/*******************************************************************************
 * 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       		        2015-12-28
 *******************************************************************************/
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace OfficeOpenXml.FormulaParsing.LexicalAnalysis.TokenSeparatorHandlers {
  public class StringHandler : SeparatorHandler {
    public override bool Handle(
        char c,
        Token tokenSeparator,
        TokenizerContext context,
        ITokenIndexProvider tokenIndexProvider) {
      if (context.IsInString) {
        if (IsDoubleQuote(tokenSeparator, tokenIndexProvider.Index, context)) {
          tokenIndexProvider.MoveIndexPointerForward();
          context.AppendToCurrentToken(c);
          return true;
        }
        if (tokenSeparator.TokenType != TokenType.String) {
          context.AppendToCurrentToken(c);
          return true;
        }
      }

      if (tokenSeparator.TokenType == TokenType.String) {
        if (context.LastToken != null
            && context.LastToken.TokenType == TokenType.OpeningEnumerable) {
          context.AppendToCurrentToken(c);
          context.ToggleIsInString();
          return true;
        }
        if (context.LastToken != null && context.LastToken.TokenType == TokenType.String) {
          context.AddToken(
              !context.CurrentTokenHasValue
                  ? new Token(string.Empty, TokenType.StringContent)
                  : new Token(context.CurrentToken, TokenType.StringContent));
        }
        context.AddToken(new Token("\"", TokenType.String));
        context.ToggleIsInString();
        context.NewToken();
        return true;
      }
      return false;
    }
  }
}