.RemoveExtraWhitespace();

using System.Diagnostics;

namespace TODO;

public static class StringExtensions
{

    /// <summary>
    /// Remove extra whitespace and trim whitespace from start and end of the string
    /// </summary>
    /// <param name="input">string to work on</param>
    /// <returns>The string with extra whitespace removed and whitespace trimmed from start and end</returns>
    [DebuggerStepThrough]
    public static string RemoveExtraWhitespace(this string input)
    {
        if (string.IsNullOrEmpty(input))
            return input;

        Span<char> result = stackalloc char[input.Length];
        var resultIndex = 0;
        var isWhitespace = false;

        foreach (var currentChar in input)
        {
            if (char.IsWhiteSpace(currentChar))
            {
                if (isWhitespace) continue;
                result[resultIndex++] = ' ';
                isWhitespace = true;
            }
            else
            {
                result[resultIndex++] = currentChar;
                isWhitespace = false;
            }
        }

        return result[..resultIndex].ToString().Trim();
    }

}

var withSpaces = "   This   is   a long                        string              ";
string removeSpaces = withSpaces.RemoveExtraWhitespace();