public static string RemoveRoslynDuplicateString()

in src/Microsoft.OpenApi.CSharpAnnotations.DocumentGeneration/Extensions/StringExtensions.cs [126:179]
39 lines of code
10 McCabe index (conditional complexity)

        public static string RemoveRoslynDuplicateString(this string value)
        {
            if (string.IsNullOrEmpty(value))
            {
                return value;
            }

            string specialCharRegex = "[^a-zA-Z0-9_]";

            // Only alphanumeric or underscore characters are allowed in an identifier name.
            // So look for special character other than these.
            Match match = Regex.Match(value, specialCharRegex);

            if (!match.Success)
            {
                return value;
            }

            string firstOccurredSpecialCharacter = match.Value;

            var specialCharIndex = value.IndexOf(firstOccurredSpecialCharacter[0]);

            // @ is allowed at the start of the identifier name, so look for special character again in the substring
            // not including first char.
            // e.g. if a param name is @skip@skip, roslyn will compile it as @skip@skip@skip.
            if (firstOccurredSpecialCharacter == "@")
            {
                match = Regex.Match(value.Substring(1), specialCharRegex);

                if (!match.Success)
                {
                    return value;
                }

                specialCharIndex = value.IndexOf(match.Value[0], 1);
            }

            // Divide the string after special character into two halves and check if they are equal.
            // If equal take only first half of string. if not equal return value as is.
            var valueLengthStartingWithSpecialCharToEnd = value.Length - specialCharIndex;

            // If the length is odd then its a mismatch, return value as is.
            if (valueLengthStartingWithSpecialCharToEnd % 2 != 0)
            {
                return value;
            }

            var firstHalf = value.Substring(specialCharIndex, valueLengthStartingWithSpecialCharToEnd / 2);
            var secondHalf = value.Substring(specialCharIndex + valueLengthStartingWithSpecialCharToEnd / 2,
                valueLengthStartingWithSpecialCharToEnd / 2);

            return firstHalf == secondHalf ? value.Substring(0, specialCharIndex + firstHalf.Length)
                : value;
        }