using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;

namespace ShareeBike.Services
{
	/// <summary> Container of service objects (locks , geolocation, ...) where one service is active. </summary>
	/// <remarks> All service objects must be of different type. </remarks>
	public class ServicesContainerMutableT<T> : IEnumerable<T>, INotifyPropertyChanged, IServicesContainer<T>
	{
		private readonly Dictionary<string, T> serviceDict;

		public event PropertyChangedEventHandler PropertyChanged;

		/// <summary> Constructs object on startup of app.</summary>
		/// <param name="services">Fixed list of service- objects .</param>
		/// <param name="activeName">LocksService name which is activated on startup of app.</param>
		public ServicesContainerMutableT(
			IEnumerable<T> services,
			string activeName)
		{
			serviceDict = services.Distinct().ToDictionary(x => x.GetType().FullName);

			if (!serviceDict.ContainsKey(activeName))
			{
				throw new ArgumentException($"Can not instantiate {typeof(T).Name}- object. Active lock service {activeName} must be contained in [{String.Join(",", serviceDict)}].");
			}

			Active = serviceDict[activeName];
		}

		/// <summary> Active locks service.</summary>
		public T Active { get; private set; }

		/// <summary> Sets a lock service as active locks service by name. </summary>
		/// <param name="active">Name of the new locks service.</param>
		public void SetActive(string active)
		{
			if (!serviceDict.ContainsKey(active))
			{
				throw new ArgumentException($"Can not set active lock service {active}. Service must be contained in [{String.Join(",", serviceDict)}].");
			}

			Active = serviceDict[active];

			PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Active)));
		}

		public IEnumerator<T> GetEnumerator()
			=> serviceDict.Values.GetEnumerator();

		IEnumerator IEnumerable.GetEnumerator()
			=> serviceDict.Values.GetEnumerator();
	}
}