using System;
using System.Collections.Generic;
using System.Text;

namespace Developpez.Dotnet.Collections
{
    /// <summary>
    /// Comparateur basé sur un delegate Comparison&lt;T&gt;.
    /// </summary>
    /// <typeparam name="T">Le type des éléments à comparer</typeparam>
    public class ComparisonComparer<T> : Comparer<T>
    {
        private Comparison<T> _comparison;

        /// <summary>
        /// Initialise une nouvelle instance ComparisonComparer&lt;T&gt;.
        /// </summary>
        /// <param name="comparison">La comparaison à utiliser</param>
        public ComparisonComparer(Comparison<T> comparison)
        {
            comparison.CheckArgumentNull("comparison");
            _comparison = comparison;
        }

        /// <summary>
        /// Compare deux instances de T
        /// </summary>
        /// <param name="x">Premier élément à comparer</param>
        /// <param name="y">Second élément à comparer</param>
        /// <returns>-1 si x &lt; y, 1 si x &gt; y, 0 si x == y</returns>
        public override int Compare(T x, T y)
        {
            return _comparison(x, y);
        }

        /// <summary>
        /// Convertit le ComparisonComparer&lt;T&gt; spécifié en Comparison&lt;T&gt;.
        /// </summary>
        /// <param name="comparisonComparer">Le ComparisonComparer&lt;T&gt; à convertir</param>
        /// <returns>La comparaison résultant de la conversion</returns>
        public static implicit operator Comparison<T>(ComparisonComparer<T> comparisonComparer)
        {
            return comparisonComparer._comparison;
        }

        /// <summary>
        /// Convertit la Comparison&lt;T&gt; spécifiée en ComparisonComparer&lt;T&gt;.
        /// </summary>
        /// <param name="comparison">La Comparison&lt;T&gt; à convertir</param>
        /// <returns>Le ComparisonComparer&lt;T&gt; résultant de la conversion</returns>
        public static implicit operator ComparisonComparer<T>(Comparison<T> comparison)
        {
            return new ComparisonComparer<T>(comparison);
        }
    }
}