using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web;
using System.Reflection;
using System.Linq.Expressions;

namespace Bowin.Common.Linq.Entity
{
    [Serializable]
    public class GridResultSet<TEntity> : IGridResultSet<TEntity>
    {
        private OrderByStatementView _orderby;

        private int listComparision(TEntity source, TEntity target)
        {
            var entityType = typeof(TEntity);
            var propertyInfo = entityType.GetProperty(_orderby.OrderBy);
            if (propertyInfo == null)
            {
                throw new Exception("类" + entityType.Name + "不包含" + _orderby.OrderBy + "属性。");
            }

            var sourceValue = propertyInfo.GetValue(source, null);
            var targetValue = propertyInfo.GetValue(target, null);

            if (_orderby.isAsc)
            {
                return Convert.ToString(sourceValue).CompareTo(Convert.ToString(targetValue));
            }
            else
            {
                return Convert.ToString(targetValue).CompareTo(Convert.ToString(sourceValue));
            }
        }

        private List<TEntity> _rows;
        public List<TEntity> rows {
            get
            {
                return _rows;
            }
            set
            {
                _orderby = (OrderByStatementView)HttpContext.Current.Session["Bowin_Common_Linq_Entity_CurOrderby"]; 
                if (_orderby != null)
                {
                    value.Sort(new Comparison<TEntity>(listComparision));
                    HttpContext.Current.Session["Bowin_Common_Linq_Entity_CurOrderby"] = null;
                }
                _rows = value;
            }
        }
        public int total { get; set; }
    }
}