sharee.bike-App/TINKLib/ViewModel/Settings/ServicesViewModel.cs

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

namespace TINK.ViewModel.Settings
{
	/// <summary> ViewModel for an active service plus a list of services which are not active.</summary>
	/// <remarks> 
	/// Example for services are lock services, geolocation services, ..., 
	/// </remarks>
	public class ServicesViewModel : INotifyPropertyChanged
	{
		/// <summary> Active service. </summary>
		private string active;

		/// <summary> Holds the dictionary which maps services to service display texts.</summary>
		private IDictionary<string, string> ServiceToText { get; }

		/// <summary> Holds the dictionary which maps service display texts to services.</summary>
		private IDictionary<string, string> TextToService { get; }

		/// <summary>Constructs view model ensuring consistency. </summary>
		/// <param name="services">List of available services.</param>
		/// <param name="serviceToText"> Dictionary holding display text for services as values.</param>
		/// <param name="active">Active service.</param>
		public ServicesViewModel(
			IEnumerable<string> services,
			IDictionary<string, string> serviceToText,
			string active)
		{
			if (!services.Contains(active))
				throw new ArgumentException($"Can not instantiate {typeof(ServicesViewModel).Name}- object. Active lock service {active} must be contained in [{String.Join(",", services)}].");

			ServiceToText = services.Distinct().ToDictionary(
				x => x,
				x => serviceToText.ContainsKey(x) ? serviceToText[x] : x);

			TextToService = ServiceToText.ToDictionary(x => x.Value, x => x.Key);
			Active = active;
		}

		/// <summary> Fired whenever active service changes.</summary>
		public event PropertyChangedEventHandler PropertyChanged;

		/// <summary> Holds active service.</summary>
		public string Active
		{
			get => active;
			set
			{
				if (active == value)
					return;

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

		/// <summary> List of display texts of services.</summary>
		public IList<string> ServicesTextList => ServiceToText.Select(x => x.Value).OrderBy(x => x).ToList();

		/// <summary> Active locks service.</summary>
		public string ActiveText
		{
			get => ServiceToText[Active];
			set
			{
				if (!TextToService.ContainsKey(value))
				{
					Log.ForContext<ServicesViewModel>().Error($"Can not set service {value} to services view model. List of services {{{string.Join(";", TextToService)}}} does not hold machting element.");
					throw new ArgumentException($"Can not set service {value} to services view model. List of services {{{string.Join(";", TextToService)}}} does not hold machting element.");
				}

				Active = TextToService[value];
			}
		}
	}
}