using System.Linq.Expressions;
using BlackRock.Reporting.API.Mediator;
using BlackRock.Reporting.API.Mediator.Model;

namespace BlackRock.Reporting.API.Extensions
{
    public static class IQueryableExtensions
    {
        public static IQueryable<T> ApplyOrdering<T>(this IQueryable<T> query,
        IPaggingAndFiltering queryObj, Dictionary<string, Expression<Func<T, object>>> columnsMap)
        {
            if (string.IsNullOrWhiteSpace(queryObj.SortBy) ||
            !columnsMap.ContainsKey(queryObj.SortBy))
                return query;
            if (queryObj.IsSortAscending)
                return query.OrderBy(columnsMap[queryObj.SortBy]);

            return query.OrderByDescending(columnsMap[queryObj.SortBy]);
        }
        public static IQueryable<T> ApplyPagging<T>(this IQueryable<T> query,
        IPaggingAndFiltering queryObj)
        {
            if (queryObj.Page <= 0)
                queryObj.Page = 1;

            if (queryObj.PageSize <= 0)
                queryObj.PageSize = 10;

            return query.Skip((queryObj.Page - 1) * queryObj.PageSize)
            .Take(queryObj.PageSize);
        }
    }
}