using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using Serilog;
using TINK.Model.Stations.StationNS;
using BikeInfo = TINK.Model.Bikes.BikeInfoNS.BC.BikeInfo;
using BikeInfoMutable = TINK.Model.Bikes.BikeInfoNS.BC.BikeInfoMutable;

namespace TINK.Model.Bikes
{
	/// <summary> Holds entity of bikes. </summary>
	public class BikeCollectionMutable : ObservableCollection<BikeInfoMutable>, IBikeDictionaryMutable<BikeInfoMutable>
	{
		/// <summary> Constructs a mutable bike collection object. </summary>
		public BikeCollectionMutable()
		{
			SelectedBike = null;
		}

		/// <summary>
		/// Updates bikes dictionary from bikes response, i.e.
		/// - removes bikes which are no more contained in bikes response
		/// - updates state of all bikes from state contained in bikes response
		/// </summary>
		/// <param name="bikesAll"> Object holding bikes info from copri to update from. Holds station id but not station name.</param>
		/// <param name="stations"> All stations to get station names from.</param>
		/// <param name="p_oDateTimeProvider">Provides date time information.</param>
		public void Update(
			IEnumerable<BikeInfo> bikesAll,
			IEnumerable<IStation> stations)
		{
			// Get list of current bikes by state(s) to update. 
			// Needed to remove bikes which switched state and have to be removed from collection.
			var bikesToBeRemoved = this.Select(x => x.Id).ToList();

			foreach (var bikeInfo in bikesAll ?? new List<BikeInfo>())
			{
				// Get name of station form station id.
				var stationName = stations?.FirstOrDefault(x => x.Id == bikeInfo.StationId)?.StationName ?? string.Empty;
				if (string.IsNullOrEmpty(stationName))
					Log.ForContext<BikeCollectionMutable>().Debug($"No name for station with id {bikeInfo.StationId} found.");

				// Check if bike has to be added to list of existing station.
				if (ContainsKey(bikeInfo.Id) == false)
				{
					var bikeInfoMutable = BikeInfoMutableFactory.Create(bikeInfo, stationName);
					if (bikeInfoMutable != null)
					{
						// Bike does not yet exist in list of bikes.
						Add(bikeInfoMutable);
					}

					continue;
				}

				// Update bike.
				var updateTarget = GetById(bikeInfo.Id);
				updateTarget.State.Load(bikeInfo.State);
				updateTarget.DataSource = bikeInfo.DataSource;

				if (bikesToBeRemoved.Contains<string>(bikeInfo.Id))
				{
					// Remove list from obsolete list.
					bikesToBeRemoved.Remove(bikeInfo.Id);
				}
			}

			// Remove obsolete bikes.
			foreach (var stationId in bikesToBeRemoved)
			{
				RemoveById(stationId);
			}
		}

		/// <summary>
		/// Adds a new bike to collection of bike.
		/// </summary>
		/// <param name="newBike">New bike to add.</param>
		/// <exception cref="Exception">Thrown if bike is not unique.</exception>
		public new void Add(BikeInfoMutable newBike)
		{
			// Ensure that bike id of new bike is unique
			foreach (BikeInfoMutable bike in Items)
			{
				if (bike.Id == newBike.Id)
				{
					throw new Exception(string.Format("Can not add bike with {0} to collection ob bike. Id is not unique.", newBike));
				}
			}

			base.Add(newBike);
		}

		/// <summary>
		/// Bike selected by user for reserving or cancel reservation.
		/// </summary>
		public BikeInfoMutable SelectedBike
		{
			get;
			private set;
		}

		public void SetSelectedBike(string id)
		{
			SelectedBike = GetById(id);
		}

		/// <summary>
		/// Gets a bike by its id.  
		/// </summary>
		/// <param name="id"></param>
		/// <returns></returns>
		public BikeInfoMutable GetById(string id)
			=> this.FirstOrDefault(bike => bike.Id == id);

		/// <summary>
		/// Determines whether a bike by given key exists.
		/// </summary>
		/// <param name="p_strKey">Key to check.</param>
		/// <returns>True if bike exists.</returns>
		public bool ContainsKey(string id)
			=> GetById(id) != null;

		/// <summary>
		/// Removes a bike by its id.
		/// </summary>
		/// <param name="id">Id of bike to be removed.</param>
		public void RemoveById(string id)
		{
			var l_oBike = GetById(id);
			if (l_oBike == null)
			{
				// Nothing to do if bike does not exists.
				return;
			}

			Remove(l_oBike);
		}

		/// <summary>
		/// Create mutable objects from immutable objects.
		/// </summary>
		public static class BikeInfoMutableFactory
		{
			public static BikeInfoMutable Create(
				BikeInfo bikeInfo,
				string stationName)
			{
				if (bikeInfo is BikeInfoNS.BluetoothLock.BikeInfo btBikeInfo)
				{
					return new BikeInfoNS.BluetoothLock.BikeInfoMutable(btBikeInfo, stationName);
				}
				else if (bikeInfo is BikeInfoNS.CopriLock.BikeInfo copriBikeInfo)
				{
					return new BikeInfoNS.CopriLock.BikeInfoMutable(copriBikeInfo, stationName);
				}

				// Unsupported type detected.
				return null;

			}
		}
	}
}