/*************************************************************************************************
  Required Notice: Copyright (C) EPPlus Software AB. 
  This software is licensed under PolyForm Noncommercial License 1.0.0 
  and may only be used for noncommercial purposes 
  https://polyformproject.org/licenses/noncommercial/1.0.0/

  A commercial license to use this software can be purchased at https://epplussoftware.com
 *************************************************************************************************
  Date               Author                       Change
 *************************************************************************************************
  01/27/2020         EPPlus Software AB       Initial release EPPlus 5
 *************************************************************************************************/
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace OfficeOpenXml.FormulaParsing
{
    /// <summary>
    /// Provides access to static, preconfigured instances of <see cref="INameValueProvider"/>
    /// </summary>
    public class NameValueProvider : INameValueProvider
    {
        private NameValueProvider()
        {

        }

        /// <summary>
        /// An empty <see cref="INameValueProvider"/>
        /// </summary>
        public static INameValueProvider Empty
        {
            get { return new NameValueProvider(); }
        }

        /// <summary>
        /// Implementation of the IsNamedValue function. In this case (Empty provider) it always return false.
        /// </summary>
        /// <param name="key"></param>
        /// <param name="worksheet"></param>
        /// <returns></returns>
        public bool IsNamedValue(string key, string worksheet)
        {
            return false;
        }

        /// <summary>
        /// Implementation of the GetNamedValue function. In this case (Empty provider) it always return null.
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        public object GetNamedValue(string key)
        {
            return null;
        }

        /// <summary>
        /// Implementation of the Reload function
        /// </summary>
        public void Reload()
        {
            
        }
        /// <summary>
        /// Get named value
        /// </summary>
        /// <param name="key"></param>
        /// <param name="worksheet"></param>
        /// <returns></returns>
        public object GetNamedValue(string key, string worksheet)
        {
            return null;
        }
    }
}
