using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using DevExpress.XtraEditors;
using DevExpress.Utils;
using System.Threading.Tasks;

namespace MFire.WinFrmUI 
{
    /// <summary>
    /// 分页控件
    /// </summary>
    public partial class PagerCtrl : XtraUserControl
    {
        public PagerCtrl()
        {
            InitializeComponent(); 
        }

        /// <summary>
        /// 查询分页数据事件
        /// </summary>
        /// 第一个参数为CurrentPage
        /// 第二个参数为PageSize
        /// 第三个参数为返回的总条数
        public event Func<int,int,Task<int>> QueryPageEvent;//返回总条数

        private int _pageSize = 40;//单页条数
        private int _pageIndex = 1;//当前页
        private int _total = 0;//总条数
        private int _pageNumber = 0;//总页数

        /// <summary>
        /// 被动查询
        /// </summary>
        public void PassiveQuery(bool reset=true)
        {
            if (reset)
            {
                _pageIndex = 1;
            }
            Query();
        }
         
        //内部查询
        private async void Query()
        {
            this.txtPageIndex.Text = _pageIndex.ToString();
            if (this.QueryPageEvent != null)
            {
                _total =await this.QueryPageEvent(_pageIndex,_pageSize);
                _pageNumber = CalcuPageCount(_total, _pageSize);
                this.labTotal.Text = $"共 {_total} 条";
                this.labPageCount.Text= $"共 {_pageNumber} 页";

                if (_pageIndex >= _pageNumber)
                {
                    this.btnNext.Enabled = false;
                    this.btnLast.Enabled = false;
                }
                else
                {
                    this.btnNext.Enabled = true;
                    this.btnLast.Enabled = true;
                }

                if (_pageIndex <= 1)
                {
                    this.btnPre.Enabled = false;
                    this.btnFirst.Enabled = false;
                }
                else
                {
                    this.btnPre.Enabled = true;
                    this.btnFirst.Enabled = true;
                }
            }
        }

        //计算页数
        private int CalcuPageCount(int total, int pageSize)
        {
            if (total % pageSize > 0)
                return total / pageSize + 1;
            return total / pageSize;
        }

        //首页
        private void btnFirst_Click(object sender, EventArgs e)
        {
            _pageIndex = 1;
            Query();
        }

        //上一页
        private void btnPre_Click(object sender, EventArgs e)
        {
            _pageIndex--;
            Query();
        }

        //下一页
        private void btnNext_Click(object sender, EventArgs e)
        {
            _pageIndex++;
            Query();
        }

        //末页
        private void btnLast_Click(object sender, EventArgs e)
        {
            _pageIndex = _pageNumber;
            Query();
        }

        //单页条数改变
        private void imgCmbPageSize_SelectedIndexChanged(object sender, EventArgs e)
        {
            _pageSize = (int)this.imgCmbPageSize.EditValue;
            _pageNumber = CalcuPageCount(_total,_pageSize);
            if (_pageIndex > _pageNumber)
                _pageIndex = _pageNumber;
            Query();
        }

        //跳转
        private void btnGo_Click(object sender, EventArgs e)
        {
            _pageIndex = int.Parse(this.txtToPageIndex.Text);
            Query();
        }

    }
}