using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;

namespace Neo.Afx.Collections
{
    /// <summary>
    /// A collection of int values that map to year values.
    /// </summary>
    public class YearCollection : ReadOnlyCollection<KeyValuePair<int, string>>
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="YearCollection"/> class.
        /// </summary>
        public YearCollection()
            : this(-5, 10)
        {
        }       /// <summary>
        /// Initializes a new instance of the <see cref="YearCollection"/> class.
        /// </summary>
        /// <param name="minusCurrent">The number to add to the current year to get the min value.</param>
        /// <param name="plusCurrent">The number to add to the current year to get the max value.</param>
        public YearCollection(int minusCurrent, int plusCurrent)
            : base(CreateList(minusCurrent, plusCurrent))
        {
        }

        static List<KeyValuePair<int, string>> CreateList(int beforeCurrent, int afterCurrent)
        {
            var min = DateTime.Today.Year + beforeCurrent;
            var max = DateTime.Today.Year + afterCurrent;

            var options = new List<KeyValuePair<int, string>>();
            for(var i = min; i <= max; i++)
            {
                options.Add(new KeyValuePair<int, string>(i, i.ToString()));
            }
            return options;
        }
    }
}