ByteDecoder/RoyalLibrary

using ByteDecoder.Common.GuardClauses;
using System.Linq;

namespace ByteDecoder.RoyalLibrary
{
    /// <summary>
    /// 
    /// </summary>
    public static class PagingExtensions
    {
        /// <summary>
        /// Generic Page query object.
        /// </summary>
        /// <param name="query">Sequence source</param>
        /// <param name="pageNumZeroStart">Starting page number offset. Zero is the first page</param>
        /// <param name="pageSize">Page size</param>
        /// <typeparam name="T">Type of the source</typeparam>
        /// <returns></returns>
        public static IQueryable<T> Page<T>(this IQueryable<T> query, int pageNumZeroStart, int pageSize)
        {
            Guard.Break.IfArgumentIsNull(query, nameof(query));
            Guard.Break.IfArgumentOutOfRange(() => pageSize == 0, nameof(pageSize), "pageSize cannot be zero.");

            if (pageNumZeroStart != 0)
                query = query.Skip(pageNumZeroStart * pageSize);

            return query.Take(pageSize);
        }
    }
}