using System;
using System.Collections.Generic;
using System.Data;
using System.Reflection;

namespace EC.Utils
{
	/// <summary>
	/// ExtTable
	/// 版 本：V3.0.0
	/// 版 权：EasyCode
	/// 作 者：LXC
	/// </summary>
	public static class ExtTable
	{
		/// <summary>
		/// 获取表里某页的数据
		/// </summary>
		/// <param name="data">表数据</param>
		/// <param name="pageIndex">当前页</param>
		/// <param name="pageSize">分页大小</param>
		/// <param name="allPage">返回总页数</param>
		/// <returns>返回当页表数据</returns>
		public static DataTable GetPage(this DataTable data, int pageIndex, int pageSize, out int allPage)
		{
			allPage = data.Rows.Count / pageSize;
			allPage += data.Rows.Count % pageSize == 0 ? 0 : 1;
			DataTable Ntable = data.Clone();
			int startIndex = pageIndex * pageSize;
			int endIndex = startIndex + pageSize > data.Rows.Count ? data.Rows.Count : startIndex + pageSize;
			if (startIndex < endIndex)
				for (int i = startIndex; i < endIndex; i++)
				{
					Ntable.ImportRow(data.Rows[i]);
				}
			return Ntable;
		}

		/// <summary>
		/// 根据字段过滤表的内容
		/// </summary>
		/// <param name="data">表数据</param>
		/// <param name="condition">条件</param>
		/// <returns></returns>
		///
		public static DataTable GetDataFilter(DataTable data, string condition)
		{
			if (data != null && data.Rows.Count > 0)
			{
				if (condition.Trim() == "")
				{
					return data;
				}
				else
				{
					DataTable newdt = new DataTable();
					newdt = data.Clone();
					DataRow[] dr = data.Select(condition);
					for (int i = 0; i < dr.Length; i++)
					{
						newdt.ImportRow((DataRow)dr[i]);
					}
					return newdt;
				}
			}
			else
			{
				return null;
			}
		}

		/// <summary>
		/// 获取表里前几条数据
		/// </summary>
		/// <param name="data">表数据</param>
		/// <param name="top"></param>
		/// <returns></returns>
		public static DataTable GetSelectTop(DataTable data, int top)
		{
			if (data.Rows.Count < top) return data;
			DataTable NewTable = data.Clone();
			DataRow[] rows = data.Select("1=1");
			for (int i = 0; i < top; i++)
			{
				NewTable.ImportRow((DataRow)rows[i]);
			}
			return NewTable;
		}

		/// <summary>
		/// List转化一个DataTable
		/// </summary>
		/// <typeparam name="T"></typeparam>
		/// <param name="list"></param>
		/// <returns></returns>
		public static DataTable ToDataTable<T>(this IEnumerable<T> list)
		{
			List<PropertyInfo> pList = new List<PropertyInfo>();
			Type type = typeof(T);
			DataTable dt = new DataTable();
			Array.ForEach<PropertyInfo>(type.GetProperties(), p => { pList.Add(p); dt.Columns.Add(p.Name); });
			foreach (var item in list)
			{
				DataRow row = dt.NewRow();
				pList.ForEach(p => row[p.Name] = p.GetValue(item, null));
				dt.Rows.Add(row);
			}
			return dt;
		}
	}
}