using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Dynamic.Core;
using System.Linq.Expressions;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using Furion.DatabaseAccessor;
using Furion.DatabaseAccessor.Extensions;
using Mapster;

namespace Ewide.Core.Extension
{
    public static class PageExtensions
    {
        public static string OrderBuilder<T>(PageInputBase pageInput, bool descSort = true)
        {
            var type = typeof(T);
            var hasId = type.GetProperty("Id") != null;
            var hasSort = type.GetProperty("Sort") != null;

            var defaultField = hasId ? "Id" : (hasSort ? "Sort" : "");

            // 约定默认每张表都有Id排序
            var orderStr = string.IsNullOrEmpty(defaultField) ? "" : defaultField + (descSort ? " Desc" : " Asc");

            // 排序是否可用-排序字段和排序顺序都为非空才启用排序            
            if (!string.IsNullOrEmpty(pageInput.SortField) && !string.IsNullOrEmpty(pageInput.SortOrder))
            {
                orderStr = $"{pageInput.SortField} {(pageInput.SortOrder == pageInput.DescStr ? "Desc" : "Asc")}";
            }
            return orderStr;
        }

        public static Task<PagedList<T>> ToPageData<T>(this IQueryable<T> source, PageInputBase input) where T : new()
        {
            return source.OrderBy(OrderBuilder<T>(input)).ToPagedListAsync(input.PageNo, input.PageSize);
        }

        public static Task<PagedList<O>> ToPageData<T, O>(this IQueryable<T> source, PageInputBase input) where O : new()
        {
            return source.OrderBy(OrderBuilder<T>(input)).Select(u => u.Adapt<O>()).ToPagedListAsync(input.PageNo, input.PageSize);
        }
    }
}