using System.ComponentModel;

namespace TINK.Model.Bikes.BikeInfoNS.DriveNS.BatteryNS
{
	/// <summary>
	/// Manages the state of a chargeable battery.
	/// </summary>
	public class BatteryMutable : IBatteryMutable, INotifyPropertyChanged
	{
		public event PropertyChangedEventHandler PropertyChanged;

		IBattery _battery;

		public BatteryMutable(IBattery battery)
		{
			_battery = battery;
		}

		/// <summary>
		/// Gets the current charging level of the battery in percent, double.NaN if unknown.
		/// </summary>
		public double CurrentChargePercent => _battery.CurrentChargePercent;

		/// <summary>
		/// Gets or sets the current charging level of the battery in bars, null if unknown.
		/// </summary>
		public int? CurrentChargeBars
		{
			get => _battery.CurrentChargeBars;
			set
			{
				double GetCurrentChargePercent()
				{
					if (value == null)
					{
						// Filling level is unknown.
						return double.NaN;
					}

					if (_battery.MaxChargeBars == null || _battery.MaxChargeBars == 0)
					{
						// Percentage filling level can not be calculated.
						return _battery.CurrentChargePercent;
					}

					return (int)(100 * value / _battery.MaxChargeBars);
				}

				if (_battery.CurrentChargeBars == value)
				{
					// Nothing to do.
					return;
				}

				_battery = new Battery.Builder
				{
					MaxChargeBars = _battery.MaxChargeBars,
					IsBackendAccessible = _battery.IsBackendAccessible,
					IsHidden = _battery.IsHidden,
					CurrentChargeBars = value,
					CurrentChargePercent = GetCurrentChargePercent(),
				}.Build();

				PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(CurrentChargeBars)));
				PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(CurrentChargePercent)));
			}
		}

		/// <summary>
		/// Gets the maximum charging level of the battery in bars, null if unknown.
		/// </summary>
		public int? MaxChargeBars => _battery.MaxChargeBars;

		/// <summary>
		/// Gets whether backend is aware of battery charging level.
		/// </summary>
		public bool? IsBackendAccessible => _battery.IsBackendAccessible;

		/// <summary>
		/// Gets whether to display battery level or not.
		/// </summary>
		public bool? IsHidden => _battery.IsHidden;
	}
}