using System;

namespace AppLimit.CloudComputing.SharpBox.Common.Net.Json
{
    /// <summary>
    /// This class implements a json helper to convert a date time string 
    /// into the DateTime-Class of .NET
    /// </summary>
    internal class JsonDateTimeConverter
    {
        private enum Month
        {
            Jan = 1,
            Feb,
            Mar,
            Apr,
            May,
            Jun,
            Jul,
            Aug,
            Sep,
            Oct,
            Nov,
            Dec
        }

        private static Month ToMonth(string Input)
        {
            return (Month)Enum.Parse(typeof (Month), Input, true);
        }

        /// <summary>
        /// This method converts and returns a json date time string into a .NET date time
        /// string
        /// </summary>
        /// <param name="dateTime">The JSON datetime string</param>
        /// <returns>The .NET dateTime string</returns>
        public static DateTime GetDateTimeProperty(string dateTime)
        {
            // Sat, 21 Aug 2010 22:31:20 +0000            

            // check1
            if (dateTime.Length == 0)
                return DateTime.MinValue;

            // check2
            if (dateTime.Length != 31)
                throw new InvalidOperationException();

            // date
            var day = dateTime.Substring(5, 2);
            var month = dateTime.Substring(8, 3);
            var m = ToMonth(month);
            var year = dateTime.Substring(12, 4);

            // time
            var hour = dateTime.Substring(17, 2);
            var min = dateTime.Substring(20, 2);
            var sec = dateTime.Substring(23, 2);

            return new DateTime(Convert.ToInt32(year), Convert.ToInt32(m), Convert.ToInt32(day),
                                Convert.ToInt32(hour), Convert.ToInt32(min), Convert.ToInt32(sec),
                                DateTimeKind.Utc);
        }
    }
}