using System;

namespace Chernobyl.Creation
{
    /// <summary>
    /// Converts the <typeparamref name="TFromResult"/> result from a
    /// <see cref="IFactory{TFromResult, T1}"/> to a
    /// <typeparamref name="TToResult"/> result.
    /// </summary>
    /// <typeparam name="TFromResult">The type of from result.</typeparam>
    /// <typeparam name="TToResult">The type of to result.</typeparam>
    /// <typeparam name="T1">The type of the 1.</typeparam>
    public class ResultConversionFactory<T1, TFromResult, TToResult>
        : Builder<TToResult>, IFactory<T1, TToResult>
    {
        /// <param name="fromFactory">The instance whose result is to be converted.</param>
        /// <param name="converter">The instance that converts the result from
        /// a factory from one type to another.</param>
        public ResultConversionFactory(IFactory<T1, TFromResult> fromFactory,
                                       Func<TFromResult, TToResult> converter)
        {
            fromFactory.ThrowIfNull("fromFactory");
            _fromFactory = fromFactory;

            converter.ThrowIfNull("converter");
            _converter = converter;
        }

        /// <inheritdoc />
        public TToResult Create(T1 arg1)
        {
            var result = _converter(_fromFactory.Create(arg1));
            ReportCreation(result);
            return result;
        }

        /// <summary>
        /// The instance whose result is to be converted.
        /// </summary>
        readonly IFactory<T1, TFromResult> _fromFactory;

        /// <summary>
        /// The instance that converts the <typeparamref name="TFromResult"/>
        /// result from a <see cref="IFactory{TFromResult, T1}"/> to a
        /// <typeparamref name="TToResult"/> result.
        /// </summary>
        readonly Func<TFromResult, TToResult> _converter;
    }
}