//#define INCLUDE_WEB_FUNCTIONS

using DocumentFormat.OpenXml;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Spreadsheet;
using LoggingHelper;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Diagnostics;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Web.UI.WebControls;

namespace ExportToExcel
{
  //
  //  November 2013
  //  http://www.mikesknowledgebase.com
  //
  //  Note: if you plan to use this in an ASP.Net application, remember to add a reference to "System.Web", and to uncomment
  //  the "INCLUDE_WEB_FUNCTIONS" definition at the top of this file.
  //
  //  Release history
  //   - Nov 2013: 
  //        Changed "CreateExcelDocument(DataTable dt, string xlsxFilePath)" to remove the DataTable from the DataSet after creating the Excel file.
  //        You can now create an Excel file via a Stream (making it more ASP.Net friendly)
  //   - Jan 2013: Fix: Couldn't open .xlsx files using OLEDB  (was missing "WorkbookStylesPart" part)
  //   - Nov 2012: 
  //        List<>s with Nullable columns weren't be handled properly.
  //        If a value in a numeric column doesn't have any data, don't write anything to the Excel file (previously, it'd write a '0')
  //   - Jul 2012: Fix: Some worksheets weren't exporting their numeric data properly, causing "Excel found unreadable content in '___.xslx'" errors.
  //   - Mar 2012: Fixed issue, where Microsoft.ACE.OLEDB.12.0 wasn't able to connect to the Excel files created using this class.
  //

  public class CreateExcelFile
  {
    public static bool CreateExcelDocument<T>(List<T> list, string xlsxFilePath)
    {
      DataSet ds = new DataSet();
      ds.Tables.Add(ListToDataTable(list));

      return CreateExcelDocument(ds, xlsxFilePath);
    }
    #region HELPER_FUNCTIONS
    //  This function is adapated from: http://www.codeguru.com/forum/showthread.php?t=450171
    //  My thanks to Carl Quirion, for making it "nullable-friendly".
    public static DataTable ListToDataTable<T>(List<T> list)
    {
      DataTable dt = new DataTable();

      foreach (PropertyInfo info in typeof(T).GetProperties())
      {
        dt.Columns.Add(new DataColumn(info.Name, GetNullableType(info.PropertyType)));
      }
      foreach (T t in list)
      {
        DataRow row = dt.NewRow();
        foreach (PropertyInfo info in typeof(T).GetProperties())
        {
          if (!IsNullableType(info.PropertyType))
            row[info.Name] = info.GetValue(t, null);
          else
            row[info.Name] = (info.GetValue(t, null) ?? DBNull.Value);
        }
        dt.Rows.Add(row);
      }
      return dt;
    }
    private static Type GetNullableType(Type t)
    {
      Type returnType = t;
      if (t.IsGenericType && t.GetGenericTypeDefinition().Equals(typeof(Nullable<>)))
      {
        returnType = Nullable.GetUnderlyingType(t);
      }
      return returnType;
    }
    private static bool IsNullableType(Type type)
    {
      return (type == typeof(string) ||
              type.IsArray ||
              (type.IsGenericType &&
               type.GetGenericTypeDefinition().Equals(typeof(Nullable<>))));
    }

    public static bool CreateExcelDocument(DataTable dt, string xlsxFilePath)
    {
      DataSet ds = new DataSet();
      ds.Tables.Add(dt);
      bool result = CreateExcelDocument(ds, xlsxFilePath);
      ds.Tables.Remove(dt);
      return result;
    }
    #endregion

#if INCLUDE_WEB_FUNCTIONS
        /// <summary>
        /// Create an Excel file, and write it out to a MemoryStream (rather than directly to a file)
        /// </summary>
        /// <param name="dt">DataTable containing the data to be written to the Excel.</param>
        /// <param name="filename">The filename (without a path) to call the new Excel file.</param>
        /// <param name="Response">HttpResponse of the current page.</param>
        /// <returns>True if it was created succesfully, otherwise false.</returns>
        public static bool CreateExcelDocument(DataTable dt, string filename, System.Web.HttpResponse Response)
        {
            try
            {
                DataSet ds = new DataSet();
                ds.Tables.Add(dt);
                CreateExcelDocumentAsStream(ds, filename, Response);
                ds.Tables.Remove(dt);
                return true;
            }
            catch (Exception ex)
            {
                Trace.WriteLine("Failed, exception thrown: " + ex.Message);
                return false;
            }
        }

        public static bool CreateExcelDocument<T>(List<T> list, string filename, System.Web.HttpResponse Response)
        {
            try
            {
                DataSet ds = new DataSet();
                ds.Tables.Add(ListToDataTable(list));
                CreateExcelDocumentAsStream(ds, filename, Response);
                return true;
            }
            catch (Exception ex)
            {
                Trace.WriteLine("Failed, exception thrown: " + ex.Message);
                return false;
            }
        }

        /// <summary>
        /// Create an Excel file, and write it out to a MemoryStream (rather than directly to a file)
        /// </summary>
        /// <param name="ds">DataSet containing the data to be written to the Excel.</param>
        /// <param name="filename">The filename (without a path) to call the new Excel file.</param>
        /// <param name="Response">HttpResponse of the current page.</param>
        /// <returns>Either a MemoryStream, or NULL if something goes wrong.</returns>
        public static bool CreateExcelDocumentAsStream(DataSet ds, string filename, System.Web.HttpResponse Response)
        {
            try
            {
                System.IO.MemoryStream stream = new System.IO.MemoryStream();
                using (SpreadsheetDocument document = SpreadsheetDocument.Create(stream, SpreadsheetDocumentType.Workbook, true))
                {
                    WriteExcelFile(ds, document);
                }
                stream.Flush();
                stream.Position = 0;

                Response.ClearContent();
                Response.Clear();
                Response.Buffer = true;
                Response.Charset = "";

                //  NOTE: If you get an "HttpCacheability does not exist" error on the following line, make sure you have
                //  manually added System.Web to this project's References.

                Response.Cache.SetCacheability(System.Web.HttpCacheability.NoCache);
                Response.AddHeader("content-disposition", "attachment; filename=" + filename);
                Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
                byte[] data1 = new byte[stream.Length];
                stream.Read(data1, 0, data1.Length);
                stream.Close();
                Response.BinaryWrite(data1);
                Response.Flush();
                Response.End();

                return true;
            }
            catch (Exception ex)
            {
                Trace.WriteLine("Failed, exception thrown: " + ex.Message);
                return false;
            }
        }
#endif      //  End of "INCLUDE_WEB_FUNCTIONS" section

    /// <summary>
    /// Create an Excel file, and write it to a file.
    /// </summary>
    /// <param name="ds">DataSet containing the data to be written to the Excel.</param>
    /// <param name="excelFilename">Name of file to be written.</param>
    /// <returns>True if successful, false if something went wrong.</returns>
    public static bool CreateExcelDocument(DataSet ds, string excelFilename)
    {
      try
      {
        using (SpreadsheetDocument document = SpreadsheetDocument.Create(excelFilename, SpreadsheetDocumentType.Workbook))
        {
          WriteExcelFile(ds, document);
        }
        Trace.WriteLine("Successfully created: " + excelFilename);
        return true;
      }
      catch (Exception ex)
      {
        LoggingUtility objLog = new LoggingUtility();
        string path = System.Web.HttpContext.Current.Server.MapPath(ConfigurationManager.AppSettings["PathLog"]);

        /// <summary>
        /// Represent string object contain log status
        /// </summary>
        string errorlogtf = (ConfigurationManager.AppSettings["ErrorLog"]);
        objLog.ErrorLogFile("ManageEscalation_ExportToExcel", ex.Message, path, errorlogtf);
        //objLog.AddLogFile(DateTime.Now.ToString(ConfigurationManager.AppSettings["dateTimeFormat"]), path, logtf);

        Trace.WriteLine("Failed, exception thrown: " + ex.Message);
        return false;
      }
    }

    private static void WriteExcelFile(DataSet ds, SpreadsheetDocument spreadsheet)
    {
      //  Create the Excel file contents.  This function is used when creating an Excel file either writing 
      //  to a file, or writing to a MemoryStream.
      spreadsheet.AddWorkbookPart();
      spreadsheet.WorkbookPart.Workbook = new DocumentFormat.OpenXml.Spreadsheet.Workbook();

      //  My thanks to James Miera for the following line of code (which prevents crashes in Excel 2010)
      spreadsheet.WorkbookPart.Workbook.Append(new BookViews(new WorkbookView()));

      //  If we don't add a "WorkbookStylesPart", OLEDB will refuse to connect to this .xlsx file !
      WorkbookStylesPart workbookStylesPart = spreadsheet.WorkbookPart.AddNewPart<WorkbookStylesPart>("rIdStyles");
      Stylesheet stylesheet = new Stylesheet();
      workbookStylesPart.Stylesheet = stylesheet;

      //  Loop through each of the DataTables in our DataSet, and create a new Excel Worksheet for each.
      uint worksheetNumber = 1;
      foreach (DataTable dt in ds.Tables)
      {
        //  For each worksheet you want to create
        string workSheetID = "rId" + worksheetNumber.ToString();
        string worksheetName = dt.TableName;

        WorksheetPart newWorksheetPart = spreadsheet.WorkbookPart.AddNewPart<WorksheetPart>();
        newWorksheetPart.Worksheet = new DocumentFormat.OpenXml.Spreadsheet.Worksheet();

        // create sheet data
        newWorksheetPart.Worksheet.AppendChild(new DocumentFormat.OpenXml.Spreadsheet.SheetData());

        // save worksheet
        WriteDataTableToExcelWorksheet(dt, newWorksheetPart);
        newWorksheetPart.Worksheet.Save();

        // create the worksheet to workbook relation
        if (worksheetNumber == 1)
          spreadsheet.WorkbookPart.Workbook.AppendChild(new DocumentFormat.OpenXml.Spreadsheet.Sheets());

        spreadsheet.WorkbookPart.Workbook.GetFirstChild<DocumentFormat.OpenXml.Spreadsheet.Sheets>().AppendChild(new DocumentFormat.OpenXml.Spreadsheet.Sheet()
        {
          Id = spreadsheet.WorkbookPart.GetIdOfPart(newWorksheetPart),
          SheetId = (uint)worksheetNumber,
          Name = dt.TableName
        });

        worksheetNumber++;
      }

      spreadsheet.WorkbookPart.Workbook.Save();
    }


    private static void WriteDataTableToExcelWorksheet(DataTable dt, WorksheetPart worksheetPart)
    {
      var worksheet = worksheetPart.Worksheet;
      var sheetData = worksheet.GetFirstChild<SheetData>();

      string cellValue = "";

      //  Create a Header Row in our Excel file, containing one header for each Column of data in our DataTable.
      //
      //  We'll also create an array, showing which type each column of data is (Text or Numeric), so when we come to write the actual
      //  cells of data, we'll know if to write Text values or Numeric cell values.
      int numberOfColumns = dt.Columns.Count;
      bool[] IsNumericColumn = new bool[numberOfColumns];

      string[] excelColumnNames = new string[numberOfColumns];
      for (int n = 0; n < numberOfColumns; n++)
        excelColumnNames[n] = GetExcelColumnName(n);

      //
      //  Create the Header row in our Excel Worksheet
      //
      uint rowIndex = 1;

      var headerRow = new Row { RowIndex = rowIndex };  // add a row at the top of spreadsheet
      sheetData.Append(headerRow);

      for (int colInx = 0; colInx < numberOfColumns; colInx++)
      {
        DataColumn col = dt.Columns[colInx];
        AppendTextCell(excelColumnNames[colInx] + "1", col.ColumnName, headerRow);
        IsNumericColumn[colInx] = (col.DataType.FullName == "System.Decimal") || (col.DataType.FullName == "System.Int32");
      }

      //
      //  Now, step through each row of data in our DataTable...
      //
      double cellNumericValue = 0;
      foreach (DataRow dr in dt.Rows)
      {
        // ...create a new row, and append a set of this row's data to it.
        ++rowIndex;
        var newExcelRow = new Row { RowIndex = rowIndex };  // add a row at the top of spreadsheet
        sheetData.Append(newExcelRow);

        for (int colInx = 0; colInx < numberOfColumns; colInx++)
        {
          cellValue = dr.ItemArray[colInx].ToString();

          // Create cell with data
          if (IsNumericColumn[colInx])
          {
            //  For numeric cells, make sure our input data IS a number, then write it out to the Excel file.
            //  If this numeric value is NULL, then don't write anything to the Excel file.
            cellNumericValue = 0;
            if (double.TryParse(cellValue, out cellNumericValue))
            {
              cellValue = cellNumericValue.ToString();
              AppendNumericCell(excelColumnNames[colInx] + rowIndex.ToString(), cellValue, newExcelRow);
            }
          }
          else
          {
            //  For text cells, just write the input data straight out to the Excel file.
            AppendTextCell(excelColumnNames[colInx] + rowIndex.ToString(), cellValue, newExcelRow);
          }
        }
      }
    }

    private static void AppendTextCell(string cellReference, string cellStringValue, Row excelRow)
    {
      //  Add a new Excel Cell to our Row 
      Cell cell = new Cell() { CellReference = cellReference, DataType = CellValues.String };
      CellValue cellValue = new CellValue();
      cellValue.Text = cellStringValue;
      cell.Append(cellValue);
      excelRow.Append(cell);
    }

    private static void AppendNumericCell(string cellReference, string cellStringValue, Row excelRow)
    {
      //  Add a new Excel Cell to our Row 
      Cell cell = new Cell() { CellReference = cellReference };
      CellValue cellValue = new CellValue();
      cellValue.Text = cellStringValue;
      cell.Append(cellValue);
      excelRow.Append(cell);
    }

    private static string GetExcelColumnName(int columnIndex)
    {
      //  Convert a zero-based column index into an Excel column reference  (A, B, C.. Y, Y, AA, AB, AC... AY, AZ, B1, B2..)
      //
      //  eg  GetExcelColumnName(0) should return "A"
      //      GetExcelColumnName(1) should return "B"
      //      GetExcelColumnName(25) should return "Z"
      //      GetExcelColumnName(26) should return "AA"
      //      GetExcelColumnName(27) should return "AB"
      //      ..etc..
      //
      if (columnIndex < 26)
        return ((char)('A' + columnIndex)).ToString();

      char firstChar = (char)('A' + (columnIndex / 26) - 1);
      char secondChar = (char)('A' + (columnIndex % 26));

      return string.Format("{0}{1}", firstChar, secondChar);
    }
  }
}