/*
* Copyright (c) 2018 Algolia
* http://www.algolia.com/
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/

using System;

namespace Algolia.Search.Utils
{
    /// <summary>
    /// We need this helper because the ToUnixTimeSeconds() is not supported in 4.5 framework
    /// Inspired by : https://www.fluxbytes.com/csharp/convert-datetime-to-unix-time-in-c/
    /// </summary>
    public static class DateTimeHelper
    {
        /// <summary>
        /// Convert a date time object to Unix time representation.
        /// </summary>
        /// <param name="date">The datetime object to convert to Unix time stamp.</param>
        /// <returns>Returns a numerical representation (Unix time) of the DateTime object.</returns>
        public static long ToUnixTimeSeconds(this DateTime date)
        {
            DateTime sTime = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
            return (long)(date - sTime).TotalSeconds;
        }

        /// <summary>
        /// Convert Unix time value to a DateTime object.
        /// </summary>
        /// <param name="unixTime">The Unix time stamp you want to convert to DateTime.</param>
        /// <returns>Returns a DateTime object that represents value of the Unix time.</returns>
        public static DateTime UnixTimeToDateTime(long unixTime)
        {
            DateTime sTime = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
            return sTime.AddSeconds(unixTime);
        }
    }
}
