using Serilog;
using System;
using System.ComponentModel;
using System.Text.RegularExpressions;
using ShareeBike.Model.Bikes.BikeInfoNS.BikeNS;
using ShareeBike.Model.Bikes.BikeInfoNS.DriveNS.BatteryNS;
using ShareeBike.Model.Connector;
using ShareeBike.Model.Device;
using ShareeBike.Model.State;
using ShareeBike.Model.User;
using ShareeBike.MultilingualResources;
using ShareeBike.View;
using Xamarin.Forms;

using BikeInfoMutable = ShareeBike.Model.Bikes.BikeInfoNS.BC.BikeInfoMutable;

namespace ShareeBike.ViewModel.Bikes.Bike
{
	/// <summary>
	/// Defines the type of BikesViewModel child items, i.e. BikesViewModel derives from ObservableCollection&ltBikeViewModelBase&gt. 
	/// Holds references to 
	/// - connection state services
	/// - copri service
	/// - view service
	/// </summary>
	public abstract class BikeViewModelBase
	{
		/// <summary>
		/// Time format for text "Gebucht seit".
		/// </summary>
		public const string TIMEFORMAT = "dd. MMMM HH:mm";

		/// <summary> Provides info about the smart device (phone, tablet, ...).</summary>
		protected ISmartDevice SmartDevice;

		/// <summary>
		/// Reference on view service to show modal notifications and to perform navigation.
		/// </summary>
		protected IViewService ViewService { get; }

		/// <summary> Provides a connect object.</summary>
		protected Func<bool, IConnector> ConnectorFactory { get; }

		/// <summary> Delegate to retrieve connected state. </summary>
		protected Func<bool> IsConnectedDelegate { get; }

		/// <summary> Removes bike from bikes view model. </summary>
		protected Action<string> BikeRemoveDelegate { get; }

		/// <summary> Object to manage update of view model objects from Copri.</summary>
		public Func<IPollingUpdateTaskManager> ViewUpdateManager { get; }

		/// <summary>
		/// Holds the bike to display.
		/// </summary>
		protected BikeInfoMutable Bike;

		/// <summary> Reference on the user </summary>
		protected IUser ActiveUser { get; }

		/// <summary> Holds the view context in which bike view model is used.</summary>
		protected ViewContext ViewContext { get; }

		/// <summary>
		/// Provides context related info.
		/// </summary>
		private IInUseStateInfoProvider StateInfoProvider { get; }

		/// <summary>View model to be used for progress report and unlocking/ locking view.</summary>
		protected IBikesViewModel BikesViewModel { get; }

		/// <summary> Delegate to open browser. </summary>
		private Action<string> OpenUrlInBrowser;

		/// <summary>
		/// Notifies GUI about changes.
		/// </summary>
		public abstract event PropertyChangedEventHandler PropertyChanged;

		/// <summary>
		/// Notifies children about changed bike state.
		/// </summary>
		public abstract void OnSelectedBikeStateChanged();

		/// <summary> Raises events in order to update GUI.</summary>
		public abstract void RaisePropertyChanged(object sender, PropertyChangedEventArgs eventArgs);

		/// <summary>
		/// Constructs a bike view model object.
		/// </summary>
		/// <param name="smartDevice">Provides info about the smart device (phone, tablet, ...).</param>
		/// <param name="selectedBike">Bike to be displayed.</param>
		/// <param name="activeUser">Object holding logged in user or an empty user object.</param>
		/// <param name="viewContext"> Holds the view context in which bike view model is used.</param>
		/// <param name="stateInfoProvider">Provides in use state information.</param>
		/// <param name="bikesViewModel">View model to be used for progress report and unlocking/ locking view.</param>
		/// <param name="openUrlInBrowser">Delegate to open browser.</param>
		public BikeViewModelBase(
			Func<bool> isConnectedDelegate,
			Func<bool, IConnector> connectorFactory,
			Action<string> bikeRemoveDelegate,
			Func<IPollingUpdateTaskManager> viewUpdateManager,
			ISmartDevice smartDevice,
			IViewService viewService,
			BikeInfoMutable selectedBike,
			IUser activeUser,
			ViewContext viewContext,
			IInUseStateInfoProvider stateInfoProvider,
			IBikesViewModel bikesViewModel,
			Action<string> openUrlInBrowser)
		{
			IsConnectedDelegate = isConnectedDelegate;

			ConnectorFactory = connectorFactory;

			BikeRemoveDelegate = bikeRemoveDelegate;

			ViewUpdateManager = viewUpdateManager;

			SmartDevice = smartDevice;

			ViewService = viewService;

			Bike = selectedBike
				?? throw new ArgumentException(string.Format("Can not construct {0}- object, bike object is null.", typeof(BikeViewModelBase)));

			ActiveUser = activeUser
				?? throw new ArgumentException(string.Format("Can not construct {0}- object, user object is null.", typeof(BikeViewModelBase)));

			ViewContext = viewContext;

			StateInfoProvider = stateInfoProvider
				?? throw new ArgumentException(string.Format("Can not construct {0}- object, user object is null.", typeof(IInUseStateInfoProvider)));

			selectedBike.PropertyChanged +=
				(sender, eventargs) => OnSelectedBikePropertyChanged(eventargs.PropertyName);

			var battery = selectedBike.Drive?.Battery;
			if (battery != null)
			{
				battery.PropertyChanged += (_, args) =>
				{
					if (args.PropertyName == nameof(BatteryMutable.CurrentChargeBars))
					{
						RaisePropertyChanged(this, new PropertyChangedEventArgs(nameof(CurrentChargeBars)));
					}
				};
			}

			BikesViewModel = bikesViewModel
								?? throw new ArgumentException($"Can not construct {GetType().Name}-object. {nameof(bikesViewModel)} must not be null.");

			OpenUrlInBrowser = openUrlInBrowser ?? (url => { Log.ForContext<BikeViewModelBase>().Error($"No browse service available to open {url}."); });
		}

		/// <summary>
		/// Handles BikeInfoMutable events. 
		/// Helper member to raise events. Maps model event change notification to view model events.
		/// </summary>
		/// <param name="nameOfProp"></param>
		private void OnSelectedBikePropertyChanged(string nameOfProp)
		{
			if (nameOfProp == nameof(State))
			{
				OnSelectedBikeStateChanged(); // Notify derived class about change of state.
			}

			var state = State;
			if (LastState != state)
			{
				RaisePropertyChanged(this, new PropertyChangedEventArgs(nameof(State)));
				LastState = state;
			}

			var stateText = StateText;
			if (LastStateText != stateText)
			{
				RaisePropertyChanged(this, new PropertyChangedEventArgs(nameof(StateText)));
				LastStateText = stateText;
			}

			var stateColor = StateColor;
			if (LastStateColor != stateColor)
			{
				RaisePropertyChanged(this, new PropertyChangedEventArgs(nameof(StateColor)));
				LastStateColor = stateColor;
			}
		}

		/// <summary>
		/// Gets the display name of the bike containing of bike id and type of bike..
		/// </summary>
		public string Name => Bike.GetDisplayName();

		public string TypeOfBike => Bike.GetDisplayTypeOfBike();

		/// <summary>
		/// Gets whether bike is a AA bike (bike must be always returned a the same station) or AB bike (start and end stations can be different stations).
		/// </summary>
		public AaRideType? AaRideType => Bike.AaRideType;

		public string WheelType => Bike.GetDisplayWheelType();

		/// <summary>
		/// Gets the unique Id of bike or an empty string, if no name is defined to avoid duplicate display of id.
		/// </summary>
		public string DisplayId => Bike.GetDisplayId();

		/// <summary>
		/// Gets the unique Id of bike used by derived model to determine which bike to remove.
		/// </summary>
		public string Id => Bike.Id;

		public string StationId => $"Station {Bike.StationId}";

		public string DisplayName => Bike.GetDisplayName();

		public bool IsBikeWithCopriLock => Bike.LockModel == Model.Bikes.BikeInfoNS.BikeNS.LockModel.Sigo;

		/// Returns if type of bike is a cargo pedelec bike.
		public bool IsBatteryChargeVisible =>
			Bike.Drive.Type == Model.Bikes.BikeInfoNS.DriveNS.DriveType.Pedelec
			&& (!Bike.Drive.Battery.IsHidden.HasValue /* no value means show battery level */ || Bike.Drive.Battery.IsHidden.Value == false);

		/// Gets the image path for bike type City bike, CargoLong, Trike or Pedelec.
		public string DisplayedBikeImageSourceString => $"bike_{Bike.TypeOfBike}_{Bike.Drive.Type}_{Bike.WheelType}.png";

		/// <summary>
		/// Gets the current charge level.
		/// </summary>
		public string CurrentChargeBars => Bike.Drive.Type == Model.Bikes.BikeInfoNS.DriveNS.DriveType.Pedelec
			? Bike.Drive.Battery.CurrentChargeBars?.ToString() ?? string.Empty
			: string.Empty;

		/// <summary>
		/// Gets the value if current charge level is low ( <= 1 ).
		/// </summary>
		public bool IsCurrentChargeLow => this.CurrentChargeBars == "1" || this.CurrentChargeBars == "0";

		/// <summary>
		/// Gets the current charge level.
		/// </summary>
		public string MaxChargeBars => Bike.Drive.Type == Model.Bikes.BikeInfoNS.DriveNS.DriveType.Pedelec
			? Bike.Drive.Battery.MaxChargeBars?.ToString() ?? string.Empty
			: string.Empty;

		/// <summary>
		/// Returns status of a bike as text (binds to GUI). 
		/// </summary>
		/// <todo> Log invalid states for diagnose purposes.</todo>
		public string StateText
		{
			get
			{
				switch (Bike.State.Value)
				{
					case InUseStateEnum.FeedbackPending:
						return AppResources.StatusTextFeedbackPending;

					case InUseStateEnum.Disposable:
						return AppResources.StatusTextAvailable;
				}

				if (!ActiveUser.IsLoggedIn)
				{
					// Nobody is logged in.
					switch (Bike.State.Value)
					{
						case InUseStateEnum.Reserved:
							return GetReservedInfo(
								Bike.State.RemainingTime,
								Bike.StationId,
								null); // Hide reservation code because no one but active user should see code

						case InUseStateEnum.Booked:
							return GetBookedInfo(
								Bike.State.From,
								Bike.StationId,
								null); // Hide reservation code because no one but active user should see code

						default:
							return string.Format("Unbekannter status {0}.", Bike.State.Value);
					}
				}

				switch (Bike.State.Value)
				{
					case InUseStateEnum.Reserved:
						return Bike.State.MailAddress == ActiveUser.Mail
							? GetReservedInfo(
								Bike.State.RemainingTime,
								Bike.StationId,
								Bike.State.Code)
							: "Fahrrad bereits reserviert durch anderen Nutzer.";

					case InUseStateEnum.Booked:
						return Bike.State.MailAddress == ActiveUser.Mail
							? GetBookedInfo(
								Bike.State.From,
								Bike.StationId,
								Bike.State.Code)
							: "Fahrrad bereits gebucht durch anderen Nutzer.";

					default:
						return string.Format("Unbekannter status {0}.", Bike.State.Value);
				}
			}
		}

		/// <summary> Gets the value of property <see cref="StateColor"/> when PropertyChanged was fired. </summary>
		private string LastStateText { get; set; }

		/// <summary>
		/// Gets reserved into display text.
		/// </summary>
		/// <todo>Log unexpected states.</todo>
		/// <param name="p_oInUseState"></param>
		/// <returns>Display text</returns>
		private string GetReservedInfo(
			TimeSpan? p_oRemainingTime,
			string p_strStation = null,
			string p_strCode = null)
		{
			return StateInfoProvider.GetReservedInfo(p_oRemainingTime, p_strStation, p_strCode);
		}

		/// <summary>
		/// Gets booked into display text.
		/// </summary>
		/// <todo>Log unexpected states.</todo>
		/// <param name="p_oInUseState"></param>
		/// <returns>Display text</returns>
		private string GetBookedInfo(
			DateTime? p_oFrom,
			string p_strStation = null,
			string p_strCode = null)
		{
			return StateInfoProvider.GetBookedInfo(p_oFrom, p_strStation, p_strCode);
		}

		/// <summary>
		/// Exposes the bike state.
		/// </summary>
		public InUseStateEnum State => Bike.State.Value;

		/// <summary> Gets the value of property <see cref="State"/> when PropertyChanged was fired. </summary>
		public InUseStateEnum LastState { get; set; }

		/// <summary>
		/// Gets the color which visualizes the state of bike in relation to logged in user.
		/// </summary>
		public Color StateColor
		{
			get
			{
				if (!ActiveUser.IsLoggedIn)
				{
					return Color.Default;
				}

				var l_oSelectedBikeState = Bike.State;
				switch (l_oSelectedBikeState.Value)
				{
					case InUseStateEnum.Reserved:
						return l_oSelectedBikeState.MailAddress == ActiveUser.Mail
							? InUseStateEnum.Reserved.GetColor()
							: Color.Red;    // Bike is reserved by someone else

					case InUseStateEnum.Booked:
						return l_oSelectedBikeState.MailAddress == ActiveUser.Mail
							? InUseStateEnum.Booked.GetColor()
							: Color.Red;    // Bike is booked by someone else

					default:
						return Color.Default;
				}
			}
		}

		/// <summary> Holds description about the tariff. </summary>
		public TariffDescriptionViewModel TariffDescription => new TariffDescriptionViewModel(Bike.TariffDescription);

		/// <summary> Gets the value of property <see cref="StateColor"/> when PropertyChanged was fired. </summary>
		public Color LastStateColor { get; set; }

		/// <summary> Gets first url from text.</summary>
		/// <param name="htmlSource">url to extract text from.</param>
		/// <returns>Gets first url or an empty string if on url is contained in text.</returns>

		public static string GetUrlFirstOrDefault(string htmlSource)
		{
			if (string.IsNullOrEmpty(htmlSource))
				return string.Empty;

			try
			{
				var matches = new Regex(@"https://[-a-zA-Z0-9+&@#/%?=~_|!:, .;]*[-a-zA-Z0-9+&@#/%=~_|]").Matches(htmlSource);
				return matches.Count > 0
					? matches[0].Value
					: string.Empty;
			}
			catch (Exception e)
			{
				Log.ForContext<BikeViewModelBase>().Error("Extracting URL failed. {Exception}", e);
				return string.Empty;
			}
		}

		/// <summary>
		/// Check if bike has to be removed and if yes invoke remove delegate.
		/// </summary>
		/// <param name="Id">Id of bike to remove.</param>
		/// <param name="lastState">Previous state used to decide whether to remove bike or not.</param>
		public void CheckRemoveBike(string Id, InUseStateEnum lastState)
		{
			switch (ViewContext.Page)
			{
				case PageContext.MyBikes:
					// Bike is shown on page My Bikes.
					switch (Bike.State.Value)
					{
						case InUseStateEnum.FeedbackPending:
						case InUseStateEnum.Reserved:
						case InUseStateEnum.Booked:
							// Bike has still to be shown at my bikes page to give feedback or manage bike.
							break;

						default:
							BikeRemoveDelegate(Id);
							break;
					}

					break;

				case PageContext.BikesAtStation:
					// Bike is shown on page Bike At Station.
					switch (lastState != InUseStateEnum.Booked)
					{
						case true:
							// Only remove bike if bike was rented before.
							break;

						default:
							switch (ViewContext.StationId == Bike.StationId)
							{
								case true:
									// Do not remove bike if bike is returned a current station.
									break;

								default:
									BikeRemoveDelegate(Id);
									break;
							}
							break;
					}

					break;
			}
		}
	}
}