : XBaseHub {
            //
            #region Validate Args ...
            //
            // check route not null ...
            if (
                route.IsNullOrEmpty () ||
                route.Trim ().IsNullOrEmpty ()
            ) {
                throw XException.InvalidArgs.ToException ();
            }

            //
            // Normalize Route ...
            route = route.ToNormalString ();

            //
            // check route and hub must be unique ...
            var isRouteExists = hubs.Any (hd => hd.Route == route);
            var isHubExists = hubs.Any (hd => hd.Hub == typeof (TXHub));
            if (
                isHubExists ||
                isRouteExists
            ) {
                throw XException.Duplicate.ToException ();
            }
            #endregion

            //
            // Add Provided Hub to List ...
            hubs.Add (new XHubDescriptor {
                Route = route,
                    Hub = typeof (TXHub)
            });
        }

        /// <summary>
        /// remove an specific hub from provided list ...
        /// </summary>
        /// <typeparam name="TXHub"></typeparam>
        public void RemoveHub<TXHub> () where TXHub : XBaseHub {
            //
            var existsHubDescriptor = hubs.SingleOrDefault (hd => hd.Hub == typeof (TXHub));
            if (!existsHubDescriptor.IsNull ()) {
                hubs.Remove (existsHubDescriptor);
            }
        }

        /// <summary>
        /// retrieve provided hubs count ...
        /// </summary>
        /// <returns></returns>
        public int Count () {
            return hubs.Count;
        }

        /// <summary>
        /// retrieve all provided hubs for registration ...
        /// </summary>
        /// <returns></returns>
        public List<XHubDescriptor> GetHubs () {
            return hubs;
        }
    }
}