﻿/*******************************************************************************
 * You may amend and distribute as you like, but don't remove this header!
 *
 * EPPlus provides server-side generation of Excel 2007/2010 spreadsheets.
 * See http://www.codeplex.com/EPPlus for details.
 *
 * Copyright (C) 2011  Jan Källman
 *
 * 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.
 *
 * The GNU Lesser General Public License can be viewed at http://www.opensource.org/licenses/lgpl-license.php
 * If you unfamiliar with this license or have questions about it, here is an http://www.gnu.org/licenses/gpl-faq.html
 *
 * All code and executables are provided "as is" with no warranty either express or implied.
 * The author accepts no liability for any damage or loss of business that this product may cause.
 *
 * Code change notes:
 *
 * Author							Change						Date
 * ******************************************************************************
 * Mats Alm   		                Added       		        2013-03-01 (Prior file history on https://github.com/swmal/ExcelFormulaParser)
 *******************************************************************************/

using System;

namespace AppsheetEpplus;

public class ExpressionConverter : IExpressionConverter {
  public StringExpression ToStringExpression(Expression expression) {
    var result = expression.Compile();
    var newExp = new StringExpression(result.Result.ToString());
    newExp.Operator = expression.Operator;
    return newExp;
  }

  public Expression FromCompileResult(CompileResult compileResult) {
    switch (compileResult.DataType) {
      case DataType.Integer:
        return compileResult.Result is string
            ? new(compileResult.Result.ToString())
            : new IntegerExpression(Convert.ToDouble(compileResult.Result));
      case DataType.String:
        return new StringExpression(compileResult.Result.ToString());
      case DataType.Decimal:
        return compileResult.Result is string
            ? new(compileResult.Result.ToString())
            : new DecimalExpression(((double)compileResult.Result));
      case DataType.Boolean:
        return compileResult.Result is string
            ? new(compileResult.Result.ToString())
            : new BooleanExpression((bool)compileResult.Result);
      //case DataType.Enumerable:
      //    return
      case DataType.ExcelError:
        //throw (new OfficeOpenXml.FormulaParsing.Exceptions.ExcelErrorValueException((ExcelErrorValue)compileResult.Result)); //Added JK
        return compileResult.Result is string
            ? new(
                compileResult.Result.ToString(),
                ExcelErrorValue.Parse(compileResult.Result.ToString()))
            : new ExcelErrorExpression((ExcelErrorValue)compileResult.Result);
      case DataType.Empty:
        return new IntegerExpression(0); //Added JK
    }
    return null;
  }

  private static IExpressionConverter _instance;

  public static IExpressionConverter Instance {
    get {
      if (_instance == null) {
        _instance = new ExpressionConverter();
      }
      return _instance;
    }
  }
}