using System.Data;
using System.IO;
using System.Text;
using System.Web;
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;

/// <summary>
/// 使用NPOI操作Excel，无需Office COM组件
/// 部分代码取自http://msdn.microsoft.com/zh-tw/ee818993.asp
/// </summary>
public class ExcelRender
{
    /// <summary>
    /// 根据Excel列类型获取列的值
    /// </summary>
    /// <param name="cell">Excel列</param>
    /// <returns></returns>
    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();
                } 
        }
    }

    /// <summary>
    /// 自动设置Excel列宽
    /// </summary>
    /// <param name="sheet">Excel表</param>
    private static void AutoSizeColumns(ISheet sheet)
    {
        if (sheet.PhysicalNumberOfRows > 0)
        {
            IRow headerRow = sheet.GetRow(0);

            for (int i = 0, l = headerRow.LastCellNum; i < l; i++)
            {
                sheet.AutoSizeColumn(i);
            }
        }
    }

    /// <summary>
    /// 保存Excel文档流到文件
    /// </summary>
    /// <param name="ms">Excel文档流</param>
    /// <param name="fileName">文件名</param>
    private static void SaveToFile(MemoryStream ms, string fileName)
    {
        using (FileStream fs = new FileStream(fileName, FileMode.Create, FileAccess.Write))
        {
            byte[] data = ms.ToArray();

            fs.Write(data, 0, data.Length);
            fs.Flush();

            data = null;
        }
    }

    /// <summary>
    /// 输出文件到浏览器
    /// </summary>
    /// <param name="ms">Excel文档流</param>
    /// <param name="context">HTTP上下文</param>
    /// <param name="fileName">文件名</param>
    private static void RenderToBrowser(MemoryStream ms, HttpContext context, string fileName)
    {
        if (context.Request.Browser.Browser == "IE")
            fileName = HttpUtility.UrlEncode(fileName);
        context.Response.AddHeader("Content-Disposition", "attachment;fileName=" + fileName);
        context.Response.BinaryWrite(ms.ToArray());
    }

    /// <summary>
    /// DataReader转换成Excel文档流
    /// </summary>
    /// <param name="reader"></param>
    /// <returns></returns>
    public static MemoryStream RenderToExcel(IDataReader reader)
    {
        MemoryStream ms = new MemoryStream();

        using (reader)
        {
            using (IWorkbook workbook = new HSSFWorkbook())
            {
                using (ISheet sheet = workbook.CreateSheet())
                {
                    IRow headerRow = sheet.CreateRow(0);
                    int cellCount = reader.FieldCount;

                    // handling header.
                    for (int i = 0; i < cellCount; i++)
                    {
                        headerRow.CreateCell(i).SetCellValue(reader.GetName(i));
                    }

                    // handling value.
                    int rowIndex = 1;
                    while (reader.Read())
                    {
                        IRow dataRow = sheet.CreateRow(rowIndex);

                        for (int i = 0; i < cellCount; i++)
                        {
                            dataRow.CreateCell(i).SetCellValue(reader[i].ToString());
                        }

                        rowIndex++;
                    }

                    AutoSizeColumns(sheet);

                    workbook.Write(ms);
                    ms.Flush();
                    ms.Position = 0;
                }
            }
        }
        return ms;
    }

    /// <summary>
    /// DataReader转换成Excel文档流，并保存到文件
    /// </summary>
    /// <param name="reader"></param>
    /// <param name="fileName">保存的路径</param>
    public static void RenderToExcel(IDataReader reader, string fileName)
    {
        using (MemoryStream ms = RenderToExcel(reader))
        {
            SaveToFile(ms, fileName);
        }
    }

    /// <summary>
    /// DataReader转换成Excel文档流，并输出到客户端
    /// </summary>
    /// <param name="reader"></param>
    /// <param name="context">HTTP上下文</param>
    /// <param name="fileName">输出的文件名</param>
    public static void RenderToExcel(IDataReader reader, HttpContext context, string fileName)
    {
        using (MemoryStream ms = RenderToExcel(reader))
        {
            RenderToBrowser(ms, context, fileName);
        }
    }

    /// <summary>
    /// DataTable转换成Excel文档流
    /// </summary>
    /// <param name="table"></param>
    /// <returns></returns>
    public static MemoryStream RenderToExcel(DataTable table)
    {
        MemoryStream ms = new MemoryStream();

        using (table)
        {
            using (IWorkbook workbook = new HSSFWorkbook())
            {
                using (ISheet sheet = workbook.CreateSheet())
                {
                    IRow headerRow = sheet.CreateRow(0);

                    // handling header.
                    foreach (DataColumn column in table.Columns)
                        headerRow.CreateCell(column.Ordinal).SetCellValue(column.Caption);//If Caption not set, returns the ColumnName value

                    // handling value.
                    int rowIndex = 1;

                    foreach (DataRow row in table.Rows)
                    {
                        IRow dataRow = sheet.CreateRow(rowIndex);

                        foreach (DataColumn column in table.Columns)
                        {
                            dataRow.CreateCell(column.Ordinal).SetCellValue(row[column].ToString());
                        }

                        rowIndex++;
                    }
                    AutoSizeColumns(sheet);

                    workbook.Write(ms);
                    ms.Flush();
                    ms.Position = 0;
                }
            }
        }
        return ms;
    }

    /// <summary>
    /// DataTable转换成Excel文档流，并保存到文件
    /// </summary>
    /// <param name="table"></param>
    /// <param name="fileName">保存的路径</param>
    public static void RenderToExcel(DataTable table, string fileName)
    {
        using (MemoryStream ms = RenderToExcel(table))
        {
            SaveToFile(ms, fileName);
        }
    }

    /// <summary>
    /// DataTable转换成Excel文档流，并输出到客户端
    /// </summary>
    /// <param name="table"></param>
    /// <param name="response"></param>
    /// <param name="fileName">输出的文件名</param>
    public static void RenderToExcel(DataTable table, HttpContext context, string fileName)
    {
        using (MemoryStream ms = RenderToExcel(table))
        {
            RenderToBrowser(ms, context, fileName);
        }
    }

    /// <summary>
    /// Excel文档流是否有数据
    /// </summary>
    /// <param name="excelFileStream">Excel文档流</param>
    /// <returns></returns>
    public static bool HasData(Stream excelFileStream)
    {
        return HasData(excelFileStream, 0);
    }

    /// <summary>
    /// Excel文档流是否有数据
    /// </summary>
    /// <param name="excelFileStream">Excel文档流</param>
    /// <param name="sheetIndex">表索引号，如第一个表为0</param>
    /// <returns></returns>
    public static bool HasData(Stream excelFileStream, int sheetIndex)
    {
        using (excelFileStream)
        {
            using (IWorkbook workbook = new HSSFWorkbook(excelFileStream))
            {
                if (workbook.NumberOfSheets > 0)
                {
                    if (sheetIndex < workbook.NumberOfSheets)
                    {
                        using (ISheet sheet = workbook.GetSheetAt(sheetIndex))
                        {
                            return sheet.PhysicalNumberOfRows > 0;
                        }
                    }
                }
            }
        }
        return false;
    }

    /// <summary>
    /// Excel文档流转换成DataTable
    /// 第一行必须为标题行
    /// </summary>
    /// <param name="excelFileStream">Excel文档流</param>
    /// <param name="sheetName">表名称</param>
    /// <returns></returns>
    public static DataTable RenderFromExcel(Stream excelFileStream, string sheetName)
    {
        return RenderFromExcel(excelFileStream, sheetName, 0);
    }

    /// <summary>
    /// Excel文档流转换成DataTable
    /// </summary>
    /// <param name="excelFileStream">Excel文档流</param>
    /// <param name="sheetName">表名称</param>
    /// <param name="headerRowIndex">标题行索引号，如第一行为0</param>
    /// <returns></returns>
    public static DataTable RenderFromExcel(Stream excelFileStream, string sheetName, int headerRowIndex)
    {
        DataTable table = null;

        using (excelFileStream)
        {
            using (IWorkbook workbook = new HSSFWorkbook(excelFileStream))
            {
                using (ISheet sheet = workbook.GetSheet(sheetName))
                {
                    table = RenderFromExcel(sheet, headerRowIndex);
                }
            }
        }
        return table;
    }

    /// <summary>
    /// Excel文档流转换成DataTable
    /// 默认转换Excel的第一个表
    /// 第一行必须为标题行
    /// </summary>
    /// <param name="excelFileStream">Excel文档流</param>
    /// <returns></returns>
    public static DataTable RenderFromExcel(Stream excelFileStream)
    {
        return RenderFromExcel(excelFileStream, 0, 0);
    }

    /// <summary>
    /// Excel文档流转换成DataTable
    /// 第一行必须为标题行
    /// </summary>
    /// <param name="excelFileStream">Excel文档流</param>
    /// <param name="sheetIndex">表索引号，如第一个表为0</param>
    /// <returns></returns>
    public static DataTable RenderFromExcel(Stream excelFileStream, int sheetIndex)
    {
        return RenderFromExcel(excelFileStream, sheetIndex, 0);
    }

    /// <summary>
    /// Excel文档流转换成DataTable
    /// </summary>
    /// <param name="excelFileStream">Excel文档流</param>
    /// <param name="sheetIndex">表索引号，如第一个表为0</param>
    /// <param name="headerRowIndex">标题行索引号，如第一行为0</param>
    /// <returns></returns>
    public static DataTable RenderFromExcel(Stream excelFileStream, int sheetIndex, int headerRowIndex)
    {
        DataTable table = null;

        using (excelFileStream)
        {
            using (IWorkbook workbook = new HSSFWorkbook(excelFileStream))
            {
                using (ISheet sheet = workbook.GetSheetAt(sheetIndex))
                {
                    table = RenderFromExcel(sheet, headerRowIndex);
                }
            }
        }
        return table;
    }

    /// <summary>
    /// Excel表格转换成DataTable
    /// </summary>
    /// <param name="sheet">表格</param>
    /// <param name="headerRowIndex">标题行索引号，如第一行为0</param>
    /// <returns></returns>
    private static DataTable RenderFromExcel(ISheet sheet, int headerRowIndex)
    {
        DataTable table = new DataTable();

        IRow headerRow = sheet.GetRow(headerRowIndex);
        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;
    }

    /// <summary>
    /// Excel文档导入到数据库
    /// 默认取Excel的第一个表
    /// 第一行必须为标题行
    /// </summary>
    /// <param name="excelFileStream">Excel文档流</param>
    /// <param name="insertSql">插入语句</param>
    /// <param name="dbAction">更新到数据库的方法</param>
    /// <returns></returns>
    public static int RenderToDb(Stream excelFileStream, string insertSql, DBAction dbAction)
    {
        return RenderToDb(excelFileStream, insertSql, dbAction, 0, 0);
    }

    public delegate int DBAction(string sql, params IDataParameter[] parameters);

    /// <summary>
    /// Excel文档导入到数据库
    /// </summary>
    /// <param name="excelFileStream">Excel文档流</param>
    /// <param name="insertSql">插入语句</param>
    /// <param name="dbAction">更新到数据库的方法</param>
    /// <param name="sheetIndex">表索引号，如第一个表为0</param>
    /// <param name="headerRowIndex">标题行索引号，如第一行为0</param>
    /// <returns></returns>
    public static int RenderToDb(Stream excelFileStream, string insertSql, DBAction dbAction, int sheetIndex, int headerRowIndex)
    {
        int rowAffected = 0;
        using (excelFileStream)
        {
            using (IWorkbook workbook = new HSSFWorkbook(excelFileStream))
            {
                using (ISheet sheet = workbook.GetSheetAt(sheetIndex))
                {
                    StringBuilder builder = new StringBuilder();

                    IRow headerRow = sheet.GetRow(headerRowIndex);
                    int cellCount = headerRow.LastCellNum;//LastCellNum = PhysicalNumberOfCells
                    int rowCount = sheet.LastRowNum;//LastRowNum = PhysicalNumberOfRows - 1

                    for (int i = (sheet.FirstRowNum + 1); i <= rowCount; i++)
                    {
                        IRow row = sheet.GetRow(i);
                        if (row != null)
                        {
                            builder.Append(insertSql);
                            builder.Append(" values (");
                            for (int j = row.FirstCellNum; j < cellCount; j++)
                            {
                                builder.AppendFormat("'{0}',", GetCellValue(row.GetCell(j)).Replace("'", "''"));
                            }
                            builder.Length = builder.Length - 1;
                            builder.Append(");");
                        }

                        if ((i % 50 == 0 || i == rowCount) && builder.Length > 0)
                        {
                            //每50条记录一次批量插入到数据库
                            rowAffected += dbAction(builder.ToString());
                            builder.Length = 0;
                        }
                    }
                }
            }
        }
        return rowAffected;
    }
}