using System;
using System.Collections;
using System.Collections.Generic;
using ShareeBike.Model.Stations.StationNS;

namespace ShareeBike.Model.Stations
{
	public class StationDictionary : IEnumerable<IStation>
	{
		/// <summary> Holds the list of stations. </summary>
		private readonly IDictionary<string, IStation> m_oStationDictionary;

		/// <summary>
		/// Gets a station by key.
		/// </summary>
		/// <param name="key">Key to get station.</param>
		/// <returns>Station for given key.</returns>
		public IStation this[string key] =>
			ContainsKey(key) ? m_oStationDictionary[key] : new NullStation();

		/// <summary> Count of stations. </summary>
		public int Count { get { return m_oStationDictionary.Count; } }

		public Version CopriVersion { get; }

		/// <summary> Constructs a station dictionary object. </summary>
		/// <param name="version">Version of copri- service.</param>
		public StationDictionary(Version version = null, IDictionary<string, IStation> stations = null)
		{
			m_oStationDictionary = stations ?? new Dictionary<string, IStation>();

			CopriVersion = version != null
				? new Version(version.Major, version.Minor, version.Revision, version.Build)
				: new Version(0, 0, 0, 0);
		}

		public IEnumerator<IStation> GetEnumerator()
		{
			return m_oStationDictionary.Values.GetEnumerator();
		}

		/// <summary>
		/// Determines whether a station by given key exists.
		/// </summary>
		/// <param name="key">Key to check.</param>
		/// <returns>True if station exists.</returns>
		public bool ContainsKey(string key)
		{
			return m_oStationDictionary.ContainsKey(key);
		}

		/// <summary>
		/// Remove a station by station id.
		/// </summary>
		/// <param name="id"></param>
		public void RemoveById(string id)
		{
			if (!m_oStationDictionary.ContainsKey(id))
			{
				// Nothing to do if there is no station with given name.
				return;
			}

			m_oStationDictionary.Remove(id);
		}

		/// <summary>
		/// Remove a station by station name.
		/// </summary>
		/// <param name="id"></param>
		public IStation GetById(string id)
		{
			if (!m_oStationDictionary.ContainsKey(id))
			{
				// Nothing to do if there is no station with given name.
				return null;
			}

			return m_oStationDictionary[id];
		}

		/// <summary>
		/// Adds a station to dictionary of stations.
		/// </summary>
		/// <param name="p_oStation"></param>
		public void Add(Station p_oStation)
		{
			if (p_oStation == null)
			{
				throw new ArgumentException("Can not add empty station to collection of stations.");
			}

			if (m_oStationDictionary.ContainsKey(p_oStation.Id))
			{
				throw new ArgumentException(string.Format("Can not add station {0} to collection of stations. A station with given name already exists.", p_oStation.Id));
			}

			m_oStationDictionary.Add(p_oStation.Id, p_oStation);
		}

		IEnumerator IEnumerable.GetEnumerator()
		{
			return m_oStationDictionary.Values.GetEnumerator();
		}
	}
}