using System.Collections.Generic;

namespace WindowsFormsApp1.OP
{
    /// <summary>
    /// Owns some important state and notifies observers when the state changes.
    /// </summary>
    public class Subject<T> : ISubject<T>
    { 
        private protected List<IObserver<T>> _observers = null;
        private object state { get;set; }

        public Subject()
        {
            _observers = new List<IObserver<T>>();
        }

        public virtual void Subscribe(IObserver<T> observer)
        {
            _observers.Add(observer);
        }
        public virtual void Unsubscribe(IObserver<T> observer)
        {
            _observers.Remove(observer);
        }
        public void Notify()
        {
            foreach (IObserver<T> observer in _observers)
            {
                observer.Update(this);
            }
        }
        public virtual void SetState(T state)
        {
            this.state = state;
            Notify();
        }
        public virtual T GetState()
        {
            return (T)state;
        }
    }
}