private static IEnumerable GetSupportedProperties()

in wwauth/Google.Solutions.WWAuth/Util/CommandLineParser.cs [48:111]
54 lines of code
7 McCabe index (conditional complexity)

        private static IEnumerable<PropertyInfo> GetSupportedProperties<TOptions>()
            => typeof(TOptions)
                .GetProperties(BindingFlags.Public | BindingFlags.Instance)
                .Where(p => p.CustomAttributes
                    .EnsureNotNull()
                    .Any(a => a.AttributeType == typeof(CommandLineArgumentAttribute)))
                .Where(p => p.PropertyType.IsEnum || p.PropertyType == typeof(string));

        public static TOptions Parse<TOptions>(string commandLine)
            where TOptions : class, ICommandLineOptions, new()
        {
            var commandLineParts = commandLine
                .SplitQuotedString(' ')
                .Select(arg => arg.Trim())
                .Where(arg => !string.IsNullOrWhiteSpace(arg));

            var options = new TOptions()
            {
                Executable = commandLineParts.FirstOrDefault()
            };

            var arguments = commandLineParts
                .Skip(1) // Ignore the executable path
                .ToList();

            if ((arguments.Count % 2) != 0)
            {
                throw new ArgumentException(
                    "Command line contains too many options");
            }

            var properties = GetSupportedProperties<TOptions>();

            for (int i = 0; i < arguments.Count / 2; i++)
            {
                var key = arguments[i * 2];
                var value = arguments[i * 2 + 1];
                if (!key.StartsWith("/"))
                {
                    throw new ArgumentException(
                        "Unrecognized command line option: " + key);
                }

                var property = properties.FirstOrDefault(
                    p => p.Name.Equals(key.Substring(1), StringComparison.OrdinalIgnoreCase));

                if (property == null)
                {
                    throw new ArgumentException(
                        "Unrecognized command line option: " + key);
                }

                if (property.PropertyType.IsEnum)
                {
                    property.SetValue(options, Enum.Parse(property.PropertyType, value));
                }
                else
                {
                    property.SetValue(options, value);
                }
            }

            return options;
        }