using System;
using System.Globalization;
using System.Linq;
using System.Windows.Data;

namespace CordonelAssemblyLine.Converter
{
    /// <inheritdoc />
    /// <summary>
    /// Conversion between strings and doubles
    /// </summary>
    public class MathConverter : IValueConverter
    {
        /// <summary>
        /// Converts a string to double which contains a pure floating point value
        /// </summary>
        /// <param name="value">string containing the double</param>
        /// <param name="targetType">UNUSED</param>
        /// <param name="parameter">UNUSED</param>
        /// <param name="culture"></param>
        /// <returns>value in double format</returns>
        public Object Convert(Object value, Type targetType, Object parameter, CultureInfo culture)
        {
            return double.Parse((String)value ?? string.Empty, CultureInfo.CurrentUICulture);
        }

        /// <summary>
        /// Converts a string containing an exponential value to a pure double returned as string
        /// </summary>
        /// <param name="value"></param>
        /// <param name="targetType"></param>
        /// <param name="parameter"></param>
        /// <param name="culture"></param>
        /// <returns></returns>
        public Object ConvertBack(Object value, Type targetType, Object parameter, CultureInfo culture)
        {
            String format = "";
            String strValue = (String)value;
            if (strValue != null)
            {
                strValue = strValue.Replace("x", "*").Replace("X", "*");

                //2E-07
                if (strValue.ToUpper().Contains("E"))
                {
                    return double.Parse(strValue, CultureInfo.InvariantCulture).ToString(format);
                }

                //2*10^-3
                if (strValue.Contains("^-") && strValue.Contains("*"))
                {
                    var split = strValue.Split('*');
                    var multiply = double.Parse(split.First());
                    var powNumber = double.Parse(split.Last().Split('^').First());
                    var powBy = double.Parse(split.Last().Split('^').Last());
                    return (multiply * Math.Pow(powNumber, powBy)).ToString(format);
                }


                if (strValue.Contains("-") && strValue.Contains("*"))
                {
                    var split = strValue.Split('*');
                    var multiply = double.Parse(split.First());
                    var powNumber = double.Parse(split.Last().Split('-').First());
                    var powBy = double.Parse(split.Last().Split('-').Last());
                    powBy *= -1;
                    return (multiply * Math.Pow(powNumber, powBy)).ToString(format);
                }

                if (strValue.Contains("0,0") || strValue.Contains("0.0"))
                {
                    return double.Parse(strValue, CultureInfo.CurrentUICulture).ToString(format);
                }
            }

            return value;
        }
    }
}