using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;
using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Linq;
using System.Web;

namespace DSWeb.MvcShipping.Helper
{
    public static class ExcelHelper
    {


        /// <summary>
        /// 将excel文件内容读取到DataTable数据表中
        /// </summary>
        /// <param name="fileName">文件完整路径名</param>
        /// <param name="sheetName">指定读取excel工作薄sheet的名称</param>
        /// <param name="isFirstRowColumn">第一行是否是DataTable的列名：true=是，false=否</param>
        /// <returns>DataTable数据表</returns>
        public static DataTable ReadExcelToDataTable(string fileName, out string strMsg, string sheetName = null, bool isFirstRowColumn = true)
        {

            strMsg = "";
            //定义要返回的datatable对象
            DataTable data = new DataTable();
            //excel工作表
            NPOI.SS.UserModel.ISheet sheet = null;
            //数据开始行(排除标题行)
            int startRow = 0;
            try
            {
                if (!File.Exists(fileName))
                {
                    return null;
                }
                //根据指定路径读取文件
                FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
                //根据文件流创建excel数据结构
                NPOI.SS.UserModel.IWorkbook workbook = NPOI.SS.UserModel.WorkbookFactory.Create(fs);
                //IWorkbook workbook = new HSSFWorkbook(fs);
                //如果有指定工作表名称
                if (!string.IsNullOrEmpty(sheetName))
                {
                    sheet = workbook.GetSheet(sheetName);
                    //如果没有找到指定的sheetName对应的sheet，则尝试获取第一个sheet
                    if (sheet == null)
                    {
                        sheet = workbook.GetSheetAt(0);
                    }
                }
                else
                {
                    //如果没有指定的sheetName，则尝试获取第一个sheet
                    sheet = workbook.GetSheetAt(0);
                }
                if (sheet != null)
                {
                    NPOI.SS.UserModel.IRow firstRow = sheet.GetRow(0);
                    //一行最后一个cell的编号 即总的列数
                    int cellCount = firstRow.LastCellNum;
                    //如果第一行是标题列名
                    if (isFirstRowColumn)
                    {
                        for (int i = firstRow.FirstCellNum; i < cellCount; ++i)
                        {
                            NPOI.SS.UserModel.ICell cell = firstRow.GetCell(i);
                            if (cell != null)
                            {
                                string cellValue = cell.StringCellValue;
                                if (cellValue != null)
                                {
                                    DataColumn column = new DataColumn(cellValue);
                                    data.Columns.Add(column);
                                }
                            }
                        }
                        startRow = sheet.FirstRowNum + 1;
                    }
                    else
                    {
                        startRow = sheet.FirstRowNum;
                    }
                    //最后一列的标号
                    int rowCount = sheet.LastRowNum;
                    for (int i = startRow; i <= rowCount; ++i)
                    {
                        NPOI.SS.UserModel.IRow row = sheet.GetRow(i);
                        if (row == null) continue; //没有数据的行默认是null

                        DataRow dataRow = data.NewRow();
                        for (int j = row.FirstCellNum; j < cellCount; ++j)
                        {
                            if (row.GetCell(j) != null) //同理，没有数据的单元格都默认是null
                                dataRow[j] = row.GetCell(j).ToString();
                        }
                        data.Rows.Add(dataRow);
                    }
                }
                
            }
            catch (Exception ex)
            {
                strMsg = ex.Message;
            }
            return data;
        }

        public static DateTime GetDateTime(int timestamp)
        {
            //DateTime dtStart = TimeZone.CurrentTimeZone.ToLocalTime(new DateTime(1970, 1, 1)); 
            //使用上面的方式会显示TimeZone已过时
            //DateTime dtStart = TimeZoneInfo.ConvertTime(new DateTime(1970, 1, 1), TimeZoneInfo.Local);
            //long lTime = long.Parse(timestamp + "0000");
            //TimeSpan timeSpan = new TimeSpan(lTime);
            //DateTime targetDt = dtStart.Add(timeSpan).AddHours(8);
            DateTime dtStart = Convert.ToDateTime("1970-01-01");
            DateTime targetDt = dtStart.AddDays(timestamp-1);
            return targetDt;
        }

        /// <summary>
        /// 将文件流读取到DataTable数据表中
        /// </summary>
        /// <param name="fileStream">文件流</param>
        /// <param name="sheetName">指定读取excel工作薄sheet的名称</param>
        /// <param name="isFirstRowColumn">第一行是否是DataTable的列名：true=是，false=否</param>
        /// <returns>DataTable数据表</returns>
        public static DataTable ReadStreamToDataTable(Stream fileStream, out string strMsg, string sheetName = null, bool isFirstRowColumn = true)
        {
            strMsg = "";
            //定义要返回的datatable对象
            DataTable data = new DataTable();
            //excel工作表
            NPOI.SS.UserModel.ISheet sheet = null;
            
            //数据开始行(排除标题行)
            int startRow = 0;
            try
            {
                //根据文件流创建excel数据结构,NPOI的工厂类WorkbookFactory会自动识别excel版本，创建出不同的excel数据结构
                NPOI.SS.UserModel.IWorkbook workbook = NPOI.SS.UserModel.WorkbookFactory.Create(fileStream);
                //如果有指定工作表名称
                if (!string.IsNullOrEmpty(sheetName))
                {
                    sheet = workbook.GetSheet(sheetName);
                    //如果没有找到指定的sheetName对应的sheet，则尝试获取第一个sheet
                    if (sheet == null)
                    {
                        sheet = workbook.GetSheetAt(0);
                    }
                }
                else
                {
                    //如果没有指定的sheetName，则尝试获取第一个sheet
                    sheet = workbook.GetSheetAt(0);
                }
                if (sheet != null)
                {
                    NPOI.SS.UserModel.IRow firstRow = sheet.GetRow(0);
                    //一行最后一个cell的编号 即总的列数
                    int cellCount = firstRow.LastCellNum;
                    //如果第一行是标题列名
                    if (isFirstRowColumn)
                    {
                        for (int i = firstRow.FirstCellNum; i < cellCount; ++i)
                        {
                            NPOI.SS.UserModel.ICell cell = firstRow.GetCell(i);
                            if (cell != null)
                            {
                                string cellValue = cell.StringCellValue;
                                if (cellValue != null)
                                {
                                    DataColumn column = new DataColumn(cellValue);
                                    data.Columns.Add(column);
                                }
                            }
                        }
                        startRow = sheet.FirstRowNum + 1;
                    }
                    else
                    {
                        startRow = sheet.FirstRowNum;
                    }
                    //最后一列的标号
                    int rowCount = sheet.LastRowNum;
                    for (int i = startRow; i <= rowCount; ++i)
                    {
                        NPOI.SS.UserModel.IRow row = sheet.GetRow(i);
                        if (row == null || row.FirstCellNum < 0) continue; //没有数据的行默认是null

                        DataRow dataRow = data.NewRow();
                        for (int j = row.FirstCellNum; j < cellCount; ++j)
                        {
                            //同理，没有数据的单元格都默认是null
                            NPOI.SS.UserModel.ICell cell = row.GetCell(j);
                            if (cell != null)
                            {

                                if (cell.CellType == NPOI.SS.UserModel.CellType.Numeric)
                                {
                                    //判断是否日期类型
                                    if (NPOI.SS.UserModel.DateUtil.IsCellDateFormatted(cell))
                                    {
                                        try
                                        {
                                            dataRow[j] = row.GetCell(j).DateCellValue;
                                        }
                                        catch
                                        {
                                            dataRow[j] = GetDateTime((int)row.GetCell(j).NumericCellValue);
                                            //strMsg = row.GetCell(j).NumericCellValue.ToString();
                                        }
                                    }
                                    else
                                    {
                                        dataRow[j] = row.GetCell(j).ToString().Trim();
                                    }
                                }
                                else
                                {
                                    dataRow[j] = row.GetCell(j).ToString().Trim();
                                }
                            }
                        }
                        data.Rows.Add(dataRow);
                    }
                }
          
            }
            catch (Exception ex)
            {
                strMsg = ex.Message;
            }
            return data;
        }

        /// <summary>
        /// 将Excel单表转为Datatable
        /// </summary>
        /// <param name="stream"></param>
        /// <param name="fileType"></param>
        /// <param name="strMsg"></param>
        /// <param name="sheetName"></param>
        /// <returns></returns>
        public static DataTable ExcelToDatatable(Stream stream, string fileType, out string strMsg, string sheetName = null,int startrow=0)
        {
            strMsg = "";
            DataTable dt = new DataTable();
            ISheet sheet = null;
            IWorkbook workbook = null;
            try
            {
                #region 判断excel版本
                //2007以上版本excel

                
                if (fileType == ".xlsx")
                {
                    stream.Seek(0, SeekOrigin.Begin);
                    //                    workbook = new XSSFWorkbook(stream);
                    workbook = NPOI.SS.UserModel.WorkbookFactory.Create(stream);

                }
                //2007以下版本excel
                else if (fileType == ".xls")
                {
                    workbook = new HSSFWorkbook(stream);
                }
                else
                {
                    throw new Exception("传入的不是Excel文件！");
                }
                #endregion
                if (!string.IsNullOrEmpty(sheetName))
                {
                    sheet = workbook.GetSheet(sheetName);
                    if (sheet == null)
                    {
                        sheet = workbook.GetSheetAt(0);
                    }
                }
                else
                {
                    sheet = workbook.GetSheetAt(0);
                }
                if (sheet != null)
                {
                    IRow firstRow = sheet.GetRow(startrow);
                    int cellCount = firstRow.LastCellNum;
                    for (int i = firstRow.FirstCellNum; i < cellCount; i++)
                    {
                        ICell cell = firstRow.GetCell(i);
                        if (cell != null)
                        {
                            string cellValue = cell.StringCellValue.Trim();
                            if (!string.IsNullOrEmpty(cellValue))
                            {
                                DataColumn dataColumn = new DataColumn(cellValue);
                                dt.Columns.Add(dataColumn);
                            }
                        }
                    }
                    DataRow dataRow = null;
                    //遍历行
                    for (int j = sheet.FirstRowNum + 1; j <= sheet.LastRowNum; j++)
                    {
                        IRow row = sheet.GetRow(j);
                        dataRow = dt.NewRow();
                        if (row == null || row.FirstCellNum < 0)
                        {
                            continue;
                        }
                        //遍历列

                        var isadd =false;
                        for (int i = row.FirstCellNum; i < cellCount; i++)
                        {
                            ICell cellData = row.GetCell(i);
                            if (cellData != null)
                            {
                                if (cellData.CellType == NPOI.SS.UserModel.CellType.Numeric)
                                {
                                    //判断是否日期类型
                                    if (NPOI.SS.UserModel.DateUtil.IsCellDateFormatted(cellData))
                                    {
                                        try
                                        {
                                            dataRow[j] = cellData.DateCellValue;
                                        }
                                        catch
                                        {
                                            try
                                            {
                                                dataRow[j] = GetDateTime((int)cellData.NumericCellValue);
                                            }
                                            catch {

                                                dataRow[i] = "";
                                            }
                                            //strMsg = row.GetCell(j).NumericCellValue.ToString();
                                        }
                                    }
                                    else
                                    {
                                        try
                                        {
                                            dataRow[i] = cellData.NumericCellValue;
                                        }
                                        catch
                                        {
                                            try
                                            { 
                                            dataRow[i] = cellData.StringCellValue;
                                            }
                                            catch
                                            {

                                                dataRow[i] = "";
                                            }
                                        }

                                    }
                                }
                                else
                                {
                                    try
                                    {
                                        dataRow[i] = cellData.StringCellValue;
                                    }
                                    catch
                                    {
                                        try
                                        { 
                                        dataRow[i] = cellData.NumericCellValue;
                                        }
                                        catch
                                        {

                                            dataRow[i] = "";
                                        }
                                    }
                                }

                                //判断是否为数字型，必须加这个判断不然下面的日期判断会异常
                                //if (cellData.CellType == CellType.Numeric)
                                //{
                                //    try
                                //    {
                                //        dataRow[j] = row.GetCell(j).DateCellValue;
                                //    }
                                //    catch
                                //    {
                                //        dataRow[j] = GetDateTime((int)row.GetCell(j).NumericCellValue);
                                //        //strMsg = row.GetCell(j).NumericCellValue.ToString();
                                //    }
                                //} else if (cellData.CellType == CellType.Formula)
                                //{
                                //    try
                                //    {
                                //        dataRow[i] = cellData.StringCellValue;
                                //    }
                                //    catch {
                                //        dataRow[i] = cellData.NumericCellValue;
                                //    }
                                //}
                                //else
                                //{
                                //    dataRow[i] = cellData.ToString().Trim();
                                //}
                                //                                dt.Rows.Add(dataRow);
                                isadd = true;
                            }
                            else
                            {
                                dataRow[i] ="";
                            }
                        }
                        if (isadd) dt.Rows.Add(dataRow);
                    }
                }
                else
                {
                    throw new Exception("没有获取到Excel中的数据表！");
                }

            }
            catch (Exception ex)
            {
                stream.Position = 0; // 增加这句
                workbook = new HSSFWorkbook(stream);
                strMsg = ex.Message;
            }
            return dt;
        }
    }
}