/*********************************************************************
*
*      Copyright (C) 2002 Andrew Khan
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
***************************************************************************/

package jxl.read.biff;

import jxl.common.Assert;

import jxl.CellType;
import jxl.ErrorCell;
import jxl.ErrorFormulaCell;
import jxl.biff.FormattingRecords;
import jxl.biff.FormulaData;
import jxl.biff.WorkbookMethods;
import jxl.biff.formula.ExternalSheet;
import jxl.biff.formula.FormulaErrorCode;
import jxl.biff.formula.FormulaException;
import jxl.biff.formula.FormulaParser;

/**
 * An error resulting from the calculation of a formula
 */
class ErrorFormulaRecord extends CellValue
  implements ErrorCell, FormulaData, ErrorFormulaCell
{
  /**
   * The error code of this cell
   */
  private int errorCode;

  /**
   * A handle to the class needed to access external sheets
   */
  private ExternalSheet externalSheet;

  /**
   * A handle to the name table
   */
  private WorkbookMethods nameTable;

  /**
   * The formula as an excel string
   */
  private String formulaString;

  /**
   * The raw data
   */
  private byte[] data;

  /**
   * The error code
   */
  private FormulaErrorCode error;

  /**
   * Constructs this object from the raw data
   *
   * @param t the raw data
   * @param fr the formatting records
   * @param es the external sheet
   * @param nt the name table
   * @param si the sheet
   */
  public ErrorFormulaRecord(Record t, FormattingRecords fr, ExternalSheet es,
                            WorkbookMethods nt,
                            SheetImpl si)
  {
    super(t, fr, si);

    externalSheet = es;
    nameTable = nt;
    data = getRecord().getData();

    Assert.verify(data[6] == 2);

    errorCode = data[8];
  }

  /**
   * Interface method which gets the error code for this cell.  If this cell
   * does not represent an error, then it returns 0.  Always use the
   * method isError() to  determine this prior to calling this method
   *
   * @return the error code if this cell contains an error, 0 otherwise
   */
  public int getErrorCode()
  {
    return errorCode;
  }

  /**
   * Returns the numerical value as a string
   *
   * @return The numerical value of the formula as a string
   */
  public String getContents()
  {
    if (error == null)
    {
      error = FormulaErrorCode.getErrorCode(errorCode);
    }

    return error != FormulaErrorCode.UNKNOWN ? 
      error.getDescription() : "ERROR " + errorCode;
  }

  /**
   * Returns the cell type
   *
   * @return The cell type
   */
  public CellType getType()
  {
    return CellType.FORMULA_ERROR;
  }

  /**
   * Gets the raw bytes for the formula.  This will include the
   * parsed tokens array
   *
   * @return the raw record data
   */
  public byte[] getFormulaData() throws FormulaException
  {
    if (!getSheet().getWorkbookBof().isBiff8())
    {
      throw new FormulaException(FormulaException.BIFF8_SUPPORTED);
    }

    // Lop off the standard information
    byte[] d = new byte[data.length - 6];
    System.arraycopy(data, 6, d, 0, data.length - 6);

    return d;
  }

  /**
   * Gets the formula as an excel string
   *
   * @return the formula as an excel string
   * @exception FormulaException
   */
  public String getFormula() throws FormulaException
  {
    if (formulaString == null)
    {
      byte[] tokens = new byte[data.length - 22];
      System.arraycopy(data, 22, tokens, 0, tokens.length);
      FormulaParser fp = new FormulaParser
        (tokens, this, externalSheet, nameTable,
         getSheet().getWorkbook().getSettings());
      fp.parse();
      formulaString = fp.getFormula();
    }

    return formulaString;
  }
}