namespace Chernobyl.Creation
{
    /// <summary>
    /// An <see cref="IFactory{T1, TResult}"/> that wraps an
    /// <see cref="IFactory{TResult}"/> so that the <see cref="IFactory{TResult}"/>
    /// can be used as if it takes an argument. This type is an implementation
    /// of the composite pattern (http://en.wikipedia.org/wiki/Composite_pattern).
    /// </summary>
    public class ArgumentedFactory<T1, TResult> : Builder<TResult>, IFactory<T1, TResult>
    {
        /// <summary>
        /// Initializes a new instance of the
        /// <see cref="ArgumentedFactory{T1, TResult}"/> class.
        /// </summary>
        /// <param name="factory">The <see cref="IFactory{TResult}"/> that is to
        /// be wrapped.</param>
        public ArgumentedFactory(IFactory<TResult> factory)
        {
            factory.ThrowIfNull("factory");
            _factory = factory;
            _factory.Created += OnCreated;
        }


        /// <inheritdoc />
        public TResult Create(T1 arg1) => _factory.Create();

        // Forwards creation events from the decorated factory through this instance.
        void OnCreated(object sender, CreationEventArgs<TResult> e) => CreatedMethod?.Invoke(this, e);

        readonly IFactory<TResult> _factory;
    }

    /// <summary>
    /// Extensions for the <see cref="ArgumentedFactory{T1, TResult}"/> type.
    /// </summary>
    public static class ArgumentedFactoryExtensions
    {
        /// <summary>
        /// Converts the passed in <see cref="IFactory{TResult}"/> to an
        /// <see cref="IFactory{T1, TResult}"/> whose <typeparamref name="T1"/>
        /// is ignored.
        /// </summary>
        public static IFactory<T1, TResult> AsArgumented<T1, TResult>(this IFactory<TResult> factory) =>
            new ArgumentedFactory<T1, TResult>(factory);
    }
}