private static void WriteHostInfoV2()

in src/Microsoft.OpenApi/Models/OpenApiDocument.cs [255:319]
50 lines of code
9 McCabe index (conditional complexity)

        private static void WriteHostInfoV2(IOpenApiWriter writer, IList<OpenApiServer> servers)
        {
            if (servers == null || !servers.Any())
            {
                return;
            }

            // Arbitrarily choose the first server given that V2 only allows 
            // one host, port, and base path.
            var firstServer = servers.First();

            // Divide the URL in the Url property into host and basePath required in OpenAPI V2
            // The Url property cannotcontain path templating to be valid for V2 serialization.
            var firstServerUrl = new Uri(firstServer.Url, UriKind.RelativeOrAbsolute);

            // host
            if (firstServerUrl.IsAbsoluteUri)
            {
                writer.WriteProperty(
                    OpenApiConstants.Host,
                    firstServerUrl.GetComponents(UriComponents.Host | UriComponents.Port, UriFormat.SafeUnescaped));
                
                // basePath
                if (firstServerUrl.AbsolutePath != "/")
                {
                    writer.WriteProperty(OpenApiConstants.BasePath, firstServerUrl.AbsolutePath);
                }
            } else
            {
                var relativeUrl = firstServerUrl.OriginalString;
                if (relativeUrl.StartsWith("//"))
                {
                    var pathPosition = relativeUrl.IndexOf('/', 3);
                    writer.WriteProperty(OpenApiConstants.Host, relativeUrl.Substring(0, pathPosition));
                    relativeUrl = relativeUrl.Substring(pathPosition);
                }
                if (!String.IsNullOrEmpty(relativeUrl) && relativeUrl != "/")
                {
                    writer.WriteProperty(OpenApiConstants.BasePath, relativeUrl);
                }
            }

            // Consider all schemes of the URLs in the server list that have the same
            // host, port, and base path as the first server.
            var schemes = servers.Select(
                    s =>
                    {
                        Uri.TryCreate(s.Url, UriKind.RelativeOrAbsolute, out var url);
                        return url;
                    })
                .Where(
                    u => Uri.Compare(
                            u,
                            firstServerUrl,
                            UriComponents.Host | UriComponents.Port | UriComponents.Path,
                            UriFormat.SafeUnescaped,
                            StringComparison.OrdinalIgnoreCase) ==
                        0 && u.IsAbsoluteUri)
                .Select(u => u.Scheme)
                .Distinct()
                .ToList();

            // schemes
            writer.WriteOptionalCollection(OpenApiConstants.Schemes, schemes, (w, s) => w.WriteValue(s));
        }