using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Windows.Forms;
using System.Collections;
using System.IO;

using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.HSSF.Record;
using WMS.Common;
using NPOI.XSSF.UserModel;

namespace WMS.FrmCK
{
    class NPOIHelper
    {  
        private static string GetCellValue(ICell cell)
        {
            if (cell == null)
                return string.Empty;
            switch (cell.CellType)
            {
                case CellType.Blank:
                    return string.Empty;
                case CellType.Boolean:
                    return cell.BooleanCellValue.ToString();
                case CellType.Error:
                    return cell.ErrorCellValue.ToString();
                case CellType.Numeric:
                case CellType.Unknown:
                default:
                    return cell.ToString();//This is a trick to get the correct value of the cell. NumericCellValue will return a numeric value no matter the cell value is a date or a number
                case CellType.String:
                    return cell.StringCellValue;
                case CellType.Formula:
                    try
                    {
                        HSSFFormulaEvaluator e = new HSSFFormulaEvaluator(cell.Sheet.Workbook);
                        e.EvaluateInCell(cell);
                        return cell.ToString();
                    }
                    catch
                    {
                        return cell.NumericCellValue.ToString();
                    }
            }
        }

        public static DataTable Import(OpenFileDialog fileDialog)
        {
            DataTable table = new DataTable();
            Stream excelFileStream;
            try
            {
                excelFileStream = fileDialog.OpenFile();
            }
            catch (IOException e)
            {
                if (e.ToString().Contains("正由另一进程使用"))
                {
                    SystemCommon.ShowErrorMessageBox("所选Excel文件处于打开状态，请关闭后重试");
                }
                else
                {
                    SystemCommon.ShowErrorMessageBox("文件读取失败");
                }
                return null;
            }

            if (excelFileStream == null)
            {
                excelFileStream.Close();
                SystemCommon.ShowErrorMessageBox("文件读取失败");
                return null;
            }
            //读取excel
            using (excelFileStream)
            {
                IWorkbook workbook = new HSSFWorkbook();

                if (fileDialog.SafeFileName.Substring(fileDialog.SafeFileName.Length - 1, 1) == "s")
                {
                    try
                    {
                        workbook = new HSSFWorkbook(excelFileStream);//xls
                    }
                    catch (LeftoverDataException)
                    {
                        SystemCommon.ShowErrorMessageBox("导入失败，请将所选Excel文件另存为一个新的Excel文件后再次导入");
                        return null;
                    }
                    catch (IOException)
                    {
                        SystemCommon.ShowErrorMessageBox("导入失败，请将所选Excel文件另存为一个新的Excel文件后再次导入");
                        return null;
                    }
                    catch (Exception)
                    {
                        SystemCommon.ShowErrorMessageBox("导入失败，读取Excel文件时遇到未知错误");
                        return null;
                    }

                }
                else
                {
                    workbook = new XSSFWorkbook(excelFileStream);//xlsx
                }

                ISheet sheet = workbook.GetSheetAt(0);//取第一个表

                IRow headerRow = sheet.GetRow(0);//第一行为标题行
                if (headerRow == null)
                {
                    SystemCommon.ShowErrorMessageBox("导入失败，所选Excel没有数据");
                    return null;
                }
                int cellCount = headerRow.LastCellNum;//LastCellNum = PhysicalNumberOfCells
                int rowCount = sheet.LastRowNum;//LastRowNum = PhysicalNumberOfRows - 1

                //handling header.
                for (int i = headerRow.FirstCellNum; i < cellCount; i++)
                {

                    DataColumn column = new DataColumn(headerRow.GetCell(i).StringCellValue);
                    table.Columns.Add(column);
                }

                for (int i = (sheet.FirstRowNum + 1); i <= rowCount; i++)
                {
                    IRow row = sheet.GetRow(i);
                    DataRow dataRow = table.NewRow();

                    if (row != null)
                    {
                        for (int j = row.FirstCellNum; j < cellCount; j++)
                        {
                            if (row.GetCell(j) != null)
                            {
                                dataRow[j] = GetCellValue(row.GetCell(j));
                            }
                        }
                    }

                    table.Rows.Add(dataRow);
                }
            }


            return table;
                    

                
        }
    }
}