using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Linq.Dynamic.Core;

namespace Core.Util
{
    public static partial class Extention
    {
        /// <summary>
        /// 复制序列中的数据
        /// </summary>
        /// <typeparam name="T">泛型</typeparam>
        /// <param name="iEnumberable">原数据</param>
        /// <param name="startIndex">原数据开始复制的起始位置</param>
        /// <param name="length">需要复制的数据长度</param>
        /// <returns></returns>
        public static IEnumerable<T> Copy<T>(this IEnumerable<T> iEnumberable, int startIndex, int length)
        {
            var sourceArray = iEnumberable.ToArray();
            T[] newArray = new T[length];
            Array.Copy(sourceArray, startIndex, newArray, 0, length);

            return newArray;
        }

        /// <summary>
        /// 给IEnumerable拓展ForEach方法
        /// </summary>
        /// <typeparam name="T">模型类</typeparam>
        /// <param name="iEnumberable">数据源</param>
        /// <param name="func">方法</param>
        public static void ForEach<T>(this IEnumerable<T> iEnumberable, Action<T> func)
        {
            foreach (var item in iEnumberable)
            {
                func(item);
            }
        }

        /// <summary>
        /// 给IEnumerable拓展ForEach方法
        /// </summary>
        /// <typeparam name="T">模型类</typeparam>
        /// <param name="iEnumberable">数据源</param>
        /// <param name="func">方法</param>
        public static void ForEach<T>(this IEnumerable<T> iEnumberable, Action<T, int> func)
        {
            var array = iEnumberable.ToArray();
            for (int i = 0; i < array.Count(); i++)
            {
                func(array[i], i);
            }
        }

        /// <summary>
        /// IEnumerable转换为List'T'
        /// </summary>
        /// <typeparam name="T">参数</typeparam>
        /// <param name="source">数据源</param>
        /// <returns></returns>
        public static List<T> CastToList<T>(this IEnumerable source)
        {
            return new List<T>(source.Cast<T>());
        }

        /// <summary>
        /// 将IEnumerable'T'转为对应的DataTable
        /// </summary>
        /// <typeparam name="T">数据模型</typeparam>
        /// <param name="iEnumberable">数据源</param>
        /// <returns>DataTable</returns>
        public static DataTable ToDataTable<T>(this IEnumerable<T> iEnumberable)
        {
            return iEnumberable.ToJson().ToDataTable();
        }

        /// <summary>
        /// 获取分页数据(包括总数量)
        /// </summary>
        /// <typeparam name="T">泛型</typeparam>
        /// <param name="iEnumberable">数据源</param>
        /// <param name="pageInput">分页参数</param>
        /// <returns></returns>
        public static PageResult<T> GetPageResult<T>(this IEnumerable<T> iEnumberable, PageInput pageInput)
        {
            int count = iEnumberable.Count();

            var list = iEnumberable.AsQueryable()
                .OrderBy($@"{pageInput.SortField} {pageInput.SortType}")
                .Skip((pageInput.PageIndex - 1) * pageInput.PageRows)
                .Take(pageInput.PageRows)
                .ToList();

            return new PageResult<T> { Data = list, Total = count };
        }

        /// <summary>
        /// 获取分页数据(仅获取列表,不获取总数量)
        /// </summary>
        /// <typeparam name="T">泛型</typeparam>
        /// <param name="iEnumberable">数据源</param>
        /// <param name="pageInput">分页参数</param>
        /// <returns></returns>
        public static List<T> GetPageList<T>(this IEnumerable<T> iEnumberable, PageInput pageInput)
        {
            var list = iEnumberable.AsQueryable()
                .OrderBy($@"{pageInput.SortField} {pageInput.SortType}")
                .Skip((pageInput.PageIndex - 1) * pageInput.PageRows)
                .Take(pageInput.PageRows)
                .ToList();

            return list;
        }
    }
}