using System;

namespace TINK.Model.State
{
	/// <summary>
	/// Types of rent states
	/// </summary>
	public enum InUseStateEnum
	{
		/// <summary>
		/// Bike was returned but no feedback given. 
		/// This applies to COPRI locks only because returning of bike is not done using app (Status: Supported locks are ILockIt and COPRI).
		/// </summary>
		FeedbackPending,

		/// <summary>
		/// Bike is not in use. Corresponding COPRI state is "available".
		/// </summary>
		Disposable,

		/// <summary>
		/// Bike is reserved. Corresponding COPRI state is "requested".
		/// </summary>
		Reserved,

		/// <summary>
		/// Bike is booked. Corresponding COPRI state is "occupied".
		/// </summary>
		Booked
	}

	/// <summary>
	/// Manages the state of a bike.
	/// </summary>
	public class StateInfo : IStateInfo
	{
		// Holds the current disposable state value.
		private readonly BaseState _InUseState;

		/// <summary>
		/// Constructs a state info object when state is available.
		/// </summary>
		/// <param name="isFeedbackPending">Specifies whether feedback is pending or not.</param>
		public StateInfo(bool isFeedbackPending = false)
		{
			_InUseState = isFeedbackPending
				? (BaseState)new StateFeedbackPendingInfo()
				: new StateAvailableInfo();
		}

		/// <summary>
		/// Constructs a state info object when state is requested.
		/// </summary>
		/// <param name="requestedAt">Date time when bike was requested</param>
		/// <param name="maxReservationTimeSpan">Time span for which a bike can be reserved.</param>
		/// <param name="mailAddress">Mail address of user which requested bike.</param>
		/// <param name="code">Booking code.</param>
		/// <param name="dateTimeNowProvider">Date time provider to calculate remaining time.</param>
		public StateInfo(
			Func<DateTime> dateTimeNowProvider,
			DateTime requestedAt,
			TimeSpan maxReservationTimeSpan,
			string mailAddress,
			string code)
		{
			_InUseState = new StateRequestedInfo(
				dateTimeNowProvider ?? (() => DateTime.Now),
				requestedAt,
				maxReservationTimeSpan,
				mailAddress,
				code);
		}

		/// <summary>
		/// Constructs a state info object when state is booked.
		/// </summary>
		/// <param name="p_oBookedAt">Date time when bike was booked</param>
		/// <param name="p_strMailAddress">Mail address of user which booked bike.</param>
		/// <param name="p_strCode">Booking code.</param>
		public StateInfo(
			DateTime p_oBookedAt,
			string p_strMailAddress,
			string p_strCode)
		{
			_InUseState = new StateOccupiedInfo(
				p_oBookedAt,
				p_strMailAddress,
				p_strCode);
		}

		/// <summary>
		/// Gets the state value of object.
		/// </summary>
		public InUseStateEnum Value
		{
			get { return _InUseState.Value; }
		}

		/// <summary>
		/// Member for serialization purposes.
		/// </summary>
		internal BaseState StateInfoObject
		{
			get { return _InUseState; }
		}
		/// Transforms object to string.
		/// </summary>
		/// <returns></returns>
		public new string ToString()
		{
			return _InUseState.Value.ToString("g");
		}

		/// <summary>
		/// Date of request/ booking action.
		/// </summary>
		public DateTime? From
		{
			get
			{
				var l_oNotDisposableInfo = _InUseState as INotAvailableState;
				return l_oNotDisposableInfo != null ? l_oNotDisposableInfo.From : (DateTime?)null;
			}
		}

		/// <summary>
		/// Time span for which a bike can be reserved.
		/// </summary>
		public TimeSpan? MaxReservationTimeSpan =>
			_InUseState is StateRequestedInfo reserved
				? reserved.MaxReservationTimeSpan
				: (TimeSpan?)null;

		/// <summary>
		/// Mail address.
		/// </summary>
		public string MailAddress
		{
			get
			{
				var l_oNotDisposableInfo = _InUseState as INotAvailableState;
				return l_oNotDisposableInfo?.MailAddress;
			}
		}

		/// <summary>
		/// Reservation code.
		/// </summary>
		public string Code
		{
			get
			{
				var l_oNotDisposableInfo = _InUseState as INotAvailableState;
				return l_oNotDisposableInfo?.Code;
			}
		}

		/// <summary>
		/// Tries update 
		/// </summary>
		/// <returns>True if reservation span has not exceeded and state remains reserved, false otherwise.</returns>
		/// <todo>Implement logging of time stamps.</todo>
		public bool GetIsStillReserved(out TimeSpan? p_oRemainingTime)
		{
			var l_oReservedInfo = _InUseState as StateRequestedInfo;
			if (l_oReservedInfo == null)
			{
				p_oRemainingTime = null;
				return false;
			}

			return l_oReservedInfo.GetIsStillReserved(out p_oRemainingTime);
		}
	}
}