using System.Collections;
using System.Collections.Generic;
using Chernobyl.Utility;

namespace Chernobyl.Collections.Generic.Event
{
    /// <summary>
    /// An <see cref="IEnumerable"/> type that makes creating new 
    /// <see cref="IEnumerable"/> types easier.
    /// </summary>
    public abstract class DecoratingEventEnumerable : EventEnumerable
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="DecoratingEventEnumerable"/> class.
        /// </summary>
        /// <param name="enumerableDecorated">The <see cref="IEventEnumerable"/> 
        /// being decorated or extended with event capabilities.</param>
        protected DecoratingEventEnumerable(IEnumerable enumerableDecorated)
        {
            enumerableDecorated.ThrowIfNull("enumerableDecorated");
            _enumerableDecorated = enumerableDecorated;
        }

        /// <summary>
        /// The <see cref="IEventEnumerable" /> being decorated or extended
        /// with event capabilities.
        /// </summary>
        protected override IEnumerable EnumerableDecorated
        {
            get { return _enumerableDecorated; }
        }

        /// <summary>
        /// The backing field to <see cref="EnumerableDecorated"/>.
        /// </summary>
        readonly IEnumerable _enumerableDecorated;
    }

    /// <summary>
    /// An <see cref="IEnumerable{T}"/> type that makes creating new 
    /// <see cref="IEnumerable{T}"/> types easier.
    /// </summary>
    /// <typeparam name="T">The type that is to be held within this 
    /// <see cref="IEnumerable{T}"/>.</typeparam>
    public abstract class DecoratingEventEnumerable<T> : EventEnumerable<T>
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="DecoratingEventCollection{T}"/> 
        /// class.
        /// </summary>
        /// <param name="genericEnumerableDecorated">The <see cref="IEnumerable{T}"/> 
        /// being decorated or extended with event capabilities.</param>
        protected DecoratingEventEnumerable(IEnumerable<T> genericEnumerableDecorated)
        {
            genericEnumerableDecorated.ThrowIfNull("genericEnumerableDecorated");
            _genericEnumerableDecorated = genericEnumerableDecorated;
        }

        /// <summary>
        /// The <see cref="IEventEnumerable{T}" /> being decorated or extended
        /// with event capabilities.
        /// </summary>
        protected override IEnumerable<T> GenericEnumerableDecorated
        {
            get { return _genericEnumerableDecorated; }
        }

        /// <summary>
        /// The backing field to <see cref="GenericEnumerableDecorated"/>.
        /// </summary>
        readonly IEnumerable<T> _genericEnumerableDecorated;
    }
}